Arrh SOl nrner oftHI 0IJlOI1l (1960 ) 1 ill

CLIN1CAL RETINOSCOPY

ny

AHTHUIl 1 SAyaL O D

J oh ~ nneshLlr 5011 10 Arrica

Re tinoscopy Uf kiascopy (l ile wonl is dlriv(d from Ihe Greck Irnnslalion of shadow kSI) as il is so oftlll I(rmed is Ihe ciellce of mCllsuring IIIC rdracli ve

cOlHliliull of Ihe eye objcc li cl)

In Ihal tllis pa pe r is a (lescripliol1 of Ihl clill ica l npplieal ioll of rIl in05CoJlY iexclhe undcrlyillg olljenl p rincipies will nol he (liscwcII Howcer il musl be kcpl 111 1I1inll Iha l Ihe prillci ple underlrillg Ihi 11 1lIIlu cl of rdrael ioll is ~ illlply Ihal il i Ihe emergen lighl from Ilw pal iell s cye Iha l is bcouiexclJI to a puiul whieh 15

coillciltlcnl lo Ihe relina of Ihe exu milllrs ere T hcse (111(rgenl iexcligbl ca) a re (ltp~1(l enl upon Ihe rcfracling media o f tlll palien l5 cye aud 1101 011 IIIt in ilt run lcnl

whic1J c iiexclllcr l11lrcl) prOides lhe sourcc (l f lighl (~el f luminOIlS rel inoscolgtC) v r

rdlcel il fmm Slt11111 cxlrmeous sourcc (110 1l l ul11 illoU5 rcti nosc0Jc)

Slalic rCUacuteI105COiexcliexclY

This ed inoseupy i Ilw Oll clIrricd oul 0 11 1111 Ie whieh is fi xing a dislanl targrt

The theer 11I0s1 cl rs irable conclitions in s lolic re tinoseop) are firsl l) 111111 Ihe palients eye shd l bc unaCCOlll1l1odaled stcondl Ih al his linc o f s ig lll shall be str ad) ami Ihi rdl y Ihal Ilu ret inoscopc Leom shull coinc ide o r tS IIca rl ) a pussible wi lh 11 Iacuteua l axis of Ihe (xa m il1er

It i ~ alw importllnl iexclhal Ihe CXlll1l i11t r WCU f llIacuteE iexcliexclropee dislal1ce co rr (Cli oll so

Ihal hc has 1Il8x imu m IIcuily PCIsbopic cXllm i lle r~ shuld lar a pl us ol1e lel111 il1 ildllilioll if Ilw) a re Iurr yi ng oul rll i1108cOII a l 011C Ilwln

TIII fir sl eC(lui remcnl cu n Iw achiend witll cr lain t ) onl by Ihe use o f drugs lo pural)St llw 3CcoIlHllOdal imiddot( fu cully of iexclhl cye lI uwcc r os iexclIll use o f dru gll

3 1

AHTlIUII L SAtLI

is nol perlllittlcI for oplolllltr i ~l s uses in sorne cO llnlril s olher rnct llOus musl be found lo inhibil Ihe palienh 1t llclency lo ncconlnlodah lo Ihe grlalP$t exlNII A sim ple Ihough usdul melholt1 is Ihe use uf a bluc fixalion ]gtoil11 in u ~lllimiddotltl u rkl n l1

room

The wriler u~s Iwo such fi xalioll poinls so arronged al opl ical infinilY Ihal wllen sittiug in fronl of tllt palienl IIIt ere nol uncler ex am jnation t~ Illc liglll nn Ihat side onlr Ihe cxaminers head oacutehstructing Ihe olher oml vice versa

Tilere is Ihus a IIUIlIIlI urn o f oLliltluil y 11lIfl Ihe HC0J1(1 unu Ihird flltuinlllen ts a n adcluullly salisficd

With er) yo ung ehildren spcciul nlclilods IllIve In he IHloptcd 5choo1 age cil ilclfln can oft cn 1gt1 Irlulld likl lelult5 bul wi lll ynungcr cll ildren SOlnl otlwr 11I11 1111er o f ilolding Iheir attcnlion must he used Thi~ i ~ hrnughl ahoul by Ihe (ixalion la rgel hcing a ligll l hdd by Ihe nurSt will) I1Il1inlllins inltresl by switshychi ng il on und o ff This flicke ring ur flashillg holds Illir inIITIill huI can a lso be addeel lo hy Ihe child calJing out when Ihc ligh t is on tiC o ff Tllc H1dil ioll o ( COIOUTCd fil lcrs bdore Ihe ligill fur th r slimulatls Illt ehi lds inlcresl aud Ihc) oftn Idighl in Ihis colound ligllls gUille

A cllild undcr the age of aboul fi v should sil Oll ils Molhcr lap wjlll ils back lo Iwr so Ih91 811c ltloes not dislrael Ihe childs all cll lion from lhc fixalion tilrgt t hdd o) lIle nurSl In Ihese Cl~ o (1011 ur lu) uSt-d as the fixllli nn largll furlhcr main lllins lIle inlcrc~ t

On passing lile Ttl inosc0ll ocam sluacutewly acros~ Ihe ohservcd Iup il 1111 inslru l1len l nol I)t ing lihed mO Tmiddot Ihan a fe rnillimctcu lo ao il l losi ng 111( refleclioll from il a round ov1I1 or somc~ l la l tin en r SIIOI of )I lIow ihTtd rcfleclion i~ seen in lIle pupillary urca The appca ranee or Ihis rdlciexclt ion varies OeiexclJfoding 011 Illc rdraelion of Ihe eye Ihc Iranspu rency o f Ilw media Ihe omounl o( pigmclltation iexclalbino hlond brunllle) Ihe allloun l o r illuminalion and Ihe dis tancc frum Ihe eye al Wllich tlw TI linoscopy i ~ being performed If Ih e rcfl ex is d ul1 IIlu l sllw a high error oI lefnllliun is u~ua l l ) preslnt If howler il j5 hrighl 811(1 (asl lile error i ~ small

bull The lighl in tlu- pnl ients pupiJlar ) IIrell ma) mo cilhcr in the SltlUlI or in

Ihe opposile direclion being a willl ur un againsl llOCIlltnl If 1111 1ighled area mmes faster in Qne dir(cl inll Ihan in the meridi tl1l al riglll allgles lo il nslilmatism i5 prlsent

Using a IIIlin rnirror an1 a worki ng d islllll t-C uf one rnel rc a wi lh moclll(nl cun he ltI ue lo hrpcr mclropia crlllllClropil or lll Yflpin of I(ss Ihull 10

32

c lI srrl1 rr~ 1lNOSCOrY

A wilh mOlemell is lltulrali 1oCd by placillg plus sphercs of illercasin g slrcnglh Ldur tl lt paticlllS 1I ull til tlw W( lIbSI len is fuun(1 which will just neulral ise nr change Ihe wilh int o an agai H~ t UlU VCIIlCUt Al aglillst mocrncrr l is neulralmiddot isc(1 hy pbcing minus spllerc of increasing slrenglh bdorf lhe palillIlS (ye unli l Ih( wcak l1 lln is (uum whieh i ll just l1eulr~lilte lhe hlOICllIen l ar dHlngc Ihe aga ill ~ in[ltI a wi lh lllOlIlllnl This po ill l o f reversal is Ihe onc whcrc a lens will j usI IlLulrali gt5C Ihc movClltculs in tlrc Iwo principal llltri(li ans al rig hl angll5 lo cach ollllr It is on Ihis pOl in o f rCWrsal IIHII Ih l principal o f rClinowopic rmiddot(radion is ba5(middotd

If aSligmlIi1lI is precnl 1111 apl)Ca ranltC o f Ilre rc(lcx al1(l Illc IlIcl lJ(lll ~ of IIcutraliing il ill he (Iif(r(n In a case of simplr h )pe-TllHlrOp ic asl igmatism (tU xampl wilh lile mcridillll of pOWCf erl iea1 Ilre rclinocope healll Ira( rsing Ihe ObSeT I(1 1)1 hurizonlall y will give a rltul ral r Hect wJlilt in Ihe mer idian al righl angk-s t wi tll ]1101eIIlI I11 1ill Iw ubsiexcl n crl No correding lens is thu~

1Il CiexclId in 111( horizonlal nll riclian AUenli oll is now (Ii recle lo tire verli ca l IIlcridiun iexclmd Ilre Il lOlClIlluls o( lile rc tillo~eop ( Iil illll eo nfinNI lo this (lirection oul y Th wilh 11l()11~ l1lrllt is Ilr r ll ncutralised hy placing plus eylinders before tl1l jlMiln ls lC witl axi lOriwnlul unlil nc ulrali~alion is nached

iexcl i milur lTociexclrurtgt is adopte(1 for simple myoph aSligHla l i~m minus cylinders heing U~C(1

Shoul iexcllle 110 principal rner idia ns nol be crlical iexcliexcl no ho riwnlul bul oblique all thc l1I c rilli iexcllIl ~ in turn must 1)( tra rscO unlil Ihe majar Il ireclions of movemiddot 1I lt1I1 arc fou nd In simple aSligmatisllI 1lis is freiiWled by Ill hll~t 111111 tire uhsln c( n fI Ilas a iexclIislindic ha r or hand of light eXlcnd ing across the Impil ill a mcrid inn coincidenl 1 illl lhal J f Ilre I01( r axis u f Ihe q lillllcr pcr premiddot ~ I l lt lInd wi lh mol ion in Ihe mcridian al ri ghl all gles

Willr eOll1pou lld Isligmal isrn 111( brsl mdhod 1(1 l(l upl i ~ lo kep placing appromiddot prialr ~ pllt rc~ beff( IllI pali enls eytS ami makillg lhe relinoscopc heam Iraverse slve ral IIlcridians uf 111( pupil lIit h cach changiexcl unlil Ihe niexclig mali c haniexclJ appea r Ihu s (IOnn lill g Ih e majar axi~ uf 111I errur Tlle n linnscp 1I1)elllcll1 s aH Illcn eOl lfilll1 IlJ Ihs lVo prin cipl lllt ridians Orre nlcri(lilln i ~ nculrali~i1

hy 1111IIns of ~ uitlhl ~ phlff thu~ rcduc ing Ih( crro r rt lI111inil1 g lo onc of ~ illlple aslig llmlislIl wJl ih i ~ c rcctcd as airead) dtltCrihed Tlll lllusl relinhle r1sults are oblained wlll1l Ilre res ilulll ~Iigllla li iexcl rdlex is olai]](d in Iht fo n n o f ti

wilh Illolcmnl 10 1)( co rr(clld hy plus cyli n(l e r~

1he g rcnlcsl difficuh ) ill Illis lllelllOd uf utilisillg hullr SVllelcs 1I11d cylind(niexcl for 1Iuw liing 11r rdl ) - or cylinder retinoscopy a Ih is ltchniqll l 15 eamiddot IIc( - is lile dd rmi nalillll of Ill l corred I xis uf Ihe astiglllalic d CIllCl1 1 If tire

AR TH UII L SAmiddot Il

rCl in()~c(jpt bcam trne rSts an) mef idian olhe r Ihon onc oiacute ti le principIe merimiddot dians a fresh sel of llloCllllnls ill rcsuiexcl in t o meridian s no sel olJilud) ilh rcfc rellcc lo the or igi nal IIwridians This d leel is purlIacutelulatly ma rked when Ihe aSlismnl ic co nd it ion of tH e)t i 011( o f silll l-lc astigmalism or has betn remiddot d uced to th is for lllil iOI1 by IllCIIII S of a basie cnrrecl in g splH rieal lens in Ihe ma nller dClltCribcd aboc hellwr Ihe prelimina r) neulrlisal ion is ea rr it(1 oul so tha thr rtidual error is Ol1t of illlple nl)opie or simple h)lJefmclrupic astigmatism is 11 ma lltt oiacute Iersonal choice

For eorreelion iexcllh plus eylindt n and iexclhe aS5umplioll that one meridilln f lh c asli gmalic cre has alread y been eorreell) neulralised 11 i th iexclnOmiddottmenl is no Idl in 11 11 olher principIe meridill n hieh is approxi maltly lIoriwlI lal To eoshyrreel Ihis a plus cylinder is usecl 111 poer bcing tSlimale(1 by Ihe degree of error evalualcd by thl spted of Ihe rfl eiexcliexcl mocmenl This is Ihcn checkcd SIlOUld al1y moCmenl ~ IiexclII be pr SCll t the subslilulioll o f eylilldcr o f a (Iifrerenl lJOwer is indicated and cllll nged unlil nculralisation is tlchi c(1

Hoct r had 1IIt true axis o f 11ll correcling clinder becn al W IlIel whcJl liten eslimuled cyli ndtr was sel al t)()9 Ih( TI Bflpearecl 10 IIlcri(lians of IlOVlmiddot ment Thcsc iJl lie oiexcliqudy with rcicence lo Ih( origi nal Iosiliun o f lhe cotrccling cyl inder al 909 The rx islenef of these lew meridians of 1Il0cment i ~ dut lo Ihe all(ral iOIl ill aXlS eaused by tl e resultant cfeets o f 110 ohliquel y Vosilioned cylindtfs of 0PI08ile power iexclhe fir~ 1 hcin g Iha in Ih e eye ilsclf ancl StCond il1 Ihe corrccling cylinder If IIJc rctinoscopic bcarn is now Illllde to lra ersc eadl o f Ihe lew obli qul Illeriliuns in lu rn il wiJl revea thal in o ne dimiddot rection Ihere is a wilh nlOvtme nl hi lsl in the other al rigll a ngles Ihert iacutes un aga insl moemenl In o rder lo correel Illis Ih e uiexcliexcl is of Ihf plus cyli ndcr is momiddot ved R few uegretS Ihrough Ihe acule algl e whieh now separalcs it frotll IIIt ne merid iun o f Ihe again l mOlJ1Icnt ~o Ihal il approllchcs Ihe laller This ill uga in C8USC u shif in Ihe ohliquit y of Ihe fLSu1ta nl axes and Ihc proccdure is repfUINi as IIIC obl iq uiacutel) di minshcs un lil finall Ihe axis of lhe Irue error o f Iht eye shoulll lile corrccling cylindcT he rolale(1 beyond litis lJOin l a fnsh eondi middot lion of 1ll0tlllcnl in obl iltluc lllcridillns ill a rise Ihis tinle Ill t dircclions of molIacuteon being reersed

t rdinemenl o f thi s lechnique is thal ~hollld Ihc lIlo(m enls in tllt obliquc I1Ic rid iall~ Le ralher ind efinil e all alternlion of the I)() wer o f Ihe cylindoacute r U ~t 1

eXIH rimtll lall) will in crellse the apPltlfcnt obJiq uily Ih us making for cll~ilr reshycognition o f the discrepuney belwetn Ihe axis o ( Ihe co rnt ling eylinder ami the Irue er ror of IIIt C) iexcllslmiddot]f

Pascal rdcrs lo Ih is va riable anglt blween Ihe eorrtCling cylinder and Ihe eOfTe5pondi ng meridian of ublique 111011 (11 1 us the Cuide Angle Aecurale

34

bull

AHTlIUII L SAtLI

is nol perlllittlcI for oplolllltr i ~l s uses in sorne cO llnlril s olher rnct llOus musl be found lo inhibil Ihe palienh 1t llclency lo ncconlnlodah lo Ihe grlalP$t exlNII A sim ple Ihough usdul melholt1 is Ihe use uf a bluc fixalion ]gtoil11 in u ~lllimiddotltl u rkl n l1

room

The wriler u~s Iwo such fi xalioll poinls so arronged al opl ical infinilY Ihal wllen sittiug in fronl of tllt palienl IIIt ere nol uncler ex am jnation t~ Illc liglll nn Ihat side onlr Ihe cxaminers head oacutehstructing Ihe olher oml vice versa

Tilere is Ihus a IIUIlIIlI urn o f oLliltluil y 11lIfl Ihe HC0J1(1 unu Ihird flltuinlllen ts a n adcluullly salisficd

With er) yo ung ehildren spcciul nlclilods IllIve In he IHloptcd 5choo1 age cil ilclfln can oft cn 1gt1 Irlulld likl lelult5 bul wi lll ynungcr cll ildren SOlnl otlwr 11I11 1111er o f ilolding Iheir attcnlion must he used Thi~ i ~ hrnughl ahoul by Ihe (ixalion la rgel hcing a ligll l hdd by Ihe nurSt will) I1Il1inlllins inltresl by switshychi ng il on und o ff This flicke ring ur flashillg holds Illir inIITIill huI can a lso be addeel lo hy Ihe child calJing out when Ihc ligh t is on tiC o ff Tllc H1dil ioll o ( COIOUTCd fil lcrs bdore Ihe ligill fur th r slimulatls Illt ehi lds inlcresl aud Ihc) oftn Idighl in Ihis colound ligllls gUille

A cllild undcr the age of aboul fi v should sil Oll ils Molhcr lap wjlll ils back lo Iwr so Ih91 811c ltloes not dislrael Ihe childs all cll lion from lhc fixalion tilrgt t hdd o) lIle nurSl In Ihese Cl~ o (1011 ur lu) uSt-d as the fixllli nn largll furlhcr main lllins lIle inlcrc~ t

On passing lile Ttl inosc0ll ocam sluacutewly acros~ Ihe ohservcd Iup il 1111 inslru l1len l nol I)t ing lihed mO Tmiddot Ihan a fe rnillimctcu lo ao il l losi ng 111( refleclioll from il a round ov1I1 or somc~ l la l tin en r SIIOI of )I lIow ihTtd rcfleclion i~ seen in lIle pupillary urca The appca ranee or Ihis rdlciexclt ion varies OeiexclJfoding 011 Illc rdraelion of Ihe eye Ihc Iranspu rency o f Ilw media Ihe omounl o( pigmclltation iexclalbino hlond brunllle) Ihe allloun l o r illuminalion and Ihe dis tancc frum Ihe eye al Wllich tlw TI linoscopy i ~ being performed If Ih e rcfl ex is d ul1 IIlu l sllw a high error oI lefnllliun is u~ua l l ) preslnt If howler il j5 hrighl 811(1 (asl lile error i ~ small

bull The lighl in tlu- pnl ients pupiJlar ) IIrell ma) mo cilhcr in the SltlUlI or in

Ihe opposile direclion being a willl ur un againsl llOCIlltnl If 1111 1ighled area mmes faster in Qne dir(cl inll Ihan in the meridi tl1l al riglll allgles lo il nslilmatism i5 prlsent

Using a IIIlin rnirror an1 a worki ng d islllll t-C uf one rnel rc a wi lh moclll(nl cun he ltI ue lo hrpcr mclropia crlllllClropil or lll Yflpin of I(ss Ihull 10

32

c lI srrl1 rr~ 1lNOSCOrY

A wilh mOlemell is lltulrali 1oCd by placillg plus sphercs of illercasin g slrcnglh Ldur tl lt paticlllS 1I ull til tlw W( lIbSI len is fuun(1 which will just neulral ise nr change Ihe wilh int o an agai H~ t UlU VCIIlCUt Al aglillst mocrncrr l is neulralmiddot isc(1 hy pbcing minus spllerc of increasing slrenglh bdorf lhe palillIlS (ye unli l Ih( wcak l1 lln is (uum whieh i ll just l1eulr~lilte lhe hlOICllIen l ar dHlngc Ihe aga ill ~ in[ltI a wi lh lllOlIlllnl This po ill l o f reversal is Ihe onc whcrc a lens will j usI IlLulrali gt5C Ihc movClltculs in tlrc Iwo principal llltri(li ans al rig hl angll5 lo cach ollllr It is on Ihis pOl in o f rCWrsal IIHII Ih l principal o f rClinowopic rmiddot(radion is ba5(middotd

If aSligmlIi1lI is precnl 1111 apl)Ca ranltC o f Ilre rc(lcx al1(l Illc IlIcl lJ(lll ~ of IIcutraliing il ill he (Iif(r(n In a case of simplr h )pe-TllHlrOp ic asl igmatism (tU xampl wilh lile mcridillll of pOWCf erl iea1 Ilre rclinocope healll Ira( rsing Ihe ObSeT I(1 1)1 hurizonlall y will give a rltul ral r Hect wJlilt in Ihe mer idian al righl angk-s t wi tll ]1101eIIlI I11 1ill Iw ubsiexcl n crl No correding lens is thu~

1Il CiexclId in 111( horizonlal nll riclian AUenli oll is now (Ii recle lo tire verli ca l IIlcridiun iexclmd Ilre Il lOlClIlluls o( lile rc tillo~eop ( Iil illll eo nfinNI lo this (lirection oul y Th wilh 11l()11~ l1lrllt is Ilr r ll ncutralised hy placing plus eylinders before tl1l jlMiln ls lC witl axi lOriwnlul unlil nc ulrali~alion is nached

iexcl i milur lTociexclrurtgt is adopte(1 for simple myoph aSligHla l i~m minus cylinders heing U~C(1

Shoul iexcllle 110 principal rner idia ns nol be crlical iexcliexcl no ho riwnlul bul oblique all thc l1I c rilli iexcllIl ~ in turn must 1)( tra rscO unlil Ihe majar Il ireclions of movemiddot 1I lt1I1 arc fou nd In simple aSligmatisllI 1lis is freiiWled by Ill hll~t 111111 tire uhsln c( n fI Ilas a iexclIislindic ha r or hand of light eXlcnd ing across the Impil ill a mcrid inn coincidenl 1 illl lhal J f Ilre I01( r axis u f Ihe q lillllcr pcr premiddot ~ I l lt lInd wi lh mol ion in Ihe mcridian al ri ghl all gles

Willr eOll1pou lld Isligmal isrn 111( brsl mdhod 1(1 l(l upl i ~ lo kep placing appromiddot prialr ~ pllt rc~ beff( IllI pali enls eytS ami makillg lhe relinoscopc heam Iraverse slve ral IIlcridians uf 111( pupil lIit h cach changiexcl unlil Ihe niexclig mali c haniexclJ appea r Ihu s (IOnn lill g Ih e majar axi~ uf 111I errur Tlle n linnscp 1I1)elllcll1 s aH Illcn eOl lfilll1 IlJ Ihs lVo prin cipl lllt ridians Orre nlcri(lilln i ~ nculrali~i1

hy 1111IIns of ~ uitlhl ~ phlff thu~ rcduc ing Ih( crro r rt lI111inil1 g lo onc of ~ illlple aslig llmlislIl wJl ih i ~ c rcctcd as airead) dtltCrihed Tlll lllusl relinhle r1sults are oblained wlll1l Ilre res ilulll ~Iigllla li iexcl rdlex is olai]](d in Iht fo n n o f ti

wilh Illolcmnl 10 1)( co rr(clld hy plus cyli n(l e r~

1he g rcnlcsl difficuh ) ill Illis lllelllOd uf utilisillg hullr SVllelcs 1I11d cylind(niexcl for 1Iuw liing 11r rdl ) - or cylinder retinoscopy a Ih is ltchniqll l 15 eamiddot IIc( - is lile dd rmi nalillll of Ill l corred I xis uf Ihe astiglllalic d CIllCl1 1 If tire

AR TH UII L SAmiddot Il

rCl in()~c(jpt bcam trne rSts an) mef idian olhe r Ihon onc oiacute ti le principIe merimiddot dians a fresh sel of llloCllllnls ill rcsuiexcl in t o meridian s no sel olJilud) ilh rcfc rellcc lo the or igi nal IIwridians This d leel is purlIacutelulatly ma rked when Ihe aSlismnl ic co nd it ion of tH e)t i 011( o f silll l-lc astigmalism or has betn remiddot d uced to th is for lllil iOI1 by IllCIIII S of a basie cnrrecl in g splH rieal lens in Ihe ma nller dClltCribcd aboc hellwr Ihe prelimina r) neulrlisal ion is ea rr it(1 oul so tha thr rtidual error is Ol1t of illlple nl)opie or simple h)lJefmclrupic astigmatism is 11 ma lltt oiacute Iersonal choice

For eorreelion iexcllh plus eylindt n and iexclhe aS5umplioll that one meridilln f lh c asli gmalic cre has alread y been eorreell) neulralised 11 i th iexclnOmiddottmenl is no Idl in 11 11 olher principIe meridill n hieh is approxi maltly lIoriwlI lal To eoshyrreel Ihis a plus cylinder is usecl 111 poer bcing tSlimale(1 by Ihe degree of error evalualcd by thl spted of Ihe rfl eiexcliexcl mocmenl This is Ihcn checkcd SIlOUld al1y moCmenl ~ IiexclII be pr SCll t the subslilulioll o f eylilldcr o f a (Iifrerenl lJOwer is indicated and cllll nged unlil nculralisation is tlchi c(1

Hoct r had 1IIt true axis o f 11ll correcling clinder becn al W IlIel whcJl liten eslimuled cyli ndtr was sel al t)()9 Ih( TI Bflpearecl 10 IIlcri(lians of IlOVlmiddot ment Thcsc iJl lie oiexcliqudy with rcicence lo Ih( origi nal Iosiliun o f lhe cotrccling cyl inder al 909 The rx islenef of these lew meridians of 1Il0cment i ~ dut lo Ihe all(ral iOIl ill aXlS eaused by tl e resultant cfeets o f 110 ohliquel y Vosilioned cylindtfs of 0PI08ile power iexclhe fir~ 1 hcin g Iha in Ih e eye ilsclf ancl StCond il1 Ihe corrccling cylinder If IIJc rctinoscopic bcarn is now Illllde to lra ersc eadl o f Ihe lew obli qul Illeriliuns in lu rn il wiJl revea thal in o ne dimiddot rection Ihere is a wilh nlOvtme nl hi lsl in the other al rigll a ngles Ihert iacutes un aga insl moemenl In o rder lo correel Illis Ih e uiexcliexcl is of Ihf plus cyli ndcr is momiddot ved R few uegretS Ihrough Ihe acule algl e whieh now separalcs it frotll IIIt ne merid iun o f Ihe again l mOlJ1Icnt ~o Ihal il approllchcs Ihe laller This ill uga in C8USC u shif in Ihe ohliquit y of Ihe fLSu1ta nl axes and Ihc proccdure is repfUINi as IIIC obl iq uiacutel) di minshcs un lil finall Ihe axis of lhe Irue error o f Iht eye shoulll lile corrccling cylindcT he rolale(1 beyond litis lJOin l a fnsh eondi middot lion of 1ll0tlllcnl in obl iltluc lllcridillns ill a rise Ihis tinle Ill t dircclions of molIacuteon being reersed

t rdinemenl o f thi s lechnique is thal ~hollld Ihc lIlo(m enls in tllt obliquc I1Ic rid iall~ Le ralher ind efinil e all alternlion of the I)() wer o f Ihe cylindoacute r U ~t 1

eXIH rimtll lall) will in crellse the apPltlfcnt obJiq uily Ih us making for cll~ilr reshycognition o f the discrepuney belwetn Ihe axis o ( Ihe co rnt ling eylinder ami the Irue er ror of IIIt C) iexcllslmiddot]f

Pascal rdcrs lo Ih is va riable anglt blween Ihe eorrtCling cylinder and Ihe eOfTe5pondi ng meridian of ublique 111011 (11 1 us the Cuide Angle Aecurale

34

bull

c lI srrl1 rr~ 1lNOSCOrY

A wilh mOlemell is lltulrali 1oCd by placillg plus sphercs of illercasin g slrcnglh Ldur tl lt paticlllS 1I ull til tlw W( lIbSI len is fuun(1 which will just neulral ise nr change Ihe wilh int o an agai H~ t UlU VCIIlCUt Al aglillst mocrncrr l is neulralmiddot isc(1 hy pbcing minus spllerc of increasing slrenglh bdorf lhe palillIlS (ye unli l Ih( wcak l1 lln is (uum whieh i ll just l1eulr~lilte lhe hlOICllIen l ar dHlngc Ihe aga ill ~ in[ltI a wi lh lllOlIlllnl This po ill l o f reversal is Ihe onc whcrc a lens will j usI IlLulrali gt5C Ihc movClltculs in tlrc Iwo principal llltri(li ans al rig hl angll5 lo cach ollllr It is on Ihis pOl in o f rCWrsal IIHII Ih l principal o f rClinowopic rmiddot(radion is ba5(middotd

If aSligmlIi1lI is precnl 1111 apl)Ca ranltC o f Ilre rc(lcx al1(l Illc IlIcl lJ(lll ~ of IIcutraliing il ill he (Iif(r(n In a case of simplr h )pe-TllHlrOp ic asl igmatism (tU xampl wilh lile mcridillll of pOWCf erl iea1 Ilre rclinocope healll Ira( rsing Ihe ObSeT I(1 1)1 hurizonlall y will give a rltul ral r Hect wJlilt in Ihe mer idian al righl angk-s t wi tll ]1101eIIlI I11 1ill Iw ubsiexcl n crl No correding lens is thu~

1Il CiexclId in 111( horizonlal nll riclian AUenli oll is now (Ii recle lo tire verli ca l IIlcridiun iexclmd Ilre Il lOlClIlluls o( lile rc tillo~eop ( Iil illll eo nfinNI lo this (lirection oul y Th wilh 11l()11~ l1lrllt is Ilr r ll ncutralised hy placing plus eylinders before tl1l jlMiln ls lC witl axi lOriwnlul unlil nc ulrali~alion is nached

iexcl i milur lTociexclrurtgt is adopte(1 for simple myoph aSligHla l i~m minus cylinders heing U~C(1

Shoul iexcllle 110 principal rner idia ns nol be crlical iexcliexcl no ho riwnlul bul oblique all thc l1I c rilli iexcllIl ~ in turn must 1)( tra rscO unlil Ihe majar Il ireclions of movemiddot 1I lt1I1 arc fou nd In simple aSligmatisllI 1lis is freiiWled by Ill hll~t 111111 tire uhsln c( n fI Ilas a iexclIislindic ha r or hand of light eXlcnd ing across the Impil ill a mcrid inn coincidenl 1 illl lhal J f Ilre I01( r axis u f Ihe q lillllcr pcr premiddot ~ I l lt lInd wi lh mol ion in Ihe mcridian al ri ghl all gles

Willr eOll1pou lld Isligmal isrn 111( brsl mdhod 1(1 l(l upl i ~ lo kep placing appromiddot prialr ~ pllt rc~ beff( IllI pali enls eytS ami makillg lhe relinoscopc heam Iraverse slve ral IIlcridians uf 111( pupil lIit h cach changiexcl unlil Ihe niexclig mali c haniexclJ appea r Ihu s (IOnn lill g Ih e majar axi~ uf 111I errur Tlle n linnscp 1I1)elllcll1 s aH Illcn eOl lfilll1 IlJ Ihs lVo prin cipl lllt ridians Orre nlcri(lilln i ~ nculrali~i1

hy 1111IIns of ~ uitlhl ~ phlff thu~ rcduc ing Ih( crro r rt lI111inil1 g lo onc of ~ illlple aslig llmlislIl wJl ih i ~ c rcctcd as airead) dtltCrihed Tlll lllusl relinhle r1sults are oblained wlll1l Ilre res ilulll ~Iigllla li iexcl rdlex is olai]](d in Iht fo n n o f ti

wilh Illolcmnl 10 1)( co rr(clld hy plus cyli n(l e r~

1he g rcnlcsl difficuh ) ill Illis lllelllOd uf utilisillg hullr SVllelcs 1I11d cylind(niexcl for 1Iuw liing 11r rdl ) - or cylinder retinoscopy a Ih is ltchniqll l 15 eamiddot IIc( - is lile dd rmi nalillll of Ill l corred I xis uf Ihe astiglllalic d CIllCl1 1 If tire

AR TH UII L SAmiddot Il

rCl in()~c(jpt bcam trne rSts an) mef idian olhe r Ihon onc oiacute ti le principIe merimiddot dians a fresh sel of llloCllllnls ill rcsuiexcl in t o meridian s no sel olJilud) ilh rcfc rellcc lo the or igi nal IIwridians This d leel is purlIacutelulatly ma rked when Ihe aSlismnl ic co nd it ion of tH e)t i 011( o f silll l-lc astigmalism or has betn remiddot d uced to th is for lllil iOI1 by IllCIIII S of a basie cnrrecl in g splH rieal lens in Ihe ma nller dClltCribcd aboc hellwr Ihe prelimina r) neulrlisal ion is ea rr it(1 oul so tha thr rtidual error is Ol1t of illlple nl)opie or simple h)lJefmclrupic astigmatism is 11 ma lltt oiacute Iersonal choice

For eorreelion iexcllh plus eylindt n and iexclhe aS5umplioll that one meridilln f lh c asli gmalic cre has alread y been eorreell) neulralised 11 i th iexclnOmiddottmenl is no Idl in 11 11 olher principIe meridill n hieh is approxi maltly lIoriwlI lal To eoshyrreel Ihis a plus cylinder is usecl 111 poer bcing tSlimale(1 by Ihe degree of error evalualcd by thl spted of Ihe rfl eiexcliexcl mocmenl This is Ihcn checkcd SIlOUld al1y moCmenl ~ IiexclII be pr SCll t the subslilulioll o f eylilldcr o f a (Iifrerenl lJOwer is indicated and cllll nged unlil nculralisation is tlchi c(1

Hoct r had 1IIt true axis o f 11ll correcling clinder becn al W IlIel whcJl liten eslimuled cyli ndtr was sel al t)()9 Ih( TI Bflpearecl 10 IIlcri(lians of IlOVlmiddot ment Thcsc iJl lie oiexcliqudy with rcicence lo Ih( origi nal Iosiliun o f lhe cotrccling cyl inder al 909 The rx islenef of these lew meridians of 1Il0cment i ~ dut lo Ihe all(ral iOIl ill aXlS eaused by tl e resultant cfeets o f 110 ohliquel y Vosilioned cylindtfs of 0PI08ile power iexclhe fir~ 1 hcin g Iha in Ih e eye ilsclf ancl StCond il1 Ihe corrccling cylinder If IIJc rctinoscopic bcarn is now Illllde to lra ersc eadl o f Ihe lew obli qul Illeriliuns in lu rn il wiJl revea thal in o ne dimiddot rection Ihere is a wilh nlOvtme nl hi lsl in the other al rigll a ngles Ihert iacutes un aga insl moemenl In o rder lo correel Illis Ih e uiexcliexcl is of Ihf plus cyli ndcr is momiddot ved R few uegretS Ihrough Ihe acule algl e whieh now separalcs it frotll IIIt ne merid iun o f Ihe again l mOlJ1Icnt ~o Ihal il approllchcs Ihe laller This ill uga in C8USC u shif in Ihe ohliquit y of Ihe fLSu1ta nl axes and Ihc proccdure is repfUINi as IIIC obl iq uiacutel) di minshcs un lil finall Ihe axis of lhe Irue error o f Iht eye shoulll lile corrccling cylindcT he rolale(1 beyond litis lJOin l a fnsh eondi middot lion of 1ll0tlllcnl in obl iltluc lllcridillns ill a rise Ihis tinle Ill t dircclions of molIacuteon being reersed

t rdinemenl o f thi s lechnique is thal ~hollld Ihc lIlo(m enls in tllt obliquc I1Ic rid iall~ Le ralher ind efinil e all alternlion of the I)() wer o f Ihe cylindoacute r U ~t 1

eXIH rimtll lall) will in crellse the apPltlfcnt obJiq uily Ih us making for cll~ilr reshycognition o f the discrepuney belwetn Ihe axis o ( Ihe co rnt ling eylinder ami the Irue er ror of IIIt C) iexcllslmiddot]f

Pascal rdcrs lo Ih is va riable anglt blween Ihe eorrtCling cylinder and Ihe eOfTe5pondi ng meridian of ublique 111011 (11 1 us the Cuide Angle Aecurale

34

bull

AR TH UII L SAmiddot Il

rCl in()~c(jpt bcam trne rSts an) mef idian olhe r Ihon onc oiacute ti le principIe merimiddot dians a fresh sel of llloCllllnls ill rcsuiexcl in t o meridian s no sel olJilud) ilh rcfc rellcc lo the or igi nal IIwridians This d leel is purlIacutelulatly ma rked when Ihe aSlismnl ic co nd it ion of tH e)t i 011( o f silll l-lc astigmalism or has betn remiddot d uced to th is for lllil iOI1 by IllCIIII S of a basie cnrrecl in g splH rieal lens in Ihe ma nller dClltCribcd aboc hellwr Ihe prelimina r) neulrlisal ion is ea rr it(1 oul so tha thr rtidual error is Ol1t of illlple nl)opie or simple h)lJefmclrupic astigmatism is 11 ma lltt oiacute Iersonal choice

For eorreelion iexcllh plus eylindt n and iexclhe aS5umplioll that one meridilln f lh c asli gmalic cre has alread y been eorreell) neulralised 11 i th iexclnOmiddottmenl is no Idl in 11 11 olher principIe meridill n hieh is approxi maltly lIoriwlI lal To eoshyrreel Ihis a plus cylinder is usecl 111 poer bcing tSlimale(1 by Ihe degree of error evalualcd by thl spted of Ihe rfl eiexcliexcl mocmenl This is Ihcn checkcd SIlOUld al1y moCmenl ~ IiexclII be pr SCll t the subslilulioll o f eylilldcr o f a (Iifrerenl lJOwer is indicated and cllll nged unlil nculralisation is tlchi c(1

Hoct r had 1IIt true axis o f 11ll correcling clinder becn al W IlIel whcJl liten eslimuled cyli ndtr was sel al t)()9 Ih( TI Bflpearecl 10 IIlcri(lians of IlOVlmiddot ment Thcsc iJl lie oiexcliqudy with rcicence lo Ih( origi nal Iosiliun o f lhe cotrccling cyl inder al 909 The rx islenef of these lew meridians of 1Il0cment i ~ dut lo Ihe all(ral iOIl ill aXlS eaused by tl e resultant cfeets o f 110 ohliquel y Vosilioned cylindtfs of 0PI08ile power iexclhe fir~ 1 hcin g Iha in Ih e eye ilsclf ancl StCond il1 Ihe corrccling cylinder If IIJc rctinoscopic bcarn is now Illllde to lra ersc eadl o f Ihe lew obli qul Illeriliuns in lu rn il wiJl revea thal in o ne dimiddot rection Ihere is a wilh nlOvtme nl hi lsl in the other al rigll a ngles Ihert iacutes un aga insl moemenl In o rder lo correel Illis Ih e uiexcliexcl is of Ihf plus cyli ndcr is momiddot ved R few uegretS Ihrough Ihe acule algl e whieh now separalcs it frotll IIIt ne merid iun o f Ihe again l mOlJ1Icnt ~o Ihal il approllchcs Ihe laller This ill uga in C8USC u shif in Ihe ohliquit y of Ihe fLSu1ta nl axes and Ihc proccdure is repfUINi as IIIC obl iq uiacutel) di minshcs un lil finall Ihe axis of lhe Irue error o f Iht eye shoulll lile corrccling cylindcT he rolale(1 beyond litis lJOin l a fnsh eondi middot lion of 1ll0tlllcnl in obl iltluc lllcridillns ill a rise Ihis tinle Ill t dircclions of molIacuteon being reersed

t rdinemenl o f thi s lechnique is thal ~hollld Ihc lIlo(m enls in tllt obliquc I1Ic rid iall~ Le ralher ind efinil e all alternlion of the I)() wer o f Ihe cylindoacute r U ~t 1

eXIH rimtll lall) will in crellse the apPltlfcnt obJiq uily Ih us making for cll~ilr reshycognition o f the discrepuney belwetn Ihe axis o ( Ihe co rnt ling eylinder ami the Irue er ror of IIIt C) iexcllslmiddot]f

Pascal rdcrs lo Ih is va riable anglt blween Ihe eorrtCling cylinder and Ihe eOfTe5pondi ng meridian of ublique 111011 (11 1 us the Cuide Angle Aecurale

34

bull

CUii ICAL RtTINOSCOIY

obseralion of Ihi5 guide angle lI1akes il Jlossible lo corred bolh iexclgtQcr and axis ilil a miacutenimum of rolations or changes in lhe power of Ihe experimental correemiddot lillg cylinder

When correcling ilh minus cylinders Ihe lIIelllOd i5 precisely analngou5 tmiddotxcepl Ihal lo filld tlle eurrt t uxio Ihe minus cylillders placelt bdore Ihe palients eye mus be rOlalcd lowards Ihe obl iquc Illcridian which show a wiexcl111 Of hypenncmiddot Iopie 1II0elllenl

Th e use of llIinu ~ cylimleu will follow ir iexclhe IHecssu fy iniiexclial sphc rical comiddot rrection 8S such Ilml u simple aSligmalic 1ll0v(lllcnl of Ibe againsl or myopie Iype is presclIl

Should Ihis be Ihe case al1(l IIIt direclion of Ihe aga insl Illovelllenl is uppromiddot ximalcl y horiwnlUI a lIlil1U ~ r yli lldt i8 placed before Ihe patients eye al 9()

lf Illis is u correel el imUle no furtllC r 1Il0VelnCIl t ill be sel up fherc ill be neutralisalioll alollg lhe vt rtieul Illfmiddotriclian whilsl in Ihe borizon tal Ihere may be ngainst mOlcmenl or a ilh mOImenl inJ ieating that the power is eorrecl loo wluk or too slrong rtspcclivcly

Th is is adjuslcd as pnviously dlSCribcd

If howevcr the true axis o f error il tl le ey is at 80 eornand lhe Cling ey li nder sel aL 909 1Il00cmcnls witl ue obC rvetl in Iwo mr rid ians which run obliqucly lo t lll~ 9()Q mlridian To filld Ilw corrlel axis l ile llIi nus cylilldcr is rolaled throught lile acul angle lowards Ihc nlfridian of with or hypiexclrmelropic IIIOell1ent Bere ngain the same ciacutefccts will appl y sllOuld tlu cy linucr re rolalelt1 Oer the mean positioll

In pacc of a eombill ed spherucylind rical co rrclion for lHulralisalion sphercs alone can be used Irealing Ihe major Illcridi nns of Ihe asligmatic o ye as scparale c1elllcll ls

It must he bOTlle in lIIind howlcr Lhul Ihe ultimalc aun uf Ihe rclinoscopic cxu min at ion is lo makt Ihe far point of Ihe eye under cxami nati on faH on Ihe

pIune of thc rClinoscorc mirror nis is lIchievcd whll the rdlcx obscred becomiddot mes neulral Tile eye howecr IUI bcen made arlificialJy myopic with rtIacutelrence lo Ihe cxum i ner~ pusition ulld it is ncecsary to COll1 pcnsale for this erro r by making alJuwan(C for theworking di~ lunce Tbis is Ihe diexcloptric valuc of Ihis working distance hcing + 150 D fOf 66 cm -1 050 D fur 2 mctrcs This musl 1)( ubtracted algebraieaHy rom Ihe eo rrlClion befon ti1 iexclmtien t eye

Tht writer fnour the praclice of oacuteiexclmuing up Il is working dilal1ce first an(1 Ihen 0 11 completion of the retinoscoy Simply remoing il huing the true corTlC ion ldl

35

AK1Il UK L SAnL L

Slrcflk RiIo$c0IY

T he Icchnique o f s treak rctilloSCop) diUers vc r) li lt l( rolll Ihal u f oreHuar) fll inogtocop) wilh a seU illUlllinatcd inslrum nl It can 1gt1 ull~1 staticall ) nr fli namicully wi th lli t ane optical principie Ippl yin ao in tl1l cOllngtntiollal 1I11Ihods

T hc s1rcak rdinoseope is an elcctric Tctinmcope designcd lo projtCt a Ireuk or ba nd of lighl ( n ga rd lcss of Ihe error of rdraelion) in conlradistincti un tu lile usual spuumlt o f ligllt I which is cOlIerled iuto a c irele o aL o r band of iexclight llelJelUli ng UpOIl 11 I)pc o f rcfra lti ec rror) projedNI h) co ncae o r plulI mirror 1)IIt1I uf rd inucopt Seeral ft nl ur c~ howter a id in Ihe dctl rminalion of Ihe refraelivc slale o f the )ult cach llIerid ian ean be Hutral ised Stparnlcl ) b) IIH

ru tutiun uf lhe LUIHI IllroUgl1 9() und as th t reflex is band shapl(1 inslllId o f cir cular aSligmat ism ( piexclrticula rly lmall degrees) and il axis IS 1I1 udl nwrf appa rUI

T hl rctino~cupc is 8Ct jO Ihal 11ll uncrosscd ru)s ( iexcliexclIanl lIli rror cffeel ) Il lUk n slrciexcliexclk alJOul 5 mili in width when flrojecte(l Iacutelom 1 mel re Wil h Ih palillt fi xing ti di ~tu n ll ohjet Ihe ~ trak of liglll is dirlctc(iexcl 111 the pupil uf Ihe ere ullder exnm ill atiOIl ano obpTatio ll madi uf the whi tt- hiexcltnc f ligll t hieh Ilplellrs tn IJI in the pluin of lhe pup il Ulore or les parrullcl lo Il l Zlx i of Ihe s trcuk uf Ihe N tillOSCOpt The fUIl(lus rd lex Ip lleiexcliexclrs bandshapclt bCCU USl the slreak of lig ht is llarroer tl11111 tlll pupil so Ihal 0111) 11 narro purtiull uf lhe rdinu i~ ill um illullu ObStCalion o f IIre li gilt in thl pupil ra thlT than Ih e shudow ~hou ld he rWHle as Ihe sharp dgt of Ilw ligh l is oflclI a goocl way of 10luling Iht axi 1 111 slretlk i ~ rolulell about Il ll axis r lIIullipuJating the Ilaullle uf tIre rCl inoStop l iexclIlld ObSCTvul illll mule of 11ll characler istics of tlle fUl1du s reflex Obscr t whcllwr 111 llllnd of iexcliglll is llarrow or widl whcther il is d isl iru1 Of indistincl whcther il JIlUlS wi th o r againsl whether iexclhis mOImetlt is lIuiek or Io_ UI1(1 wtd lrcr thcsc charackr i~ li cs a re the sume u r di ffcrcnl in ulJ lIlcridiam

T ire hand usuaU ) uflcu rs lIarrow in simplr h )pl rmctropiu o r JIl h ) permctropie aligmaligt- III aud wi(le iu silll fl l m)opia or m)opic astigma tism A (Iuiek 1110( 111lt111 imlicatcs a small crror o f rcfruCli on wherNls u slow 1l1Oelllnl illdicalcs a high erro r (plus Of minus)

If a wil l nlllcllleu l is Irt~ rl il is It ulru li ~ed b) IIlcuns o f plus sphcres if an aga int nlol llleul by min lls sphere Wh1I nculra lisalion o f Ihe witr o r aga inst 1Il0Clllcnl is rlHchccJ Ihe slrcnk di$l IIJea rS iexcliexcllid Jiiexclhl oeeullitlJ 1111 whol~ plIp illary area

Nlulralisalion uf a willr 1lI0elllenl i~ Lrough l about b) pludng plus spherls of grudually increa~ing strtuglh in the Irial frame o r rolak d iexclnto th e refractor heud untiJ al1 1l1Oemenl i nculra lised nnd Ihe wholc pupi l i illum inaleI

36

CIII LC AI I~J NOSCOIY

To check Ihe neulralisalion POill l cil lllr nplruaeh doscl lo Ihe pul i nl when n wilh llIUVCJIlt llt should ugain he scen o r furlher away wlUn an again st l1Iovemiddot me lll wi ll he obervecl Th e addition of u furl ll t r plus 025 will resull in un aguo insl 11I0(l11elll

An uguinst IlIUemen l is Ilelllraliscd in cxacll) lhc salllC way as for Ihe wilh lIIocm l1 onl) min us spheres a re uSed ]f howcer Ihe sl reak is adjustcd so as lo g ive a concuve mirror cHecl (producing crusscd ra)) and conerling Ihe againsiexcl moemenl lo a wilh movement rasler resll l are obla in~ Minus lenmiddot ses llre slitl uSld fu r neulralisatioll

A chlik is mude (lS bdo re h) 111O ing doser or fur lher away from lhe iexclIaien or IIH alld ilion of an txtra -025 ipherc ror reversul o f lle fIl0 velllent

Ir a(iexcl(T neul rali~alion a 1)Dnd rdltX slill nmains in 11ll meridian al rigill angles lo thul whieh hus bcen lI lulraHsed astig lllalism is presenl l Is axis is determ incd by rotali ng lhe Slrak th rough 90 iexcllIld ubst r ing lile band of li ght (slllulow) ni tJlis meridian If il haplell~ lo Jit ill 1111 axis uf asligmnlism a brighl weH ddini cd band apvea rs hieh mo~r lIil l1 or agai n~ l hui paraHel with Ihe slrtlIk uf light OIJ the fa elmiddot If il il 80 lllcwhnl o f( the principlc axis Ihe sII1HIQw nol onl y btcomes jmlislincl bul il a lso p roduce8 n brlak in conlinuil y btll(en il and Ihe sl rcak of ligiLt on Ihe fn te The ~ lr tu k is rotalcd unlil Ihe reflt x hand o f li ghl in Ihe Iye ami lhe slreak of ligiL l fin iexclJI fael a re in alignemenl and moe in pa raHd direcli ons Tht a xis is lIoll ll and Ihe ~h a(low ing eonlinucd al Ihi s axis a nd al Ihe axis al right angles lo it neulrni ing Ihe rdlex ( in Ihe p roper Ill l r idia ns) with plus eylinders in h)ptrmelropic aliiexclmntims Of mi nus cylindcrs in lIl)o l ic aslig matism

If an agn insl mocmenl i~ present in one lIleridian and a w ilh 1II0ell1enl in tll l mericlia n al r ight angles ( l11ixcl atiglllat ism) Ihe aga iniexclt 1110Cll lCnl itl neumiddot tralistmiddotd ilh minus sphcres 1111(1 lhe w itll moellltnl ith plus e) lindcfs

DYIIIIic Reil oscoiexcly

TI is melloll is uselt for Ihe ohjeetivc detcrmi nali oll n f 111( n middotfraclhe cOIl(lition of Ih c treS f Uf lu u r vis ion whil~l 10th aecmnmodalion ami tOl1vcrgeJ1ce are bl ing txerci s~middotd nI lhe urki ng dislallce (abouI 333 ell1s)

]lle iustrulIlen ls lI ~cd are a d )namie relinoscopc and ci lhcr 11 dynamie raek or n ~c rilS (f hinocul ar ad ditiolls so lIlounlcd as lo be casily piektd up and placed Lciacuteort Ihe e)t~ Tllc rack laklS lhe fo rm of a plaltie o r me tallic hulder eun laining lenses mounted in pairs ami forming a scrirs of graduall) inereasing ltliuptric

37

iexcl RTH U R l ~AVUl

powtrs oue iexcliexcl bomiddote the other T he fixiexcliexcll ion largel is eilher auached lo or huilt inlo he nlilloscope iiexcl el f alld illum inalcd by Ihe li ghl ing ~yslem oiacute Ihe illslrulllcnl

The lu rge take various forms such as T((Juced Snellen lellers of various s izes

g1nmcl ri e l a ll e r ll~ Of sil llply a rew ~ l (cl balls le l ill lo IIIl bo(l) of iexclhe rel i ll o~lope

T hl ) are mounlcJ LCl1 l rall in verl ical aligll l1letll with Ih e in sl ru lllen l in Ihe pl ane of Ihe mirro r and sligh tly (iexclhove or below Ihe li ne of sight of Ih e observer

Dylliltllic rel ino(opy is usuully e(iexclrrd out iexcliexclfler static relinosco py has beell

performed Ihe suhjective examinalion for dislance co mplcl ed al1(1 lhe lIlu(Je bao

lancls lukln Corrcctioll slwuld be IlHlU C b) prbllls of all) hypcrphor ia if presenl

ami an ) horizonlal imba lance if over 2 prism dioplres A poin l of imporla nce lo Le kept in mind is tha l Dynam ic Hctinoscopy is nol aceurule unkss Ihe palielll

has binocula r vis ion o

In IIIf follow ing r($u n]( on Dnam ic Hli inoscopy grtaleT dlat il n [ 1111 physiexclolog)

u f visiull has het cl iscuSt~ d fo r a dean r unuerslauding uf lile visual func lions inokecl The c1 ill ical appliC(lti oll is mucb Ibe sa nw bu l Ihe resulls due lo t he

uua lll ic func l iou iug of lllt ces fo llows a diffl renl cliaguosliiexcl pattern 10 facil imiddot late Ihis a sli ghl cha ngc in approaeh has heen mnd( from lhe de5eriplio n l lrcad

giVfu 011 ll lt applicatioll of t llt rlli noscopl a~ a c1iacuten ical insl ru lllcnl

Tile t~xa tlli ner plaees himself iu front of Ihe median l ine of Ihe pal ien (yes and al Ihe su ne heighl so IIHlt h is ee is equidh tanl frolll Ihe ees u f Ihe pali t]]I

RcIIacutellOSCOp is thclI carricd oul at Ilw avcr age n ading (Iislancc of 333 ems

ahhough th is ma) va r according lo Ihe particular in vestigaliun b eing conduded

T llc pUlienl is (lincle(1 lo look al lIle b rgcst leller or patteTII u f he illum illaled

charl Th e fllilloscoric li ghl palfh is passed rapidl y frOIll one eye lo Ihe ollllr in Ihe hor izontal planc a ll(1 lhe mOflIIent of the sllatlow i ~ nole (1 as is usual lVi lh

s talic rel inoscopy Wuumlh cerla in excepli ons which will be deal l wilh Jater on il

i ll he nolicnl Ihal there is a wilh mov(menl o f Ihe bado For ex ample wilh

a + 1000 OU llwre lila ) be 1 revcrsal or againsl JIlovemen l It is neccssary Ihen lo reduct Ihis add ilion unli J tbere i ~ 110 IIlOCllltnt or olll y a sliglll kickhack

lt will be found Ihal Ibe le lls with which this resull is oblaincd is a +075 Of a + 050 O This is ca llcd lhe D ) lHlIlli c Neutral FrOIll lhis fi gure is suhl raded the Obj ccli vc Lag for Ihe patiellts uge If Ih is hnppens lo coincide a nd zero r esul t~

j i llIa 1) eoncuded thal Ihe (Iislance torrcction wil be slI isfa elory for Ihe performance nf all ta ~k s whether al I islancc or for lllar work

Objlctil Lags vary accord in g lo uge as cal be seCII fr olU Ihe followillg table

+ 100 up to 30 ycar + 050 lo + 075 frorn 30 lo 45 years + 050 f rom 45 lo 70 yea rs

Over 70 years 11 il

38

bull

bull

CLlNICAI IHTlNOSCOIY

From Ihc age of 45 years and onward~ Ihrough Ihe presbyopie ycars no more Ihall + 050 is delluctcd (or Ihe Obj ect ivc Lag Larger Oynamie Neulrals Iban + 050 are eOllsidc red (IS binocu la r relld ing lldditions if close work for long periods is lo ~ leeum pli she1 wilhoul diSClllllforL For cxam plc a palient of 50 hlls 11

Oynamic Neutral of + 175 IlIen sublracting the lag of + 050 +125 is obtainc(l wllieh is Ihe readillg addition OU

Various author ities account for Ih Lag in Ilifferent wa)s It is howevcr gtneralJy aeecplcd that mosl Jlcople rarel ) exerl their full accommodatioll for rhe working (listancc At 3P cm~ Iheir aeeomodatioll is nearer 250 than the full 3D Their accommodalion may be suid lo be loo~t The) do nol reall y look at an obj lcl Sil muell as glance at il il being unneeessary lo focus exaclly ror lvery visual lask especiall y if the prinl is nol loo small Whcrc lhc palienl is oung ( up lo 10 and Il as becn Iraincd lo USl his eyes for f ine work Ihe Dynamic Neulral appcars alrea(l y lo ex ist ic the n is a slighl ki ckmiddotbaek of Ihe shadoll The placing of a billocular additiull of +050 bdon~ Ihe ps ami repea tin g the r ight lo left flash of lh e rClinoscope will probabl) reveal a definile wilh mocmellL With ( 1 + 125 additiun there lluy llUW appcar lo be a (Icfilli le reverse movemenL

Using a + 100 addition ne ulral llialion il probabl) resull What appcared al firsl lo be lleutrali~ld lOW sut isfies u Lag o[ +100 whieh is no rmal for Ihul age anJ Ihe palien t shou ld havc t1ll1llttropia for (Iistanee lIith or wilhou l eomiddot rrect ion There is TILertfore

u) Neu tralisalion wi lIL no Lag

L) Neulral isutiun wilh a + 100 OU

Tlw patienl has thercfore re1axed his aceollllllodalioll 1000 wlli lsl ma intamiddot ining full convergence whieh is nornllll fur his age

S inee Ihe iexclIel of aeeummodaliun doc not eonfurm lo geomrtrie oplies Ihe llJ110UIII of uccomllHJdulilgt11 in use fur cOlllfurtable rcudillg visiun au ul1e~ rlain

(Iuantity lf a patient i5 under tesl it is natural for him to make a greater efforl IhlUl hc will mukc in ordinary cireumslunces (Swulln)

Amplilurlc of uecummodalion lels are Useles5 in that the learer Ihe ubjecl i5 aflflroached Lo tlH~ eyes Ihe larger iexclhe visual angle becomes so Ihat the aecummudalion is not used at all and if used only partially The cards nearness llables a persoll to receie a larger and morc magnified image of the objlCt Taylo r )

AII iexclhesc fuclon render Ihe use of suLjccLie tesIs upon thl omplitudc uncerluin unle~ the true value by objeetivc means 15 first ascerlained

39

MITlI UR l SAnU

Umlouhlc(lly lhe ohj -cli e lag is Ihe Hgtu1t of Ihe eyes nol foeussing accuralcl) Of Hlel l) un Ihe In rgll lul ~omcw l lt rc hdlind il Only ir lit lurge is ndv81leed lo 2a cm in fron l of 11 plI it lI ts C CS is Ilculrali$ntio ll al 111 Iminl f hscrmiddot al ioll prod ucltL

It is prohnblc Iherd o re Illal ill enrrying out D lIomie Icli lluscopy lile uelual Negali e Hda li e ACCOllllllodalion is lul is mCI urc(L

Nlgalie HcIllie AeeollllllOdalioll al

30 ears + 025 lo -- 150 al mux imum

30 lu 35 )ca rs + 100 lu + 125 01 llIuximulll

35 lo 40 )ea rs + 100 al maxilllulll

40 lo 45 ) a rs + 075 al lllaXimUIIl

As Negalic lelali e Aiexcleo lllll1od ulioll il Ihe abili ly uf Ihe eyes lo rllax hile eOI1ergellee rcmains undlangmiddotd il is scn Ihal Ihe lable of NIgalie Il elnlie ACcollllllodalioll approx illllllls vny doscly lo l ile lublc of uhjeclic lags It i howc r un wise lo n late olle lable try dosel) lo 111( olh er for il 111111 he remo ber tlt Ihat mcu mlllodation is adeIUalc when Ihe positi vc alld Ilcgati-c ra ns a rc ill normal ral io 1f Ihe posili e nlll se is 110rrmll Ih l bull lHgalie rangc will also he no rma l

Tlle Correeion o Prcsbyopia

For Ihe correelion of PresL yofJill Ihe wit ll m()cment i3 notcd Ir il i5 fn irl ) lllarkc1 a subst ancial binocular addi tion is Irie(l eg around + 2000 sphere Ir Ihis neulralis s musl uf Ihc w itll mUJlell l u fur lher udditiun uf middotplu in hal f di oJller stcJls iiexcl maflC unlil a d finile rfI r~e 1l10Vell1enl lakfs place T hi 111 (1) be uLtain1 will a +250 A rctufIL 1 + 225 ll lln results in th e 1Il0velllcul bci ng neilhrr wi lh Ilor against This is Ihe Dyna mic Neul ra l By know ing Ihe pal icn l

uge w]iexcl ith is gicll as 55 ano substracling Ihe Obj rctive Lag + 050 Ih e TesUIt is + li5 lhis is tbe rcad in g nJlition whiel ~hould L t ~ gieu Sub jedic dweki ng can Iw madc wilh one of Ihe melhods described

1 Al la rgeT addil iou tllllll + 200 indieates that dtheT tl lt palilll l is undrmiddotcomiddot rrecled fo r d islanee or Ihc eause may be pathoJogical

2 When 1111 refl Clees arc ulleq ual it ma be ltIue lomiddot

u) Patholugical JlroccsC~ in unc Iye

40

C II N I C~I IUTIN OSCOlY

1 I m lrol~ r co rreclion 111 une o r ul11lr Ihe ees for dislance

e) Unequa convergcnce uf Ihe eps on Ihe la rgeL

In tlw case of b ) if plus is addcd o r suhlrueled unlil Ihe Ing cfjuuls Illt nOTrlHll for Ihe Iuti t nts age il is iexclJossiexclhle tu nliexcldecl reversioll lo Ihe ubj ccts di~ t llll cC

lest TI1l lmiddotxa lll in er will kil O quite 1 11 Ihul Ihe Uynumic finJing~ wil1 he e rified by cxpcricncc In euSts uf e) Slr3]iexclsHluS Dynallli c Il elinoscopy is almost 1mmiddot pussiJh un less Ihe qes a r more Of lccs ~ tru ighl

Exccsuacutev COl iexclergel cl

Ah r lile full currtCliull hus bcn g ll cn for Iislance and Illllscle halanccs 51101 a cUtllilion o f Esopho ria fo r dislancc ami l1(a r a slale of txccssi e cunv rglt llc Clt i~ t s Ths is um ull y confi lltd 111 )uung pcople but quite fretluenlly il is found ur lo l ile age o f 45 a nd Inler

The pali l1I1 i ~ iexcl[ in clt 1 lu n ucl lile illulllillaled cllnrl on Ihc rCl inoCope slarmiddot li ng with Ihe lurge lellers J)u ring Ih is pcriod iexcliexcl (Iuick (Jasll frmll rlght lo Idl usuall y diFclosiexcls quil c u sU]lt lull l iul lag Plus is lIddcl lO rcvlrsu ulIIl 11lt 1I suLmiddot Iflldcll ulllil II tulrnl is rcuclle(I Frolll Ihis is lahlI thl lag fM 1111 rI ~pcc l ivc aiexclc ulld IIkll is Icfl i ~ udrle lo Ihc disla nce currCIiu ll E 1l ir Illi s diffcrellce i5 us mucll us + 050 1111 udt lil io ll wi ll c c nluull ) be accpled by Ihe pu licll l ul lhougll il is nol aeccJlc(1 ul iexcllit li me

Oynumk BCliuoscopy lliClosc Lalenl J-1 YPNIIl l rO i1l IIhieh oer~limula l tS

COI1ergcnCt Exctssit Cou( rgence howc r 5houlfl 1101 be llUusurcd wilJiexcl basemiddot ou l prisms becaus il sl imulalcs furll lt r eOI1crgtl1ct

S tminciexcl CQIVcr tlce

This occu rs on o(rmiddotusc of lile cp 01 fi nl Iwur wtHk A low h ~ pe ropic or Ill yopi c eoudililll iiexcl u~ ual fuI d isluJlce Lul exoiexclJhorin is releuled fur near Somiddot mllilllcs il is impussible lo gic un) posili co rrcct ioJl for d illIIlCC o r if un is Jlo~s i hJ il i1 ( 111 ) ~mu l l Somltinws Ixuphoriu is found for di iexcllnllce bul a l wa ) ~

cxo phorin o r II tar Th is IlI lu ns Ihnl Ihe pali en ts Iwur visioll eOIlIfgellce hu bfo kcn d-mn a lld Ihe ()c~ urcrcolting uguillsl IIu-ir bi llocu lur fun cli on Tlley Il uc probubl r pussed Ihrou gh Ihc slage of excessivc cOIlcrg nc U1](1 ure now ul 111( tiexcliexclge hm 1 11)11 i~ middotxletiexcl lingly uncoll1fort ablc fOf close wo rk

HUIing chcchd Ihe (Iislumc rfmiddotfr action ami IWlITil1g Ihe binocula r bala ncc ctl lldilio lls in lIIi nd Ihe pat ienl i di rcctcd lo look illllll((lialdy al Ihe smiexcliexcllesl ]iexcl t1er 011 Ihl illuminaled eha rl of Ihe ret ill oscolgte whilsl Ihe li ghl is flalw(1 (iexclu ickl y fm lll ri~hl lo Idl It is ullusual lo i lld un objcClilc lag s ud + 050 O U is addcd

4l

ANTIt UN L SAVI I L

and lile rctiuoscope fla sh~middotd agaill A sl ight against nlUvlmenl llIay be observcd Hesisla nce Ihen suddenl) g iCS way and a fu rl llcr wilh mOelllcnl observed Addingplus lIltldil iolls is con linucd unlil rew rsal poi nt is reuchcd and then reshyductmiddotd to obtain tlH D)num ic Neulral Thc lag is dlducled - usuall y + loo -IInd tllt rcmn indr addell In Ihe ct islllnce pre~ri lion lf no addilion is nl(lssar_ Ihen a pr ism uf 34 JaStmiddot in di idtmiddot(1 helwtmiddottmiddotn Ihe luwo c)es is given for neac USe

bull Slrlrlgt acco llIJlation

This cllnditiun i uulIlly prtscnl in COillhi nalion wit ll st ra inoo co nvergcnce Thcrt is genernll y esophoria for dislHlcc and exophoria for near The patienl is directcd lO rcnd Iht rll ill oSCop) chart com mcllcing wilb the large letters ami obS( cvalion acled upon wllen he slarl s lo rcad Ihe small fr lellfrs MosII ) Ihen is linle ur nu lug lo htgin with allll the procedure is as in the r(iaus case 01 strained cO III( r s(nC t~ An) aIlitional plus is inCOTloraled in Ihe dislance coshyrncliol

ACCOIIIOduliofl beal) iexcllre f10fllwl

lf the lag is lurgcr Ihun IIIC no rmal fo r IllC age (wi tl Ihe palient wcaring h is fu ll dislance corrcction ) thcre is usually Oflhophoria fOf d islanee bu l a Inrg txophori a for lIear -ver) much in exe(lt of Ihe phy~iol ogical cxophor ia - nnd often as hi gl as 8 ID This cOIUitiOIl u5uall) results from some (Ieb ilily or prospeemiddot ti vt ilhwss cg boils bad I(Clh upcration cUlHalcscence o r maternil y weak middot ness and lassil ude lt is a Paresis of Acco modation aud tllt~ pulieut is ftmiddotf(middotrred

JII ropia anel DyrwIIc RelinoscoJJ

So far Ihe applieatioll of Ihe Icchnique for near vision has hlcn (]all ltl ilh in cm( of hypermelropia Ilreshyopia concrgf llce fX CCSS cte 1I should be not-d

thal in alJ Illese errors accolllll1otlal ion ami eOllergencc are slrongly linkcd In man) cuscs o f luopia how(er these fu nction a re on l) loosdy li nked Same easts

bullo f Itl)opitl ftspond in evcry a y lo Ihe lechniquc of Dynnmic Hetinoscop) as with

other arnelropie eondi lions Unfo rtunatcly a g rcat mun) rn yop( do nol reopolld in lJis way al alJ Tlw lags a rl uualJ) higl1lr in mos hyperopic cMes giv ing Ih~c

illlpression thal Ihe lIlopia is less iexclhan it js unl il il is real ised Ih lll Ihe plum o

menon is Ihe resull of inndtqualc aeeolllllloda lion IacuteI st-ems Iherefore Ihal cae

case of m)ovia musl be rcgurdld as huving il awn tliolug)

42

CLlNICAL HTI NOSCOl ~

Conellsiol

For comfortab le readi ng corrections tl ere mus be 11 comfortllblc blllllllCC bclween Ihe Ncgul ie Hdll li c iexcl cco mmoda linn und the POSilivc RlllI li c Acmiddot COlll lllod atinn If 11lf pnshyo~ ic IIddil ion is calcul31cd by subj ectie means alolle here is 11]( possibilil y o f o cr-corro CliOIl becll u~ Ihc Ncpt ic Ilclalivc Accommiddot IIOlll1l ioll when taken ~uhjetively is Ihul iexclUlIoun of plus ~phere which can be IIdded wilhoul actua l hJ urring of Ihe rea(ling matlcr uscd for Ilre lest Thc eyes lIre 11 0 1 od ng tc ~I Ctl fo r Negatic Rt-lat ic Atcum lltodalioll oul lo fin() Ihe Ch

rrect IHlohopilmiddot uddi lion whiel can be worn will comforl If tllt rCllding ad middot Iilion is loo sl rong Ih Negal iiexcl Rclali e ACCO llllllodll lionmiddot Pos iti vlmiddot Rclalive Acmiddot cOrlllllodat ion oalllnCI i di turlwtl and rcstricl ion (l f range wilh eomfort ill cnsue

T he following chart diexclvised hy Colin B Fryer alJlI h3lt(1 on lIl ucs rcco rdcll by L Swoan iJl reprodllced 3 a referellce gu idiexcl nf Ihe man) phCI10llil II11 o lJscfed IV itl l ile Dylltu nic Reli lloscolc Basically Ihc chuTI -lIl1l1l1a riscs all Ihe avni lnhlc ill fMI1H1 tion concerl1 illg th l fou r ml ill condil iO l1s likely lo be iexcll1coun lered in 1111

presb)opie )ea rs

lIi(h ( tlyn ic) neulrlI (Ir fimlI VcTS~1 I (l intl afil es

Up 10 35 35 40 10 45 45 50 5055 160

H N + 1 50 +li5 +2l + 25 250 +215

DI lo 30 J O 35 35middot10 40 405 SO 55

N R A 1 50J) 1 25 1l I OOD 0150 0 51)1) 025 11

N n Tu be d ~ dll rhd hom 11 N - Itemaintle r ~ i c lI u near ltorrclmiddotl ioll

Piy illsllll i e i e t IINomlllQda tiQtI

( d u e 10 EXre~ i e collvulcmiddote) i1u ~dc ha l ~ te Disl 3nd lI ~ ur E Hi ~h Neuln l H i ~h Cnrreel i Add Iu n Ui ~ l lJ e ll ule~ Ltlenl Uypropill

I r i r eI[(OJsie IIIToIi ( U~ l o ~ e i vc CUIl rjlenre) (O erarl iva ted or rai ne)

MII ~ le b3lanre Disl t~jjo Ncur E~o E~ HiJlIt Neunl Lo remai ui JI 1 on onin~ one eye CrTml i Atld Ius 10 Uisl LI ~ nl 1I )Ie r O IJi ~

43

AATIIIlII L S L

A Oommoduli heln normal ExlJao~led o laTc ~ i 01 Arroao nlodulion ) Mu rl ll b~ lwnre lJi~ l Orlho E~o Ne iexcl-J i ~ h E~o Hi~ h Neurral IIi ~h II ll fe lo MmiddotoI imiddotpl Pr l middotr tonbull

~olO(y exmiddotlt~ie 111

Sbullbulluined of We k Cone d e lo Com-c lI el re I rri r ienmiddot )111 ~ rI bal r l)i ~ l Orl lr o E~o Ne~ Hih EllO H i~h Neubullbullal Lo o 1 O middotomiddot iI un e~ t ore1 ion

tI 1 iexcllo lo oIi51 H u aoldi l irm rruinI

11 111 39 ~9 divided bN een bolh ~middot e f O T len uo only 111 Orlbollr exrebullbull i ~e~

D)uQmit al(I dloctrome farpcL rdiIlOSCOiexclJy

A rectlll 1tvlu lr11ent ill the InllI1iq ul uf I Yl1l1mie retinosc0IY io Ihl CockerhulI1 MImiddottllOll n hieh Ihe fixutiul1 Isrg l co ns i ~l s of IIn IIlaiexclhmc nl lo 111C lum inouiexclo Tdinn8lupc making U ~l of tlle du odtn)ll1c filtres red II l1d grecn

Cockcrham clu ims Ihal tlllrt arc a numhr of adan laiexcles itlt Illis Iu omiddot probabJy passtmiddot1 Ihrou1oacute h tlw slngl uf o cssic OI1Vcrgcncc and arl lHiexclW al IIIt chronH fi xatiOI1 nllachnlrnl O(T Ihc ordinary iIIumillale1 largd

1 Colourl(1 ta rglls cneoulugc tllt IUlitnt to mainlain fi xaliun lu a grcalcr dcg rec 1111H1 11lt bl1Ck nnl hite

2 The lrogrCS l I ZC IIlId chllractcr o f the ohj (cls IWTm il eoarsc and finc fixa liol1

t TllI c al11l111r enrl nhlnin dUlwhrnme crJualil y al a precribed wo rking di _o lance

4 Since Ihe largd conist o f (liagrlIlls ralher Ilmll lelllmiddot s tlwc IS a Ul1icrsal appl ieation

Wilh a erilical dcl l rmil1111ion o f g nc ll dumilHlI1cc a the nlinoseupe iexcls mOl-d a fracliOIl neanr lo 1111 pa l ien l 111(1 r(1 dominanc E 1H1l Ihe inslrumenl is laken 1 si mila r distance a a y lile flSU]iexcl Iacutelt cunfi n lltd

Sincc thE rcflp is l1lched during the final nHlnOIUVrc il follow Ihal ilh tllc prcsloupic comlitiulI al kn1 a fiTlII I r 1111UlIrC uf cOlllrol is adl(middot(1 lo 1111 reading ur do~e o rk addil ion

Cock(fham stales Illal ith Ihe cylinrllr ax l [l11d 10 1 ( lTdull y chefke1 and Ihe ~phcricnl lIlo(lificali un cOlltrolled lhruughout itlr thc duuchrnmc dlIalllic lurgmiddot1 1111 practi timwr is in 11 pn il ion In prcscr ihe fnr fl l1 ) pTlshyoopic co rrccli on

44

Cllr-I CAL H1I Nn COI Y

I ilh grealcr eerla inly o IIICl a purd) UhjtClie lest IIl0nt 15 onl y l S nccurutc as IIIt pa l iIII confirmnti on 1011 1 a llo w 11 callnot be a rgucd he says thal IllIl

dY ll umic Icst is onlr all ohject i 1l11lhocl of nwagt uring Ihe ntgll li c rebli t ticmiddot eo rumodat ioll fOT Ihe duochronw is ac tillg as u conlrol factur a l all lI tages of Ihe

test

In IIIcnlionin g Ihe abmc Codcrharll mr lhod une his ol inlUlI Ihis is lo bring

D)na mic Rtgtl inuscupy lo i l ~ full co nclusioll ~tld is no nn xprcssio ll of fLSUIt iexcl

obta irltd hy myC1f I r~o na ll y ti u lo lack o f (xpelicncc wi lh d uocJnolllc (lpIPmic l a rgt I ~

CONCLllS ION

Agt il will be fuU y appreciatld Ihe wriUen e xpla nali olJ IlIkes considcrahl) IOllgcr

lo rltSCribc Iha n Ihe practical applical iun of lJ igt rclulicl y si mple roulil1 t TIIt In lcl ilior1rr- a hi lil ) with the rt inoscopc ir rpectit of wlrlll IJW i ~ prcfc rnmiddotd

is 1 11 objcdie I1 l1 tho(1 of Ttfraction wcll WlJrtl l hCClIllIillg skillcd in

The iexclinU spenl in decloping litis ~ ki ll heing JIIOn Ihan cOl1lptnsn l~ d for h ) lil e f( middotsult olJluiunl

IIJ J C I I ) ~ 5r P O no1 1I

REnRENciexclS

lIH KA Y FEHG USON R ~ i o tu l ) L undun Tmiddothni r 1 Mono~ ra l h NQ 5 BEB ENS Im1 Z UCKI RMA N jalm iexcl Eumnaiexcliun ur 110 E)middot ~ WELCH ALI YN IAI III LI1 Slrn k IIjlinomiddotul Y J PASCAL L Mud n linUt0 IY L SWANN puIlel KEEIEII Pa1l lhlel S TAYLO II lJynu mit Kcrinu8middotuPY and lIinuulur ncl l cx ~

1 S VELL An Inlrudurlion lo lJynamir Heil nus middot p) Vul 2 N9 2 (S A Rdnclioni lr I J un 1951

D COCK~ II I1 M Dynamjmiddot Slrea t Reiexcl n05Ur jlh duur hrunr e rita l ion lar~c l ~ Olll i cIn 1 5 ~ CXXVI II 58

45

AK1Il UK L SAnL L

Slrcflk RiIo$c0IY

T he Icchnique o f s treak rctilloSCop) diUers vc r) li lt l( rolll Ihal u f oreHuar) fll inogtocop) wilh a seU illUlllinatcd inslrum nl It can 1gt1 ull~1 staticall ) nr fli namicully wi th lli t ane optical principie Ippl yin ao in tl1l cOllngtntiollal 1I11Ihods

T hc s1rcak rdinoseope is an elcctric Tctinmcope designcd lo projtCt a Ireuk or ba nd of lighl ( n ga rd lcss of Ihe error of rdraelion) in conlradistincti un tu lile usual spuumlt o f ligllt I which is cOlIerled iuto a c irele o aL o r band of iexclight llelJelUli ng UpOIl 11 I)pc o f rcfra lti ec rror) projedNI h) co ncae o r plulI mirror 1)IIt1I uf rd inucopt Seeral ft nl ur c~ howter a id in Ihe dctl rminalion of Ihe refraelivc slale o f the )ult cach llIerid ian ean be Hutral ised Stparnlcl ) b) IIH

ru tutiun uf lhe LUIHI IllroUgl1 9() und as th t reflex is band shapl(1 inslllId o f cir cular aSligmat ism ( piexclrticula rly lmall degrees) and il axis IS 1I1 udl nwrf appa rUI

T hl rctino~cupc is 8Ct jO Ihal 11ll uncrosscd ru)s ( iexcliexclIanl lIli rror cffeel ) Il lUk n slrciexcliexclk alJOul 5 mili in width when flrojecte(l Iacutelom 1 mel re Wil h Ih palillt fi xing ti di ~tu n ll ohjet Ihe ~ trak of liglll is dirlctc(iexcl 111 the pupil uf Ihe ere ullder exnm ill atiOIl ano obpTatio ll madi uf the whi tt- hiexcltnc f ligll t hieh Ilplellrs tn IJI in the pluin of lhe pup il Ulore or les parrullcl lo Il l Zlx i of Ihe s trcuk uf Ihe N tillOSCOpt The fUIl(lus rd lex Ip lleiexcliexclrs bandshapclt bCCU USl the slreak of lig ht is llarroer tl11111 tlll pupil so Ihal 0111) 11 narro purtiull uf lhe rdinu i~ ill um illullu ObStCalion o f IIre li gilt in thl pupil ra thlT than Ih e shudow ~hou ld he rWHle as Ihe sharp dgt of Ilw ligh l is oflclI a goocl way of 10luling Iht axi 1 111 slretlk i ~ rolulell about Il ll axis r lIIullipuJating the Ilaullle uf tIre rCl inoStop l iexclIlld ObSCTvul illll mule of 11ll characler istics of tlle fUl1du s reflex Obscr t whcllwr 111 llllnd of iexcliglll is llarrow or widl whcther il is d isl iru1 Of indistincl whcther il JIlUlS wi th o r againsl whether iexclhis mOImetlt is lIuiek or Io_ UI1(1 wtd lrcr thcsc charackr i~ li cs a re the sume u r di ffcrcnl in ulJ lIlcridiam

T ire hand usuaU ) uflcu rs lIarrow in simplr h )pl rmctropiu o r JIl h ) permctropie aligmaligt- III aud wi(le iu silll fl l m)opia or m)opic astigma tism A (Iuiek 1110( 111lt111 imlicatcs a small crror o f rcfruCli on wherNls u slow 1l1Oelllnl illdicalcs a high erro r (plus Of minus)

If a wil l nlllcllleu l is Irt~ rl il is It ulru li ~ed b) IIlcuns o f plus sphcres if an aga int nlol llleul by min lls sphere Wh1I nculra lisalion o f Ihe witr o r aga inst 1Il0Clllcnl is rlHchccJ Ihe slrcnk di$l IIJea rS iexcliexcllid Jiiexclhl oeeullitlJ 1111 whol~ plIp illary area

Nlulralisalion uf a willr 1lI0elllenl i~ Lrough l about b) pludng plus spherls of grudually increa~ing strtuglh in the Irial frame o r rolak d iexclnto th e refractor heud untiJ al1 1l1Oemenl i nculra lised nnd Ihe wholc pupi l i illum inaleI

36

CIII LC AI I~J NOSCOIY

To check Ihe neulralisalion POill l cil lllr nplruaeh doscl lo Ihe pul i nl when n wilh llIUVCJIlt llt should ugain he scen o r furlher away wlUn an again st l1Iovemiddot me lll wi ll he obervecl Th e addition of u furl ll t r plus 025 will resull in un aguo insl 11I0(l11elll

An uguinst IlIUemen l is Ilelllraliscd in cxacll) lhc salllC way as for Ihe wilh lIIocm l1 onl) min us spheres a re uSed ]f howcer Ihe sl reak is adjustcd so as lo g ive a concuve mirror cHecl (producing crusscd ra)) and conerling Ihe againsiexcl moemenl lo a wilh movement rasler resll l are obla in~ Minus lenmiddot ses llre slitl uSld fu r neulralisatioll

A chlik is mude (lS bdo re h) 111O ing doser or fur lher away from lhe iexclIaien or IIH alld ilion of an txtra -025 ipherc ror reversul o f lle fIl0 velllent

Ir a(iexcl(T neul rali~alion a 1)Dnd rdltX slill nmains in 11ll meridian al rigill angles lo thul whieh hus bcen lI lulraHsed astig lllalism is presenl l Is axis is determ incd by rotali ng lhe Slrak th rough 90 iexcllIld ubst r ing lile band of li ght (slllulow) ni tJlis meridian If il haplell~ lo Jit ill 1111 axis uf asligmnlism a brighl weH ddini cd band apvea rs hieh mo~r lIil l1 or agai n~ l hui paraHel with Ihe slrtlIk uf light OIJ the fa elmiddot If il il 80 lllcwhnl o f( the principlc axis Ihe sII1HIQw nol onl y btcomes jmlislincl bul il a lso p roduce8 n brlak in conlinuil y btll(en il and Ihe sl rcak of ligiLt on Ihe fn te The ~ lr tu k is rotalcd unlil Ihe reflt x hand o f li ghl in Ihe Iye ami lhe slreak of ligiL l fin iexclJI fael a re in alignemenl and moe in pa raHd direcli ons Tht a xis is lIoll ll and Ihe ~h a(low ing eonlinucd al Ihi s axis a nd al Ihe axis al right angles lo it neulrni ing Ihe rdlex ( in Ihe p roper Ill l r idia ns) with plus eylinders in h)ptrmelropic aliiexclmntims Of mi nus cylindcrs in lIl)o l ic aslig matism

If an agn insl mocmenl i~ present in one lIleridian and a w ilh 1II0ell1enl in tll l mericlia n al r ight angles ( l11ixcl atiglllat ism) Ihe aga iniexclt 1110Cll lCnl itl neumiddot tralistmiddotd ilh minus sphcres 1111(1 lhe w itll moellltnl ith plus e) lindcfs

DYIIIIic Reil oscoiexcly

TI is melloll is uselt for Ihe ohjeetivc detcrmi nali oll n f 111( n middotfraclhe cOIl(lition of Ih c treS f Uf lu u r vis ion whil~l 10th aecmnmodalion ami tOl1vcrgeJ1ce are bl ing txerci s~middotd nI lhe urki ng dislallce (abouI 333 ell1s)

]lle iustrulIlen ls lI ~cd are a d )namie relinoscopc and ci lhcr 11 dynamie raek or n ~c rilS (f hinocul ar ad ditiolls so lIlounlcd as lo be casily piektd up and placed Lciacuteort Ihe e)t~ Tllc rack laklS lhe fo rm of a plaltie o r me tallic hulder eun laining lenses mounted in pairs ami forming a scrirs of graduall) inereasing ltliuptric

37

iexcl RTH U R l ~AVUl

powtrs oue iexcliexcl bomiddote the other T he fixiexcliexcll ion largel is eilher auached lo or huilt inlo he nlilloscope iiexcl el f alld illum inalcd by Ihe li ghl ing ~yslem oiacute Ihe illslrulllcnl

The lu rge take various forms such as T((Juced Snellen lellers of various s izes

g1nmcl ri e l a ll e r ll~ Of sil llply a rew ~ l (cl balls le l ill lo IIIl bo(l) of iexclhe rel i ll o~lope

T hl ) are mounlcJ LCl1 l rall in verl ical aligll l1letll with Ih e in sl ru lllen l in Ihe pl ane of Ihe mirro r and sligh tly (iexclhove or below Ihe li ne of sight of Ih e observer

Dylliltllic rel ino(opy is usuully e(iexclrrd out iexcliexclfler static relinosco py has beell

performed Ihe suhjective examinalion for dislance co mplcl ed al1(1 lhe lIlu(Je bao

lancls lukln Corrcctioll slwuld be IlHlU C b) prbllls of all) hypcrphor ia if presenl

ami an ) horizonlal imba lance if over 2 prism dioplres A poin l of imporla nce lo Le kept in mind is tha l Dynam ic Hctinoscopy is nol aceurule unkss Ihe palielll

has binocula r vis ion o

In IIIf follow ing r($u n]( on Dnam ic Hli inoscopy grtaleT dlat il n [ 1111 physiexclolog)

u f visiull has het cl iscuSt~ d fo r a dean r unuerslauding uf lile visual func lions inokecl The c1 ill ical appliC(lti oll is mucb Ibe sa nw bu l Ihe resulls due lo t he

uua lll ic func l iou iug of lllt ces fo llows a diffl renl cliaguosliiexcl pattern 10 facil imiddot late Ihis a sli ghl cha ngc in approaeh has heen mnd( from lhe de5eriplio n l lrcad

giVfu 011 ll lt applicatioll of t llt rlli noscopl a~ a c1iacuten ical insl ru lllcnl

Tile t~xa tlli ner plaees himself iu front of Ihe median l ine of Ihe pal ien (yes and al Ihe su ne heighl so IIHlt h is ee is equidh tanl frolll Ihe ees u f Ihe pali t]]I

RcIIacutellOSCOp is thclI carricd oul at Ilw avcr age n ading (Iislancc of 333 ems

ahhough th is ma) va r according lo Ihe particular in vestigaliun b eing conduded

T llc pUlienl is (lincle(1 lo look al lIle b rgcst leller or patteTII u f he illum illaled

charl Th e fllilloscoric li ghl palfh is passed rapidl y frOIll one eye lo Ihe ollllr in Ihe hor izontal planc a ll(1 lhe mOflIIent of the sllatlow i ~ nole (1 as is usual lVi lh

s talic rel inoscopy Wuumlh cerla in excepli ons which will be deal l wilh Jater on il

i ll he nolicnl Ihal there is a wilh mov(menl o f Ihe bado For ex ample wilh

a + 1000 OU llwre lila ) be 1 revcrsal or againsl JIlovemen l It is neccssary Ihen lo reduct Ihis add ilion unli J tbere i ~ 110 IIlOCllltnt or olll y a sliglll kickhack

lt will be found Ihal Ibe le lls with which this resull is oblaincd is a +075 Of a + 050 O This is ca llcd lhe D ) lHlIlli c Neutral FrOIll lhis fi gure is suhl raded the Obj ccli vc Lag for Ihe patiellts uge If Ih is hnppens lo coincide a nd zero r esul t~

j i llIa 1) eoncuded thal Ihe (Iislance torrcction wil be slI isfa elory for Ihe performance nf all ta ~k s whether al I islancc or for lllar work

Objlctil Lags vary accord in g lo uge as cal be seCII fr olU Ihe followillg table

+ 100 up to 30 ycar + 050 lo + 075 frorn 30 lo 45 years + 050 f rom 45 lo 70 yea rs

Over 70 years 11 il

38

bull

bull

CLlNICAI IHTlNOSCOIY

From Ihc age of 45 years and onward~ Ihrough Ihe presbyopie ycars no more Ihall + 050 is delluctcd (or Ihe Obj ect ivc Lag Larger Oynamie Neulrals Iban + 050 are eOllsidc red (IS binocu la r relld ing lldditions if close work for long periods is lo ~ leeum pli she1 wilhoul diSClllllforL For cxam plc a palient of 50 hlls 11

Oynamic Neutral of + 175 IlIen sublracting the lag of + 050 +125 is obtainc(l wllieh is Ihe readillg addition OU

Various author ities account for Ih Lag in Ilifferent wa)s It is howevcr gtneralJy aeecplcd that mosl Jlcople rarel ) exerl their full accommodatioll for rhe working (listancc At 3P cm~ Iheir aeeomodatioll is nearer 250 than the full 3D Their accommodalion may be suid lo be loo~t The) do nol reall y look at an obj lcl Sil muell as glance at il il being unneeessary lo focus exaclly ror lvery visual lask especiall y if the prinl is nol loo small Whcrc lhc palienl is oung ( up lo 10 and Il as becn Iraincd lo USl his eyes for f ine work Ihe Dynamic Neulral appcars alrea(l y lo ex ist ic the n is a slighl ki ckmiddotbaek of Ihe shadoll The placing of a billocular additiull of +050 bdon~ Ihe ps ami repea tin g the r ight lo left flash of lh e rClinoscope will probabl) reveal a definile wilh mocmellL With ( 1 + 125 additiun there lluy llUW appcar lo be a (Icfilli le reverse movemenL

Using a + 100 addition ne ulral llialion il probabl) resull What appcared al firsl lo be lleutrali~ld lOW sut isfies u Lag o[ +100 whieh is no rmal for Ihul age anJ Ihe palien t shou ld havc t1ll1llttropia for (Iistanee lIith or wilhou l eomiddot rrect ion There is TILertfore

u) Neu tralisalion wi lIL no Lag

L) Neulral isutiun wilh a + 100 OU

Tlw patienl has thercfore re1axed his aceollllllodalioll 1000 wlli lsl ma intamiddot ining full convergence whieh is nornllll fur his age

S inee Ihe iexclIel of aeeummodaliun doc not eonfurm lo geomrtrie oplies Ihe llJ110UIII of uccomllHJdulilgt11 in use fur cOlllfurtable rcudillg visiun au ul1e~ rlain

(Iuantity lf a patient i5 under tesl it is natural for him to make a greater efforl IhlUl hc will mukc in ordinary cireumslunces (Swulln)

Amplilurlc of uecummodalion lels are Useles5 in that the learer Ihe ubjecl i5 aflflroached Lo tlH~ eyes Ihe larger iexclhe visual angle becomes so Ihat the aecummudalion is not used at all and if used only partially The cards nearness llables a persoll to receie a larger and morc magnified image of the objlCt Taylo r )

AII iexclhesc fuclon render Ihe use of suLjccLie tesIs upon thl omplitudc uncerluin unle~ the true value by objeetivc means 15 first ascerlained

39

MITlI UR l SAnU

Umlouhlc(lly lhe ohj -cli e lag is Ihe Hgtu1t of Ihe eyes nol foeussing accuralcl) Of Hlel l) un Ihe In rgll lul ~omcw l lt rc hdlind il Only ir lit lurge is ndv81leed lo 2a cm in fron l of 11 plI it lI ts C CS is Ilculrali$ntio ll al 111 Iminl f hscrmiddot al ioll prod ucltL

It is prohnblc Iherd o re Illal ill enrrying out D lIomie Icli lluscopy lile uelual Negali e Hda li e ACCOllllllodalion is lul is mCI urc(L

Nlgalie HcIllie AeeollllllOdalioll al

30 ears + 025 lo -- 150 al mux imum

30 lu 35 )ca rs + 100 lu + 125 01 llIuximulll

35 lo 40 )ea rs + 100 al maxilllulll

40 lo 45 ) a rs + 075 al lllaXimUIIl

As Negalic lelali e Aiexcleo lllll1od ulioll il Ihe abili ly uf Ihe eyes lo rllax hile eOI1ergellee rcmains undlangmiddotd il is scn Ihal Ihe lable of NIgalie Il elnlie ACcollllllodalioll approx illllllls vny doscly lo l ile lublc of uhjeclic lags It i howc r un wise lo n late olle lable try dosel) lo 111( olh er for il 111111 he remo ber tlt Ihat mcu mlllodation is adeIUalc when Ihe positi vc alld Ilcgati-c ra ns a rc ill normal ral io 1f Ihe posili e nlll se is 110rrmll Ih l bull lHgalie rangc will also he no rma l

Tlle Correeion o Prcsbyopia

For Ihe correelion of PresL yofJill Ihe wit ll m()cment i3 notcd Ir il i5 fn irl ) lllarkc1 a subst ancial binocular addi tion is Irie(l eg around + 2000 sphere Ir Ihis neulralis s musl uf Ihc w itll mUJlell l u fur lher udditiun uf middotplu in hal f di oJller stcJls iiexcl maflC unlil a d finile rfI r~e 1l10Vell1enl lakfs place T hi 111 (1) be uLtain1 will a +250 A rctufIL 1 + 225 ll lln results in th e 1Il0velllcul bci ng neilhrr wi lh Ilor against This is Ihe Dyna mic Neul ra l By know ing Ihe pal icn l

uge w]iexcl ith is gicll as 55 ano substracling Ihe Obj rctive Lag + 050 Ih e TesUIt is + li5 lhis is tbe rcad in g nJlition whiel ~hould L t ~ gieu Sub jedic dweki ng can Iw madc wilh one of Ihe melhods described

1 Al la rgeT addil iou tllllll + 200 indieates that dtheT tl lt palilll l is undrmiddotcomiddot rrecled fo r d islanee or Ihc eause may be pathoJogical

2 When 1111 refl Clees arc ulleq ual it ma be ltIue lomiddot

u) Patholugical JlroccsC~ in unc Iye

40

C II N I C~I IUTIN OSCOlY

1 I m lrol~ r co rreclion 111 une o r ul11lr Ihe ees for dislance

e) Unequa convergcnce uf Ihe eps on Ihe la rgeL

In tlw case of b ) if plus is addcd o r suhlrueled unlil Ihe Ing cfjuuls Illt nOTrlHll for Ihe Iuti t nts age il is iexclJossiexclhle tu nliexcldecl reversioll lo Ihe ubj ccts di~ t llll cC

lest TI1l lmiddotxa lll in er will kil O quite 1 11 Ihul Ihe Uynumic finJing~ wil1 he e rified by cxpcricncc In euSts uf e) Slr3]iexclsHluS Dynallli c Il elinoscopy is almost 1mmiddot pussiJh un less Ihe qes a r more Of lccs ~ tru ighl

Exccsuacutev COl iexclergel cl

Ah r lile full currtCliull hus bcn g ll cn for Iislance and Illllscle halanccs 51101 a cUtllilion o f Esopho ria fo r dislancc ami l1(a r a slale of txccssi e cunv rglt llc Clt i~ t s Ths is um ull y confi lltd 111 )uung pcople but quite fretluenlly il is found ur lo l ile age o f 45 a nd Inler

The pali l1I1 i ~ iexcl[ in clt 1 lu n ucl lile illulllillaled cllnrl on Ihc rCl inoCope slarmiddot li ng with Ihe lurge lellers J)u ring Ih is pcriod iexcliexcl (Iuick (Jasll frmll rlght lo Idl usuall y diFclosiexcls quil c u sU]lt lull l iul lag Plus is lIddcl lO rcvlrsu ulIIl 11lt 1I suLmiddot Iflldcll ulllil II tulrnl is rcuclle(I Frolll Ihis is lahlI thl lag fM 1111 rI ~pcc l ivc aiexclc ulld IIkll is Icfl i ~ udrle lo Ihc disla nce currCIiu ll E 1l ir Illi s diffcrellce i5 us mucll us + 050 1111 udt lil io ll wi ll c c nluull ) be accpled by Ihe pu licll l ul lhougll il is nol aeccJlc(1 ul iexcllit li me

Oynumk BCliuoscopy lliClosc Lalenl J-1 YPNIIl l rO i1l IIhieh oer~limula l tS

COI1ergcnCt Exctssit Cou( rgence howc r 5houlfl 1101 be llUusurcd wilJiexcl basemiddot ou l prisms becaus il sl imulalcs furll lt r eOI1crgtl1ct

S tminciexcl CQIVcr tlce

This occu rs on o(rmiddotusc of lile cp 01 fi nl Iwur wtHk A low h ~ pe ropic or Ill yopi c eoudililll iiexcl u~ ual fuI d isluJlce Lul exoiexclJhorin is releuled fur near Somiddot mllilllcs il is impussible lo gic un) posili co rrcct ioJl for d illIIlCC o r if un is Jlo~s i hJ il i1 ( 111 ) ~mu l l Somltinws Ixuphoriu is found for di iexcllnllce bul a l wa ) ~

cxo phorin o r II tar Th is IlI lu ns Ihnl Ihe pali en ts Iwur visioll eOIlIfgellce hu bfo kcn d-mn a lld Ihe ()c~ urcrcolting uguillsl IIu-ir bi llocu lur fun cli on Tlley Il uc probubl r pussed Ihrou gh Ihc slage of excessivc cOIlcrg nc U1](1 ure now ul 111( tiexcliexclge hm 1 11)11 i~ middotxletiexcl lingly uncoll1fort ablc fOf close wo rk

HUIing chcchd Ihe (Iislumc rfmiddotfr action ami IWlITil1g Ihe binocula r bala ncc ctl lldilio lls in lIIi nd Ihe pat ienl i di rcctcd lo look illllll((lialdy al Ihe smiexcliexcllesl ]iexcl t1er 011 Ihl illuminaled eha rl of Ihe ret ill oscolgte whilsl Ihe li ghl is flalw(1 (iexclu ickl y fm lll ri~hl lo Idl It is ullusual lo i lld un objcClilc lag s ud + 050 O U is addcd

4l

ANTIt UN L SAVI I L

and lile rctiuoscope fla sh~middotd agaill A sl ight against nlUvlmenl llIay be observcd Hesisla nce Ihen suddenl) g iCS way and a fu rl llcr wilh mOelllcnl observed Addingplus lIltldil iolls is con linucd unlil rew rsal poi nt is reuchcd and then reshyductmiddotd to obtain tlH D)num ic Neulral Thc lag is dlducled - usuall y + loo -IInd tllt rcmn indr addell In Ihe ct islllnce pre~ri lion lf no addilion is nl(lssar_ Ihen a pr ism uf 34 JaStmiddot in di idtmiddot(1 helwtmiddottmiddotn Ihe luwo c)es is given for neac USe

bull Slrlrlgt acco llIJlation

This cllnditiun i uulIlly prtscnl in COillhi nalion wit ll st ra inoo co nvergcnce Thcrt is genernll y esophoria for dislHlcc and exophoria for near The patienl is directcd lO rcnd Iht rll ill oSCop) chart com mcllcing wilb the large letters ami obS( cvalion acled upon wllen he slarl s lo rcad Ihe small fr lellfrs MosII ) Ihen is linle ur nu lug lo htgin with allll the procedure is as in the r(iaus case 01 strained cO III( r s(nC t~ An) aIlitional plus is inCOTloraled in Ihe dislance coshyrncliol

ACCOIIIOduliofl beal) iexcllre f10fllwl

lf the lag is lurgcr Ihun IIIC no rmal fo r IllC age (wi tl Ihe palient wcaring h is fu ll dislance corrcction ) thcre is usually Oflhophoria fOf d islanee bu l a Inrg txophori a for lIear -ver) much in exe(lt of Ihe phy~iol ogical cxophor ia - nnd often as hi gl as 8 ID This cOIUitiOIl u5uall) results from some (Ieb ilily or prospeemiddot ti vt ilhwss cg boils bad I(Clh upcration cUlHalcscence o r maternil y weak middot ness and lassil ude lt is a Paresis of Acco modation aud tllt~ pulieut is ftmiddotf(middotrred

JII ropia anel DyrwIIc RelinoscoJJ

So far Ihe applieatioll of Ihe Icchnique for near vision has hlcn (]all ltl ilh in cm( of hypermelropia Ilreshyopia concrgf llce fX CCSS cte 1I should be not-d

thal in alJ Illese errors accolllll1otlal ion ami eOllergencc are slrongly linkcd In man) cuscs o f luopia how(er these fu nction a re on l) loosdy li nked Same easts

bullo f Itl)opitl ftspond in evcry a y lo Ihe lechniquc of Dynnmic Hetinoscop) as with

other arnelropie eondi lions Unfo rtunatcly a g rcat mun) rn yop( do nol reopolld in lJis way al alJ Tlw lags a rl uualJ) higl1lr in mos hyperopic cMes giv ing Ih~c

illlpression thal Ihe lIlopia is less iexclhan it js unl il il is real ised Ih lll Ihe plum o

menon is Ihe resull of inndtqualc aeeolllllloda lion IacuteI st-ems Iherefore Ihal cae

case of m)ovia musl be rcgurdld as huving il awn tliolug)

42

CLlNICAL HTI NOSCOl ~

Conellsiol

For comfortab le readi ng corrections tl ere mus be 11 comfortllblc blllllllCC bclween Ihe Ncgul ie Hdll li c iexcl cco mmoda linn und the POSilivc RlllI li c Acmiddot COlll lllod atinn If 11lf pnshyo~ ic IIddil ion is calcul31cd by subj ectie means alolle here is 11]( possibilil y o f o cr-corro CliOIl becll u~ Ihc Ncpt ic Ilclalivc Accommiddot IIOlll1l ioll when taken ~uhjetively is Ihul iexclUlIoun of plus ~phere which can be IIdded wilhoul actua l hJ urring of Ihe rea(ling matlcr uscd for Ilre lest Thc eyes lIre 11 0 1 od ng tc ~I Ctl fo r Negatic Rt-lat ic Atcum lltodalioll oul lo fin() Ihe Ch

rrect IHlohopilmiddot uddi lion whiel can be worn will comforl If tllt rCllding ad middot Iilion is loo sl rong Ih Negal iiexcl Rclali e ACCO llllllodll lionmiddot Pos iti vlmiddot Rclalive Acmiddot cOrlllllodat ion oalllnCI i di turlwtl and rcstricl ion (l f range wilh eomfort ill cnsue

T he following chart diexclvised hy Colin B Fryer alJlI h3lt(1 on lIl ucs rcco rdcll by L Swoan iJl reprodllced 3 a referellce gu idiexcl nf Ihe man) phCI10llil II11 o lJscfed IV itl l ile Dylltu nic Reli lloscolc Basically Ihc chuTI -lIl1l1l1a riscs all Ihe avni lnhlc ill fMI1H1 tion concerl1 illg th l fou r ml ill condil iO l1s likely lo be iexcll1coun lered in 1111

presb)opie )ea rs

lIi(h ( tlyn ic) neulrlI (Ir fimlI VcTS~1 I (l intl afil es

Up 10 35 35 40 10 45 45 50 5055 160

H N + 1 50 +li5 +2l + 25 250 +215

DI lo 30 J O 35 35middot10 40 405 SO 55

N R A 1 50J) 1 25 1l I OOD 0150 0 51)1) 025 11

N n Tu be d ~ dll rhd hom 11 N - Itemaintle r ~ i c lI u near ltorrclmiddotl ioll

Piy illsllll i e i e t IINomlllQda tiQtI

( d u e 10 EXre~ i e collvulcmiddote) i1u ~dc ha l ~ te Disl 3nd lI ~ ur E Hi ~h Neuln l H i ~h Cnrreel i Add Iu n Ui ~ l lJ e ll ule~ Ltlenl Uypropill

I r i r eI[(OJsie IIIToIi ( U~ l o ~ e i vc CUIl rjlenre) (O erarl iva ted or rai ne)

MII ~ le b3lanre Disl t~jjo Ncur E~o E~ HiJlIt Neunl Lo remai ui JI 1 on onin~ one eye CrTml i Atld Ius 10 Uisl LI ~ nl 1I )Ie r O IJi ~

43

AATIIIlII L S L

A Oommoduli heln normal ExlJao~led o laTc ~ i 01 Arroao nlodulion ) Mu rl ll b~ lwnre lJi~ l Orlho E~o Ne iexcl-J i ~ h E~o Hi~ h Neurral IIi ~h II ll fe lo MmiddotoI imiddotpl Pr l middotr tonbull

~olO(y exmiddotlt~ie 111

Sbullbulluined of We k Cone d e lo Com-c lI el re I rri r ienmiddot )111 ~ rI bal r l)i ~ l Orl lr o E~o Ne~ Hih EllO H i~h Neubullbullal Lo o 1 O middotomiddot iI un e~ t ore1 ion

tI 1 iexcllo lo oIi51 H u aoldi l irm rruinI

11 111 39 ~9 divided bN een bolh ~middot e f O T len uo only 111 Orlbollr exrebullbull i ~e~

D)uQmit al(I dloctrome farpcL rdiIlOSCOiexclJy

A rectlll 1tvlu lr11ent ill the InllI1iq ul uf I Yl1l1mie retinosc0IY io Ihl CockerhulI1 MImiddottllOll n hieh Ihe fixutiul1 Isrg l co ns i ~l s of IIn IIlaiexclhmc nl lo 111C lum inouiexclo Tdinn8lupc making U ~l of tlle du odtn)ll1c filtres red II l1d grecn

Cockcrham clu ims Ihal tlllrt arc a numhr of adan laiexcles itlt Illis Iu omiddot probabJy passtmiddot1 Ihrou1oacute h tlw slngl uf o cssic OI1Vcrgcncc and arl lHiexclW al IIIt chronH fi xatiOI1 nllachnlrnl O(T Ihc ordinary iIIumillale1 largd

1 Colourl(1 ta rglls cneoulugc tllt IUlitnt to mainlain fi xaliun lu a grcalcr dcg rec 1111H1 11lt bl1Ck nnl hite

2 The lrogrCS l I ZC IIlId chllractcr o f the ohj (cls IWTm il eoarsc and finc fixa liol1

t TllI c al11l111r enrl nhlnin dUlwhrnme crJualil y al a precribed wo rking di _o lance

4 Since Ihe largd conist o f (liagrlIlls ralher Ilmll lelllmiddot s tlwc IS a Ul1icrsal appl ieation

Wilh a erilical dcl l rmil1111ion o f g nc ll dumilHlI1cc a the nlinoseupe iexcls mOl-d a fracliOIl neanr lo 1111 pa l ien l 111(1 r(1 dominanc E 1H1l Ihe inslrumenl is laken 1 si mila r distance a a y lile flSU]iexcl Iacutelt cunfi n lltd

Sincc thE rcflp is l1lched during the final nHlnOIUVrc il follow Ihal ilh tllc prcsloupic comlitiulI al kn1 a fiTlII I r 1111UlIrC uf cOlllrol is adl(middot(1 lo 1111 reading ur do~e o rk addil ion

Cock(fham stales Illal ith Ihe cylinrllr ax l [l11d 10 1 ( lTdull y chefke1 and Ihe ~phcricnl lIlo(lificali un cOlltrolled lhruughout itlr thc duuchrnmc dlIalllic lurgmiddot1 1111 practi timwr is in 11 pn il ion In prcscr ihe fnr fl l1 ) pTlshyoopic co rrccli on

44

Cllr-I CAL H1I Nn COI Y

I ilh grealcr eerla inly o IIICl a purd) UhjtClie lest IIl0nt 15 onl y l S nccurutc as IIIt pa l iIII confirmnti on 1011 1 a llo w 11 callnot be a rgucd he says thal IllIl

dY ll umic Icst is onlr all ohject i 1l11lhocl of nwagt uring Ihe ntgll li c rebli t ticmiddot eo rumodat ioll fOT Ihe duochronw is ac tillg as u conlrol factur a l all lI tages of Ihe

test

In IIIcnlionin g Ihe abmc Codcrharll mr lhod une his ol inlUlI Ihis is lo bring

D)na mic Rtgtl inuscupy lo i l ~ full co nclusioll ~tld is no nn xprcssio ll of fLSUIt iexcl

obta irltd hy myC1f I r~o na ll y ti u lo lack o f (xpelicncc wi lh d uocJnolllc (lpIPmic l a rgt I ~

CONCLllS ION

Agt il will be fuU y appreciatld Ihe wriUen e xpla nali olJ IlIkes considcrahl) IOllgcr

lo rltSCribc Iha n Ihe practical applical iun of lJ igt rclulicl y si mple roulil1 t TIIt In lcl ilior1rr- a hi lil ) with the rt inoscopc ir rpectit of wlrlll IJW i ~ prcfc rnmiddotd

is 1 11 objcdie I1 l1 tho(1 of Ttfraction wcll WlJrtl l hCClIllIillg skillcd in

The iexclinU spenl in decloping litis ~ ki ll heing JIIOn Ihan cOl1lptnsn l~ d for h ) lil e f( middotsult olJluiunl

IIJ J C I I ) ~ 5r P O no1 1I

REnRENciexclS

lIH KA Y FEHG USON R ~ i o tu l ) L undun Tmiddothni r 1 Mono~ ra l h NQ 5 BEB ENS Im1 Z UCKI RMA N jalm iexcl Eumnaiexcliun ur 110 E)middot ~ WELCH ALI YN IAI III LI1 Slrn k IIjlinomiddotul Y J PASCAL L Mud n linUt0 IY L SWANN puIlel KEEIEII Pa1l lhlel S TAYLO II lJynu mit Kcrinu8middotuPY and lIinuulur ncl l cx ~

1 S VELL An Inlrudurlion lo lJynamir Heil nus middot p) Vul 2 N9 2 (S A Rdnclioni lr I J un 1951

D COCK~ II I1 M Dynamjmiddot Slrea t Reiexcl n05Ur jlh duur hrunr e rita l ion lar~c l ~ Olll i cIn 1 5 ~ CXXVI II 58

45

CIII LC AI I~J NOSCOIY

To check Ihe neulralisalion POill l cil lllr nplruaeh doscl lo Ihe pul i nl when n wilh llIUVCJIlt llt should ugain he scen o r furlher away wlUn an again st l1Iovemiddot me lll wi ll he obervecl Th e addition of u furl ll t r plus 025 will resull in un aguo insl 11I0(l11elll

An uguinst IlIUemen l is Ilelllraliscd in cxacll) lhc salllC way as for Ihe wilh lIIocm l1 onl) min us spheres a re uSed ]f howcer Ihe sl reak is adjustcd so as lo g ive a concuve mirror cHecl (producing crusscd ra)) and conerling Ihe againsiexcl moemenl lo a wilh movement rasler resll l are obla in~ Minus lenmiddot ses llre slitl uSld fu r neulralisatioll

A chlik is mude (lS bdo re h) 111O ing doser or fur lher away from lhe iexclIaien or IIH alld ilion of an txtra -025 ipherc ror reversul o f lle fIl0 velllent

Ir a(iexcl(T neul rali~alion a 1)Dnd rdltX slill nmains in 11ll meridian al rigill angles lo thul whieh hus bcen lI lulraHsed astig lllalism is presenl l Is axis is determ incd by rotali ng lhe Slrak th rough 90 iexcllIld ubst r ing lile band of li ght (slllulow) ni tJlis meridian If il haplell~ lo Jit ill 1111 axis uf asligmnlism a brighl weH ddini cd band apvea rs hieh mo~r lIil l1 or agai n~ l hui paraHel with Ihe slrtlIk uf light OIJ the fa elmiddot If il il 80 lllcwhnl o f( the principlc axis Ihe sII1HIQw nol onl y btcomes jmlislincl bul il a lso p roduce8 n brlak in conlinuil y btll(en il and Ihe sl rcak of ligiLt on Ihe fn te The ~ lr tu k is rotalcd unlil Ihe reflt x hand o f li ghl in Ihe Iye ami lhe slreak of ligiL l fin iexclJI fael a re in alignemenl and moe in pa raHd direcli ons Tht a xis is lIoll ll and Ihe ~h a(low ing eonlinucd al Ihi s axis a nd al Ihe axis al right angles lo it neulrni ing Ihe rdlex ( in Ihe p roper Ill l r idia ns) with plus eylinders in h)ptrmelropic aliiexclmntims Of mi nus cylindcrs in lIl)o l ic aslig matism

If an agn insl mocmenl i~ present in one lIleridian and a w ilh 1II0ell1enl in tll l mericlia n al r ight angles ( l11ixcl atiglllat ism) Ihe aga iniexclt 1110Cll lCnl itl neumiddot tralistmiddotd ilh minus sphcres 1111(1 lhe w itll moellltnl ith plus e) lindcfs

DYIIIIic Reil oscoiexcly

TI is melloll is uselt for Ihe ohjeetivc detcrmi nali oll n f 111( n middotfraclhe cOIl(lition of Ih c treS f Uf lu u r vis ion whil~l 10th aecmnmodalion ami tOl1vcrgeJ1ce are bl ing txerci s~middotd nI lhe urki ng dislallce (abouI 333 ell1s)

]lle iustrulIlen ls lI ~cd are a d )namie relinoscopc and ci lhcr 11 dynamie raek or n ~c rilS (f hinocul ar ad ditiolls so lIlounlcd as lo be casily piektd up and placed Lciacuteort Ihe e)t~ Tllc rack laklS lhe fo rm of a plaltie o r me tallic hulder eun laining lenses mounted in pairs ami forming a scrirs of graduall) inereasing ltliuptric

37

iexcl RTH U R l ~AVUl

powtrs oue iexcliexcl bomiddote the other T he fixiexcliexcll ion largel is eilher auached lo or huilt inlo he nlilloscope iiexcl el f alld illum inalcd by Ihe li ghl ing ~yslem oiacute Ihe illslrulllcnl

The lu rge take various forms such as T((Juced Snellen lellers of various s izes

g1nmcl ri e l a ll e r ll~ Of sil llply a rew ~ l (cl balls le l ill lo IIIl bo(l) of iexclhe rel i ll o~lope

T hl ) are mounlcJ LCl1 l rall in verl ical aligll l1letll with Ih e in sl ru lllen l in Ihe pl ane of Ihe mirro r and sligh tly (iexclhove or below Ihe li ne of sight of Ih e observer

Dylliltllic rel ino(opy is usuully e(iexclrrd out iexcliexclfler static relinosco py has beell

performed Ihe suhjective examinalion for dislance co mplcl ed al1(1 lhe lIlu(Je bao

lancls lukln Corrcctioll slwuld be IlHlU C b) prbllls of all) hypcrphor ia if presenl

ami an ) horizonlal imba lance if over 2 prism dioplres A poin l of imporla nce lo Le kept in mind is tha l Dynam ic Hctinoscopy is nol aceurule unkss Ihe palielll

has binocula r vis ion o

In IIIf follow ing r($u n]( on Dnam ic Hli inoscopy grtaleT dlat il n [ 1111 physiexclolog)

u f visiull has het cl iscuSt~ d fo r a dean r unuerslauding uf lile visual func lions inokecl The c1 ill ical appliC(lti oll is mucb Ibe sa nw bu l Ihe resulls due lo t he

uua lll ic func l iou iug of lllt ces fo llows a diffl renl cliaguosliiexcl pattern 10 facil imiddot late Ihis a sli ghl cha ngc in approaeh has heen mnd( from lhe de5eriplio n l lrcad

giVfu 011 ll lt applicatioll of t llt rlli noscopl a~ a c1iacuten ical insl ru lllcnl

Tile t~xa tlli ner plaees himself iu front of Ihe median l ine of Ihe pal ien (yes and al Ihe su ne heighl so IIHlt h is ee is equidh tanl frolll Ihe ees u f Ihe pali t]]I

RcIIacutellOSCOp is thclI carricd oul at Ilw avcr age n ading (Iislancc of 333 ems

ahhough th is ma) va r according lo Ihe particular in vestigaliun b eing conduded

T llc pUlienl is (lincle(1 lo look al lIle b rgcst leller or patteTII u f he illum illaled

charl Th e fllilloscoric li ghl palfh is passed rapidl y frOIll one eye lo Ihe ollllr in Ihe hor izontal planc a ll(1 lhe mOflIIent of the sllatlow i ~ nole (1 as is usual lVi lh

s talic rel inoscopy Wuumlh cerla in excepli ons which will be deal l wilh Jater on il

i ll he nolicnl Ihal there is a wilh mov(menl o f Ihe bado For ex ample wilh

a + 1000 OU llwre lila ) be 1 revcrsal or againsl JIlovemen l It is neccssary Ihen lo reduct Ihis add ilion unli J tbere i ~ 110 IIlOCllltnt or olll y a sliglll kickhack

lt will be found Ihal Ibe le lls with which this resull is oblaincd is a +075 Of a + 050 O This is ca llcd lhe D ) lHlIlli c Neutral FrOIll lhis fi gure is suhl raded the Obj ccli vc Lag for Ihe patiellts uge If Ih is hnppens lo coincide a nd zero r esul t~

j i llIa 1) eoncuded thal Ihe (Iislance torrcction wil be slI isfa elory for Ihe performance nf all ta ~k s whether al I islancc or for lllar work

Objlctil Lags vary accord in g lo uge as cal be seCII fr olU Ihe followillg table

+ 100 up to 30 ycar + 050 lo + 075 frorn 30 lo 45 years + 050 f rom 45 lo 70 yea rs

Over 70 years 11 il

38

bull

bull

CLlNICAI IHTlNOSCOIY

From Ihc age of 45 years and onward~ Ihrough Ihe presbyopie ycars no more Ihall + 050 is delluctcd (or Ihe Obj ect ivc Lag Larger Oynamie Neulrals Iban + 050 are eOllsidc red (IS binocu la r relld ing lldditions if close work for long periods is lo ~ leeum pli she1 wilhoul diSClllllforL For cxam plc a palient of 50 hlls 11

Oynamic Neutral of + 175 IlIen sublracting the lag of + 050 +125 is obtainc(l wllieh is Ihe readillg addition OU

Various author ities account for Ih Lag in Ilifferent wa)s It is howevcr gtneralJy aeecplcd that mosl Jlcople rarel ) exerl their full accommodatioll for rhe working (listancc At 3P cm~ Iheir aeeomodatioll is nearer 250 than the full 3D Their accommodalion may be suid lo be loo~t The) do nol reall y look at an obj lcl Sil muell as glance at il il being unneeessary lo focus exaclly ror lvery visual lask especiall y if the prinl is nol loo small Whcrc lhc palienl is oung ( up lo 10 and Il as becn Iraincd lo USl his eyes for f ine work Ihe Dynamic Neulral appcars alrea(l y lo ex ist ic the n is a slighl ki ckmiddotbaek of Ihe shadoll The placing of a billocular additiull of +050 bdon~ Ihe ps ami repea tin g the r ight lo left flash of lh e rClinoscope will probabl) reveal a definile wilh mocmellL With ( 1 + 125 additiun there lluy llUW appcar lo be a (Icfilli le reverse movemenL

Using a + 100 addition ne ulral llialion il probabl) resull What appcared al firsl lo be lleutrali~ld lOW sut isfies u Lag o[ +100 whieh is no rmal for Ihul age anJ Ihe palien t shou ld havc t1ll1llttropia for (Iistanee lIith or wilhou l eomiddot rrect ion There is TILertfore

u) Neu tralisalion wi lIL no Lag

L) Neulral isutiun wilh a + 100 OU

Tlw patienl has thercfore re1axed his aceollllllodalioll 1000 wlli lsl ma intamiddot ining full convergence whieh is nornllll fur his age

S inee Ihe iexclIel of aeeummodaliun doc not eonfurm lo geomrtrie oplies Ihe llJ110UIII of uccomllHJdulilgt11 in use fur cOlllfurtable rcudillg visiun au ul1e~ rlain

(Iuantity lf a patient i5 under tesl it is natural for him to make a greater efforl IhlUl hc will mukc in ordinary cireumslunces (Swulln)

Amplilurlc of uecummodalion lels are Useles5 in that the learer Ihe ubjecl i5 aflflroached Lo tlH~ eyes Ihe larger iexclhe visual angle becomes so Ihat the aecummudalion is not used at all and if used only partially The cards nearness llables a persoll to receie a larger and morc magnified image of the objlCt Taylo r )

AII iexclhesc fuclon render Ihe use of suLjccLie tesIs upon thl omplitudc uncerluin unle~ the true value by objeetivc means 15 first ascerlained

39

MITlI UR l SAnU

Umlouhlc(lly lhe ohj -cli e lag is Ihe Hgtu1t of Ihe eyes nol foeussing accuralcl) Of Hlel l) un Ihe In rgll lul ~omcw l lt rc hdlind il Only ir lit lurge is ndv81leed lo 2a cm in fron l of 11 plI it lI ts C CS is Ilculrali$ntio ll al 111 Iminl f hscrmiddot al ioll prod ucltL

It is prohnblc Iherd o re Illal ill enrrying out D lIomie Icli lluscopy lile uelual Negali e Hda li e ACCOllllllodalion is lul is mCI urc(L

Nlgalie HcIllie AeeollllllOdalioll al

30 ears + 025 lo -- 150 al mux imum

30 lu 35 )ca rs + 100 lu + 125 01 llIuximulll

35 lo 40 )ea rs + 100 al maxilllulll

40 lo 45 ) a rs + 075 al lllaXimUIIl

As Negalic lelali e Aiexcleo lllll1od ulioll il Ihe abili ly uf Ihe eyes lo rllax hile eOI1ergellee rcmains undlangmiddotd il is scn Ihal Ihe lable of NIgalie Il elnlie ACcollllllodalioll approx illllllls vny doscly lo l ile lublc of uhjeclic lags It i howc r un wise lo n late olle lable try dosel) lo 111( olh er for il 111111 he remo ber tlt Ihat mcu mlllodation is adeIUalc when Ihe positi vc alld Ilcgati-c ra ns a rc ill normal ral io 1f Ihe posili e nlll se is 110rrmll Ih l bull lHgalie rangc will also he no rma l

Tlle Correeion o Prcsbyopia

For Ihe correelion of PresL yofJill Ihe wit ll m()cment i3 notcd Ir il i5 fn irl ) lllarkc1 a subst ancial binocular addi tion is Irie(l eg around + 2000 sphere Ir Ihis neulralis s musl uf Ihc w itll mUJlell l u fur lher udditiun uf middotplu in hal f di oJller stcJls iiexcl maflC unlil a d finile rfI r~e 1l10Vell1enl lakfs place T hi 111 (1) be uLtain1 will a +250 A rctufIL 1 + 225 ll lln results in th e 1Il0velllcul bci ng neilhrr wi lh Ilor against This is Ihe Dyna mic Neul ra l By know ing Ihe pal icn l

uge w]iexcl ith is gicll as 55 ano substracling Ihe Obj rctive Lag + 050 Ih e TesUIt is + li5 lhis is tbe rcad in g nJlition whiel ~hould L t ~ gieu Sub jedic dweki ng can Iw madc wilh one of Ihe melhods described

1 Al la rgeT addil iou tllllll + 200 indieates that dtheT tl lt palilll l is undrmiddotcomiddot rrecled fo r d islanee or Ihc eause may be pathoJogical

2 When 1111 refl Clees arc ulleq ual it ma be ltIue lomiddot

u) Patholugical JlroccsC~ in unc Iye

40

C II N I C~I IUTIN OSCOlY

1 I m lrol~ r co rreclion 111 une o r ul11lr Ihe ees for dislance

e) Unequa convergcnce uf Ihe eps on Ihe la rgeL

In tlw case of b ) if plus is addcd o r suhlrueled unlil Ihe Ing cfjuuls Illt nOTrlHll for Ihe Iuti t nts age il is iexclJossiexclhle tu nliexcldecl reversioll lo Ihe ubj ccts di~ t llll cC

lest TI1l lmiddotxa lll in er will kil O quite 1 11 Ihul Ihe Uynumic finJing~ wil1 he e rified by cxpcricncc In euSts uf e) Slr3]iexclsHluS Dynallli c Il elinoscopy is almost 1mmiddot pussiJh un less Ihe qes a r more Of lccs ~ tru ighl

Exccsuacutev COl iexclergel cl

Ah r lile full currtCliull hus bcn g ll cn for Iislance and Illllscle halanccs 51101 a cUtllilion o f Esopho ria fo r dislancc ami l1(a r a slale of txccssi e cunv rglt llc Clt i~ t s Ths is um ull y confi lltd 111 )uung pcople but quite fretluenlly il is found ur lo l ile age o f 45 a nd Inler

The pali l1I1 i ~ iexcl[ in clt 1 lu n ucl lile illulllillaled cllnrl on Ihc rCl inoCope slarmiddot li ng with Ihe lurge lellers J)u ring Ih is pcriod iexcliexcl (Iuick (Jasll frmll rlght lo Idl usuall y diFclosiexcls quil c u sU]lt lull l iul lag Plus is lIddcl lO rcvlrsu ulIIl 11lt 1I suLmiddot Iflldcll ulllil II tulrnl is rcuclle(I Frolll Ihis is lahlI thl lag fM 1111 rI ~pcc l ivc aiexclc ulld IIkll is Icfl i ~ udrle lo Ihc disla nce currCIiu ll E 1l ir Illi s diffcrellce i5 us mucll us + 050 1111 udt lil io ll wi ll c c nluull ) be accpled by Ihe pu licll l ul lhougll il is nol aeccJlc(1 ul iexcllit li me

Oynumk BCliuoscopy lliClosc Lalenl J-1 YPNIIl l rO i1l IIhieh oer~limula l tS

COI1ergcnCt Exctssit Cou( rgence howc r 5houlfl 1101 be llUusurcd wilJiexcl basemiddot ou l prisms becaus il sl imulalcs furll lt r eOI1crgtl1ct

S tminciexcl CQIVcr tlce

This occu rs on o(rmiddotusc of lile cp 01 fi nl Iwur wtHk A low h ~ pe ropic or Ill yopi c eoudililll iiexcl u~ ual fuI d isluJlce Lul exoiexclJhorin is releuled fur near Somiddot mllilllcs il is impussible lo gic un) posili co rrcct ioJl for d illIIlCC o r if un is Jlo~s i hJ il i1 ( 111 ) ~mu l l Somltinws Ixuphoriu is found for di iexcllnllce bul a l wa ) ~

cxo phorin o r II tar Th is IlI lu ns Ihnl Ihe pali en ts Iwur visioll eOIlIfgellce hu bfo kcn d-mn a lld Ihe ()c~ urcrcolting uguillsl IIu-ir bi llocu lur fun cli on Tlley Il uc probubl r pussed Ihrou gh Ihc slage of excessivc cOIlcrg nc U1](1 ure now ul 111( tiexcliexclge hm 1 11)11 i~ middotxletiexcl lingly uncoll1fort ablc fOf close wo rk

HUIing chcchd Ihe (Iislumc rfmiddotfr action ami IWlITil1g Ihe binocula r bala ncc ctl lldilio lls in lIIi nd Ihe pat ienl i di rcctcd lo look illllll((lialdy al Ihe smiexcliexcllesl ]iexcl t1er 011 Ihl illuminaled eha rl of Ihe ret ill oscolgte whilsl Ihe li ghl is flalw(1 (iexclu ickl y fm lll ri~hl lo Idl It is ullusual lo i lld un objcClilc lag s ud + 050 O U is addcd

4l

ANTIt UN L SAVI I L

and lile rctiuoscope fla sh~middotd agaill A sl ight against nlUvlmenl llIay be observcd Hesisla nce Ihen suddenl) g iCS way and a fu rl llcr wilh mOelllcnl observed Addingplus lIltldil iolls is con linucd unlil rew rsal poi nt is reuchcd and then reshyductmiddotd to obtain tlH D)num ic Neulral Thc lag is dlducled - usuall y + loo -IInd tllt rcmn indr addell In Ihe ct islllnce pre~ri lion lf no addilion is nl(lssar_ Ihen a pr ism uf 34 JaStmiddot in di idtmiddot(1 helwtmiddottmiddotn Ihe luwo c)es is given for neac USe

bull Slrlrlgt acco llIJlation

This cllnditiun i uulIlly prtscnl in COillhi nalion wit ll st ra inoo co nvergcnce Thcrt is genernll y esophoria for dislHlcc and exophoria for near The patienl is directcd lO rcnd Iht rll ill oSCop) chart com mcllcing wilb the large letters ami obS( cvalion acled upon wllen he slarl s lo rcad Ihe small fr lellfrs MosII ) Ihen is linle ur nu lug lo htgin with allll the procedure is as in the r(iaus case 01 strained cO III( r s(nC t~ An) aIlitional plus is inCOTloraled in Ihe dislance coshyrncliol

ACCOIIIOduliofl beal) iexcllre f10fllwl

lf the lag is lurgcr Ihun IIIC no rmal fo r IllC age (wi tl Ihe palient wcaring h is fu ll dislance corrcction ) thcre is usually Oflhophoria fOf d islanee bu l a Inrg txophori a for lIear -ver) much in exe(lt of Ihe phy~iol ogical cxophor ia - nnd often as hi gl as 8 ID This cOIUitiOIl u5uall) results from some (Ieb ilily or prospeemiddot ti vt ilhwss cg boils bad I(Clh upcration cUlHalcscence o r maternil y weak middot ness and lassil ude lt is a Paresis of Acco modation aud tllt~ pulieut is ftmiddotf(middotrred

JII ropia anel DyrwIIc RelinoscoJJ

So far Ihe applieatioll of Ihe Icchnique for near vision has hlcn (]all ltl ilh in cm( of hypermelropia Ilreshyopia concrgf llce fX CCSS cte 1I should be not-d

thal in alJ Illese errors accolllll1otlal ion ami eOllergencc are slrongly linkcd In man) cuscs o f luopia how(er these fu nction a re on l) loosdy li nked Same easts

bullo f Itl)opitl ftspond in evcry a y lo Ihe lechniquc of Dynnmic Hetinoscop) as with

other arnelropie eondi lions Unfo rtunatcly a g rcat mun) rn yop( do nol reopolld in lJis way al alJ Tlw lags a rl uualJ) higl1lr in mos hyperopic cMes giv ing Ih~c

illlpression thal Ihe lIlopia is less iexclhan it js unl il il is real ised Ih lll Ihe plum o

menon is Ihe resull of inndtqualc aeeolllllloda lion IacuteI st-ems Iherefore Ihal cae

case of m)ovia musl be rcgurdld as huving il awn tliolug)

42

CLlNICAL HTI NOSCOl ~

Conellsiol

For comfortab le readi ng corrections tl ere mus be 11 comfortllblc blllllllCC bclween Ihe Ncgul ie Hdll li c iexcl cco mmoda linn und the POSilivc RlllI li c Acmiddot COlll lllod atinn If 11lf pnshyo~ ic IIddil ion is calcul31cd by subj ectie means alolle here is 11]( possibilil y o f o cr-corro CliOIl becll u~ Ihc Ncpt ic Ilclalivc Accommiddot IIOlll1l ioll when taken ~uhjetively is Ihul iexclUlIoun of plus ~phere which can be IIdded wilhoul actua l hJ urring of Ihe rea(ling matlcr uscd for Ilre lest Thc eyes lIre 11 0 1 od ng tc ~I Ctl fo r Negatic Rt-lat ic Atcum lltodalioll oul lo fin() Ihe Ch

rrect IHlohopilmiddot uddi lion whiel can be worn will comforl If tllt rCllding ad middot Iilion is loo sl rong Ih Negal iiexcl Rclali e ACCO llllllodll lionmiddot Pos iti vlmiddot Rclalive Acmiddot cOrlllllodat ion oalllnCI i di turlwtl and rcstricl ion (l f range wilh eomfort ill cnsue

T he following chart diexclvised hy Colin B Fryer alJlI h3lt(1 on lIl ucs rcco rdcll by L Swoan iJl reprodllced 3 a referellce gu idiexcl nf Ihe man) phCI10llil II11 o lJscfed IV itl l ile Dylltu nic Reli lloscolc Basically Ihc chuTI -lIl1l1l1a riscs all Ihe avni lnhlc ill fMI1H1 tion concerl1 illg th l fou r ml ill condil iO l1s likely lo be iexcll1coun lered in 1111

presb)opie )ea rs

lIi(h ( tlyn ic) neulrlI (Ir fimlI VcTS~1 I (l intl afil es

Up 10 35 35 40 10 45 45 50 5055 160

H N + 1 50 +li5 +2l + 25 250 +215

DI lo 30 J O 35 35middot10 40 405 SO 55

N R A 1 50J) 1 25 1l I OOD 0150 0 51)1) 025 11

N n Tu be d ~ dll rhd hom 11 N - Itemaintle r ~ i c lI u near ltorrclmiddotl ioll

Piy illsllll i e i e t IINomlllQda tiQtI

( d u e 10 EXre~ i e collvulcmiddote) i1u ~dc ha l ~ te Disl 3nd lI ~ ur E Hi ~h Neuln l H i ~h Cnrreel i Add Iu n Ui ~ l lJ e ll ule~ Ltlenl Uypropill

I r i r eI[(OJsie IIIToIi ( U~ l o ~ e i vc CUIl rjlenre) (O erarl iva ted or rai ne)

MII ~ le b3lanre Disl t~jjo Ncur E~o E~ HiJlIt Neunl Lo remai ui JI 1 on onin~ one eye CrTml i Atld Ius 10 Uisl LI ~ nl 1I )Ie r O IJi ~

43

AATIIIlII L S L

A Oommoduli heln normal ExlJao~led o laTc ~ i 01 Arroao nlodulion ) Mu rl ll b~ lwnre lJi~ l Orlho E~o Ne iexcl-J i ~ h E~o Hi~ h Neurral IIi ~h II ll fe lo MmiddotoI imiddotpl Pr l middotr tonbull

~olO(y exmiddotlt~ie 111

Sbullbulluined of We k Cone d e lo Com-c lI el re I rri r ienmiddot )111 ~ rI bal r l)i ~ l Orl lr o E~o Ne~ Hih EllO H i~h Neubullbullal Lo o 1 O middotomiddot iI un e~ t ore1 ion

tI 1 iexcllo lo oIi51 H u aoldi l irm rruinI

11 111 39 ~9 divided bN een bolh ~middot e f O T len uo only 111 Orlbollr exrebullbull i ~e~

D)uQmit al(I dloctrome farpcL rdiIlOSCOiexclJy

A rectlll 1tvlu lr11ent ill the InllI1iq ul uf I Yl1l1mie retinosc0IY io Ihl CockerhulI1 MImiddottllOll n hieh Ihe fixutiul1 Isrg l co ns i ~l s of IIn IIlaiexclhmc nl lo 111C lum inouiexclo Tdinn8lupc making U ~l of tlle du odtn)ll1c filtres red II l1d grecn

Cockcrham clu ims Ihal tlllrt arc a numhr of adan laiexcles itlt Illis Iu omiddot probabJy passtmiddot1 Ihrou1oacute h tlw slngl uf o cssic OI1Vcrgcncc and arl lHiexclW al IIIt chronH fi xatiOI1 nllachnlrnl O(T Ihc ordinary iIIumillale1 largd

1 Colourl(1 ta rglls cneoulugc tllt IUlitnt to mainlain fi xaliun lu a grcalcr dcg rec 1111H1 11lt bl1Ck nnl hite

2 The lrogrCS l I ZC IIlId chllractcr o f the ohj (cls IWTm il eoarsc and finc fixa liol1

t TllI c al11l111r enrl nhlnin dUlwhrnme crJualil y al a precribed wo rking di _o lance

4 Since Ihe largd conist o f (liagrlIlls ralher Ilmll lelllmiddot s tlwc IS a Ul1icrsal appl ieation

Wilh a erilical dcl l rmil1111ion o f g nc ll dumilHlI1cc a the nlinoseupe iexcls mOl-d a fracliOIl neanr lo 1111 pa l ien l 111(1 r(1 dominanc E 1H1l Ihe inslrumenl is laken 1 si mila r distance a a y lile flSU]iexcl Iacutelt cunfi n lltd

Sincc thE rcflp is l1lched during the final nHlnOIUVrc il follow Ihal ilh tllc prcsloupic comlitiulI al kn1 a fiTlII I r 1111UlIrC uf cOlllrol is adl(middot(1 lo 1111 reading ur do~e o rk addil ion

Cock(fham stales Illal ith Ihe cylinrllr ax l [l11d 10 1 ( lTdull y chefke1 and Ihe ~phcricnl lIlo(lificali un cOlltrolled lhruughout itlr thc duuchrnmc dlIalllic lurgmiddot1 1111 practi timwr is in 11 pn il ion In prcscr ihe fnr fl l1 ) pTlshyoopic co rrccli on

44

Cllr-I CAL H1I Nn COI Y

I ilh grealcr eerla inly o IIICl a purd) UhjtClie lest IIl0nt 15 onl y l S nccurutc as IIIt pa l iIII confirmnti on 1011 1 a llo w 11 callnot be a rgucd he says thal IllIl

dY ll umic Icst is onlr all ohject i 1l11lhocl of nwagt uring Ihe ntgll li c rebli t ticmiddot eo rumodat ioll fOT Ihe duochronw is ac tillg as u conlrol factur a l all lI tages of Ihe

test

In IIIcnlionin g Ihe abmc Codcrharll mr lhod une his ol inlUlI Ihis is lo bring

D)na mic Rtgtl inuscupy lo i l ~ full co nclusioll ~tld is no nn xprcssio ll of fLSUIt iexcl

obta irltd hy myC1f I r~o na ll y ti u lo lack o f (xpelicncc wi lh d uocJnolllc (lpIPmic l a rgt I ~

CONCLllS ION

Agt il will be fuU y appreciatld Ihe wriUen e xpla nali olJ IlIkes considcrahl) IOllgcr

lo rltSCribc Iha n Ihe practical applical iun of lJ igt rclulicl y si mple roulil1 t TIIt In lcl ilior1rr- a hi lil ) with the rt inoscopc ir rpectit of wlrlll IJW i ~ prcfc rnmiddotd

is 1 11 objcdie I1 l1 tho(1 of Ttfraction wcll WlJrtl l hCClIllIillg skillcd in

The iexclinU spenl in decloping litis ~ ki ll heing JIIOn Ihan cOl1lptnsn l~ d for h ) lil e f( middotsult olJluiunl

IIJ J C I I ) ~ 5r P O no1 1I

REnRENciexclS

lIH KA Y FEHG USON R ~ i o tu l ) L undun Tmiddothni r 1 Mono~ ra l h NQ 5 BEB ENS Im1 Z UCKI RMA N jalm iexcl Eumnaiexcliun ur 110 E)middot ~ WELCH ALI YN IAI III LI1 Slrn k IIjlinomiddotul Y J PASCAL L Mud n linUt0 IY L SWANN puIlel KEEIEII Pa1l lhlel S TAYLO II lJynu mit Kcrinu8middotuPY and lIinuulur ncl l cx ~

1 S VELL An Inlrudurlion lo lJynamir Heil nus middot p) Vul 2 N9 2 (S A Rdnclioni lr I J un 1951

D COCK~ II I1 M Dynamjmiddot Slrea t Reiexcl n05Ur jlh duur hrunr e rita l ion lar~c l ~ Olll i cIn 1 5 ~ CXXVI II 58

45

iexcl RTH U R l ~AVUl

powtrs oue iexcliexcl bomiddote the other T he fixiexcliexcll ion largel is eilher auached lo or huilt inlo he nlilloscope iiexcl el f alld illum inalcd by Ihe li ghl ing ~yslem oiacute Ihe illslrulllcnl

The lu rge take various forms such as T((Juced Snellen lellers of various s izes

g1nmcl ri e l a ll e r ll~ Of sil llply a rew ~ l (cl balls le l ill lo IIIl bo(l) of iexclhe rel i ll o~lope

T hl ) are mounlcJ LCl1 l rall in verl ical aligll l1letll with Ih e in sl ru lllen l in Ihe pl ane of Ihe mirro r and sligh tly (iexclhove or below Ihe li ne of sight of Ih e observer

Dylliltllic rel ino(opy is usuully e(iexclrrd out iexcliexclfler static relinosco py has beell

performed Ihe suhjective examinalion for dislance co mplcl ed al1(1 lhe lIlu(Je bao

lancls lukln Corrcctioll slwuld be IlHlU C b) prbllls of all) hypcrphor ia if presenl

ami an ) horizonlal imba lance if over 2 prism dioplres A poin l of imporla nce lo Le kept in mind is tha l Dynam ic Hctinoscopy is nol aceurule unkss Ihe palielll

has binocula r vis ion o

In IIIf follow ing r($u n]( on Dnam ic Hli inoscopy grtaleT dlat il n [ 1111 physiexclolog)

u f visiull has het cl iscuSt~ d fo r a dean r unuerslauding uf lile visual func lions inokecl The c1 ill ical appliC(lti oll is mucb Ibe sa nw bu l Ihe resulls due lo t he

uua lll ic func l iou iug of lllt ces fo llows a diffl renl cliaguosliiexcl pattern 10 facil imiddot late Ihis a sli ghl cha ngc in approaeh has heen mnd( from lhe de5eriplio n l lrcad

giVfu 011 ll lt applicatioll of t llt rlli noscopl a~ a c1iacuten ical insl ru lllcnl

Tile t~xa tlli ner plaees himself iu front of Ihe median l ine of Ihe pal ien (yes and al Ihe su ne heighl so IIHlt h is ee is equidh tanl frolll Ihe ees u f Ihe pali t]]I

RcIIacutellOSCOp is thclI carricd oul at Ilw avcr age n ading (Iislancc of 333 ems

ahhough th is ma) va r according lo Ihe particular in vestigaliun b eing conduded

T llc pUlienl is (lincle(1 lo look al lIle b rgcst leller or patteTII u f he illum illaled

charl Th e fllilloscoric li ghl palfh is passed rapidl y frOIll one eye lo Ihe ollllr in Ihe hor izontal planc a ll(1 lhe mOflIIent of the sllatlow i ~ nole (1 as is usual lVi lh

s talic rel inoscopy Wuumlh cerla in excepli ons which will be deal l wilh Jater on il

i ll he nolicnl Ihal there is a wilh mov(menl o f Ihe bado For ex ample wilh

a + 1000 OU llwre lila ) be 1 revcrsal or againsl JIlovemen l It is neccssary Ihen lo reduct Ihis add ilion unli J tbere i ~ 110 IIlOCllltnt or olll y a sliglll kickhack

lt will be found Ihal Ibe le lls with which this resull is oblaincd is a +075 Of a + 050 O This is ca llcd lhe D ) lHlIlli c Neutral FrOIll lhis fi gure is suhl raded the Obj ccli vc Lag for Ihe patiellts uge If Ih is hnppens lo coincide a nd zero r esul t~

j i llIa 1) eoncuded thal Ihe (Iislance torrcction wil be slI isfa elory for Ihe performance nf all ta ~k s whether al I islancc or for lllar work

Objlctil Lags vary accord in g lo uge as cal be seCII fr olU Ihe followillg table

+ 100 up to 30 ycar + 050 lo + 075 frorn 30 lo 45 years + 050 f rom 45 lo 70 yea rs

Over 70 years 11 il

38

bull

bull

CLlNICAI IHTlNOSCOIY

From Ihc age of 45 years and onward~ Ihrough Ihe presbyopie ycars no more Ihall + 050 is delluctcd (or Ihe Obj ect ivc Lag Larger Oynamie Neulrals Iban + 050 are eOllsidc red (IS binocu la r relld ing lldditions if close work for long periods is lo ~ leeum pli she1 wilhoul diSClllllforL For cxam plc a palient of 50 hlls 11

Oynamic Neutral of + 175 IlIen sublracting the lag of + 050 +125 is obtainc(l wllieh is Ihe readillg addition OU

Various author ities account for Ih Lag in Ilifferent wa)s It is howevcr gtneralJy aeecplcd that mosl Jlcople rarel ) exerl their full accommodatioll for rhe working (listancc At 3P cm~ Iheir aeeomodatioll is nearer 250 than the full 3D Their accommodalion may be suid lo be loo~t The) do nol reall y look at an obj lcl Sil muell as glance at il il being unneeessary lo focus exaclly ror lvery visual lask especiall y if the prinl is nol loo small Whcrc lhc palienl is oung ( up lo 10 and Il as becn Iraincd lo USl his eyes for f ine work Ihe Dynamic Neulral appcars alrea(l y lo ex ist ic the n is a slighl ki ckmiddotbaek of Ihe shadoll The placing of a billocular additiull of +050 bdon~ Ihe ps ami repea tin g the r ight lo left flash of lh e rClinoscope will probabl) reveal a definile wilh mocmellL With ( 1 + 125 additiun there lluy llUW appcar lo be a (Icfilli le reverse movemenL

Using a + 100 addition ne ulral llialion il probabl) resull What appcared al firsl lo be lleutrali~ld lOW sut isfies u Lag o[ +100 whieh is no rmal for Ihul age anJ Ihe palien t shou ld havc t1ll1llttropia for (Iistanee lIith or wilhou l eomiddot rrect ion There is TILertfore

u) Neu tralisalion wi lIL no Lag

L) Neulral isutiun wilh a + 100 OU

Tlw patienl has thercfore re1axed his aceollllllodalioll 1000 wlli lsl ma intamiddot ining full convergence whieh is nornllll fur his age

S inee Ihe iexclIel of aeeummodaliun doc not eonfurm lo geomrtrie oplies Ihe llJ110UIII of uccomllHJdulilgt11 in use fur cOlllfurtable rcudillg visiun au ul1e~ rlain

(Iuantity lf a patient i5 under tesl it is natural for him to make a greater efforl IhlUl hc will mukc in ordinary cireumslunces (Swulln)

Amplilurlc of uecummodalion lels are Useles5 in that the learer Ihe ubjecl i5 aflflroached Lo tlH~ eyes Ihe larger iexclhe visual angle becomes so Ihat the aecummudalion is not used at all and if used only partially The cards nearness llables a persoll to receie a larger and morc magnified image of the objlCt Taylo r )

AII iexclhesc fuclon render Ihe use of suLjccLie tesIs upon thl omplitudc uncerluin unle~ the true value by objeetivc means 15 first ascerlained

39

MITlI UR l SAnU

Umlouhlc(lly lhe ohj -cli e lag is Ihe Hgtu1t of Ihe eyes nol foeussing accuralcl) Of Hlel l) un Ihe In rgll lul ~omcw l lt rc hdlind il Only ir lit lurge is ndv81leed lo 2a cm in fron l of 11 plI it lI ts C CS is Ilculrali$ntio ll al 111 Iminl f hscrmiddot al ioll prod ucltL

It is prohnblc Iherd o re Illal ill enrrying out D lIomie Icli lluscopy lile uelual Negali e Hda li e ACCOllllllodalion is lul is mCI urc(L

Nlgalie HcIllie AeeollllllOdalioll al

30 ears + 025 lo -- 150 al mux imum

30 lu 35 )ca rs + 100 lu + 125 01 llIuximulll

35 lo 40 )ea rs + 100 al maxilllulll

40 lo 45 ) a rs + 075 al lllaXimUIIl

As Negalic lelali e Aiexcleo lllll1od ulioll il Ihe abili ly uf Ihe eyes lo rllax hile eOI1ergellee rcmains undlangmiddotd il is scn Ihal Ihe lable of NIgalie Il elnlie ACcollllllodalioll approx illllllls vny doscly lo l ile lublc of uhjeclic lags It i howc r un wise lo n late olle lable try dosel) lo 111( olh er for il 111111 he remo ber tlt Ihat mcu mlllodation is adeIUalc when Ihe positi vc alld Ilcgati-c ra ns a rc ill normal ral io 1f Ihe posili e nlll se is 110rrmll Ih l bull lHgalie rangc will also he no rma l

Tlle Correeion o Prcsbyopia

For Ihe correelion of PresL yofJill Ihe wit ll m()cment i3 notcd Ir il i5 fn irl ) lllarkc1 a subst ancial binocular addi tion is Irie(l eg around + 2000 sphere Ir Ihis neulralis s musl uf Ihc w itll mUJlell l u fur lher udditiun uf middotplu in hal f di oJller stcJls iiexcl maflC unlil a d finile rfI r~e 1l10Vell1enl lakfs place T hi 111 (1) be uLtain1 will a +250 A rctufIL 1 + 225 ll lln results in th e 1Il0velllcul bci ng neilhrr wi lh Ilor against This is Ihe Dyna mic Neul ra l By know ing Ihe pal icn l

uge w]iexcl ith is gicll as 55 ano substracling Ihe Obj rctive Lag + 050 Ih e TesUIt is + li5 lhis is tbe rcad in g nJlition whiel ~hould L t ~ gieu Sub jedic dweki ng can Iw madc wilh one of Ihe melhods described

1 Al la rgeT addil iou tllllll + 200 indieates that dtheT tl lt palilll l is undrmiddotcomiddot rrecled fo r d islanee or Ihc eause may be pathoJogical

2 When 1111 refl Clees arc ulleq ual it ma be ltIue lomiddot

u) Patholugical JlroccsC~ in unc Iye

40

C II N I C~I IUTIN OSCOlY

1 I m lrol~ r co rreclion 111 une o r ul11lr Ihe ees for dislance

e) Unequa convergcnce uf Ihe eps on Ihe la rgeL

In tlw case of b ) if plus is addcd o r suhlrueled unlil Ihe Ing cfjuuls Illt nOTrlHll for Ihe Iuti t nts age il is iexclJossiexclhle tu nliexcldecl reversioll lo Ihe ubj ccts di~ t llll cC

lest TI1l lmiddotxa lll in er will kil O quite 1 11 Ihul Ihe Uynumic finJing~ wil1 he e rified by cxpcricncc In euSts uf e) Slr3]iexclsHluS Dynallli c Il elinoscopy is almost 1mmiddot pussiJh un less Ihe qes a r more Of lccs ~ tru ighl

Exccsuacutev COl iexclergel cl

Ah r lile full currtCliull hus bcn g ll cn for Iislance and Illllscle halanccs 51101 a cUtllilion o f Esopho ria fo r dislancc ami l1(a r a slale of txccssi e cunv rglt llc Clt i~ t s Ths is um ull y confi lltd 111 )uung pcople but quite fretluenlly il is found ur lo l ile age o f 45 a nd Inler

The pali l1I1 i ~ iexcl[ in clt 1 lu n ucl lile illulllillaled cllnrl on Ihc rCl inoCope slarmiddot li ng with Ihe lurge lellers J)u ring Ih is pcriod iexcliexcl (Iuick (Jasll frmll rlght lo Idl usuall y diFclosiexcls quil c u sU]lt lull l iul lag Plus is lIddcl lO rcvlrsu ulIIl 11lt 1I suLmiddot Iflldcll ulllil II tulrnl is rcuclle(I Frolll Ihis is lahlI thl lag fM 1111 rI ~pcc l ivc aiexclc ulld IIkll is Icfl i ~ udrle lo Ihc disla nce currCIiu ll E 1l ir Illi s diffcrellce i5 us mucll us + 050 1111 udt lil io ll wi ll c c nluull ) be accpled by Ihe pu licll l ul lhougll il is nol aeccJlc(1 ul iexcllit li me

Oynumk BCliuoscopy lliClosc Lalenl J-1 YPNIIl l rO i1l IIhieh oer~limula l tS

COI1ergcnCt Exctssit Cou( rgence howc r 5houlfl 1101 be llUusurcd wilJiexcl basemiddot ou l prisms becaus il sl imulalcs furll lt r eOI1crgtl1ct

S tminciexcl CQIVcr tlce

This occu rs on o(rmiddotusc of lile cp 01 fi nl Iwur wtHk A low h ~ pe ropic or Ill yopi c eoudililll iiexcl u~ ual fuI d isluJlce Lul exoiexclJhorin is releuled fur near Somiddot mllilllcs il is impussible lo gic un) posili co rrcct ioJl for d illIIlCC o r if un is Jlo~s i hJ il i1 ( 111 ) ~mu l l Somltinws Ixuphoriu is found for di iexcllnllce bul a l wa ) ~

cxo phorin o r II tar Th is IlI lu ns Ihnl Ihe pali en ts Iwur visioll eOIlIfgellce hu bfo kcn d-mn a lld Ihe ()c~ urcrcolting uguillsl IIu-ir bi llocu lur fun cli on Tlley Il uc probubl r pussed Ihrou gh Ihc slage of excessivc cOIlcrg nc U1](1 ure now ul 111( tiexcliexclge hm 1 11)11 i~ middotxletiexcl lingly uncoll1fort ablc fOf close wo rk

HUIing chcchd Ihe (Iislumc rfmiddotfr action ami IWlITil1g Ihe binocula r bala ncc ctl lldilio lls in lIIi nd Ihe pat ienl i di rcctcd lo look illllll((lialdy al Ihe smiexcliexcllesl ]iexcl t1er 011 Ihl illuminaled eha rl of Ihe ret ill oscolgte whilsl Ihe li ghl is flalw(1 (iexclu ickl y fm lll ri~hl lo Idl It is ullusual lo i lld un objcClilc lag s ud + 050 O U is addcd

4l

ANTIt UN L SAVI I L

and lile rctiuoscope fla sh~middotd agaill A sl ight against nlUvlmenl llIay be observcd Hesisla nce Ihen suddenl) g iCS way and a fu rl llcr wilh mOelllcnl observed Addingplus lIltldil iolls is con linucd unlil rew rsal poi nt is reuchcd and then reshyductmiddotd to obtain tlH D)num ic Neulral Thc lag is dlducled - usuall y + loo -IInd tllt rcmn indr addell In Ihe ct islllnce pre~ri lion lf no addilion is nl(lssar_ Ihen a pr ism uf 34 JaStmiddot in di idtmiddot(1 helwtmiddottmiddotn Ihe luwo c)es is given for neac USe

bull Slrlrlgt acco llIJlation

This cllnditiun i uulIlly prtscnl in COillhi nalion wit ll st ra inoo co nvergcnce Thcrt is genernll y esophoria for dislHlcc and exophoria for near The patienl is directcd lO rcnd Iht rll ill oSCop) chart com mcllcing wilb the large letters ami obS( cvalion acled upon wllen he slarl s lo rcad Ihe small fr lellfrs MosII ) Ihen is linle ur nu lug lo htgin with allll the procedure is as in the r(iaus case 01 strained cO III( r s(nC t~ An) aIlitional plus is inCOTloraled in Ihe dislance coshyrncliol

ACCOIIIOduliofl beal) iexcllre f10fllwl

lf the lag is lurgcr Ihun IIIC no rmal fo r IllC age (wi tl Ihe palient wcaring h is fu ll dislance corrcction ) thcre is usually Oflhophoria fOf d islanee bu l a Inrg txophori a for lIear -ver) much in exe(lt of Ihe phy~iol ogical cxophor ia - nnd often as hi gl as 8 ID This cOIUitiOIl u5uall) results from some (Ieb ilily or prospeemiddot ti vt ilhwss cg boils bad I(Clh upcration cUlHalcscence o r maternil y weak middot ness and lassil ude lt is a Paresis of Acco modation aud tllt~ pulieut is ftmiddotf(middotrred

JII ropia anel DyrwIIc RelinoscoJJ

So far Ihe applieatioll of Ihe Icchnique for near vision has hlcn (]all ltl ilh in cm( of hypermelropia Ilreshyopia concrgf llce fX CCSS cte 1I should be not-d

thal in alJ Illese errors accolllll1otlal ion ami eOllergencc are slrongly linkcd In man) cuscs o f luopia how(er these fu nction a re on l) loosdy li nked Same easts

bullo f Itl)opitl ftspond in evcry a y lo Ihe lechniquc of Dynnmic Hetinoscop) as with

other arnelropie eondi lions Unfo rtunatcly a g rcat mun) rn yop( do nol reopolld in lJis way al alJ Tlw lags a rl uualJ) higl1lr in mos hyperopic cMes giv ing Ih~c

illlpression thal Ihe lIlopia is less iexclhan it js unl il il is real ised Ih lll Ihe plum o

menon is Ihe resull of inndtqualc aeeolllllloda lion IacuteI st-ems Iherefore Ihal cae

case of m)ovia musl be rcgurdld as huving il awn tliolug)

42

CLlNICAL HTI NOSCOl ~

Conellsiol

For comfortab le readi ng corrections tl ere mus be 11 comfortllblc blllllllCC bclween Ihe Ncgul ie Hdll li c iexcl cco mmoda linn und the POSilivc RlllI li c Acmiddot COlll lllod atinn If 11lf pnshyo~ ic IIddil ion is calcul31cd by subj ectie means alolle here is 11]( possibilil y o f o cr-corro CliOIl becll u~ Ihc Ncpt ic Ilclalivc Accommiddot IIOlll1l ioll when taken ~uhjetively is Ihul iexclUlIoun of plus ~phere which can be IIdded wilhoul actua l hJ urring of Ihe rea(ling matlcr uscd for Ilre lest Thc eyes lIre 11 0 1 od ng tc ~I Ctl fo r Negatic Rt-lat ic Atcum lltodalioll oul lo fin() Ihe Ch

rrect IHlohopilmiddot uddi lion whiel can be worn will comforl If tllt rCllding ad middot Iilion is loo sl rong Ih Negal iiexcl Rclali e ACCO llllllodll lionmiddot Pos iti vlmiddot Rclalive Acmiddot cOrlllllodat ion oalllnCI i di turlwtl and rcstricl ion (l f range wilh eomfort ill cnsue

T he following chart diexclvised hy Colin B Fryer alJlI h3lt(1 on lIl ucs rcco rdcll by L Swoan iJl reprodllced 3 a referellce gu idiexcl nf Ihe man) phCI10llil II11 o lJscfed IV itl l ile Dylltu nic Reli lloscolc Basically Ihc chuTI -lIl1l1l1a riscs all Ihe avni lnhlc ill fMI1H1 tion concerl1 illg th l fou r ml ill condil iO l1s likely lo be iexcll1coun lered in 1111

presb)opie )ea rs

lIi(h ( tlyn ic) neulrlI (Ir fimlI VcTS~1 I (l intl afil es

Up 10 35 35 40 10 45 45 50 5055 160

H N + 1 50 +li5 +2l + 25 250 +215

DI lo 30 J O 35 35middot10 40 405 SO 55

N R A 1 50J) 1 25 1l I OOD 0150 0 51)1) 025 11

N n Tu be d ~ dll rhd hom 11 N - Itemaintle r ~ i c lI u near ltorrclmiddotl ioll

Piy illsllll i e i e t IINomlllQda tiQtI

( d u e 10 EXre~ i e collvulcmiddote) i1u ~dc ha l ~ te Disl 3nd lI ~ ur E Hi ~h Neuln l H i ~h Cnrreel i Add Iu n Ui ~ l lJ e ll ule~ Ltlenl Uypropill

I r i r eI[(OJsie IIIToIi ( U~ l o ~ e i vc CUIl rjlenre) (O erarl iva ted or rai ne)

MII ~ le b3lanre Disl t~jjo Ncur E~o E~ HiJlIt Neunl Lo remai ui JI 1 on onin~ one eye CrTml i Atld Ius 10 Uisl LI ~ nl 1I )Ie r O IJi ~

43

AATIIIlII L S L

A Oommoduli heln normal ExlJao~led o laTc ~ i 01 Arroao nlodulion ) Mu rl ll b~ lwnre lJi~ l Orlho E~o Ne iexcl-J i ~ h E~o Hi~ h Neurral IIi ~h II ll fe lo MmiddotoI imiddotpl Pr l middotr tonbull

~olO(y exmiddotlt~ie 111

Sbullbulluined of We k Cone d e lo Com-c lI el re I rri r ienmiddot )111 ~ rI bal r l)i ~ l Orl lr o E~o Ne~ Hih EllO H i~h Neubullbullal Lo o 1 O middotomiddot iI un e~ t ore1 ion

tI 1 iexcllo lo oIi51 H u aoldi l irm rruinI

11 111 39 ~9 divided bN een bolh ~middot e f O T len uo only 111 Orlbollr exrebullbull i ~e~

D)uQmit al(I dloctrome farpcL rdiIlOSCOiexclJy

A rectlll 1tvlu lr11ent ill the InllI1iq ul uf I Yl1l1mie retinosc0IY io Ihl CockerhulI1 MImiddottllOll n hieh Ihe fixutiul1 Isrg l co ns i ~l s of IIn IIlaiexclhmc nl lo 111C lum inouiexclo Tdinn8lupc making U ~l of tlle du odtn)ll1c filtres red II l1d grecn

Cockcrham clu ims Ihal tlllrt arc a numhr of adan laiexcles itlt Illis Iu omiddot probabJy passtmiddot1 Ihrou1oacute h tlw slngl uf o cssic OI1Vcrgcncc and arl lHiexclW al IIIt chronH fi xatiOI1 nllachnlrnl O(T Ihc ordinary iIIumillale1 largd

1 Colourl(1 ta rglls cneoulugc tllt IUlitnt to mainlain fi xaliun lu a grcalcr dcg rec 1111H1 11lt bl1Ck nnl hite

2 The lrogrCS l I ZC IIlId chllractcr o f the ohj (cls IWTm il eoarsc and finc fixa liol1

t TllI c al11l111r enrl nhlnin dUlwhrnme crJualil y al a precribed wo rking di _o lance

4 Since Ihe largd conist o f (liagrlIlls ralher Ilmll lelllmiddot s tlwc IS a Ul1icrsal appl ieation

Wilh a erilical dcl l rmil1111ion o f g nc ll dumilHlI1cc a the nlinoseupe iexcls mOl-d a fracliOIl neanr lo 1111 pa l ien l 111(1 r(1 dominanc E 1H1l Ihe inslrumenl is laken 1 si mila r distance a a y lile flSU]iexcl Iacutelt cunfi n lltd

Sincc thE rcflp is l1lched during the final nHlnOIUVrc il follow Ihal ilh tllc prcsloupic comlitiulI al kn1 a fiTlII I r 1111UlIrC uf cOlllrol is adl(middot(1 lo 1111 reading ur do~e o rk addil ion

Cock(fham stales Illal ith Ihe cylinrllr ax l [l11d 10 1 ( lTdull y chefke1 and Ihe ~phcricnl lIlo(lificali un cOlltrolled lhruughout itlr thc duuchrnmc dlIalllic lurgmiddot1 1111 practi timwr is in 11 pn il ion In prcscr ihe fnr fl l1 ) pTlshyoopic co rrccli on

44

Cllr-I CAL H1I Nn COI Y

I ilh grealcr eerla inly o IIICl a purd) UhjtClie lest IIl0nt 15 onl y l S nccurutc as IIIt pa l iIII confirmnti on 1011 1 a llo w 11 callnot be a rgucd he says thal IllIl

dY ll umic Icst is onlr all ohject i 1l11lhocl of nwagt uring Ihe ntgll li c rebli t ticmiddot eo rumodat ioll fOT Ihe duochronw is ac tillg as u conlrol factur a l all lI tages of Ihe

test

In IIIcnlionin g Ihe abmc Codcrharll mr lhod une his ol inlUlI Ihis is lo bring

D)na mic Rtgtl inuscupy lo i l ~ full co nclusioll ~tld is no nn xprcssio ll of fLSUIt iexcl

obta irltd hy myC1f I r~o na ll y ti u lo lack o f (xpelicncc wi lh d uocJnolllc (lpIPmic l a rgt I ~

CONCLllS ION

Agt il will be fuU y appreciatld Ihe wriUen e xpla nali olJ IlIkes considcrahl) IOllgcr

lo rltSCribc Iha n Ihe practical applical iun of lJ igt rclulicl y si mple roulil1 t TIIt In lcl ilior1rr- a hi lil ) with the rt inoscopc ir rpectit of wlrlll IJW i ~ prcfc rnmiddotd

is 1 11 objcdie I1 l1 tho(1 of Ttfraction wcll WlJrtl l hCClIllIillg skillcd in

The iexclinU spenl in decloping litis ~ ki ll heing JIIOn Ihan cOl1lptnsn l~ d for h ) lil e f( middotsult olJluiunl

IIJ J C I I ) ~ 5r P O no1 1I

REnRENciexclS

lIH KA Y FEHG USON R ~ i o tu l ) L undun Tmiddothni r 1 Mono~ ra l h NQ 5 BEB ENS Im1 Z UCKI RMA N jalm iexcl Eumnaiexcliun ur 110 E)middot ~ WELCH ALI YN IAI III LI1 Slrn k IIjlinomiddotul Y J PASCAL L Mud n linUt0 IY L SWANN puIlel KEEIEII Pa1l lhlel S TAYLO II lJynu mit Kcrinu8middotuPY and lIinuulur ncl l cx ~

1 S VELL An Inlrudurlion lo lJynamir Heil nus middot p) Vul 2 N9 2 (S A Rdnclioni lr I J un 1951

D COCK~ II I1 M Dynamjmiddot Slrea t Reiexcl n05Ur jlh duur hrunr e rita l ion lar~c l ~ Olll i cIn 1 5 ~ CXXVI II 58

45

CLlNICAI IHTlNOSCOIY

From Ihc age of 45 years and onward~ Ihrough Ihe presbyopie ycars no more Ihall + 050 is delluctcd (or Ihe Obj ect ivc Lag Larger Oynamie Neulrals Iban + 050 are eOllsidc red (IS binocu la r relld ing lldditions if close work for long periods is lo ~ leeum pli she1 wilhoul diSClllllforL For cxam plc a palient of 50 hlls 11

Oynamic Neutral of + 175 IlIen sublracting the lag of + 050 +125 is obtainc(l wllieh is Ihe readillg addition OU

Various author ities account for Ih Lag in Ilifferent wa)s It is howevcr gtneralJy aeecplcd that mosl Jlcople rarel ) exerl their full accommodatioll for rhe working (listancc At 3P cm~ Iheir aeeomodatioll is nearer 250 than the full 3D Their accommodalion may be suid lo be loo~t The) do nol reall y look at an obj lcl Sil muell as glance at il il being unneeessary lo focus exaclly ror lvery visual lask especiall y if the prinl is nol loo small Whcrc lhc palienl is oung ( up lo 10 and Il as becn Iraincd lo USl his eyes for f ine work Ihe Dynamic Neulral appcars alrea(l y lo ex ist ic the n is a slighl ki ckmiddotbaek of Ihe shadoll The placing of a billocular additiull of +050 bdon~ Ihe ps ami repea tin g the r ight lo left flash of lh e rClinoscope will probabl) reveal a definile wilh mocmellL With ( 1 + 125 additiun there lluy llUW appcar lo be a (Icfilli le reverse movemenL

Using a + 100 addition ne ulral llialion il probabl) resull What appcared al firsl lo be lleutrali~ld lOW sut isfies u Lag o[ +100 whieh is no rmal for Ihul age anJ Ihe palien t shou ld havc t1ll1llttropia for (Iistanee lIith or wilhou l eomiddot rrect ion There is TILertfore

u) Neu tralisalion wi lIL no Lag

L) Neulral isutiun wilh a + 100 OU

Tlw patienl has thercfore re1axed his aceollllllodalioll 1000 wlli lsl ma intamiddot ining full convergence whieh is nornllll fur his age

S inee Ihe iexclIel of aeeummodaliun doc not eonfurm lo geomrtrie oplies Ihe llJ110UIII of uccomllHJdulilgt11 in use fur cOlllfurtable rcudillg visiun au ul1e~ rlain

(Iuantity lf a patient i5 under tesl it is natural for him to make a greater efforl IhlUl hc will mukc in ordinary cireumslunces (Swulln)

Amplilurlc of uecummodalion lels are Useles5 in that the learer Ihe ubjecl i5 aflflroached Lo tlH~ eyes Ihe larger iexclhe visual angle becomes so Ihat the aecummudalion is not used at all and if used only partially The cards nearness llables a persoll to receie a larger and morc magnified image of the objlCt Taylo r )

AII iexclhesc fuclon render Ihe use of suLjccLie tesIs upon thl omplitudc uncerluin unle~ the true value by objeetivc means 15 first ascerlained

39

MITlI UR l SAnU

Umlouhlc(lly lhe ohj -cli e lag is Ihe Hgtu1t of Ihe eyes nol foeussing accuralcl) Of Hlel l) un Ihe In rgll lul ~omcw l lt rc hdlind il Only ir lit lurge is ndv81leed lo 2a cm in fron l of 11 plI it lI ts C CS is Ilculrali$ntio ll al 111 Iminl f hscrmiddot al ioll prod ucltL

It is prohnblc Iherd o re Illal ill enrrying out D lIomie Icli lluscopy lile uelual Negali e Hda li e ACCOllllllodalion is lul is mCI urc(L

Nlgalie HcIllie AeeollllllOdalioll al

30 ears + 025 lo -- 150 al mux imum

30 lu 35 )ca rs + 100 lu + 125 01 llIuximulll

35 lo 40 )ea rs + 100 al maxilllulll

40 lo 45 ) a rs + 075 al lllaXimUIIl

As Negalic lelali e Aiexcleo lllll1od ulioll il Ihe abili ly uf Ihe eyes lo rllax hile eOI1ergellee rcmains undlangmiddotd il is scn Ihal Ihe lable of NIgalie Il elnlie ACcollllllodalioll approx illllllls vny doscly lo l ile lublc of uhjeclic lags It i howc r un wise lo n late olle lable try dosel) lo 111( olh er for il 111111 he remo ber tlt Ihat mcu mlllodation is adeIUalc when Ihe positi vc alld Ilcgati-c ra ns a rc ill normal ral io 1f Ihe posili e nlll se is 110rrmll Ih l bull lHgalie rangc will also he no rma l

Tlle Correeion o Prcsbyopia

For Ihe correelion of PresL yofJill Ihe wit ll m()cment i3 notcd Ir il i5 fn irl ) lllarkc1 a subst ancial binocular addi tion is Irie(l eg around + 2000 sphere Ir Ihis neulralis s musl uf Ihc w itll mUJlell l u fur lher udditiun uf middotplu in hal f di oJller stcJls iiexcl maflC unlil a d finile rfI r~e 1l10Vell1enl lakfs place T hi 111 (1) be uLtain1 will a +250 A rctufIL 1 + 225 ll lln results in th e 1Il0velllcul bci ng neilhrr wi lh Ilor against This is Ihe Dyna mic Neul ra l By know ing Ihe pal icn l

uge w]iexcl ith is gicll as 55 ano substracling Ihe Obj rctive Lag + 050 Ih e TesUIt is + li5 lhis is tbe rcad in g nJlition whiel ~hould L t ~ gieu Sub jedic dweki ng can Iw madc wilh one of Ihe melhods described

1 Al la rgeT addil iou tllllll + 200 indieates that dtheT tl lt palilll l is undrmiddotcomiddot rrecled fo r d islanee or Ihc eause may be pathoJogical

2 When 1111 refl Clees arc ulleq ual it ma be ltIue lomiddot

u) Patholugical JlroccsC~ in unc Iye

40

C II N I C~I IUTIN OSCOlY

1 I m lrol~ r co rreclion 111 une o r ul11lr Ihe ees for dislance

e) Unequa convergcnce uf Ihe eps on Ihe la rgeL

In tlw case of b ) if plus is addcd o r suhlrueled unlil Ihe Ing cfjuuls Illt nOTrlHll for Ihe Iuti t nts age il is iexclJossiexclhle tu nliexcldecl reversioll lo Ihe ubj ccts di~ t llll cC

lest TI1l lmiddotxa lll in er will kil O quite 1 11 Ihul Ihe Uynumic finJing~ wil1 he e rified by cxpcricncc In euSts uf e) Slr3]iexclsHluS Dynallli c Il elinoscopy is almost 1mmiddot pussiJh un less Ihe qes a r more Of lccs ~ tru ighl

Exccsuacutev COl iexclergel cl

Ah r lile full currtCliull hus bcn g ll cn for Iislance and Illllscle halanccs 51101 a cUtllilion o f Esopho ria fo r dislancc ami l1(a r a slale of txccssi e cunv rglt llc Clt i~ t s Ths is um ull y confi lltd 111 )uung pcople but quite fretluenlly il is found ur lo l ile age o f 45 a nd Inler

The pali l1I1 i ~ iexcl[ in clt 1 lu n ucl lile illulllillaled cllnrl on Ihc rCl inoCope slarmiddot li ng with Ihe lurge lellers J)u ring Ih is pcriod iexcliexcl (Iuick (Jasll frmll rlght lo Idl usuall y diFclosiexcls quil c u sU]lt lull l iul lag Plus is lIddcl lO rcvlrsu ulIIl 11lt 1I suLmiddot Iflldcll ulllil II tulrnl is rcuclle(I Frolll Ihis is lahlI thl lag fM 1111 rI ~pcc l ivc aiexclc ulld IIkll is Icfl i ~ udrle lo Ihc disla nce currCIiu ll E 1l ir Illi s diffcrellce i5 us mucll us + 050 1111 udt lil io ll wi ll c c nluull ) be accpled by Ihe pu licll l ul lhougll il is nol aeccJlc(1 ul iexcllit li me

Oynumk BCliuoscopy lliClosc Lalenl J-1 YPNIIl l rO i1l IIhieh oer~limula l tS

COI1ergcnCt Exctssit Cou( rgence howc r 5houlfl 1101 be llUusurcd wilJiexcl basemiddot ou l prisms becaus il sl imulalcs furll lt r eOI1crgtl1ct

S tminciexcl CQIVcr tlce

This occu rs on o(rmiddotusc of lile cp 01 fi nl Iwur wtHk A low h ~ pe ropic or Ill yopi c eoudililll iiexcl u~ ual fuI d isluJlce Lul exoiexclJhorin is releuled fur near Somiddot mllilllcs il is impussible lo gic un) posili co rrcct ioJl for d illIIlCC o r if un is Jlo~s i hJ il i1 ( 111 ) ~mu l l Somltinws Ixuphoriu is found for di iexcllnllce bul a l wa ) ~

cxo phorin o r II tar Th is IlI lu ns Ihnl Ihe pali en ts Iwur visioll eOIlIfgellce hu bfo kcn d-mn a lld Ihe ()c~ urcrcolting uguillsl IIu-ir bi llocu lur fun cli on Tlley Il uc probubl r pussed Ihrou gh Ihc slage of excessivc cOIlcrg nc U1](1 ure now ul 111( tiexcliexclge hm 1 11)11 i~ middotxletiexcl lingly uncoll1fort ablc fOf close wo rk

HUIing chcchd Ihe (Iislumc rfmiddotfr action ami IWlITil1g Ihe binocula r bala ncc ctl lldilio lls in lIIi nd Ihe pat ienl i di rcctcd lo look illllll((lialdy al Ihe smiexcliexcllesl ]iexcl t1er 011 Ihl illuminaled eha rl of Ihe ret ill oscolgte whilsl Ihe li ghl is flalw(1 (iexclu ickl y fm lll ri~hl lo Idl It is ullusual lo i lld un objcClilc lag s ud + 050 O U is addcd

4l

ANTIt UN L SAVI I L

and lile rctiuoscope fla sh~middotd agaill A sl ight against nlUvlmenl llIay be observcd Hesisla nce Ihen suddenl) g iCS way and a fu rl llcr wilh mOelllcnl observed Addingplus lIltldil iolls is con linucd unlil rew rsal poi nt is reuchcd and then reshyductmiddotd to obtain tlH D)num ic Neulral Thc lag is dlducled - usuall y + loo -IInd tllt rcmn indr addell In Ihe ct islllnce pre~ri lion lf no addilion is nl(lssar_ Ihen a pr ism uf 34 JaStmiddot in di idtmiddot(1 helwtmiddottmiddotn Ihe luwo c)es is given for neac USe

bull Slrlrlgt acco llIJlation

This cllnditiun i uulIlly prtscnl in COillhi nalion wit ll st ra inoo co nvergcnce Thcrt is genernll y esophoria for dislHlcc and exophoria for near The patienl is directcd lO rcnd Iht rll ill oSCop) chart com mcllcing wilb the large letters ami obS( cvalion acled upon wllen he slarl s lo rcad Ihe small fr lellfrs MosII ) Ihen is linle ur nu lug lo htgin with allll the procedure is as in the r(iaus case 01 strained cO III( r s(nC t~ An) aIlitional plus is inCOTloraled in Ihe dislance coshyrncliol

ACCOIIIOduliofl beal) iexcllre f10fllwl

lf the lag is lurgcr Ihun IIIC no rmal fo r IllC age (wi tl Ihe palient wcaring h is fu ll dislance corrcction ) thcre is usually Oflhophoria fOf d islanee bu l a Inrg txophori a for lIear -ver) much in exe(lt of Ihe phy~iol ogical cxophor ia - nnd often as hi gl as 8 ID This cOIUitiOIl u5uall) results from some (Ieb ilily or prospeemiddot ti vt ilhwss cg boils bad I(Clh upcration cUlHalcscence o r maternil y weak middot ness and lassil ude lt is a Paresis of Acco modation aud tllt~ pulieut is ftmiddotf(middotrred

JII ropia anel DyrwIIc RelinoscoJJ

So far Ihe applieatioll of Ihe Icchnique for near vision has hlcn (]all ltl ilh in cm( of hypermelropia Ilreshyopia concrgf llce fX CCSS cte 1I should be not-d

thal in alJ Illese errors accolllll1otlal ion ami eOllergencc are slrongly linkcd In man) cuscs o f luopia how(er these fu nction a re on l) loosdy li nked Same easts

bullo f Itl)opitl ftspond in evcry a y lo Ihe lechniquc of Dynnmic Hetinoscop) as with

other arnelropie eondi lions Unfo rtunatcly a g rcat mun) rn yop( do nol reopolld in lJis way al alJ Tlw lags a rl uualJ) higl1lr in mos hyperopic cMes giv ing Ih~c

illlpression thal Ihe lIlopia is less iexclhan it js unl il il is real ised Ih lll Ihe plum o

menon is Ihe resull of inndtqualc aeeolllllloda lion IacuteI st-ems Iherefore Ihal cae

case of m)ovia musl be rcgurdld as huving il awn tliolug)

42

CLlNICAL HTI NOSCOl ~

Conellsiol

For comfortab le readi ng corrections tl ere mus be 11 comfortllblc blllllllCC bclween Ihe Ncgul ie Hdll li c iexcl cco mmoda linn und the POSilivc RlllI li c Acmiddot COlll lllod atinn If 11lf pnshyo~ ic IIddil ion is calcul31cd by subj ectie means alolle here is 11]( possibilil y o f o cr-corro CliOIl becll u~ Ihc Ncpt ic Ilclalivc Accommiddot IIOlll1l ioll when taken ~uhjetively is Ihul iexclUlIoun of plus ~phere which can be IIdded wilhoul actua l hJ urring of Ihe rea(ling matlcr uscd for Ilre lest Thc eyes lIre 11 0 1 od ng tc ~I Ctl fo r Negatic Rt-lat ic Atcum lltodalioll oul lo fin() Ihe Ch

rrect IHlohopilmiddot uddi lion whiel can be worn will comforl If tllt rCllding ad middot Iilion is loo sl rong Ih Negal iiexcl Rclali e ACCO llllllodll lionmiddot Pos iti vlmiddot Rclalive Acmiddot cOrlllllodat ion oalllnCI i di turlwtl and rcstricl ion (l f range wilh eomfort ill cnsue

T he following chart diexclvised hy Colin B Fryer alJlI h3lt(1 on lIl ucs rcco rdcll by L Swoan iJl reprodllced 3 a referellce gu idiexcl nf Ihe man) phCI10llil II11 o lJscfed IV itl l ile Dylltu nic Reli lloscolc Basically Ihc chuTI -lIl1l1l1a riscs all Ihe avni lnhlc ill fMI1H1 tion concerl1 illg th l fou r ml ill condil iO l1s likely lo be iexcll1coun lered in 1111

presb)opie )ea rs

lIi(h ( tlyn ic) neulrlI (Ir fimlI VcTS~1 I (l intl afil es

Up 10 35 35 40 10 45 45 50 5055 160

H N + 1 50 +li5 +2l + 25 250 +215

DI lo 30 J O 35 35middot10 40 405 SO 55

N R A 1 50J) 1 25 1l I OOD 0150 0 51)1) 025 11

N n Tu be d ~ dll rhd hom 11 N - Itemaintle r ~ i c lI u near ltorrclmiddotl ioll

Piy illsllll i e i e t IINomlllQda tiQtI

( d u e 10 EXre~ i e collvulcmiddote) i1u ~dc ha l ~ te Disl 3nd lI ~ ur E Hi ~h Neuln l H i ~h Cnrreel i Add Iu n Ui ~ l lJ e ll ule~ Ltlenl Uypropill

I r i r eI[(OJsie IIIToIi ( U~ l o ~ e i vc CUIl rjlenre) (O erarl iva ted or rai ne)

MII ~ le b3lanre Disl t~jjo Ncur E~o E~ HiJlIt Neunl Lo remai ui JI 1 on onin~ one eye CrTml i Atld Ius 10 Uisl LI ~ nl 1I )Ie r O IJi ~

43

AATIIIlII L S L

A Oommoduli heln normal ExlJao~led o laTc ~ i 01 Arroao nlodulion ) Mu rl ll b~ lwnre lJi~ l Orlho E~o Ne iexcl-J i ~ h E~o Hi~ h Neurral IIi ~h II ll fe lo MmiddotoI imiddotpl Pr l middotr tonbull

~olO(y exmiddotlt~ie 111

Sbullbulluined of We k Cone d e lo Com-c lI el re I rri r ienmiddot )111 ~ rI bal r l)i ~ l Orl lr o E~o Ne~ Hih EllO H i~h Neubullbullal Lo o 1 O middotomiddot iI un e~ t ore1 ion

tI 1 iexcllo lo oIi51 H u aoldi l irm rruinI

11 111 39 ~9 divided bN een bolh ~middot e f O T len uo only 111 Orlbollr exrebullbull i ~e~

D)uQmit al(I dloctrome farpcL rdiIlOSCOiexclJy

A rectlll 1tvlu lr11ent ill the InllI1iq ul uf I Yl1l1mie retinosc0IY io Ihl CockerhulI1 MImiddottllOll n hieh Ihe fixutiul1 Isrg l co ns i ~l s of IIn IIlaiexclhmc nl lo 111C lum inouiexclo Tdinn8lupc making U ~l of tlle du odtn)ll1c filtres red II l1d grecn

Cockcrham clu ims Ihal tlllrt arc a numhr of adan laiexcles itlt Illis Iu omiddot probabJy passtmiddot1 Ihrou1oacute h tlw slngl uf o cssic OI1Vcrgcncc and arl lHiexclW al IIIt chronH fi xatiOI1 nllachnlrnl O(T Ihc ordinary iIIumillale1 largd

1 Colourl(1 ta rglls cneoulugc tllt IUlitnt to mainlain fi xaliun lu a grcalcr dcg rec 1111H1 11lt bl1Ck nnl hite

2 The lrogrCS l I ZC IIlId chllractcr o f the ohj (cls IWTm il eoarsc and finc fixa liol1

t TllI c al11l111r enrl nhlnin dUlwhrnme crJualil y al a precribed wo rking di _o lance

4 Since Ihe largd conist o f (liagrlIlls ralher Ilmll lelllmiddot s tlwc IS a Ul1icrsal appl ieation

Wilh a erilical dcl l rmil1111ion o f g nc ll dumilHlI1cc a the nlinoseupe iexcls mOl-d a fracliOIl neanr lo 1111 pa l ien l 111(1 r(1 dominanc E 1H1l Ihe inslrumenl is laken 1 si mila r distance a a y lile flSU]iexcl Iacutelt cunfi n lltd

Sincc thE rcflp is l1lched during the final nHlnOIUVrc il follow Ihal ilh tllc prcsloupic comlitiulI al kn1 a fiTlII I r 1111UlIrC uf cOlllrol is adl(middot(1 lo 1111 reading ur do~e o rk addil ion

Cock(fham stales Illal ith Ihe cylinrllr ax l [l11d 10 1 ( lTdull y chefke1 and Ihe ~phcricnl lIlo(lificali un cOlltrolled lhruughout itlr thc duuchrnmc dlIalllic lurgmiddot1 1111 practi timwr is in 11 pn il ion In prcscr ihe fnr fl l1 ) pTlshyoopic co rrccli on

44

Cllr-I CAL H1I Nn COI Y

I ilh grealcr eerla inly o IIICl a purd) UhjtClie lest IIl0nt 15 onl y l S nccurutc as IIIt pa l iIII confirmnti on 1011 1 a llo w 11 callnot be a rgucd he says thal IllIl

dY ll umic Icst is onlr all ohject i 1l11lhocl of nwagt uring Ihe ntgll li c rebli t ticmiddot eo rumodat ioll fOT Ihe duochronw is ac tillg as u conlrol factur a l all lI tages of Ihe

test

In IIIcnlionin g Ihe abmc Codcrharll mr lhod une his ol inlUlI Ihis is lo bring

D)na mic Rtgtl inuscupy lo i l ~ full co nclusioll ~tld is no nn xprcssio ll of fLSUIt iexcl

obta irltd hy myC1f I r~o na ll y ti u lo lack o f (xpelicncc wi lh d uocJnolllc (lpIPmic l a rgt I ~

CONCLllS ION

Agt il will be fuU y appreciatld Ihe wriUen e xpla nali olJ IlIkes considcrahl) IOllgcr

lo rltSCribc Iha n Ihe practical applical iun of lJ igt rclulicl y si mple roulil1 t TIIt In lcl ilior1rr- a hi lil ) with the rt inoscopc ir rpectit of wlrlll IJW i ~ prcfc rnmiddotd

is 1 11 objcdie I1 l1 tho(1 of Ttfraction wcll WlJrtl l hCClIllIillg skillcd in

The iexclinU spenl in decloping litis ~ ki ll heing JIIOn Ihan cOl1lptnsn l~ d for h ) lil e f( middotsult olJluiunl

IIJ J C I I ) ~ 5r P O no1 1I

REnRENciexclS

lIH KA Y FEHG USON R ~ i o tu l ) L undun Tmiddothni r 1 Mono~ ra l h NQ 5 BEB ENS Im1 Z UCKI RMA N jalm iexcl Eumnaiexcliun ur 110 E)middot ~ WELCH ALI YN IAI III LI1 Slrn k IIjlinomiddotul Y J PASCAL L Mud n linUt0 IY L SWANN puIlel KEEIEII Pa1l lhlel S TAYLO II lJynu mit Kcrinu8middotuPY and lIinuulur ncl l cx ~

1 S VELL An Inlrudurlion lo lJynamir Heil nus middot p) Vul 2 N9 2 (S A Rdnclioni lr I J un 1951

D COCK~ II I1 M Dynamjmiddot Slrea t Reiexcl n05Ur jlh duur hrunr e rita l ion lar~c l ~ Olll i cIn 1 5 ~ CXXVI II 58

45

MITlI UR l SAnU

Umlouhlc(lly lhe ohj -cli e lag is Ihe Hgtu1t of Ihe eyes nol foeussing accuralcl) Of Hlel l) un Ihe In rgll lul ~omcw l lt rc hdlind il Only ir lit lurge is ndv81leed lo 2a cm in fron l of 11 plI it lI ts C CS is Ilculrali$ntio ll al 111 Iminl f hscrmiddot al ioll prod ucltL

It is prohnblc Iherd o re Illal ill enrrying out D lIomie Icli lluscopy lile uelual Negali e Hda li e ACCOllllllodalion is lul is mCI urc(L

Nlgalie HcIllie AeeollllllOdalioll al

30 ears + 025 lo -- 150 al mux imum

30 lu 35 )ca rs + 100 lu + 125 01 llIuximulll

35 lo 40 )ea rs + 100 al maxilllulll

40 lo 45 ) a rs + 075 al lllaXimUIIl

As Negalic lelali e Aiexcleo lllll1od ulioll il Ihe abili ly uf Ihe eyes lo rllax hile eOI1ergellee rcmains undlangmiddotd il is scn Ihal Ihe lable of NIgalie Il elnlie ACcollllllodalioll approx illllllls vny doscly lo l ile lublc of uhjeclic lags It i howc r un wise lo n late olle lable try dosel) lo 111( olh er for il 111111 he remo ber tlt Ihat mcu mlllodation is adeIUalc when Ihe positi vc alld Ilcgati-c ra ns a rc ill normal ral io 1f Ihe posili e nlll se is 110rrmll Ih l bull lHgalie rangc will also he no rma l

Tlle Correeion o Prcsbyopia

For Ihe correelion of PresL yofJill Ihe wit ll m()cment i3 notcd Ir il i5 fn irl ) lllarkc1 a subst ancial binocular addi tion is Irie(l eg around + 2000 sphere Ir Ihis neulralis s musl uf Ihc w itll mUJlell l u fur lher udditiun uf middotplu in hal f di oJller stcJls iiexcl maflC unlil a d finile rfI r~e 1l10Vell1enl lakfs place T hi 111 (1) be uLtain1 will a +250 A rctufIL 1 + 225 ll lln results in th e 1Il0velllcul bci ng neilhrr wi lh Ilor against This is Ihe Dyna mic Neul ra l By know ing Ihe pal icn l

uge w]iexcl ith is gicll as 55 ano substracling Ihe Obj rctive Lag + 050 Ih e TesUIt is + li5 lhis is tbe rcad in g nJlition whiel ~hould L t ~ gieu Sub jedic dweki ng can Iw madc wilh one of Ihe melhods described

1 Al la rgeT addil iou tllllll + 200 indieates that dtheT tl lt palilll l is undrmiddotcomiddot rrecled fo r d islanee or Ihc eause may be pathoJogical

2 When 1111 refl Clees arc ulleq ual it ma be ltIue lomiddot

u) Patholugical JlroccsC~ in unc Iye

40

C II N I C~I IUTIN OSCOlY

1 I m lrol~ r co rreclion 111 une o r ul11lr Ihe ees for dislance

e) Unequa convergcnce uf Ihe eps on Ihe la rgeL

In tlw case of b ) if plus is addcd o r suhlrueled unlil Ihe Ing cfjuuls Illt nOTrlHll for Ihe Iuti t nts age il is iexclJossiexclhle tu nliexcldecl reversioll lo Ihe ubj ccts di~ t llll cC

lest TI1l lmiddotxa lll in er will kil O quite 1 11 Ihul Ihe Uynumic finJing~ wil1 he e rified by cxpcricncc In euSts uf e) Slr3]iexclsHluS Dynallli c Il elinoscopy is almost 1mmiddot pussiJh un less Ihe qes a r more Of lccs ~ tru ighl

Exccsuacutev COl iexclergel cl

Ah r lile full currtCliull hus bcn g ll cn for Iislance and Illllscle halanccs 51101 a cUtllilion o f Esopho ria fo r dislancc ami l1(a r a slale of txccssi e cunv rglt llc Clt i~ t s Ths is um ull y confi lltd 111 )uung pcople but quite fretluenlly il is found ur lo l ile age o f 45 a nd Inler

The pali l1I1 i ~ iexcl[ in clt 1 lu n ucl lile illulllillaled cllnrl on Ihc rCl inoCope slarmiddot li ng with Ihe lurge lellers J)u ring Ih is pcriod iexcliexcl (Iuick (Jasll frmll rlght lo Idl usuall y diFclosiexcls quil c u sU]lt lull l iul lag Plus is lIddcl lO rcvlrsu ulIIl 11lt 1I suLmiddot Iflldcll ulllil II tulrnl is rcuclle(I Frolll Ihis is lahlI thl lag fM 1111 rI ~pcc l ivc aiexclc ulld IIkll is Icfl i ~ udrle lo Ihc disla nce currCIiu ll E 1l ir Illi s diffcrellce i5 us mucll us + 050 1111 udt lil io ll wi ll c c nluull ) be accpled by Ihe pu licll l ul lhougll il is nol aeccJlc(1 ul iexcllit li me

Oynumk BCliuoscopy lliClosc Lalenl J-1 YPNIIl l rO i1l IIhieh oer~limula l tS

COI1ergcnCt Exctssit Cou( rgence howc r 5houlfl 1101 be llUusurcd wilJiexcl basemiddot ou l prisms becaus il sl imulalcs furll lt r eOI1crgtl1ct

S tminciexcl CQIVcr tlce

This occu rs on o(rmiddotusc of lile cp 01 fi nl Iwur wtHk A low h ~ pe ropic or Ill yopi c eoudililll iiexcl u~ ual fuI d isluJlce Lul exoiexclJhorin is releuled fur near Somiddot mllilllcs il is impussible lo gic un) posili co rrcct ioJl for d illIIlCC o r if un is Jlo~s i hJ il i1 ( 111 ) ~mu l l Somltinws Ixuphoriu is found for di iexcllnllce bul a l wa ) ~

cxo phorin o r II tar Th is IlI lu ns Ihnl Ihe pali en ts Iwur visioll eOIlIfgellce hu bfo kcn d-mn a lld Ihe ()c~ urcrcolting uguillsl IIu-ir bi llocu lur fun cli on Tlley Il uc probubl r pussed Ihrou gh Ihc slage of excessivc cOIlcrg nc U1](1 ure now ul 111( tiexcliexclge hm 1 11)11 i~ middotxletiexcl lingly uncoll1fort ablc fOf close wo rk

HUIing chcchd Ihe (Iislumc rfmiddotfr action ami IWlITil1g Ihe binocula r bala ncc ctl lldilio lls in lIIi nd Ihe pat ienl i di rcctcd lo look illllll((lialdy al Ihe smiexcliexcllesl ]iexcl t1er 011 Ihl illuminaled eha rl of Ihe ret ill oscolgte whilsl Ihe li ghl is flalw(1 (iexclu ickl y fm lll ri~hl lo Idl It is ullusual lo i lld un objcClilc lag s ud + 050 O U is addcd

4l

ANTIt UN L SAVI I L

and lile rctiuoscope fla sh~middotd agaill A sl ight against nlUvlmenl llIay be observcd Hesisla nce Ihen suddenl) g iCS way and a fu rl llcr wilh mOelllcnl observed Addingplus lIltldil iolls is con linucd unlil rew rsal poi nt is reuchcd and then reshyductmiddotd to obtain tlH D)num ic Neulral Thc lag is dlducled - usuall y + loo -IInd tllt rcmn indr addell In Ihe ct islllnce pre~ri lion lf no addilion is nl(lssar_ Ihen a pr ism uf 34 JaStmiddot in di idtmiddot(1 helwtmiddottmiddotn Ihe luwo c)es is given for neac USe

bull Slrlrlgt acco llIJlation

This cllnditiun i uulIlly prtscnl in COillhi nalion wit ll st ra inoo co nvergcnce Thcrt is genernll y esophoria for dislHlcc and exophoria for near The patienl is directcd lO rcnd Iht rll ill oSCop) chart com mcllcing wilb the large letters ami obS( cvalion acled upon wllen he slarl s lo rcad Ihe small fr lellfrs MosII ) Ihen is linle ur nu lug lo htgin with allll the procedure is as in the r(iaus case 01 strained cO III( r s(nC t~ An) aIlitional plus is inCOTloraled in Ihe dislance coshyrncliol

ACCOIIIOduliofl beal) iexcllre f10fllwl

lf the lag is lurgcr Ihun IIIC no rmal fo r IllC age (wi tl Ihe palient wcaring h is fu ll dislance corrcction ) thcre is usually Oflhophoria fOf d islanee bu l a Inrg txophori a for lIear -ver) much in exe(lt of Ihe phy~iol ogical cxophor ia - nnd often as hi gl as 8 ID This cOIUitiOIl u5uall) results from some (Ieb ilily or prospeemiddot ti vt ilhwss cg boils bad I(Clh upcration cUlHalcscence o r maternil y weak middot ness and lassil ude lt is a Paresis of Acco modation aud tllt~ pulieut is ftmiddotf(middotrred

JII ropia anel DyrwIIc RelinoscoJJ

So far Ihe applieatioll of Ihe Icchnique for near vision has hlcn (]all ltl ilh in cm( of hypermelropia Ilreshyopia concrgf llce fX CCSS cte 1I should be not-d

thal in alJ Illese errors accolllll1otlal ion ami eOllergencc are slrongly linkcd In man) cuscs o f luopia how(er these fu nction a re on l) loosdy li nked Same easts

bullo f Itl)opitl ftspond in evcry a y lo Ihe lechniquc of Dynnmic Hetinoscop) as with

other arnelropie eondi lions Unfo rtunatcly a g rcat mun) rn yop( do nol reopolld in lJis way al alJ Tlw lags a rl uualJ) higl1lr in mos hyperopic cMes giv ing Ih~c

illlpression thal Ihe lIlopia is less iexclhan it js unl il il is real ised Ih lll Ihe plum o

menon is Ihe resull of inndtqualc aeeolllllloda lion IacuteI st-ems Iherefore Ihal cae

case of m)ovia musl be rcgurdld as huving il awn tliolug)

42

CLlNICAL HTI NOSCOl ~

Conellsiol

For comfortab le readi ng corrections tl ere mus be 11 comfortllblc blllllllCC bclween Ihe Ncgul ie Hdll li c iexcl cco mmoda linn und the POSilivc RlllI li c Acmiddot COlll lllod atinn If 11lf pnshyo~ ic IIddil ion is calcul31cd by subj ectie means alolle here is 11]( possibilil y o f o cr-corro CliOIl becll u~ Ihc Ncpt ic Ilclalivc Accommiddot IIOlll1l ioll when taken ~uhjetively is Ihul iexclUlIoun of plus ~phere which can be IIdded wilhoul actua l hJ urring of Ihe rea(ling matlcr uscd for Ilre lest Thc eyes lIre 11 0 1 od ng tc ~I Ctl fo r Negatic Rt-lat ic Atcum lltodalioll oul lo fin() Ihe Ch

rrect IHlohopilmiddot uddi lion whiel can be worn will comforl If tllt rCllding ad middot Iilion is loo sl rong Ih Negal iiexcl Rclali e ACCO llllllodll lionmiddot Pos iti vlmiddot Rclalive Acmiddot cOrlllllodat ion oalllnCI i di turlwtl and rcstricl ion (l f range wilh eomfort ill cnsue

T he following chart diexclvised hy Colin B Fryer alJlI h3lt(1 on lIl ucs rcco rdcll by L Swoan iJl reprodllced 3 a referellce gu idiexcl nf Ihe man) phCI10llil II11 o lJscfed IV itl l ile Dylltu nic Reli lloscolc Basically Ihc chuTI -lIl1l1l1a riscs all Ihe avni lnhlc ill fMI1H1 tion concerl1 illg th l fou r ml ill condil iO l1s likely lo be iexcll1coun lered in 1111

presb)opie )ea rs

lIi(h ( tlyn ic) neulrlI (Ir fimlI VcTS~1 I (l intl afil es

Up 10 35 35 40 10 45 45 50 5055 160

H N + 1 50 +li5 +2l + 25 250 +215

DI lo 30 J O 35 35middot10 40 405 SO 55

N R A 1 50J) 1 25 1l I OOD 0150 0 51)1) 025 11

N n Tu be d ~ dll rhd hom 11 N - Itemaintle r ~ i c lI u near ltorrclmiddotl ioll

Piy illsllll i e i e t IINomlllQda tiQtI

( d u e 10 EXre~ i e collvulcmiddote) i1u ~dc ha l ~ te Disl 3nd lI ~ ur E Hi ~h Neuln l H i ~h Cnrreel i Add Iu n Ui ~ l lJ e ll ule~ Ltlenl Uypropill

I r i r eI[(OJsie IIIToIi ( U~ l o ~ e i vc CUIl rjlenre) (O erarl iva ted or rai ne)

MII ~ le b3lanre Disl t~jjo Ncur E~o E~ HiJlIt Neunl Lo remai ui JI 1 on onin~ one eye CrTml i Atld Ius 10 Uisl LI ~ nl 1I )Ie r O IJi ~

43

AATIIIlII L S L

A Oommoduli heln normal ExlJao~led o laTc ~ i 01 Arroao nlodulion ) Mu rl ll b~ lwnre lJi~ l Orlho E~o Ne iexcl-J i ~ h E~o Hi~ h Neurral IIi ~h II ll fe lo MmiddotoI imiddotpl Pr l middotr tonbull

~olO(y exmiddotlt~ie 111

Sbullbulluined of We k Cone d e lo Com-c lI el re I rri r ienmiddot )111 ~ rI bal r l)i ~ l Orl lr o E~o Ne~ Hih EllO H i~h Neubullbullal Lo o 1 O middotomiddot iI un e~ t ore1 ion

tI 1 iexcllo lo oIi51 H u aoldi l irm rruinI

11 111 39 ~9 divided bN een bolh ~middot e f O T len uo only 111 Orlbollr exrebullbull i ~e~

D)uQmit al(I dloctrome farpcL rdiIlOSCOiexclJy

A rectlll 1tvlu lr11ent ill the InllI1iq ul uf I Yl1l1mie retinosc0IY io Ihl CockerhulI1 MImiddottllOll n hieh Ihe fixutiul1 Isrg l co ns i ~l s of IIn IIlaiexclhmc nl lo 111C lum inouiexclo Tdinn8lupc making U ~l of tlle du odtn)ll1c filtres red II l1d grecn

Cockcrham clu ims Ihal tlllrt arc a numhr of adan laiexcles itlt Illis Iu omiddot probabJy passtmiddot1 Ihrou1oacute h tlw slngl uf o cssic OI1Vcrgcncc and arl lHiexclW al IIIt chronH fi xatiOI1 nllachnlrnl O(T Ihc ordinary iIIumillale1 largd

1 Colourl(1 ta rglls cneoulugc tllt IUlitnt to mainlain fi xaliun lu a grcalcr dcg rec 1111H1 11lt bl1Ck nnl hite

2 The lrogrCS l I ZC IIlId chllractcr o f the ohj (cls IWTm il eoarsc and finc fixa liol1

t TllI c al11l111r enrl nhlnin dUlwhrnme crJualil y al a precribed wo rking di _o lance

4 Since Ihe largd conist o f (liagrlIlls ralher Ilmll lelllmiddot s tlwc IS a Ul1icrsal appl ieation

Wilh a erilical dcl l rmil1111ion o f g nc ll dumilHlI1cc a the nlinoseupe iexcls mOl-d a fracliOIl neanr lo 1111 pa l ien l 111(1 r(1 dominanc E 1H1l Ihe inslrumenl is laken 1 si mila r distance a a y lile flSU]iexcl Iacutelt cunfi n lltd

Sincc thE rcflp is l1lched during the final nHlnOIUVrc il follow Ihal ilh tllc prcsloupic comlitiulI al kn1 a fiTlII I r 1111UlIrC uf cOlllrol is adl(middot(1 lo 1111 reading ur do~e o rk addil ion

Cock(fham stales Illal ith Ihe cylinrllr ax l [l11d 10 1 ( lTdull y chefke1 and Ihe ~phcricnl lIlo(lificali un cOlltrolled lhruughout itlr thc duuchrnmc dlIalllic lurgmiddot1 1111 practi timwr is in 11 pn il ion In prcscr ihe fnr fl l1 ) pTlshyoopic co rrccli on

44

Cllr-I CAL H1I Nn COI Y

I ilh grealcr eerla inly o IIICl a purd) UhjtClie lest IIl0nt 15 onl y l S nccurutc as IIIt pa l iIII confirmnti on 1011 1 a llo w 11 callnot be a rgucd he says thal IllIl

dY ll umic Icst is onlr all ohject i 1l11lhocl of nwagt uring Ihe ntgll li c rebli t ticmiddot eo rumodat ioll fOT Ihe duochronw is ac tillg as u conlrol factur a l all lI tages of Ihe

test

In IIIcnlionin g Ihe abmc Codcrharll mr lhod une his ol inlUlI Ihis is lo bring

D)na mic Rtgtl inuscupy lo i l ~ full co nclusioll ~tld is no nn xprcssio ll of fLSUIt iexcl

obta irltd hy myC1f I r~o na ll y ti u lo lack o f (xpelicncc wi lh d uocJnolllc (lpIPmic l a rgt I ~

CONCLllS ION

Agt il will be fuU y appreciatld Ihe wriUen e xpla nali olJ IlIkes considcrahl) IOllgcr

lo rltSCribc Iha n Ihe practical applical iun of lJ igt rclulicl y si mple roulil1 t TIIt In lcl ilior1rr- a hi lil ) with the rt inoscopc ir rpectit of wlrlll IJW i ~ prcfc rnmiddotd

is 1 11 objcdie I1 l1 tho(1 of Ttfraction wcll WlJrtl l hCClIllIillg skillcd in

The iexclinU spenl in decloping litis ~ ki ll heing JIIOn Ihan cOl1lptnsn l~ d for h ) lil e f( middotsult olJluiunl

IIJ J C I I ) ~ 5r P O no1 1I

REnRENciexclS

lIH KA Y FEHG USON R ~ i o tu l ) L undun Tmiddothni r 1 Mono~ ra l h NQ 5 BEB ENS Im1 Z UCKI RMA N jalm iexcl Eumnaiexcliun ur 110 E)middot ~ WELCH ALI YN IAI III LI1 Slrn k IIjlinomiddotul Y J PASCAL L Mud n linUt0 IY L SWANN puIlel KEEIEII Pa1l lhlel S TAYLO II lJynu mit Kcrinu8middotuPY and lIinuulur ncl l cx ~

1 S VELL An Inlrudurlion lo lJynamir Heil nus middot p) Vul 2 N9 2 (S A Rdnclioni lr I J un 1951

D COCK~ II I1 M Dynamjmiddot Slrea t Reiexcl n05Ur jlh duur hrunr e rita l ion lar~c l ~ Olll i cIn 1 5 ~ CXXVI II 58

45

C II N I C~I IUTIN OSCOlY

1 I m lrol~ r co rreclion 111 une o r ul11lr Ihe ees for dislance

e) Unequa convergcnce uf Ihe eps on Ihe la rgeL

In tlw case of b ) if plus is addcd o r suhlrueled unlil Ihe Ing cfjuuls Illt nOTrlHll for Ihe Iuti t nts age il is iexclJossiexclhle tu nliexcldecl reversioll lo Ihe ubj ccts di~ t llll cC

lest TI1l lmiddotxa lll in er will kil O quite 1 11 Ihul Ihe Uynumic finJing~ wil1 he e rified by cxpcricncc In euSts uf e) Slr3]iexclsHluS Dynallli c Il elinoscopy is almost 1mmiddot pussiJh un less Ihe qes a r more Of lccs ~ tru ighl

Exccsuacutev COl iexclergel cl

Ah r lile full currtCliull hus bcn g ll cn for Iislance and Illllscle halanccs 51101 a cUtllilion o f Esopho ria fo r dislancc ami l1(a r a slale of txccssi e cunv rglt llc Clt i~ t s Ths is um ull y confi lltd 111 )uung pcople but quite fretluenlly il is found ur lo l ile age o f 45 a nd Inler

The pali l1I1 i ~ iexcl[ in clt 1 lu n ucl lile illulllillaled cllnrl on Ihc rCl inoCope slarmiddot li ng with Ihe lurge lellers J)u ring Ih is pcriod iexcliexcl (Iuick (Jasll frmll rlght lo Idl usuall y diFclosiexcls quil c u sU]lt lull l iul lag Plus is lIddcl lO rcvlrsu ulIIl 11lt 1I suLmiddot Iflldcll ulllil II tulrnl is rcuclle(I Frolll Ihis is lahlI thl lag fM 1111 rI ~pcc l ivc aiexclc ulld IIkll is Icfl i ~ udrle lo Ihc disla nce currCIiu ll E 1l ir Illi s diffcrellce i5 us mucll us + 050 1111 udt lil io ll wi ll c c nluull ) be accpled by Ihe pu licll l ul lhougll il is nol aeccJlc(1 ul iexcllit li me

Oynumk BCliuoscopy lliClosc Lalenl J-1 YPNIIl l rO i1l IIhieh oer~limula l tS

COI1ergcnCt Exctssit Cou( rgence howc r 5houlfl 1101 be llUusurcd wilJiexcl basemiddot ou l prisms becaus il sl imulalcs furll lt r eOI1crgtl1ct

S tminciexcl CQIVcr tlce

This occu rs on o(rmiddotusc of lile cp 01 fi nl Iwur wtHk A low h ~ pe ropic or Ill yopi c eoudililll iiexcl u~ ual fuI d isluJlce Lul exoiexclJhorin is releuled fur near Somiddot mllilllcs il is impussible lo gic un) posili co rrcct ioJl for d illIIlCC o r if un is Jlo~s i hJ il i1 ( 111 ) ~mu l l Somltinws Ixuphoriu is found for di iexcllnllce bul a l wa ) ~

cxo phorin o r II tar Th is IlI lu ns Ihnl Ihe pali en ts Iwur visioll eOIlIfgellce hu bfo kcn d-mn a lld Ihe ()c~ urcrcolting uguillsl IIu-ir bi llocu lur fun cli on Tlley Il uc probubl r pussed Ihrou gh Ihc slage of excessivc cOIlcrg nc U1](1 ure now ul 111( tiexcliexclge hm 1 11)11 i~ middotxletiexcl lingly uncoll1fort ablc fOf close wo rk

HUIing chcchd Ihe (Iislumc rfmiddotfr action ami IWlITil1g Ihe binocula r bala ncc ctl lldilio lls in lIIi nd Ihe pat ienl i di rcctcd lo look illllll((lialdy al Ihe smiexcliexcllesl ]iexcl t1er 011 Ihl illuminaled eha rl of Ihe ret ill oscolgte whilsl Ihe li ghl is flalw(1 (iexclu ickl y fm lll ri~hl lo Idl It is ullusual lo i lld un objcClilc lag s ud + 050 O U is addcd

4l

ANTIt UN L SAVI I L

and lile rctiuoscope fla sh~middotd agaill A sl ight against nlUvlmenl llIay be observcd Hesisla nce Ihen suddenl) g iCS way and a fu rl llcr wilh mOelllcnl observed Addingplus lIltldil iolls is con linucd unlil rew rsal poi nt is reuchcd and then reshyductmiddotd to obtain tlH D)num ic Neulral Thc lag is dlducled - usuall y + loo -IInd tllt rcmn indr addell In Ihe ct islllnce pre~ri lion lf no addilion is nl(lssar_ Ihen a pr ism uf 34 JaStmiddot in di idtmiddot(1 helwtmiddottmiddotn Ihe luwo c)es is given for neac USe

bull Slrlrlgt acco llIJlation

This cllnditiun i uulIlly prtscnl in COillhi nalion wit ll st ra inoo co nvergcnce Thcrt is genernll y esophoria for dislHlcc and exophoria for near The patienl is directcd lO rcnd Iht rll ill oSCop) chart com mcllcing wilb the large letters ami obS( cvalion acled upon wllen he slarl s lo rcad Ihe small fr lellfrs MosII ) Ihen is linle ur nu lug lo htgin with allll the procedure is as in the r(iaus case 01 strained cO III( r s(nC t~ An) aIlitional plus is inCOTloraled in Ihe dislance coshyrncliol

ACCOIIIOduliofl beal) iexcllre f10fllwl

lf the lag is lurgcr Ihun IIIC no rmal fo r IllC age (wi tl Ihe palient wcaring h is fu ll dislance corrcction ) thcre is usually Oflhophoria fOf d islanee bu l a Inrg txophori a for lIear -ver) much in exe(lt of Ihe phy~iol ogical cxophor ia - nnd often as hi gl as 8 ID This cOIUitiOIl u5uall) results from some (Ieb ilily or prospeemiddot ti vt ilhwss cg boils bad I(Clh upcration cUlHalcscence o r maternil y weak middot ness and lassil ude lt is a Paresis of Acco modation aud tllt~ pulieut is ftmiddotf(middotrred

JII ropia anel DyrwIIc RelinoscoJJ

So far Ihe applieatioll of Ihe Icchnique for near vision has hlcn (]all ltl ilh in cm( of hypermelropia Ilreshyopia concrgf llce fX CCSS cte 1I should be not-d

thal in alJ Illese errors accolllll1otlal ion ami eOllergencc are slrongly linkcd In man) cuscs o f luopia how(er these fu nction a re on l) loosdy li nked Same easts

bullo f Itl)opitl ftspond in evcry a y lo Ihe lechniquc of Dynnmic Hetinoscop) as with

other arnelropie eondi lions Unfo rtunatcly a g rcat mun) rn yop( do nol reopolld in lJis way al alJ Tlw lags a rl uualJ) higl1lr in mos hyperopic cMes giv ing Ih~c

illlpression thal Ihe lIlopia is less iexclhan it js unl il il is real ised Ih lll Ihe plum o

menon is Ihe resull of inndtqualc aeeolllllloda lion IacuteI st-ems Iherefore Ihal cae

case of m)ovia musl be rcgurdld as huving il awn tliolug)

42

CLlNICAL HTI NOSCOl ~

Conellsiol

For comfortab le readi ng corrections tl ere mus be 11 comfortllblc blllllllCC bclween Ihe Ncgul ie Hdll li c iexcl cco mmoda linn und the POSilivc RlllI li c Acmiddot COlll lllod atinn If 11lf pnshyo~ ic IIddil ion is calcul31cd by subj ectie means alolle here is 11]( possibilil y o f o cr-corro CliOIl becll u~ Ihc Ncpt ic Ilclalivc Accommiddot IIOlll1l ioll when taken ~uhjetively is Ihul iexclUlIoun of plus ~phere which can be IIdded wilhoul actua l hJ urring of Ihe rea(ling matlcr uscd for Ilre lest Thc eyes lIre 11 0 1 od ng tc ~I Ctl fo r Negatic Rt-lat ic Atcum lltodalioll oul lo fin() Ihe Ch

rrect IHlohopilmiddot uddi lion whiel can be worn will comforl If tllt rCllding ad middot Iilion is loo sl rong Ih Negal iiexcl Rclali e ACCO llllllodll lionmiddot Pos iti vlmiddot Rclalive Acmiddot cOrlllllodat ion oalllnCI i di turlwtl and rcstricl ion (l f range wilh eomfort ill cnsue

T he following chart diexclvised hy Colin B Fryer alJlI h3lt(1 on lIl ucs rcco rdcll by L Swoan iJl reprodllced 3 a referellce gu idiexcl nf Ihe man) phCI10llil II11 o lJscfed IV itl l ile Dylltu nic Reli lloscolc Basically Ihc chuTI -lIl1l1l1a riscs all Ihe avni lnhlc ill fMI1H1 tion concerl1 illg th l fou r ml ill condil iO l1s likely lo be iexcll1coun lered in 1111

presb)opie )ea rs

lIi(h ( tlyn ic) neulrlI (Ir fimlI VcTS~1 I (l intl afil es

Up 10 35 35 40 10 45 45 50 5055 160

H N + 1 50 +li5 +2l + 25 250 +215

DI lo 30 J O 35 35middot10 40 405 SO 55

N R A 1 50J) 1 25 1l I OOD 0150 0 51)1) 025 11

N n Tu be d ~ dll rhd hom 11 N - Itemaintle r ~ i c lI u near ltorrclmiddotl ioll

Piy illsllll i e i e t IINomlllQda tiQtI

( d u e 10 EXre~ i e collvulcmiddote) i1u ~dc ha l ~ te Disl 3nd lI ~ ur E Hi ~h Neuln l H i ~h Cnrreel i Add Iu n Ui ~ l lJ e ll ule~ Ltlenl Uypropill

I r i r eI[(OJsie IIIToIi ( U~ l o ~ e i vc CUIl rjlenre) (O erarl iva ted or rai ne)

MII ~ le b3lanre Disl t~jjo Ncur E~o E~ HiJlIt Neunl Lo remai ui JI 1 on onin~ one eye CrTml i Atld Ius 10 Uisl LI ~ nl 1I )Ie r O IJi ~

43

AATIIIlII L S L

A Oommoduli heln normal ExlJao~led o laTc ~ i 01 Arroao nlodulion ) Mu rl ll b~ lwnre lJi~ l Orlho E~o Ne iexcl-J i ~ h E~o Hi~ h Neurral IIi ~h II ll fe lo MmiddotoI imiddotpl Pr l middotr tonbull

~olO(y exmiddotlt~ie 111

Sbullbulluined of We k Cone d e lo Com-c lI el re I rri r ienmiddot )111 ~ rI bal r l)i ~ l Orl lr o E~o Ne~ Hih EllO H i~h Neubullbullal Lo o 1 O middotomiddot iI un e~ t ore1 ion

tI 1 iexcllo lo oIi51 H u aoldi l irm rruinI

11 111 39 ~9 divided bN een bolh ~middot e f O T len uo only 111 Orlbollr exrebullbull i ~e~

D)uQmit al(I dloctrome farpcL rdiIlOSCOiexclJy

A rectlll 1tvlu lr11ent ill the InllI1iq ul uf I Yl1l1mie retinosc0IY io Ihl CockerhulI1 MImiddottllOll n hieh Ihe fixutiul1 Isrg l co ns i ~l s of IIn IIlaiexclhmc nl lo 111C lum inouiexclo Tdinn8lupc making U ~l of tlle du odtn)ll1c filtres red II l1d grecn

Cockcrham clu ims Ihal tlllrt arc a numhr of adan laiexcles itlt Illis Iu omiddot probabJy passtmiddot1 Ihrou1oacute h tlw slngl uf o cssic OI1Vcrgcncc and arl lHiexclW al IIIt chronH fi xatiOI1 nllachnlrnl O(T Ihc ordinary iIIumillale1 largd

1 Colourl(1 ta rglls cneoulugc tllt IUlitnt to mainlain fi xaliun lu a grcalcr dcg rec 1111H1 11lt bl1Ck nnl hite

2 The lrogrCS l I ZC IIlId chllractcr o f the ohj (cls IWTm il eoarsc and finc fixa liol1

t TllI c al11l111r enrl nhlnin dUlwhrnme crJualil y al a precribed wo rking di _o lance

4 Since Ihe largd conist o f (liagrlIlls ralher Ilmll lelllmiddot s tlwc IS a Ul1icrsal appl ieation

Wilh a erilical dcl l rmil1111ion o f g nc ll dumilHlI1cc a the nlinoseupe iexcls mOl-d a fracliOIl neanr lo 1111 pa l ien l 111(1 r(1 dominanc E 1H1l Ihe inslrumenl is laken 1 si mila r distance a a y lile flSU]iexcl Iacutelt cunfi n lltd

Sincc thE rcflp is l1lched during the final nHlnOIUVrc il follow Ihal ilh tllc prcsloupic comlitiulI al kn1 a fiTlII I r 1111UlIrC uf cOlllrol is adl(middot(1 lo 1111 reading ur do~e o rk addil ion

Cock(fham stales Illal ith Ihe cylinrllr ax l [l11d 10 1 ( lTdull y chefke1 and Ihe ~phcricnl lIlo(lificali un cOlltrolled lhruughout itlr thc duuchrnmc dlIalllic lurgmiddot1 1111 practi timwr is in 11 pn il ion In prcscr ihe fnr fl l1 ) pTlshyoopic co rrccli on

44

Cllr-I CAL H1I Nn COI Y

I ilh grealcr eerla inly o IIICl a purd) UhjtClie lest IIl0nt 15 onl y l S nccurutc as IIIt pa l iIII confirmnti on 1011 1 a llo w 11 callnot be a rgucd he says thal IllIl

dY ll umic Icst is onlr all ohject i 1l11lhocl of nwagt uring Ihe ntgll li c rebli t ticmiddot eo rumodat ioll fOT Ihe duochronw is ac tillg as u conlrol factur a l all lI tages of Ihe

test

In IIIcnlionin g Ihe abmc Codcrharll mr lhod une his ol inlUlI Ihis is lo bring

D)na mic Rtgtl inuscupy lo i l ~ full co nclusioll ~tld is no nn xprcssio ll of fLSUIt iexcl

obta irltd hy myC1f I r~o na ll y ti u lo lack o f (xpelicncc wi lh d uocJnolllc (lpIPmic l a rgt I ~

CONCLllS ION

Agt il will be fuU y appreciatld Ihe wriUen e xpla nali olJ IlIkes considcrahl) IOllgcr

lo rltSCribc Iha n Ihe practical applical iun of lJ igt rclulicl y si mple roulil1 t TIIt In lcl ilior1rr- a hi lil ) with the rt inoscopc ir rpectit of wlrlll IJW i ~ prcfc rnmiddotd

is 1 11 objcdie I1 l1 tho(1 of Ttfraction wcll WlJrtl l hCClIllIillg skillcd in

The iexclinU spenl in decloping litis ~ ki ll heing JIIOn Ihan cOl1lptnsn l~ d for h ) lil e f( middotsult olJluiunl

IIJ J C I I ) ~ 5r P O no1 1I

REnRENciexclS

lIH KA Y FEHG USON R ~ i o tu l ) L undun Tmiddothni r 1 Mono~ ra l h NQ 5 BEB ENS Im1 Z UCKI RMA N jalm iexcl Eumnaiexcliun ur 110 E)middot ~ WELCH ALI YN IAI III LI1 Slrn k IIjlinomiddotul Y J PASCAL L Mud n linUt0 IY L SWANN puIlel KEEIEII Pa1l lhlel S TAYLO II lJynu mit Kcrinu8middotuPY and lIinuulur ncl l cx ~

1 S VELL An Inlrudurlion lo lJynamir Heil nus middot p) Vul 2 N9 2 (S A Rdnclioni lr I J un 1951

D COCK~ II I1 M Dynamjmiddot Slrea t Reiexcl n05Ur jlh duur hrunr e rita l ion lar~c l ~ Olll i cIn 1 5 ~ CXXVI II 58

45

ANTIt UN L SAVI I L

and lile rctiuoscope fla sh~middotd agaill A sl ight against nlUvlmenl llIay be observcd Hesisla nce Ihen suddenl) g iCS way and a fu rl llcr wilh mOelllcnl observed Addingplus lIltldil iolls is con linucd unlil rew rsal poi nt is reuchcd and then reshyductmiddotd to obtain tlH D)num ic Neulral Thc lag is dlducled - usuall y + loo -IInd tllt rcmn indr addell In Ihe ct islllnce pre~ri lion lf no addilion is nl(lssar_ Ihen a pr ism uf 34 JaStmiddot in di idtmiddot(1 helwtmiddottmiddotn Ihe luwo c)es is given for neac USe

bull Slrlrlgt acco llIJlation

This cllnditiun i uulIlly prtscnl in COillhi nalion wit ll st ra inoo co nvergcnce Thcrt is genernll y esophoria for dislHlcc and exophoria for near The patienl is directcd lO rcnd Iht rll ill oSCop) chart com mcllcing wilb the large letters ami obS( cvalion acled upon wllen he slarl s lo rcad Ihe small fr lellfrs MosII ) Ihen is linle ur nu lug lo htgin with allll the procedure is as in the r(iaus case 01 strained cO III( r s(nC t~ An) aIlitional plus is inCOTloraled in Ihe dislance coshyrncliol

ACCOIIIOduliofl beal) iexcllre f10fllwl

lf the lag is lurgcr Ihun IIIC no rmal fo r IllC age (wi tl Ihe palient wcaring h is fu ll dislance corrcction ) thcre is usually Oflhophoria fOf d islanee bu l a Inrg txophori a for lIear -ver) much in exe(lt of Ihe phy~iol ogical cxophor ia - nnd often as hi gl as 8 ID This cOIUitiOIl u5uall) results from some (Ieb ilily or prospeemiddot ti vt ilhwss cg boils bad I(Clh upcration cUlHalcscence o r maternil y weak middot ness and lassil ude lt is a Paresis of Acco modation aud tllt~ pulieut is ftmiddotf(middotrred

JII ropia anel DyrwIIc RelinoscoJJ

So far Ihe applieatioll of Ihe Icchnique for near vision has hlcn (]all ltl ilh in cm( of hypermelropia Ilreshyopia concrgf llce fX CCSS cte 1I should be not-d

thal in alJ Illese errors accolllll1otlal ion ami eOllergencc are slrongly linkcd In man) cuscs o f luopia how(er these fu nction a re on l) loosdy li nked Same easts

bullo f Itl)opitl ftspond in evcry a y lo Ihe lechniquc of Dynnmic Hetinoscop) as with

other arnelropie eondi lions Unfo rtunatcly a g rcat mun) rn yop( do nol reopolld in lJis way al alJ Tlw lags a rl uualJ) higl1lr in mos hyperopic cMes giv ing Ih~c

illlpression thal Ihe lIlopia is less iexclhan it js unl il il is real ised Ih lll Ihe plum o

menon is Ihe resull of inndtqualc aeeolllllloda lion IacuteI st-ems Iherefore Ihal cae

case of m)ovia musl be rcgurdld as huving il awn tliolug)

42

CLlNICAL HTI NOSCOl ~

Conellsiol

For comfortab le readi ng corrections tl ere mus be 11 comfortllblc blllllllCC bclween Ihe Ncgul ie Hdll li c iexcl cco mmoda linn und the POSilivc RlllI li c Acmiddot COlll lllod atinn If 11lf pnshyo~ ic IIddil ion is calcul31cd by subj ectie means alolle here is 11]( possibilil y o f o cr-corro CliOIl becll u~ Ihc Ncpt ic Ilclalivc Accommiddot IIOlll1l ioll when taken ~uhjetively is Ihul iexclUlIoun of plus ~phere which can be IIdded wilhoul actua l hJ urring of Ihe rea(ling matlcr uscd for Ilre lest Thc eyes lIre 11 0 1 od ng tc ~I Ctl fo r Negatic Rt-lat ic Atcum lltodalioll oul lo fin() Ihe Ch

rrect IHlohopilmiddot uddi lion whiel can be worn will comforl If tllt rCllding ad middot Iilion is loo sl rong Ih Negal iiexcl Rclali e ACCO llllllodll lionmiddot Pos iti vlmiddot Rclalive Acmiddot cOrlllllodat ion oalllnCI i di turlwtl and rcstricl ion (l f range wilh eomfort ill cnsue

T he following chart diexclvised hy Colin B Fryer alJlI h3lt(1 on lIl ucs rcco rdcll by L Swoan iJl reprodllced 3 a referellce gu idiexcl nf Ihe man) phCI10llil II11 o lJscfed IV itl l ile Dylltu nic Reli lloscolc Basically Ihc chuTI -lIl1l1l1a riscs all Ihe avni lnhlc ill fMI1H1 tion concerl1 illg th l fou r ml ill condil iO l1s likely lo be iexcll1coun lered in 1111

presb)opie )ea rs

lIi(h ( tlyn ic) neulrlI (Ir fimlI VcTS~1 I (l intl afil es

Up 10 35 35 40 10 45 45 50 5055 160

H N + 1 50 +li5 +2l + 25 250 +215

DI lo 30 J O 35 35middot10 40 405 SO 55

N R A 1 50J) 1 25 1l I OOD 0150 0 51)1) 025 11

N n Tu be d ~ dll rhd hom 11 N - Itemaintle r ~ i c lI u near ltorrclmiddotl ioll

Piy illsllll i e i e t IINomlllQda tiQtI

( d u e 10 EXre~ i e collvulcmiddote) i1u ~dc ha l ~ te Disl 3nd lI ~ ur E Hi ~h Neuln l H i ~h Cnrreel i Add Iu n Ui ~ l lJ e ll ule~ Ltlenl Uypropill

I r i r eI[(OJsie IIIToIi ( U~ l o ~ e i vc CUIl rjlenre) (O erarl iva ted or rai ne)

MII ~ le b3lanre Disl t~jjo Ncur E~o E~ HiJlIt Neunl Lo remai ui JI 1 on onin~ one eye CrTml i Atld Ius 10 Uisl LI ~ nl 1I )Ie r O IJi ~

43

AATIIIlII L S L

A Oommoduli heln normal ExlJao~led o laTc ~ i 01 Arroao nlodulion ) Mu rl ll b~ lwnre lJi~ l Orlho E~o Ne iexcl-J i ~ h E~o Hi~ h Neurral IIi ~h II ll fe lo MmiddotoI imiddotpl Pr l middotr tonbull

~olO(y exmiddotlt~ie 111

Sbullbulluined of We k Cone d e lo Com-c lI el re I rri r ienmiddot )111 ~ rI bal r l)i ~ l Orl lr o E~o Ne~ Hih EllO H i~h Neubullbullal Lo o 1 O middotomiddot iI un e~ t ore1 ion

tI 1 iexcllo lo oIi51 H u aoldi l irm rruinI

11 111 39 ~9 divided bN een bolh ~middot e f O T len uo only 111 Orlbollr exrebullbull i ~e~

D)uQmit al(I dloctrome farpcL rdiIlOSCOiexclJy

A rectlll 1tvlu lr11ent ill the InllI1iq ul uf I Yl1l1mie retinosc0IY io Ihl CockerhulI1 MImiddottllOll n hieh Ihe fixutiul1 Isrg l co ns i ~l s of IIn IIlaiexclhmc nl lo 111C lum inouiexclo Tdinn8lupc making U ~l of tlle du odtn)ll1c filtres red II l1d grecn

Cockcrham clu ims Ihal tlllrt arc a numhr of adan laiexcles itlt Illis Iu omiddot probabJy passtmiddot1 Ihrou1oacute h tlw slngl uf o cssic OI1Vcrgcncc and arl lHiexclW al IIIt chronH fi xatiOI1 nllachnlrnl O(T Ihc ordinary iIIumillale1 largd

1 Colourl(1 ta rglls cneoulugc tllt IUlitnt to mainlain fi xaliun lu a grcalcr dcg rec 1111H1 11lt bl1Ck nnl hite

2 The lrogrCS l I ZC IIlId chllractcr o f the ohj (cls IWTm il eoarsc and finc fixa liol1

t TllI c al11l111r enrl nhlnin dUlwhrnme crJualil y al a precribed wo rking di _o lance

4 Since Ihe largd conist o f (liagrlIlls ralher Ilmll lelllmiddot s tlwc IS a Ul1icrsal appl ieation

Wilh a erilical dcl l rmil1111ion o f g nc ll dumilHlI1cc a the nlinoseupe iexcls mOl-d a fracliOIl neanr lo 1111 pa l ien l 111(1 r(1 dominanc E 1H1l Ihe inslrumenl is laken 1 si mila r distance a a y lile flSU]iexcl Iacutelt cunfi n lltd

Sincc thE rcflp is l1lched during the final nHlnOIUVrc il follow Ihal ilh tllc prcsloupic comlitiulI al kn1 a fiTlII I r 1111UlIrC uf cOlllrol is adl(middot(1 lo 1111 reading ur do~e o rk addil ion

Cock(fham stales Illal ith Ihe cylinrllr ax l [l11d 10 1 ( lTdull y chefke1 and Ihe ~phcricnl lIlo(lificali un cOlltrolled lhruughout itlr thc duuchrnmc dlIalllic lurgmiddot1 1111 practi timwr is in 11 pn il ion In prcscr ihe fnr fl l1 ) pTlshyoopic co rrccli on

44

Cllr-I CAL H1I Nn COI Y

I ilh grealcr eerla inly o IIICl a purd) UhjtClie lest IIl0nt 15 onl y l S nccurutc as IIIt pa l iIII confirmnti on 1011 1 a llo w 11 callnot be a rgucd he says thal IllIl

dY ll umic Icst is onlr all ohject i 1l11lhocl of nwagt uring Ihe ntgll li c rebli t ticmiddot eo rumodat ioll fOT Ihe duochronw is ac tillg as u conlrol factur a l all lI tages of Ihe

test

In IIIcnlionin g Ihe abmc Codcrharll mr lhod une his ol inlUlI Ihis is lo bring

D)na mic Rtgtl inuscupy lo i l ~ full co nclusioll ~tld is no nn xprcssio ll of fLSUIt iexcl

obta irltd hy myC1f I r~o na ll y ti u lo lack o f (xpelicncc wi lh d uocJnolllc (lpIPmic l a rgt I ~

CONCLllS ION

Agt il will be fuU y appreciatld Ihe wriUen e xpla nali olJ IlIkes considcrahl) IOllgcr

lo rltSCribc Iha n Ihe practical applical iun of lJ igt rclulicl y si mple roulil1 t TIIt In lcl ilior1rr- a hi lil ) with the rt inoscopc ir rpectit of wlrlll IJW i ~ prcfc rnmiddotd

is 1 11 objcdie I1 l1 tho(1 of Ttfraction wcll WlJrtl l hCClIllIillg skillcd in

The iexclinU spenl in decloping litis ~ ki ll heing JIIOn Ihan cOl1lptnsn l~ d for h ) lil e f( middotsult olJluiunl

IIJ J C I I ) ~ 5r P O no1 1I

REnRENciexclS

lIH KA Y FEHG USON R ~ i o tu l ) L undun Tmiddothni r 1 Mono~ ra l h NQ 5 BEB ENS Im1 Z UCKI RMA N jalm iexcl Eumnaiexcliun ur 110 E)middot ~ WELCH ALI YN IAI III LI1 Slrn k IIjlinomiddotul Y J PASCAL L Mud n linUt0 IY L SWANN puIlel KEEIEII Pa1l lhlel S TAYLO II lJynu mit Kcrinu8middotuPY and lIinuulur ncl l cx ~

1 S VELL An Inlrudurlion lo lJynamir Heil nus middot p) Vul 2 N9 2 (S A Rdnclioni lr I J un 1951

D COCK~ II I1 M Dynamjmiddot Slrea t Reiexcl n05Ur jlh duur hrunr e rita l ion lar~c l ~ Olll i cIn 1 5 ~ CXXVI II 58

45

CLlNICAL HTI NOSCOl ~

Conellsiol

For comfortab le readi ng corrections tl ere mus be 11 comfortllblc blllllllCC bclween Ihe Ncgul ie Hdll li c iexcl cco mmoda linn und the POSilivc RlllI li c Acmiddot COlll lllod atinn If 11lf pnshyo~ ic IIddil ion is calcul31cd by subj ectie means alolle here is 11]( possibilil y o f o cr-corro CliOIl becll u~ Ihc Ncpt ic Ilclalivc Accommiddot IIOlll1l ioll when taken ~uhjetively is Ihul iexclUlIoun of plus ~phere which can be IIdded wilhoul actua l hJ urring of Ihe rea(ling matlcr uscd for Ilre lest Thc eyes lIre 11 0 1 od ng tc ~I Ctl fo r Negatic Rt-lat ic Atcum lltodalioll oul lo fin() Ihe Ch

rrect IHlohopilmiddot uddi lion whiel can be worn will comforl If tllt rCllding ad middot Iilion is loo sl rong Ih Negal iiexcl Rclali e ACCO llllllodll lionmiddot Pos iti vlmiddot Rclalive Acmiddot cOrlllllodat ion oalllnCI i di turlwtl and rcstricl ion (l f range wilh eomfort ill cnsue

T he following chart diexclvised hy Colin B Fryer alJlI h3lt(1 on lIl ucs rcco rdcll by L Swoan iJl reprodllced 3 a referellce gu idiexcl nf Ihe man) phCI10llil II11 o lJscfed IV itl l ile Dylltu nic Reli lloscolc Basically Ihc chuTI -lIl1l1l1a riscs all Ihe avni lnhlc ill fMI1H1 tion concerl1 illg th l fou r ml ill condil iO l1s likely lo be iexcll1coun lered in 1111

presb)opie )ea rs

lIi(h ( tlyn ic) neulrlI (Ir fimlI VcTS~1 I (l intl afil es

Up 10 35 35 40 10 45 45 50 5055 160

H N + 1 50 +li5 +2l + 25 250 +215

DI lo 30 J O 35 35middot10 40 405 SO 55

N R A 1 50J) 1 25 1l I OOD 0150 0 51)1) 025 11

N n Tu be d ~ dll rhd hom 11 N - Itemaintle r ~ i c lI u near ltorrclmiddotl ioll

Piy illsllll i e i e t IINomlllQda tiQtI

( d u e 10 EXre~ i e collvulcmiddote) i1u ~dc ha l ~ te Disl 3nd lI ~ ur E Hi ~h Neuln l H i ~h Cnrreel i Add Iu n Ui ~ l lJ e ll ule~ Ltlenl Uypropill

I r i r eI[(OJsie IIIToIi ( U~ l o ~ e i vc CUIl rjlenre) (O erarl iva ted or rai ne)

MII ~ le b3lanre Disl t~jjo Ncur E~o E~ HiJlIt Neunl Lo remai ui JI 1 on onin~ one eye CrTml i Atld Ius 10 Uisl LI ~ nl 1I )Ie r O IJi ~

43

AATIIIlII L S L

A Oommoduli heln normal ExlJao~led o laTc ~ i 01 Arroao nlodulion ) Mu rl ll b~ lwnre lJi~ l Orlho E~o Ne iexcl-J i ~ h E~o Hi~ h Neurral IIi ~h II ll fe lo MmiddotoI imiddotpl Pr l middotr tonbull

~olO(y exmiddotlt~ie 111

Sbullbulluined of We k Cone d e lo Com-c lI el re I rri r ienmiddot )111 ~ rI bal r l)i ~ l Orl lr o E~o Ne~ Hih EllO H i~h Neubullbullal Lo o 1 O middotomiddot iI un e~ t ore1 ion

tI 1 iexcllo lo oIi51 H u aoldi l irm rruinI

11 111 39 ~9 divided bN een bolh ~middot e f O T len uo only 111 Orlbollr exrebullbull i ~e~

D)uQmit al(I dloctrome farpcL rdiIlOSCOiexclJy

A rectlll 1tvlu lr11ent ill the InllI1iq ul uf I Yl1l1mie retinosc0IY io Ihl CockerhulI1 MImiddottllOll n hieh Ihe fixutiul1 Isrg l co ns i ~l s of IIn IIlaiexclhmc nl lo 111C lum inouiexclo Tdinn8lupc making U ~l of tlle du odtn)ll1c filtres red II l1d grecn

Cockcrham clu ims Ihal tlllrt arc a numhr of adan laiexcles itlt Illis Iu omiddot probabJy passtmiddot1 Ihrou1oacute h tlw slngl uf o cssic OI1Vcrgcncc and arl lHiexclW al IIIt chronH fi xatiOI1 nllachnlrnl O(T Ihc ordinary iIIumillale1 largd

1 Colourl(1 ta rglls cneoulugc tllt IUlitnt to mainlain fi xaliun lu a grcalcr dcg rec 1111H1 11lt bl1Ck nnl hite

2 The lrogrCS l I ZC IIlId chllractcr o f the ohj (cls IWTm il eoarsc and finc fixa liol1

t TllI c al11l111r enrl nhlnin dUlwhrnme crJualil y al a precribed wo rking di _o lance

4 Since Ihe largd conist o f (liagrlIlls ralher Ilmll lelllmiddot s tlwc IS a Ul1icrsal appl ieation

Wilh a erilical dcl l rmil1111ion o f g nc ll dumilHlI1cc a the nlinoseupe iexcls mOl-d a fracliOIl neanr lo 1111 pa l ien l 111(1 r(1 dominanc E 1H1l Ihe inslrumenl is laken 1 si mila r distance a a y lile flSU]iexcl Iacutelt cunfi n lltd

Sincc thE rcflp is l1lched during the final nHlnOIUVrc il follow Ihal ilh tllc prcsloupic comlitiulI al kn1 a fiTlII I r 1111UlIrC uf cOlllrol is adl(middot(1 lo 1111 reading ur do~e o rk addil ion

Cock(fham stales Illal ith Ihe cylinrllr ax l [l11d 10 1 ( lTdull y chefke1 and Ihe ~phcricnl lIlo(lificali un cOlltrolled lhruughout itlr thc duuchrnmc dlIalllic lurgmiddot1 1111 practi timwr is in 11 pn il ion In prcscr ihe fnr fl l1 ) pTlshyoopic co rrccli on

44

Cllr-I CAL H1I Nn COI Y

I ilh grealcr eerla inly o IIICl a purd) UhjtClie lest IIl0nt 15 onl y l S nccurutc as IIIt pa l iIII confirmnti on 1011 1 a llo w 11 callnot be a rgucd he says thal IllIl

dY ll umic Icst is onlr all ohject i 1l11lhocl of nwagt uring Ihe ntgll li c rebli t ticmiddot eo rumodat ioll fOT Ihe duochronw is ac tillg as u conlrol factur a l all lI tages of Ihe

test

In IIIcnlionin g Ihe abmc Codcrharll mr lhod une his ol inlUlI Ihis is lo bring

D)na mic Rtgtl inuscupy lo i l ~ full co nclusioll ~tld is no nn xprcssio ll of fLSUIt iexcl

obta irltd hy myC1f I r~o na ll y ti u lo lack o f (xpelicncc wi lh d uocJnolllc (lpIPmic l a rgt I ~

CONCLllS ION

Agt il will be fuU y appreciatld Ihe wriUen e xpla nali olJ IlIkes considcrahl) IOllgcr

lo rltSCribc Iha n Ihe practical applical iun of lJ igt rclulicl y si mple roulil1 t TIIt In lcl ilior1rr- a hi lil ) with the rt inoscopc ir rpectit of wlrlll IJW i ~ prcfc rnmiddotd

is 1 11 objcdie I1 l1 tho(1 of Ttfraction wcll WlJrtl l hCClIllIillg skillcd in

The iexclinU spenl in decloping litis ~ ki ll heing JIIOn Ihan cOl1lptnsn l~ d for h ) lil e f( middotsult olJluiunl

IIJ J C I I ) ~ 5r P O no1 1I

REnRENciexclS

lIH KA Y FEHG USON R ~ i o tu l ) L undun Tmiddothni r 1 Mono~ ra l h NQ 5 BEB ENS Im1 Z UCKI RMA N jalm iexcl Eumnaiexcliun ur 110 E)middot ~ WELCH ALI YN IAI III LI1 Slrn k IIjlinomiddotul Y J PASCAL L Mud n linUt0 IY L SWANN puIlel KEEIEII Pa1l lhlel S TAYLO II lJynu mit Kcrinu8middotuPY and lIinuulur ncl l cx ~

1 S VELL An Inlrudurlion lo lJynamir Heil nus middot p) Vul 2 N9 2 (S A Rdnclioni lr I J un 1951

D COCK~ II I1 M Dynamjmiddot Slrea t Reiexcl n05Ur jlh duur hrunr e rita l ion lar~c l ~ Olll i cIn 1 5 ~ CXXVI II 58

45

AATIIIlII L S L

A Oommoduli heln normal ExlJao~led o laTc ~ i 01 Arroao nlodulion ) Mu rl ll b~ lwnre lJi~ l Orlho E~o Ne iexcl-J i ~ h E~o Hi~ h Neurral IIi ~h II ll fe lo MmiddotoI imiddotpl Pr l middotr tonbull

~olO(y exmiddotlt~ie 111

Sbullbulluined of We k Cone d e lo Com-c lI el re I rri r ienmiddot )111 ~ rI bal r l)i ~ l Orl lr o E~o Ne~ Hih EllO H i~h Neubullbullal Lo o 1 O middotomiddot iI un e~ t ore1 ion

tI 1 iexcllo lo oIi51 H u aoldi l irm rruinI

11 111 39 ~9 divided bN een bolh ~middot e f O T len uo only 111 Orlbollr exrebullbull i ~e~

D)uQmit al(I dloctrome farpcL rdiIlOSCOiexclJy

A rectlll 1tvlu lr11ent ill the InllI1iq ul uf I Yl1l1mie retinosc0IY io Ihl CockerhulI1 MImiddottllOll n hieh Ihe fixutiul1 Isrg l co ns i ~l s of IIn IIlaiexclhmc nl lo 111C lum inouiexclo Tdinn8lupc making U ~l of tlle du odtn)ll1c filtres red II l1d grecn

Cockcrham clu ims Ihal tlllrt arc a numhr of adan laiexcles itlt Illis Iu omiddot probabJy passtmiddot1 Ihrou1oacute h tlw slngl uf o cssic OI1Vcrgcncc and arl lHiexclW al IIIt chronH fi xatiOI1 nllachnlrnl O(T Ihc ordinary iIIumillale1 largd

1 Colourl(1 ta rglls cneoulugc tllt IUlitnt to mainlain fi xaliun lu a grcalcr dcg rec 1111H1 11lt bl1Ck nnl hite

2 The lrogrCS l I ZC IIlId chllractcr o f the ohj (cls IWTm il eoarsc and finc fixa liol1

t TllI c al11l111r enrl nhlnin dUlwhrnme crJualil y al a precribed wo rking di _o lance

4 Since Ihe largd conist o f (liagrlIlls ralher Ilmll lelllmiddot s tlwc IS a Ul1icrsal appl ieation

Wilh a erilical dcl l rmil1111ion o f g nc ll dumilHlI1cc a the nlinoseupe iexcls mOl-d a fracliOIl neanr lo 1111 pa l ien l 111(1 r(1 dominanc E 1H1l Ihe inslrumenl is laken 1 si mila r distance a a y lile flSU]iexcl Iacutelt cunfi n lltd

Sincc thE rcflp is l1lched during the final nHlnOIUVrc il follow Ihal ilh tllc prcsloupic comlitiulI al kn1 a fiTlII I r 1111UlIrC uf cOlllrol is adl(middot(1 lo 1111 reading ur do~e o rk addil ion

Cock(fham stales Illal ith Ihe cylinrllr ax l [l11d 10 1 ( lTdull y chefke1 and Ihe ~phcricnl lIlo(lificali un cOlltrolled lhruughout itlr thc duuchrnmc dlIalllic lurgmiddot1 1111 practi timwr is in 11 pn il ion In prcscr ihe fnr fl l1 ) pTlshyoopic co rrccli on

44

Cllr-I CAL H1I Nn COI Y

I ilh grealcr eerla inly o IIICl a purd) UhjtClie lest IIl0nt 15 onl y l S nccurutc as IIIt pa l iIII confirmnti on 1011 1 a llo w 11 callnot be a rgucd he says thal IllIl

dY ll umic Icst is onlr all ohject i 1l11lhocl of nwagt uring Ihe ntgll li c rebli t ticmiddot eo rumodat ioll fOT Ihe duochronw is ac tillg as u conlrol factur a l all lI tages of Ihe

test

In IIIcnlionin g Ihe abmc Codcrharll mr lhod une his ol inlUlI Ihis is lo bring

D)na mic Rtgtl inuscupy lo i l ~ full co nclusioll ~tld is no nn xprcssio ll of fLSUIt iexcl

obta irltd hy myC1f I r~o na ll y ti u lo lack o f (xpelicncc wi lh d uocJnolllc (lpIPmic l a rgt I ~

CONCLllS ION

Agt il will be fuU y appreciatld Ihe wriUen e xpla nali olJ IlIkes considcrahl) IOllgcr

lo rltSCribc Iha n Ihe practical applical iun of lJ igt rclulicl y si mple roulil1 t TIIt In lcl ilior1rr- a hi lil ) with the rt inoscopc ir rpectit of wlrlll IJW i ~ prcfc rnmiddotd

is 1 11 objcdie I1 l1 tho(1 of Ttfraction wcll WlJrtl l hCClIllIillg skillcd in

The iexclinU spenl in decloping litis ~ ki ll heing JIIOn Ihan cOl1lptnsn l~ d for h ) lil e f( middotsult olJluiunl

IIJ J C I I ) ~ 5r P O no1 1I

REnRENciexclS

lIH KA Y FEHG USON R ~ i o tu l ) L undun Tmiddothni r 1 Mono~ ra l h NQ 5 BEB ENS Im1 Z UCKI RMA N jalm iexcl Eumnaiexcliun ur 110 E)middot ~ WELCH ALI YN IAI III LI1 Slrn k IIjlinomiddotul Y J PASCAL L Mud n linUt0 IY L SWANN puIlel KEEIEII Pa1l lhlel S TAYLO II lJynu mit Kcrinu8middotuPY and lIinuulur ncl l cx ~

1 S VELL An Inlrudurlion lo lJynamir Heil nus middot p) Vul 2 N9 2 (S A Rdnclioni lr I J un 1951

D COCK~ II I1 M Dynamjmiddot Slrea t Reiexcl n05Ur jlh duur hrunr e rita l ion lar~c l ~ Olll i cIn 1 5 ~ CXXVI II 58

45

Cllr-I CAL H1I Nn COI Y

I ilh grealcr eerla inly o IIICl a purd) UhjtClie lest IIl0nt 15 onl y l S nccurutc as IIIt pa l iIII confirmnti on 1011 1 a llo w 11 callnot be a rgucd he says thal IllIl

dY ll umic Icst is onlr all ohject i 1l11lhocl of nwagt uring Ihe ntgll li c rebli t ticmiddot eo rumodat ioll fOT Ihe duochronw is ac tillg as u conlrol factur a l all lI tages of Ihe

test

In IIIcnlionin g Ihe abmc Codcrharll mr lhod une his ol inlUlI Ihis is lo bring

D)na mic Rtgtl inuscupy lo i l ~ full co nclusioll ~tld is no nn xprcssio ll of fLSUIt iexcl

obta irltd hy myC1f I r~o na ll y ti u lo lack o f (xpelicncc wi lh d uocJnolllc (lpIPmic l a rgt I ~

CONCLllS ION

Agt il will be fuU y appreciatld Ihe wriUen e xpla nali olJ IlIkes considcrahl) IOllgcr

lo rltSCribc Iha n Ihe practical applical iun of lJ igt rclulicl y si mple roulil1 t TIIt In lcl ilior1rr- a hi lil ) with the rt inoscopc ir rpectit of wlrlll IJW i ~ prcfc rnmiddotd

is 1 11 objcdie I1 l1 tho(1 of Ttfraction wcll WlJrtl l hCClIllIillg skillcd in

The iexclinU spenl in decloping litis ~ ki ll heing JIIOn Ihan cOl1lptnsn l~ d for h ) lil e f( middotsult olJluiunl

IIJ J C I I ) ~ 5r P O no1 1I

REnRENciexclS

lIH KA Y FEHG USON R ~ i o tu l ) L undun Tmiddothni r 1 Mono~ ra l h NQ 5 BEB ENS Im1 Z UCKI RMA N jalm iexcl Eumnaiexcliun ur 110 E)middot ~ WELCH ALI YN IAI III LI1 Slrn k IIjlinomiddotul Y J PASCAL L Mud n linUt0 IY L SWANN puIlel KEEIEII Pa1l lhlel S TAYLO II lJynu mit Kcrinu8middotuPY and lIinuulur ncl l cx ~

1 S VELL An Inlrudurlion lo lJynamir Heil nus middot p) Vul 2 N9 2 (S A Rdnclioni lr I J un 1951

D COCK~ II I1 M Dynamjmiddot Slrea t Reiexcl n05Ur jlh duur hrunr e rita l ion lar~c l ~ Olll i cIn 1 5 ~ CXXVI II 58

45