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8/18/2019 Glossary Only - 6-23-10
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OPTICALABBREVIATIONS
& GLOSSARY
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OPTICAL ABBREVIATIONS
20/20 best vision
≈ approximate
∆ prism diopter
º degree of prism
< less than
> greater than↑ increase
↓ decrease
♀ female
male
combined !ith
" infinit#
$ pl%s
& min%s
'() hori*ontal box meas%rement
a applanation tension
ac before meals
acc accommodation
(++ add po!er ,m%ltifocal-
(. anti&reflective coating
ax axis
') vertical box meas%rement
bbl barrel of hinge
base c%rve
+ base do!n prism
1 base in prism
bif bifocalbid t!ice dail#
base o%t prism
distance bet!een optical center
and top of segment
3 base %p prism
45 bac6 vertex distance
c !idth
cc c%bic centimeter
cc comfort cable temple
cc !ith correctioncf co%nt fingers
cl contact lens
cm centimeter
.&78 plastic lens material
conv convergent
.5 orneal reflection p%pilometer
c#l c#linder
+ diopter
+5 distance portion of lens
+9 distance bet!een lenses ,bridge-
+ distance bet!een centers
div divergent
+x diagnosis:5 e#ecare professional
:+ effective diameter
eom extraoc%lar movements
eso tendenc# to t%rn in
exo tendenc# to t%rn o%t!ard
exam examination
et esotropia
:; edge thic6ness
fb foreign bod#
+ frame distance center
5 far point
t flat top bifocal
= geometric center
gtts drops
+ hori*ontal decentration of
optical center
hgt height
1 hi&index lens material
hm hand motion
hori* hori*ontal
hs at bedtimeh#per %p
h#po do!n
hx histor#
ic bet!een meals
15 intraoc%lar press%re
19 intraoc%lar lens
15+ interp%pillar# distance
9 left
lib librar# temple
lp light perceptionm meter
mc mechanical center
?+5 monoc%lar p%pillar# distance
mm millimeter
?.5 ma@or reference point
n index of refraction
Aeg negative
__
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Alp no light perception
nn nanometer
np near point
nrp near reference point
nv near vision
Ava near vis%al ac%it# optical center
+ oc%l%s dexter & right e#e
B+B +octor of ptometr#
9 overall length
5 optical prod%ct code
pht ophthalmic&pertaining to the e#es
rtho straight
C oc%l%s sinister & left e#e
3 oc%l%s %niter & both e#es
o* optical *one
5(9 progressive addition lens
5c after meals
5+ papillar# distance
ph pinhole
5l plano
po per os & orall#
prn as needed
5.5 prism reference point
Dd ever# da#
Did E times a da#
D2h ever# 2 ho%rsDh ever# ho%r
Dod ever# other da#
. right
.ef refraction
.x prescription
s !itho%t
sc !itho%t correction
seg segment
seg ht segment height
C1 segment inserts6 s6%ll
Cph sphere
C5 standard operating proced%re
C. scratch resistant coating
Ctat at once
C4 single vision
Cx s#mptoms
t tension
temp temporal to!ard the temple
tid 7 times a da#
tri trifocal
34 %ltraviolet
v A% val%eF (: val%e4( vis%al anal#sis ,e#e examination-
4+ vertical decentration of optical center
vert vertical
vf vis%al field
GA9 !ithin normal limits
x axis
xp exophoria
xt exotropia
*#l plastic frame material
__
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Air ,empering H ;he strengthening of a lens as a
res%lt of cooling a heated lensB
Albinism H 5igmentation is deficient or absentB
?a# occ%r in s6inF hairF and e#esB c%lar albinism
is a pigmentation deficienc# occ%rring mainl# in the
e#esB 1ndivid%als !ith albinism incl%ding oc%laralbinism commonl# have decreased vis%al ac%it#
,20/N0 H 20/200-F strabism%sF photophobiaF and
n#stagm%sB ;here is no 6no!n treatmentB
1ndivid%als ma# benefit from lo!&vision aidsB
;reatment options for strabism%s and n#stagm%s
does appl# to these individ%alsB
Alignment H ;he placing of the retinal D%adrants of
the e#e so that the light stim%l%s is eD%all#
distrib%ted on all fo%r D%adrantsB
Ambl!opia & +efective vision that cannot be
corrected b# e#eglasses or contact lensesB ftenreferred to as 'la*# e#e)B
Ametropia H :#e disorders that prevent a clear
image from forming on the retina ,m#opiaF
h#peropiaF astigmatism-B
Ambl!opia -xanopsia $la.! e!e% H 3ncorrectable
bl%rred vision d%e to a lac6 of %seL the vis%al
path!a# fails to mat%reL an e#e can become
ambl#opic from being crossedF having a large
refractive error or having the brain s%ppress its
visionB orrective lensesF vision therap#F or
patching therap# ma# be prescribedBAM H (ge related mac%lar degenerationF a
disease that damages the mac%laF the central part
of the retinaF leading to loss of central vision and
leaving onl# the peripheral or lateral vision in tactB
Amplitude +unctional $or anal!tical% H ;he range
over !hich clearF binoc%lar vision can be
maintained %pon reading material of 20/E0 ang%lar
si*e placed at a fixed distance ,%s%all# K7 inches-B
Amplitude o( Accommodation $AA% H (
meas%rement of the e#eJs abilit# to foc%s clearl# on
ob@ects at near distancesB ;his e#e foc%sing rangefor a child is %s%all# abo%t 2&7 inchesB or a #o%ng
ad%ltF it is E&I inchesB ;he foc%s range for a EO&
#ear&old ad%lt is abo%t 20 inchesB or an P0ear&
old ad%ltF it is I0 inchesB
Anal!sis H ( scientific proced%re for dividing a
complex experience into simpler constit%entsB
Anal!tical -xamination H ( 2K&point optometric
examinationB :ach point is a meas%rement of
performance of a vis%al behavior patternB ;hese
meas%rementsF made thro%gh the application of
prism and sphereF sho! the absorption of the
potential of inhibitionF meas%re the existing learnedassociations bet!een patternsF and probe for the
degree or organi*ation existing in the vis%al patternB
Anisei1onia H ;he image of an ob@ect as seen b#
one e#e is different in si*e and shape from the
other oneB
Anisometropia H 3neD%al different refractive
errors of the t!o e#esB
Annealing & ;he heating of a material to a
s%fficientl# high temperat%re !ith s%bseD%ent
controlled cooling to relieve an# internal stress and
strainsBAnomal! H (n# stri6ing deviation from t#pical or
normalB
Anomalous Retinal Correspondence $ARC% H (
t#pe of retinal pro@ectionF occ%rring freD%entl# in
strabism%sF in !hich the foveae ,center of the retina
that prod%ces the sharpest e#esight- of the t!o
e#es do not facilitate a common vis%al directionL the
fovea of one e#e has the same f%nctional direction
!ith an extrafoveal ,non&fovea- area of the other
e#eB
A'* $American 'ational tandards *nstitute% H:#e!ear that meets this standard is considered
safer than e#e!ear that does notB
Anterior egment H ;he space in front of the iris
and behind the corneaF !hich incl%des corneaF
con@%nctivaF irisF lens and aD%eo%s h%morB
Antimetropia H ne e#e m#opic ,near sighted-F the
other h#peropic ,far sighted-B
Anti)Re(lective Coating H ( m%lti&la#er thin
coating applied to the lens s%rface to red%ce the
amo%nt of reflection from the lens and increase light
transmissionBApex H ;he thin edge of a prismBApa1ia H ( condition ca%sed b# the removal ofthe cr#stalline lens most often d%e to cataractsB
Aperture H ;he opening in an ophthalmic frame
front into !hich the lens is insertedB (pert%re
dimensions ,in millimeters- do not incl%de the depth
of the lens groveB
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A3ueous 4umor H ( clear !ater# liD%id in the
chamber of the e#e that flo!s bet!een the cornea
and the cr#stalline lens and no%rishes bothL
secreted b# the ciliar# processesB
AR tac1 H ombined la#ers ma6ing %p an (.
coating ,%s%all# five or more-B omposition ofla#ers can var# bet!een (. coatersB
Asepsis H ree fromF absence of infection or
infectio%s materialB
Asperic H ( lens that is not sphericalB ;he lens
s%rface is mar6ed b# a variet# of ellipticall#
changing c%rvat%resB (n aspheric design allo!s a
lens to be m%ch flatter !itho%t compromising the
optics of the lensB ;he benefitsM flatter lenses are
less noticeable in framesF and ma6e the !earerJs
e#es loo6 more nat%ral and less magnified or
minifiedBAsperic Compensation o( "o#er H 5o!er is
compensated in each area of the lens b# appl#ing
aspheric principlesB
Astenopia H C#mptoms of 'e#e&strain) incl%ding
headachesF tearingF itchingF b%rningF and bl%rred
visionB
Astigmatism H ( condition !here a misshaped
cornea ca%ses light to be foc%sed over a range of
distances rather than on a pointB ;his can be
corrected b# a lens !ith c#linder po!er in a certain
directionBAs!mmetrical esign H ( lens design that has
conto%r line patterns positioned differentl# into the
nasal and temporal area to prod%ce a right and left
lens designB ;his is e#e specific so the lens can not
be rotated to ma6e a right or left lensB
Atoric Lens H 9ens !ith astigmatic po!er in !hich
at least one principal meridian is not sphericalB
Automated Re(ractor H ;his method determines
the e#eJs refractive error and the best corrective
lenses to be prescribed b# %sing a comp%teri*ed
device that varies its optical po!er mechanicall#and prints o%t the res%ltsB
Axis C!linder H ;hat principal meridian !hich
contains onl# the spherical po!er component of a
sphero&c#linder lensB (xis !ill intersect a spherical
lens of min%s po!er at its thinnest point and a
spherical pl%s lens at its thic6est pointB
Axis 5ptical ) ,Q- H (n imaginar# line at right
angles to the s%rface of a lensF !hich passes
thro%gh the optical centerB ;he meridian of least
po!er 80º a!a# from the meridian of greatest
po!er in a c#lindrical lensL %sed in correcting
astigmatismBAxis Aligner "lier H (n# device %sed for aligning a
c#linder axis of a spectacle lens at its proper angleB
Axis *ndicator o( Lensometer H ( device in !hich
a scale from 0º to KP0º can be aligned to give the
axis of c#linder po!er on a spectacle lensB
B
“B” Box Measurement H 1n lens meas%rementF
the longest vertical distance from the %ppermost
point to the lo!ermost point of a shapeBBac1 +ocal Lengt H ;he distance from the bac6
s%rface of a lens to the image of an infinitel# distant
ob@ectB
Balance Lens H ( lens placed in a frame !hich
loo6s li6e the lens for the opposite e#e to balance
cosmeticsL similar in thic6ness and st#le !ith no
specific .x po!erB
Barium 6lass H ommonl# %sed for a t#pe of
cro!n glassF one of the ingredients is bari%m oxide
added for the p%rpose of increasing refractive
indexF !hile maintaining relativel# lo! dispersionBBarrel ) ,bbl- H ,K- ;he component of a hinge that
interloc6s !ith the mating component of the hinge
setF ,2- ( threaded clos%re device attached to a
metal e#e!ireB
Bar!ta 6lass H ( t#pe of glass containing lead for
increasing the index together !ith bari%m to
increase refractive indexF !hile maintaining a
relativel# lo! dispersionB
Base Curve H ;he sing%lar dioptric c%rve on the
front s%rface of a lensB ;his c%rve is generall# in
place !hen the lens blan6 is man%fact%red and ass%ch !ill control the selection of bac6 c%rves
necessar# to prod%ce a given prescriptionB ;his
s%rface c%rve becomes the basis from !hich the
other remaining c%rves are meas%redB Ghen
applied to lenses in generalF the base c%rve is the
gro%p c%rve or the c%rve common to a gro%p of lens
po!ersB
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Base o#n $B% "rism H ( !edged shaped lens
!hich is thic6er at the bottom of the lensB 5risms
bend light in the opposite direction from its thic6er
edge so base do!n prism t%rns the light %p!ard
th%s ca%sing the e#e to also move %p!ardB ;his
prism is %sed to meas%re an e#e alignment and /ortreat a binoc%lar d#sf%nction ,e#e teaming
problem-B 5risms are sometimes added to glasses
to help improve e#esight d%e to a misalignment or
vis%al field lossB
Base *n $B*% "rism H ( !edged shaped lens !hich
is thic6er at the nasal area of the lensB 5risms bend
light in the opposite direction from its thic6er edge
so base in prism t%rns the light o%t!ard ,to!ard the
ear- th%s ca%sing the e#e to also move o%t!ardB
;his prism is %sed to meas%re an e#e alignment
and /or treat a binoc%lar d#sf%nction ,e#e teamingproblem-B 5risms are sometimes added to glasses
to help improve e#esight d%e to a misalignment or
vis%al field lossB
Base 5ut $B5% "rism H ( !edged shape lens
!hich is thic6er on the o%t!ard edge of the lensF
closest to the earB 5risms bend light in the opposite
direction from its thic6er edge so base o%t prism
t%rns the light in!ard th%s ca%sing the e#e to also
move in!ardB ;his prism is %sed to meas%re an
e#e alignment and /or treat a binoc%lar d#sf%nction
,e#e teaming problem-B 5risms are sometimesadded to glasses to help improve e#esight d%e to a
misalignment or vis%al field lossB
Base 7p $B7% "rism H ( !edged shape lens !hich
is thic6er on the %p!ard edge of the lensB 5risms
bend light in the opposite direction from its thic6er
edge so base %p prism t%rns the light do!n!ard
th%s ca%sing the e#e to also move do!n!ardB ;his
prism is %sed to meas%re an e#e alignment and /or
treat a binoc%lar d#sf%nction ,e#e teaming
problem-B 5risms are sometimes added to glasses
to help improve e#esight d%e to a misalignment orvis%al field lossB
Basic +ormula H ;he s%b@ectiveL it is the lens
po!er that alters the light ra#s entering an e#e and
ca%ses a change in the foc%sing mechanism in the
greatest degree !itho%t ca%sing a s%b@ectivel#
detected alteration in the convergence mechanismB
Batc H =enerall# considered to be the n%mber of
lenses that fit into an (. chamber at one timeB
Baume 6auge H 3sed to chec6 the specific gravit#
of a polishing sol%tionB
Beam H ( gro%p of parallel ra#s of lightB
Bevel H ;he shaping of the edge aro%nd theperipher# of a lens necessar# to hold the lens !ithin
the groove of a specific frameB
Bevel -dger H ( machine b# !hich an %nc%t lens
is given a bevel on its edge b# a special lens
grinding !heelB
Bi)centric 6rinding $lab 5((% H ;he process of
grinding base %p prism to correct vertical
imbalanceB
Biconcave H ( lens st#le !here both front and
bac6 s%rfaces are min%s ,concave-B
Biconvex H ( lens st#le !here both the front andbac6 s%rfaces are pl%s ,convex-B
Bi(ocal H ( lens !ith t!o focal pointsF one for
distance vision and one for nearB .eg%lar bifocals
have a line bet!een the prescriptionsL 5rogressive
bifocals change grad%all# from the near to far
prescriptions !ith no visible line on the lensB
Binocular " H ;he single meas%red distance
from p%pil center to p%pil centerB
Binocular $binocularit!% Vision H ;he blending of
the separate images b# each e#e into a single
imageL allo!s images to be seen !ith depthBBi)5cularit! H %sing both e#esF b%t not together as
a teamB
Bire(rigence H ;#pe of lens aberration that is
ind%ced d%ring the man%fact%ring process !hich
res%lts in chromatic aberrationB ( rainbo!&li6e effect
,sometimes called Ae!ton .ings-B
Bitoric Lens H ( lensF both s%rfaces of !hich are
gro%nd and polishedF in toric or c#lindrical formB
Blan1 Molded H ( lens blan6 that is %nfinished on
both sides !hen it arrives from the lens factor#B
Blan1 emi)+inised H ( lens blan6 that isgro%nd and polished on one side to ma6e a
prescriptionB
Bleac H ( process to remove the tint from a d#ed
lensB
Blended Bi(ocals H ( ro%nd st#le bifocal t#pe lens
designed so that there is no discernable line of
demarcation bet!een the distance portion and the
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reading portionB ;he blended area is vis%all# non&
%sableB
Blended M!o)disc H 9enses have a f%ll field
c%rved or 5lano front s%rface !ith a high min%s
bo!l&shaped s%rface on the oc%lar side s%rro%nded
b# a 5lano s%rface called a carrierBBlemises H ,K- C%rface H present on the convex
or concave s%rface of the lensB ,2- 1nternal H
present in the material %sed for s%bstrate lens
prod%ctionB ,7- oating H formed or appearing
d%ring or in coatingB
Bleparitis H ( condition that describes an
inflammation of the e#elid margins characteri*ed b#
a stic6# cr%st that forms on the e#elidsB
Blinding 6lare H .eflected glare ca%sed b# light
reflected off smoothF shin# s%rfaces bloc6ing visionB
Blind pot H ,K- ( small area of the retina !herethe optic nerve enters the e#eL occ%rs normall# in
all e#esB ,2- (n# gap in the vis%al field
corresponding to an area of the retina !here no
vis%al cells are presentL associated !ith e#e
diseaseB
Bloc1er H ( mechanical device for affixing an
ophthalmic lens blan6 to a plastic or metal lens
carrierL %sed in lens edging and lens s%rfacingB
Bloc1ing H (ttaching lenses to a bloc6ing bod# or
handle in readiness for s%rfacing or edgingB
Blue Bloc1ers H (n orange colored tint form%latedto bloc6 o%t %ltraviolet radiation and red%ce bl%e
light !hich ma# be harmf%l to the e#eB
Blue Blur H ;he condition of %nclear vision d%e to
the scattered bl%e light in the visible spectr%mB
Blurred Vision H lac6 of clarit# or ac%it#B
Bon! 5rbit H :ither of t!o bon# cavities in the s6%ll
containing an e#e and its external str%ct%resL an
e#e soc6etB
Box Measurement H ;he meas%rement of a lens
or frame b# incorporating it !ithin a sD%are and
then meas%ring the hori*ontal and vertical inmillimetersB
Brea1 "oint H the point at !hich a person can no
longer f%se ,%nite- t!o images into oneB ( bl%r
point !ill occ%r before this pointB
Bridge H ;hat portion of the frame that rests %pon
the !earerJs noseB ;he bridge si*e is the shortest
hori*ontal distance bet!een lenses ,+9-B
Bro#)Bar H ( plastic or metal piece attached to the
%pper e#e!ire of a frame front to position the frame
a!a# from the !earerJs bro! or to add stabilit# to
the frame designB
Build)7p "ads H 5lastic pads that are cemented to
the bridge section of the e#e!ire to red%ce thebridge si*e and raise the frame frontB
C
C Measurement H ;he circ%mference of a lensB
Cable ,emple H (n earpiece of metalF plasticF or
combination thereofF !ith the portion in contact !ith
the ear consisting of !o%nd !ireF !ith or !itho%t a
coreB ;his portion is t#picall# bent in the shape of a
semicircle to fit sec%rel# aro%nd the earB
Calipers H ( hand&held mechanical meas%ringinstr%ment in the form of pliersF having t!o legs or
@a!s that can be ad@%sted to determine thic6nessF
diameterF caliberF and/or distance bet!een
s%rfacesB alipers are calibrated and meas%re in
tenths of millimetersB
Cantus H ;he angle formed b# the @%nct%re of the
e#elidsB
Carrier Lens H ;he ma@or portion of a lens that has
a differing po!er component cemented or f%sed to
itF creating the combined lens po!erB
Cataract H 5artial or complete opacit# of the lens ofthe e#eF ca%sing partial or total loss of visionB
:vent%all#F the clo%ded lens in the e#e m%st be
s%rgicall# removed and an intraoc%lar lens implant
inserted to ta6e its placeB
Cataract Lens H 9enses %sed to correct vision after
cataract s%rger#B
Cellulose Acetate H ommon material %sed to
ma6e frame partsB (lso referred to as '*#l)B
Cemented egment H (n added po!er ophthalmic
lens bo%ndF %s%all# b# epox# resinF to a carrierB
Center o( Rotation H ;he imaginar# point aro%nd!hich the e#eball pivots !hen movedB
Center ,ic1ness H ;he front&to&bac6
meas%rement of a lens at its optical or geometric
centerL %s%all# expressed in 0BK mm %sing a
caliperB
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Central Retinal Arter! H ;he blood vessel that
carries blood into the e#eL s%pplies n%trition to the
retinaB
Central Retinal Vein H ;he blood vessel that
carries blood a!a# from the retinaB
Cerium H (n oxide compo%nd %sed for polishing alens s%rfaceB
Cala.ion H ( small and freD%entl# painf%l c#st of
the e#elid res%lting from a bloc6ed meibomian
glandB
Camber H ;he vac%%m compartment of an (.
coating machine into !hich the lenses are placed
for (. applicationB
Cam(ering H 3se of a tool to remove all resid%al
lens material !hen drilling a holeB
Cassis H ;he metal e#e!ire and bridge
components of a combination front that holds thelensesB
Cemical 4ardening $tempering% H ( chemical
process b# !hich the lens is strengthened b# timed
treatment in a hotF ion&exchange bath chemicall#
replacingF from each s%rface of the lensF small ions
!ith larger ions into a thinF to%ghened s%rface la#erB
Ciasm H ;he lo!er portion of the brain at !hich
point the t!o optic nerves intersectB
Coroid H ;he la#er filled !ith blood vessels that
no%rishes the retinaL part of the %vea and bet!een
the retina and the scleraBCromatic Aberration H Ghen a lens ca%ses
!hite light to be bro6en into vario%s component
colors !ith each foc%s at a different distance from
the lensF commonl# prod%cing color fringe aro%nd a
vie!ed imageB
Cuc1 H ( padded metal or plastic circ%lar piece
%sed to s%pport a lens d%ring the edging processB
Ciliar! Bod! H ( str%ct%re directl# behind the iris of
the e#e and contains the ciliar# m%scleB
Ciliar! Muscles H ( band of m%scle and fibers that
are attached to the lens that controls the shape ofthe lens and allo!s the lens to accommodate
,change foc%s-B
Ciliar! "rocesses H ;he extensions or pro@ections
of the ciliar# bod# that secrete aD%eo%s h%morB
Clip)5n H (n apparat%s that holds t!o lenses
,%s%all# colored- to filter different light !avelengthsB
( piece attached to a frameB
C'C H omp%ter A%merical ontrolL the process of
g%iding the position of a machine tool s%ch as a
c%tting tool of a freeform generator %sed comp%ter
controlled reading inp%t of a program fileB
Coating H (pplied to corrective lenses after
s%rfacingB ,iBeB scratch resistanceF anti&reflectiveFmirrorF colorF tintF antistaticF anti&sm%dge-
Colmascope H ( device !hich thro%gh %se of
polari*ed lightF demonstrates strain existing in a
piece of lens materialB
Color Blindness H ,color deficienc#- H ( condition
in !hich a personJs abilit# to disting%ish colors and
shades is less than normalB olor blind is an
incorrect term beca%se onl# a small n%mber of
people are completel# %nable to identif# an# colorsB
olor deficiencies are %s%all# hereditar#B (cD%ired
deficiencies ma# indicate a health problemB ( c%refor color deficienc# has #et to be discoveredB
o!everF people !ith this condition can be ta%ght
to adapt and the abilit# to disting%ish colors can be
improved !ith the %se of colored filtersB
Color)Coated Lenses H 9enses !ith a metallic
oxide coating applied to s%rfaces b# means of
vac%%m depositionB ;he coatings are deposited
evenl# across the s%rface regardless of
prescriptionF so color is %niformB
Color "erception ,est H ( test that meas%res the
abilit# to identif# and disting%ish colorsBCombination +rame H ( frame !herein the front
consists of a metal chassis !ith attached trimB
;hese trim parts are t#picall# plasticF al%min%mF or
other metalF and are attached to the top portion of
the chassisB
Compound Lens H (n ophthalmic lens containing
both a spherical and c#lindrical refractive po!erB (
sphero&c#linder lens design is %sed to correct
astigmatismB
Compensated Curve H ( c%rve comp%ted to attain
a desired vertex po!er considering the thic6nessfactorB
Computer Vision !ndrome $CV% H ;he
complex of
e#e and vision problems related to near !or6 that
are experienced d%ring or related to comp%ter %seB
1ts s#mptoms incl%de e#estrainF dr# or b%rning
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e#esF bl%rred visionF headachesF do%ble visionF
distorted color visionF and nec6 and bac6 achesB
Concave Lens H ( spectacle lens !hich is thic6er
at the edges than in the centerB ( concave or
'min%s) lens diverges ,decreases- the po!er of
incoming light ra#sF and is %sed in the correction ofm#opia ,nearsightedness-B
Cones Cone Cells H ne t#pe of speciali*ed light&
sensitive cells ,photoreceptors- in the retina that
provide sharp central vision and color visionB
Con&unctiva H ;he thinF moist tiss%e ,membrane-
that lines the inner s%rfaces of the e#elids and the
o%ter s%rface of the sclera and contains man# blood
vesselsB
Con&unctivitis H (n inflammation of the
con@%nctivaF the transparent la#er covering the inner
e#elid and the !hite portion ,sclera- of the e#eballBon@%nctivitis can be ca%sed b# a vir%sF bacteriaF or
f%ng%s ,infectio%s con@%nctivitisF or 'pin6 e#e)F ma#
be contagio%s-L allergies to pollenF fabricsF animalsF
or cosmetics ,allergic con@%nctivitis-L or b# air
poll%tion or noxio%s f%mes s%ch as s!imming pool
chlorine ,chemical con@%nctivitis-B C#mptoms
incl%de red or !ater# e#esF bl%rred visionF inflamed
inner e#elidsF scratchiness in the e#esF or ,!ith
infectio%s con@%nctivitis- a p%ss li6e or !ater#
discharge and matted e#elidsB on@%nctivitis is
%s%all# treated !ith antibiotic e#e drops and/orointmentB
Contact Lens H ( small soft or rigid corrective lens
that fits directl# on the s%rface of the e#e and floats
on tear film over the cornea to corrective vision
errorsB
Contact Lens $ail! 8ear% H ontact lenses
designed to be !orn onl# d%ring !a6ing ho%rsB
reD%ent R planned replacement contact lenses
general term %sed to refer to contact lens regimens
in !hich lenses are replaced on a planned
sched%leF ever# t!o !ee6sF monthl# or D%arterl#BContact Lens $isposable% H ontact lenses
defined b# the 3BCB +( as a contact lens that is
%sed one time and discardedB ;hese can be !orn
either for a single da# or %p to seven da#sF
depending on !ear sched%le prescribed b# the e#e
care professionalB (n# lens that is intended to be
removed from the e#eF cleanedF rinsedF disinfectedF
and reinserted does not D%alif# for incl%sion in this
categor#B
Contact Lens $-xtended 8ear% H ontact lenses
designed to be !orn aro%nd Hthe&cloc6 for intervals
of one to seven da#sB
Contact Lens $,erapeutic% 9 ontact lensdesigned to aid in protecting and helping a sic6 e#e
to healB ;hese %niD%e lenses are freD%entl#
combined !ith precise medication deliver#
sched%les to heal the e#eB
Contact Lens $,oric% H ontact lenses designed to
correct astigmatic refractive errorsB ;oric lenses are
!eighted to maintain a specific axis across the
corneaB
Contrast ensitivit! H ;he abilit# to perceive
differences bet!een an ob@ect and its bac6gro%ndB
Convergence H ;he abilit# to %se both e#es as ateam and to be able to t%rn the e#es in!ard tomaintain single vision close %pB
Coolant H ( liD%id %sed to red%ce the heat ca%sed
b# friction of a s%rfacing operationB
Cord Mount & ( frame st#le !here the lenses are
held in the frame b# a thin plastic cord !hich fits a
groove in a flat edge of a lensB
Core H ,K- ( central strand aro%nd !hich other
!ires are !o%nd in a core templeF ,2- Gire
reinforcement imbedded in plastic temples ,core
!ire-B
Cornea H ;he o%terF transparentF dome li6e
str%ct%re that covers the irisF p%pilF and anterior
chamber of the e#e that transmits light to the e#eF
and is the ma@or refraction element of the e#eB
Corneal Abrasion H ( c%t or scratch on the
corneaB
Corneal Astigmatism H +efect in the c%rvat%re of
the cornea !hereb# light ra#s passing thro%gh the
cornea prod%ce aberrations and are not foc%sed on
the retinaB
Corneal Re(lection H ?ethod of meas%ring the
distance from the p%pilF %sing light reflected from
the cornea to the center of the noseB
Corneal Re(lex H 1rritation of the cornea res%lting in
reflex clos%re of the e#elidsB
Corneal ,opograp! H ?apping or examination of
the s%rface of the corneaB
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Corrected Curve H ( c%rve designed to partiall# or
totall# correct either or both the marginal astigmatic
error and the marginal spherical errorB
Corrective Lenses H orrects e#esight disorders
and is a combination of materialF optical s%rfaceF
and coatingsBCorridor Lengt H ;he distance bet!een the fitting
cross and the point of f%ll add po!er on a
progressive lensB
Corundum H :xtremel# hard material !hich emer#
is madeB
Cover ,est H ( test of e#eball alignment in !hich
each e#e is covered !ith an occl%der ,e#e cover-
and then %ncovered to observe e#e movementsB
Convergence H ;he sim%ltaneo%s t%rning in of the
e#es to 6eep an ob@ect in sight as it comes nearer
to the e#eBConvex Lens H ( spectacle lens !hich is thic6er in
the center than at the edgesB ( convex or 'pl%s)
lens adds optical po!er to incoming light ra#s %sed
in the correction of h#peropia ,farsightedness-B
CR):; H ( thermostat resin material from !hich
plastic lenses are castB (lso called hard resin or
plasticF it !as the 78th form%la from ol%mbia
.esin and is no! man%fact%red and trademar6ed
b# 55= 1nd%striesB
Cra.ing H ( crac6ed or spider !eb appearance on
a lens s%rface or edgeBCribbing H .emoval of excess lens material on the
edgeB
Cross Curve H ;he strongest c%rve of a toric
s%rfaceL lies in the meridian 80 degrees from the
base c%rveB
Cross -!e H See strabismus.
Cro#n 6lass H ( spectacle lens material of KBO27
indexB
CR" $Corneal Re(lection "upilometer% H ( device
%sed to meas%re the distance bet!een p%pils of the
e#es in millimetersBCR, $Computer Reading ,ri(ocal% H ( m%ltifocal
design that feat%res !ider intermediate areas !ith a
N0S (dd strengthB ;he# are s%ited for arms&length
distance s%ch as comp%ter screenB
Cruxite H ;rade name of a glass pin6 tintB
Cr!stalline Lens H ( transparent biconvex lens
located behind the p%pil that helps to foc%s light on
the retinaB
C)si.e H ?eas%rement needed for acc%rate lens
si*ingB ;he millimeter reading of the circ%mference
of a given lensBC)si.er H ( mechanical device for meas%ring the
circ%mference of a lensB
Curve ,op H ( bifocal lens !ith the top line of the
segment slightl# c%rved instead of straightB
Custom Coating H 5rescription lenses ordered
!ith a coating that is processed from a semi&
finished blan6 and then coatedB
Customi.ation H ;he act of tailoring the optical
characteristics of a progressive lens design to the
individ%al !earer based %pon information specific to
that !earerBCut < Coat H ( method of freeform s%rfacing that
relies on achieving l%ster ,transparenc#- on a
generator s%rface b# glossing the s%rface !ith a
hard coating instead of polishing the s%rface
mechanicall#B
C!cloplegic Re(raction & (n examination method
to determine the e#eJs refractive error and best
corrective lenses to prescribeB ;he e#e is dilated
!ith the m%scles of accommodation ,e#e foc%sing
m%scles- being temporaril# paral#*ed !ith special
e#e drops or spra#B ;his is a good method for non&responsive or non comm%nicative patients s%ch as
#o%ng childrenB
C!linder Axis H ;he meridian in !hich the sphere
po!er f%nctions aloneB
C!linder Lens H ( compo%nd lens !ith a toric
s%rface !ith the t!o separate dioptric meridians 80º
apartB ?a# be recorded in ,&- or ,$- po!erB 1t is
al!a#s follo!ed b# an axisF the direction in !hich
there is no po!er of the c#linderB ( prescribed
amo%nt of po!er that is added or s%btracted to the
lens sphere po!er to create t!o different po!ers inthe principal meridiansB
D
atelite => x :? ,ri(ocal H (n occ%pational trifocal
designed for comp%ter %se !ith a !ider ,7O mm-
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and deeper intermediate seg ,KEmm- !ith
intermediate po!er of O0&IIS in the trifocal areaB
atum Line H ( line at the midpoint bet!een the
top and bottom of a lensF also referred to as the
KP0º lineB 3nless other!ise specifiedF optical
centers are gro%nd on this lineB“BC” H +istance et!een entersB
“BL” & +istance et!een 9enses H ;he closest
distance bet!een lensesB ;he fig%re is needed to
comp%te decentration and is meas%red from the
closest nasal point of one lens to the closest nasal
point of the other lensB ;his meas%rement ma# be
different that the mar6ed bridge n%mber on the
frameB
ecenter H ;o place o%t of centerB
ecentration H ;he act of moving the optical
center of a lens a!a# from the geometric center ofa shape or frame for the p%rpose of aligning the
optical center over the p%pilB ;he lens ma# also be
displaced a!a# from the !earerJs line of sight for
the p%rpose of creating prismatic effectB
egree $@% H ;he 7I0th part of the circ%mference of
a circleB ;he %nit %sed for specif#ing the position of
the axis of a c#linder or the location for the base of
a prismB
ensit! H ,K- ;he !eight of a material per %nit
vol%meL ,2- ( meas%rement of the transparenc# of
a medi%mF as related to light transmissionBept "erception H ;he abilit# to @%dge relative
distances of ob@ectsB
ept "erception ,est H ( test to meas%re the
abilit# of the vision s#stem to discern the relative
distances of vario%s ob@ectsB ,(lso called a
'Ctereopsis ;est)B-
escemets Membrane H the lining of the posterior
portion of the corneaB
evelopmental Vision Anal!sis H ?ore
comprehensive than a ro%tine e#e examF
examination !ill eval%ate all of the patientJs vis%alabilities s%ch as a vis%al ac%it#F e#e foc%sing s6illsF
e#e teaming s6illsF e#e trac6ing s6illsF vis%al motor
s6illsF and vis%al percept%al s6illsB
eviation H ,K- ;he change in direction of light d%e
to the action of a prismL ,2- a misalignment of one
or both e#es associated !ith extraoc%lar m%scle
imbalanceB
iabetic Retinopat! H Gea6ens and ca%ses
retinal changes in the small blood vessels that
no%rish the e#eJs retinaF the delicateF light sensitive
lining of the bac6 of the e#eB ;hese blood vessels
ma# begin to lea6F s!ell or develop br%sh&li6e
branchesBiagram H ( dra!ing ill%strating the basic frame
meas%rementsB
iameter H;he length of a straight line from one
edge of a lens to the other and passing thro%gh its
centerB
id!mium H ( specific tinted glass lens %sed for
!earer exposed to a soda ash or sodi%m flareB
ften %sed for 'glass blo!er) occ%pationB
ielectric Mirrors H ( mirror coating %sing
bet!een O R KK la#ers of virt%all# colorless
materialsF precisel# appliedF !hich res%lts in abrilliant color mirror effectB ;his mirror does not add
densit# to the lensB
i((raction H 9ight c%rves or travels aro%nd small
circ%lar ob@ectsB
i((usion H ;he scattering of light ra#s that ca%ses
a bl%rred image d%e to the imperfect refractionB
igital ur(acing H 5recise s%rface c%tting %sing
single point t%rningL c%tting height is controlled at all
points of the lensB
ilation H ( process b# !hich the p%pil is
temporaril# enlarged !ith special e#e drops,m#driatic-L allo!s the e#ecare specialist to better
vie! the inside and bac6 of the e#eB
iopter $% H ( %nit of meas%rement of the
refractive po!er of the lensB ( lens !hose focal
point is one meter has a po!er of one diopterB (
lens !hose focal length is one&fo%rth of a meter has
a po!er of fo%r dioptersB
iplopia H +o%ble visionL normall# the ob@ect !hich
is being observed is single and ob@ects in front and
behind this ob@ect are seen do%ble ,diplopia-B
i((use 6lare H .eflected light that does notprod%ce a clearl# discernible imageF iBeBF a ha*#F
bright lightB
irect +ield o( Vision H ;hat portion of the field
!hich is seen b# the mac%laB
irect 6lare H .elativel# bright light that is not
reflectedF b%t emanates from a so%rce s%ch as the
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s%nF oncoming a%tomobile headlightsF or other light
so%rceB
irect 5cclusion H overing the non&ambl#opic
e#eB
ispensing H ;he art of selecting a frameF ta6ing
meas%rementsF filling the lens prescriptionF andfitting a pair of glassesB
ispersion H ;his occ%rs !hen !hite light is split
into separate !ave lengths and component colorsB
istance Acuit! H ;he e#eJs abilit# to disting%ish
an ob@ectJs shape and detail at a far distanceF s%ch
as 20 feet ,I meters-B
istance Vision H 4ision !hen loo6ing at distance
ob@ectsB
istometer H ?eas%res vertex distances ,front of
the e#e to the bac6 of the lens-B
istortion H (n aberration !hich occ%rs as lightra#s move from the center of the lens to!ard the
peripher#B (s ra#s approach the edgeF the lensJs
increasing magnification ca%ses a distorting of the
imageB
ivergence H ;he abilit# to %se both e#es as a
team and be able to t%rn the e#es o%t to!ard a far
ob@ectB
ominant -!e H ;he e#e that 'leads) its partner
d%ring e#e movementsB %mans also have a
dominant handF footF e#eF and side of brain ,not
necessaril# all on the same side-Bouble Concave Lens H ( biconcave lens of
special form having hollo! s%rfaces of eD%al radii
on both sides of the lensB
ouble Convex Lens H ( biconvex lens of special
form having b%lging s%rfaces of eD%al radii on both
sides of the lensB
ouble egment Bi(ocals H 9enses !ith
segments at the top and bottom of the lensB C%ited
for those !ho reD%ire near focal length above and
belo! the headB
o#n Bend H ;he drop or do!n!ard bend of thetip end of a temple ,earpiece- to fit over and aro%nd
the earL also 6no!n as the ear bendB
rilling H ;he process of ma6ing a hole in a lens
for mo%nting on a frameB
rop Ball ,est H ( lo!&velocit#F impact resistant
testF commonl# %sing a solid steel sphere free&
falling O0 inchesB or (BABCB1B T&P0 standardsF a
O/P inch steel ball falling O0 inchesL for (BABCB1B
TPNstandardsF a K&inch steel ball falling O0 inchesB
rusen H ;in# #ello! or !hite deposits in the retina
or optic nerve headB
r! -!e !ndrome 9 1tchingF b%rningF and irritation
of the e#esB a%sed b# lac6 of D%alit# or D%antit# oftears to l%bricate e#esB ?a# prescribe 'artificial
tears) to alleviateB
uction ,est H ( test of the e#eJs abilit# to t%rn
in!ard or o%t!ard !hile maintaining singleF
binoc%lar vision !ith the grad%al introd%ction of
progressivel# stronger base&in or base&o%t prismsB
!seidetic H 5oor sight recognition of !ordsB (
form of d#slexiaB
E
-arpiece H ( component of a spectacle frame
designed to assist its stabili*ation b# extending over
the external earB
-ccentric +ixation H ;he person fixates the image
of regard !ith an area other than the fovea ,center
of the retina that prod%ces the sharpest e#esight-
area of fixationB
-C" H (bbreviation for e#ecare professionalB
-dge H 1n lens opticsF the flat or angled s%rface
!hich limits the refracting s%rfaces of a lensL the
edge determines the peripheral shape of a lensB-dge Coat H Colid color coat applied on the edge
of a lens to hide thic6ness and eliminate ring
reflections seen in the lensB 3s%all# color selected
matches the frame color closel#B
-dge "olising H ;he grinding process on edge of
lenses leaving a finished clear edge rather than a
!hite frostB
-dged Lens H ( lens that has been gro%nd to
prescription and c%t to the si*e and shape of an
e#eglass frameB
-dger H ( machine %sed to red%ce a lens to adesired si*e and shape of a frame !ith a desired
edge conto%rB
-dging H :dging a lens means hogging it do!n
from its original circ%lar shape to the precise si*e
and shape needed for it to fit into the !earerJs
frameB
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-((ective iameter $-% H ;!o times the longest
radi%s of an# given shape or lensB ;his val%e !ill
give the smallest theoretical diameter needed to c%t
o%t an# given shapeF ass%ming the center of that
blan6 !as s%perimposed over the geometric center
of the shapeB :+Js are especiall# critical in high.xs to determine appropriate blan6 si*e and lens
thic6nessB
-((ective "o#er H Cee vertex po!erB
-lectromagnetic pectrum H ;he entire range of
radient energ#F incl%ding x&ra#F visible lightF
infraredF radiationF radio !avesF etcB
-mer! H ;he abrasive %sed for grinding a lens
s%rfaceB
-mmetropia H ;heoreticall# normal e#esightB
.efractive condition of the e#e in !hich the ra#s of
light come to a point of foc%s perfectl# on the retinaB-ndotelium H ;he inner most la#er of the corneaB
-ndpiece H ;hat part of a frame !here the frame
front is @oined !ith the templeB
-pitelium H ;he o%ter most la#er of the corneaB
-pox! H ( t!o component organic coating applied
to frames for adding d%rable decorative colorationB
-3utin "risming H ( proced%re grinding base
do!n prism 3 ,both lenses- to arrive at a thinnerF
more pleasing lensB :D%ithin can be %sed on an#
prescription b%t is especiall# effective on pl%s
distance prescriptionsF progressive lensesF andexec%tive st#le m%ltifocalsB
-soporia H ;he tendenc# of the e#e to t%rn
in!ard or nasall#B
-sotropia H ( condition of misalignment of the
e#es in !hich one or both e#es t%rn in!ard or
nasall#B
-xecutive Bi(ocal H ( one&piece bifocal that
incorporates the total bottom portion of the lens for
close vision !ith a visible dividing line across the
entire lensB 1t is thic6er and heavier than flat top
st#les and disco%raged beca%se of thesedra!bac6sB
-xecutive )eg ,ri(ocal H ( plastic trifocal !ith a
flat top 2O mm seg st#le set inside the intermediate
exec%tive st#le areaB
-xecutive ,ri(ocal H ;here are t!o ledges across
the lens that represent the bifocal and trifocal area
for distanceF intermediateF and near vie!ing areasB
-xpanded Visual +ields H GiderF largerF or more
precise vision in the field of vie!B
-xtraocular Muscles H ;he m%scles attached to
the o%tside of the e#eball !hich control e#e
movementB :ach e#e has six m%scles that are
coordinated b# the brainB-xoporia H ;he tendenc# of the e#e to t%rn
o%t!ardB
-xotropia H +ivergent strabism%sB ( condition of
the e#e t%rning laterall# or temple!ard of one or
both e#esB
-xtraocular H %tside or external to the e#eB
-!e H ;he organ of visionL oc%l%sB 1n h%mansF a
spheroid bod# approximatel# one inch in diameterF
occ%rring in pairsF positioned in soc6ets in the front
of the s6%llF !hich foc%s lightB
-!eglasses H ( term commonl# %sed to describean ophthalmic frame !ith lenses insertedB
-!e 4and Coordination H ;he abilit# of the e#es
to g%ide the handsF also called vis%al motor
integrationB
-!e Lids H ?ovable folds of tiss%e that protect the
e#e from in@%r#F excessive lightF and distrib%te the
tear film over the cornea and con@%nctivaB
-!e "iece o( Lensometer H ;he telescopic portion
of the instr%ment that can be foc%sed to the
individ%al e#eJs error in order to see the ad@%stment
of the po!er !heelB-!e i.e H Ci*e of lens hole meas%red !ith a
millimeter r%ler on a frame from edge to edge to
inside frameB
-!e ,rac1ing H ;he abilit# of the e#es to smoothl#
and effortlessl# follo! a moving targetB
-!e#ire H ;he part of the frame that encircles the
lens and holds it in placeB
F
+ace +orm H ;he gentle !rap of a frame frontnecessar# to parallel the ro%ndness of the headB
+aceted Lens H 5rescription lenses fabricated !ith
highl# polished and beveled edgesB
+actor! Coating H oatings applied to large
batches of lenses !here the .x is alread#
established on the lensB
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+ar "oint H ;hat point %pon the vis%al axis of the
e#e !hich is sharpl# imaged on the retina !hen the
accommodation is relaxedB ;he far point of a
normal e#e lies at infinit#B
+arsigtedness H ( condition in !hich the optics
of the e#e are not adeD%ate to foc%s on the retina ofthe e#eB ;his res%lts in bl%rred visionF %s%all# in the
near field of visionB 1t is corrected !ith pl%s po!er
lensesB ,(lso called h#peropiaB-
+ ,ri(ocal H ;raditional near flat top segment
positioned on a f%ll lo!er portion intermediate lensB
+ield o( Vie# H +istanceF intermediate and near
vie!ing areasL part of the observable !orld thatJs
seen at an# given momentB
+ilter H 1n optical scienceF a deviceF materialF or
color for restricting transmission of certain light
ra#sB+ine Motor 1ills H ;he abilit# to coordinate hand
and finger movementsB
+ining H ;he grinding proced%re #ielding a satin
smooth finish immediatel# prior to the polishing
stage of lens s%rfaceB
+inised 7ncut Lens H (n ophthalmic lens that
has been gro%nd and polished on both sides to a
specific prescription po!er and thic6nessL has been
edged rendered impact resistantF if necessar#F and
prepared for insertion or mo%nting into a frameB
+itting H ;he meas%rement and/or ad@%stment offrames or mo%nting for the specific needs of the
!earerB
+itting Cross H ;he location on a progressive
addition lens that is normall# fit in front of the p%pil
centerL denoted b# t!o U inch lines crossed at right
angles to each other on a lens la#o%t chartB 1t is
%s%all# 2&E mm above the ma@or reference point
,?.5- or optical center of the lensB
+itting ,riangle H 1n spectacle opticsF a geometric
constr%ction from the three points !here spectacles
contact or p%t press%re against the headB ;he apexof the triangle is the press%re point on the crest of
the noseF and the base of the triangle is the t!o
press%re points @%st above the external earsF on
each side of the headB Ghen nose pads are %sedF
there !ill act%all# be t!o press%re points at the
apex of the triangle rather than oneB
+ixation H ;he abilit# to aim the e#e and hold that
aim on an ob@ectF s%ch as a !ord in a line of printB
+ixation isparit! $+% H over&convergence or
%nder&convergenceF or vertical misalignment of the
e#es %nder binoc%lar vie!ing conditions small
eno%gh in magnit%de so that f%sion is presentB+las Mirror H ( highl# reflective coating on lenses
that is added for both cosmetic and performance
reasonsB
+lat H Tero base c%rvat%re or flat s%rfaceB
+lat),op Bi(ocal H ( t#pe of m%ltifocal in !hich the
segment is flat on topB (lso 6no! as a '+) seg or
straight topB
+lexural trengt H ( materialJs abilit# to resist
deformation %nder loadB
+lint 6lass H ( glass to !hich lead has been
added res%lting in both higher index and dispersionB+loaters H ften called spotsF these are smallF
semi&transparent or blac6 spec6s !ithin the e#e
that becomes noticeable !hen the# fall in the line of
sightB ?edicall#F the# are deposits of var#ing
shapes and si*es present in the normall#
transparent vitreo%sB ne ma# be born !ith
floaters or develop themB loaters can be an
indication of serio%s vis%al problemsB
+luorescein Angiograp! H ( test to examine
blood vessels in the retinaF choroids and irisB (
special d#e is in@ected into a vein in the arm andpict%res are ta6en as the d#e passes thro%gh blood
vessels in the e#eB
+lux H ;he rate of flo! of fl%id or energ#B
+ocal Lengt H ;he distance from the bac6 vertex
of a lens to its focal pointB
+ocal "oint H Ghen parallel ra#s of light are
refracted b# a lens the# !ill converge or diverge
from the focal point of the lensB
+ocimeter H (n optical instr%ment for determining
vertex po!erF axis locationF optical centerF error&
free pointF and prism po!er at an# given point onan ophthalmic lensL also called lensometer or
vertometerB
+ocus H ( point thro%gh !hich ra#s of light
converge or from !hich ra#s of light appear to
diverge !hen entering or emerging from an optical
s#stemB
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+orm Constanc! H ;he abilit# to recogni*e t!o
ob@ects that have the same shape b%t different si*e
or positionB ;his abilit# is needed to tell the
difference bet!een 'b) and 'd)F 'p) and 'D)F 'm) and
'!)B
+ormer H (nother name for lens patternB+orm +it Bridge H ;he nasal bearing s%rface
consisting of t!o pads and a connecting strap or
one solid piece of plastic made of clear acr#lic or
silicone based materialB
+ovea H ( central part of the mac%la that provides
the sharpest vision and contains the most conesB
+rame H (n appliance that is designed to hold
corrective lensesB
+rame " & ;his is the distance bet!een centers of
the e#e!iresB ;o calc%late frame 5+F simpl# add
the e#e si*e and the bridge si*eB ( EPx20 frame
has a IP frame 5+B
+ran1lin Bi(ocal H ;he initial m%ltifocal lens made
b# %niting the %pper half of a distance po!er lens
and the lo!er half of a near po!er lens in one
frameL the t!o half lenses are independent of each
otherB
+resnel "rism H ( series of narro! prisms molded
into one piece of soft plastic that has the effect of
one prismB ;hese prisms are c%t and applied
directl# to the lens s%rfaceB ;he# are an alternative
!hen prism is reD%ired and a standard lens can not
be gro%nd or !hen lenses !ill be too thic6 and
heav#F if s%rfacedB 1n additionF the# can be
removed !itho%t rema6ing a lens !hen a patientJs
prism correction is %ndergoing several changes
over a period of timeB
+ringe H 3sed to denote lenses or blan6s of s%ch
po!erF c%rvat%re or t#pe that are not %sed in great
D%antit#B
+ront H ( component of an ophthalmic frame
t#picall# consisting of a bridge and e#e!iresB
+rosted Lens H ( transl%cent lens s%rface that
allo!s light to enter the e#e !itho%t crispF sharp
opticsB
+racture H ( crac6 in an ophthalmic lens s%rfaceB
+undus H ;he interior lining of the e#eballF
incl%ding the retinaF optic discF and mac%laL portion
of the inner e#e that can be seen d%ring an e#e
examination b# loo6ing thro%gh the p%pilB
+ull +ield Lens H 9ens in !hich the *one of the
prescription optics extends to the edge of the lensB
+used egment & 1s prod%ced b# imbedding a
piece of glass of greater densit# into a cro!n lensB
=enerall#F the segment is placed on the convex
side of the lens and the c%rves on this s%rface are%niform over the entire areaB
+using H ;he %niting of t!o pieces of lens material
b# means of high temperat%reB
+usion H ;he process of merging the images from
each e#e to form a three&dimensional ob@ectB
+usion ,est H +etermines the e#es abilit# to %nite
the images from each e#e into a single imageB
+usional Vergence H ( convergence response
!hich serves to maintain ,f%sion- the %nion of
images from each e#e into a single imageB ;he
e#es !ill t%rn !ith a slo! smooth tonic movementor a fast @%mping movement called phasicB
G
6auge H ( meas%ring instr%ment or device
calibrated to a previo%sl# established standardF or
s#stem of %nitsB
6enerating H ( rapid ro%ghing process to D%ic6l#
remove material from a lensB (ccomplished b#
c%tting tools on a machineB
6enerator +ree)+orm H ( t#pe of comp%ter&
controlled generator !ith at least three axes of
movement that can c%t most contin%o%s lens
s%rface shapes to a level of precision and
smoothness that reD%ires onl# minimal polishing
!ith a free&form polisherB
6enerator ,raditional H ( t#pe of generator !ith
either t!o or three axes of movement that can c%t
onl# basic spherical and sphero&c#lindrical lens
s%rface shapes to a minimal level of smoothness
that reD%ires additional fining !ith a c#linder
machineB
6eometric Center H ,K- ;he point of a lens that is
mid!a# bet!een the topF bottomF nasal and
temporal edgesB ;his point is most al!a#s different
from the gro%nd optical centerL ,2- the intersection
of the hori*ontal and vertical center lines of a box
that circ%mscribes the lens shapeB
6ost *mage H 1n spectacle opticsF an %n!anted
secondar# image formed b# internal reflections
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from the rear or b# reflection from the anterior
s%rface of the cornea and a second reflection from
the oc%lar ,e#e- s%rface of a spectacle lensB
6lass H ( hardF brittleF amorpho%s s%bstance made
from heat&f%sed silicates !ith soda or potashF limeF
metallic oxidesF and similar elements of transparentD%alit# %sed to man%fact%re an ophthalmic lensB
6lass Beads H Cmall balls of glass %sed in a frame
!armer to provide an evenF constant heat to the
frameB
6lare H .elativel# bright light entering the e#e
creating da**leF discomfortF or vis%al impairmentB
6laucoma H ( disease associated !ith increased
press%re of the fl%id of the e#eB ;his disease ma#
initiall# have no s#mptoms or painB ;he condition
damages the optic nerve that ma# lead to
blindnessB ?a# be treated !ith medication drops
and/or s%rger#B
6la.ing H ;he process of edging and inserting
lenses into frames or mo%ntingsB
6oggle H (n oc%lar protective device designed to
fit the orbital area of the face to shield the e#es
from a variet# of ha*ardsL ma# be ventilated or non&
ventilatedB
6onioscope H ( magnif#ing device %sed in
combination !ith strong ill%mination and a contact
lens for examining the angle of the anterior
chamber of the e#eB
6radient H 1n tinting lensesF application of d#e to a
lens ma6ing the top dar6er and fading to clear
to!ards the bottom of the lensB
6radient Mirrors H 5rimaril# %sed for driving or
reading o%tdoorsB ;his mirror helps reflect the
intensit# of the s%n above !hile leaving a slight
lighter area belo! for better visabilit# of the
dashboard or reading materialB
6re! H ondition of a lens s%rface !hen improperl#
or ins%fficientl# polishedB
6rind H ;hat process in the fabrication of a lens
!hich gives it a specific nat%reB
6roove H ;he angle formed b# the 4&shape of an
e#e!ire groove to accommodate a beveled lensB
6rooving H ;he process of c%tting a deep channel
bet!een the edges of a rimless lensB ;his allo!s
the lens to be sec%rel# mo%nted in to a frame %sing
metal or n#lon cordB
H
4al( -!e H ( frame designed in s%ch a manner that
the !earer ma# loo6 over the top %sing nat%ral
vision for distance and the correction on the bottom
for close visionB4and tone H ( rotating !heel composed of a
material than can grind a lens and not chip it %sing
the stone and appl#ing a lens edge to its s%rfaceB
4ard esign H ( progressive lens design t#picall#
having large clear distance and reading *onesB 1n
order to create these distinct areasF all of the
%n!anted s%rface astigmatism is forced to the
peripher#B ;he res%lt is a closel# pac6ed s%rface
astigmatismF on either side of the corridorF bet!een
the KP0º line and the reading areaB
4ard Resin H ( thermostat resin material from
!hich plastic lenses are castB (lso referred to
.&78 or plasticB
4a.e H 1n ophthalmic lensesF the presence of slight
scratchesF marsF coating delaminationF or similar
s%rface imperfections that interfere !ith light
transmission b# creating scatter lightF s%rface
astigmatismF on either side of the corridorF bet!een
the KP0º line and the reading areaB
4eat ,empering $ardening% H ( heat treatment
applied %nder press%re to the front and bac6
s%rface of the lens to strengthen the lens against
brea6ageB
4emeralopia H +a# blindnessL defective vision in
bright lightB
4emianopsia H lindness of half the vis%al field of
one or both e#esB
4eteroporia H ;endenc# of the e#es to deviate
from their normal position of vis%al alignmentB (
m%sc%lar imbalance existsL ho!everF a person can
overcome it and still maintain approximatel# normal
single binoc%lar visionB
4eterotropia H ;he e#es are abnormall# t%rnedB4ex 'ut H ( small hexagon n%t %sed on the end of
a post or scre! in order to retain a lens in a frame
or frame parts togetherB
4idden 4inge H (n imbedded hinge anchoring
device !hich allo!s elimination of shieldsB
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4ide)A)Bevel H ( specific t#pe of bevel %sed for
cosmetic appearanceB 1t is a flatter bevel generall#
%sed on strong min%s lensesB
4ig *ndex Lens H 9ens !ith a refractive index
greater than KBON made from this material !ith more
efficient light&bending abilit# ,high index ofrefraction- than hard resin or cro!n glassB ;he
res%lt is a thinnerF and in most casesF a lighter lensB
4inge H ?etal fastener attached to both the
endpiece of the front and the end of the templeB 1t
has 7F OF or N barrels !hich interloc6 one anotherB
4ordeolum/t!e H ( smallF sometimes painf%lF
infection of the sebaceo%s gland of the e#elidB
4ori.ontal Meridian H the KP0º meridian on a
c#lindrical s%rfaceB
4ue H ;he partic%lar aspect of color or !avelength
that enables it to be assigned a position in thevisible spectr%mB
4!dropobic H aving little or no affinit# for !aterB
4!dropobic Coating H ;he top la#er of modern
coatings designed to repel oils and dirt and other
debris on the lens s%rfaceB 1t provides sm%dge
resistanceF cleanabilit#F and s%rface d%rabilit#B
4!permetropia H .efractive error or optical defect
of the e#e in !hich parallel ra#s of lightF as from a
distant light so%rceF stri6e the retina before coming
to a foc%sB
4!peropia H arsightednessL the abilit# to seedistant ob@ects more clearl# than close ob@ectsL ma#
be corrected !ith glasses or contact lensesB
4!perporia H ( tendenc# of one e#e to t%rn
above the other e#eF ca%sing e#estrainB
Cometimes improved b# prism gro%nd in lensesB
4!pertropia H ne e#e is act%all# t%rned above
the otherB
4!po)Allergenic H 5ropert# of prod%ct offering
benefit in red%ction of sensitivit#B
4!potropia H +o!n!ard deviation of one e#eB
I
*llumination H ;he amo%nt or intensit# of light
stri6ing an ob@ectB
*mage ump H ;he apparent s%dden displacement
of an ob@ect that occ%rs !hen the fixation axis
passes abr%ptl# from one vie!ing area of a non&
progressive m%ltifocal lens to anotherB ;his ma# be
exaggerated in high po!er lensesF b%t can be
minimi*ed b# proper segment choiceB
*mbalance H ( state or condition !hen something
is o%t of eD%ilibri%m or %neD%alB
*mpact Resistance H ;he meas%red abilit# ofmaterial or lens to s%stain d#namicall# applied
external forces !itho%t brea6ingB
*n situ H 9atin for 'in the sit%ationB) (llo!s !earer to
!ear frame as the# !o%ld !ear it normall# before
ma6ing lens meas%rementsB
*n Camber H ;he action or application ta6es place
inside the vac%%m chamber d%ring coating
application processB
*ncident Ra! H ( ra# of light is said to be an
incident ra# before it stri6es a lens or prismB (fter
passing thro%gh the lens or prismF the ra# is said tobe the emergent ra#F or the refracted ra#B
*ndex o( Re(raction H ;he degree to !hich a lens
material refracts ,bends- lightB ;his res%lts from the
ratio of the speed of light in air to the speed of light
thro%gh a lens s%bstanceL the higher the index of
lens materialF the D%ic6er light ra#s are bent as the#
pass thro%gh the lensB ;he higher the indexF the
more the refractive po!er of the lensB
*nduced "rism H ;he prism po!er created !hen
the optical center of a lens is o%t of coincidence
!ith the !earerJs vis%al axesF or !hen the vis%alaxes intersects an# point on a lens !ith refractive
po!erF a!a# from the optical centerB
*n(init! H 1n optical scienceF a distance great
eno%gh so that ra#s of light from that distance ma#
be regarded as parallelL 20 feet or I meters or
greaterB
*n(rared H :lectromagnetic radiation !ith
!avelengths longer than visible lightF b%t shorter
than micro!ave radiationB
*n)mass "otocromic H 9enses in !hich the
photochromic material is dispersed evenl#thro%gho%t the s%bstrateB
*nset H =enerall# refers to the additional
decentration of a bifocal segment be#ond the
distance decentrationB
*ntermediate eg H ;he middle lens in a trifocal set
for a foc%s shorter than distance b%t longer than
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nearB ;he %s%al foc%s is half the bifocal po!erF
!hich allo!s the !earer to foc%s at armJs lengthB
*nterpupillar! istance H ;he linear distance
bet!een fixation axis of the !earerJs e#e or centers
of the p%pil !ith e#es foc%sed at distanceB
*nterval o( turm H Ceparation bet!een t!o focallines of an astigmatic imageB
*ntraocular Lens $*5L% H ( s#nthetic lens
implanted after cataract s%rger# to replace the
damaged cr#stalline lensB
*ntraocular "ressure $*5"% H 5ress%re of the fl%id
inside the e#eL normal 15 varies among
individ%alsB
*nverted *mage H 4is%al impression of an ob@ect as
formed b# a lens or mirrorF in !hich the %pper and
lo!er portions of the image appear as exchangedB
*ris H ;he colored ro%nd portion of the e#eF sit%atedbet!een the cornea and the lensF and perforated b#
the p%pilB .eg%lates the amo%nt of light entering
the e#e b# ad@%sting the si*e of the p%pilB
*ritis H 1nflammation of the irisB
*socromatic H 5ossessing the same color
thro%gho%tB
*socoria H :D%all# in si*e of the t!o p%pilsB
*ostropic H aving eD%al refractive po!er ,index of
refraction- in all directionsB
J
aeger ,est H ?eas%rement of vis%al ac%it# at the
reading distanceB
K
eratitis H (n inflammation of the corneaB
eratoconus H ( cone shaped protr%sion and
thinning of the corneaB
eratometer H (n instr%ment %sed to meas%re the
c%rves of the corneaL also 6no!n as anophthalmometerB
eratometr! H ?eas%rement of the c%rvat%re of
the anterior s%rface of the corneaB
e!ole Bridge H ( bridge design for a front that
does not permit contin%o%s contact bet!een the
nose and the front in the nasal crest areaB
.esembles an 6e#hole !ith a circ%lar arc at the top
of the opening in an antiD%e doorB
r!pto1 H ( f%sed lens !ith a ro%nd top bifocal 22
mm in diameterB
L
Lacrimal 6land H ;he small almond&shaped
str%ct%re
that prod%ces tearsL located @%st above the o%ter
corner of the e#eB
Lacrimation H 5rod%ct of tearsB
Lag o( Accommodation H ( meas%re of the e#eJs
abilit# to foc%s acc%ratel# on a given targetB ;he
dioptric difference bet!een the e#eJs foc%sing
response and the stim%l%s to foc%sB
Laminated Lens H ( lens formed b# t!o or morela#ers of refracting material firml# @oined together
for special optical or safet# p%rposesB
Lap H ( tool %sed in the man%fact%re of ophthalmic
prod%ctsL made from cast ironF al%min%mF brassF or
plastic forms !ith po!er c%rves on the top s%rfaceL
%sed either as grinding or polishing platforms to
prod%ce refractive or reflective s%rface po!ers on
lensesB
Lap ,ool $4ard% H ( rigid tool having a specific
c%rvat%re that is %sed in con@%nction !ith vario%s
abrasive pads to smooth and polish generated lenss%rfaces of the same c%rvat%reB
Lap ,ool $o(t% H ( flexible tool made from a
compliant foam or air bladder that is %sed in
con@%nction !ith free&form s%rfacing to polish
generated lens s%rfaces that have complex shapes
!ith var#ing c%rvat%reF s%ch as progressive
s%rfacesB
Laser -ngravings H :tchings or engravings on
progressive lenses to denote the position of the
fitting crossF add po!erF etcB
Lasi1 H ( s%rgical proced%re %sing a laser toreshape the cornea to correct refractive errorsB
Lateral 6radient ,int H ( cosmetic tint dar6er
temporall# and fades to!ard the centerB 1ts
application is for !earers !ith %n%s%all# narro!
5+sB
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La!out H ,K- ;he art or process of arrangingL ,2- 1n
opticalF the process of mar6ing a lens blan6 for
positioning in s%rfacing or edging eD%ipmentB
La.! -!e H See amblyopia.
Legal Blindness H 1n the 3BCBF ,K- vis%al ac%it# of
20/200 or !orse in the better e#e !ith correctivelenses ,20/200 means that a person m%st be at 20
feet from an e#e chart to see !hat a person !ith
normal vision can see at 200 feet- or ,2- vis%al field
restricted to 20 degrees diameter or less ,t%nnel
vision- in the better e#eB
Lens H ,K- ;he transparentF do%ble convex
,o%t!ard c%rve on both sides- str%ct%re of the e#e
s%spended bet!een the aD%eo%s and vitreo%sL
helps to foc%s light on the retinaB ,2- ( device or
means of ca%sing the e#e to ma6e the maxim%m
change possible in the accommodative pattern!itho%t introd%cing an %ndesirable change in the
convergence patternB
Lens $Bac1)ur(ace% H ( t#pe of free&form
progressive lens that emplo#s a factor#&molded
spherical s%rface on the front and a free&form&
s%rfaced progressive s%rface that has been
combined !ith the prescription c%rves on the bac6B
Lens $ual)ur(ace% H ( t#pe of free&form
progressive lens that emplo#s a factor#&molded
progressive s%rface !ith a portion of the total
addition po!er on the front and a free&form&s%rfaced progressive s%rface !ith the remaining
addition po!er that has been combined !ith the
prescription c%rves on the bac6B
Lens Bevel H ;he edge of a lens shaped li6e a '4)B
;he bevel helps to sec%re the lens after it has been
inserted in the frameB
Lens Cloc1 H ,base c%rve cloc6- H ( smallF ro%nd
cloc6&t#pe ob@ect !ith three prongsF !hen placed on
a lens it gives the po!er of the lens s%rfaceB 3sed
to determine base c%rves primaril#B (lso called a
sagitta ga%geBLens Coating H oatings placed on a lens for
either tinting or reflection p%rposesB
Lens Corridor H ;he channel of an ophthalmic
progressive lens @oining the distance vie!ing area
and the total reading po!er areaB
Lens i((erence H 1n spectacle opticsF the
n%merical difference expressed in millimeters
bet!een the hori*ontal ( and vertical
meas%rementsB
Lens 6roove H ;he angle formed b# the 4&shape
of an e#e!ire groove to accommodate a beveled
lensB
Lensometer H (n instr%ment to determine theprescription of an# given c%rve lensL also 6no!n as
a focimeter or vertometerB
Lens "attern H ( templateF %sed in lens edging
eD%ipment to generate correct peripheral shape
and geometric center locationB
Lens "o#er H ;he diopter po!er or prescription of
a lensB
Lens Retention H ;he abilit# of a front to 6eep a
lens from dislodging from the e#e!ire groove %nder
forceB
Lens top H 1n a lonsometerF a mechanical holderto position the lens at a fixed positionF thereb#
providing a %niform meas%ring apert%reB
Lens 8aser H 4er# thin n#lon beveled material to
fit bet!een a lens and an e#e !ire to hold the lens
in more sn%gl#B
Lenticular Asperic H 3s%all# plastic cataract
lenses gro%nd so that the overall !eight and
thic6ness is red%ced and to eliminate lens
distortions are eliminatedB
Lenticular Lens H ( strong po!er gro%nd into a
red%ced area of the lens to limit thic6nessB ;heremainder of the lens is called a carrier and
provides no refractive correction b%t gives
dimension to the frame for mo%ntingB efore high
pl%s asphericsF these lenses had a higher %sage
b%t the# are still often the onl# option for some
apha6ic patients !itho%t a lens implantB
Librar! ,emple H (n earpiece !itho%t an ear bend
or do!n bendB
Ligt H ,K- ;he radiant energ# !hichF after entering
the e#eF provides the initial stim%l%s for sightF ,2-
electromagnetic radiations visible to the h%man e#e!hich gives rise to the sensation of vision b#
stim%lating the rod and cone cells of the retinaL
absence of dar6nessB
Ligt Adaptation H (bilit# of the e#e to ad@%st itself
to an increase in the intensit# of lightB
Ligt "erception H ;he abilit# of a person to
recogni*e the presence of a l%mino%s so%rceB
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Limbus H irc%lar *one !here the cornea @oins the
sclera ,!hite of the e#e-B
Longe)Range Vision H 3s%all# from O0 inches to
infinit#B
Lo# Vision H 4is%al loss that cannot be corrected
!ith e#eglasses or contact lenses and interferes!ith dail# living activitiesB
M
Macula H ;he smallF sensitive area of the central
retinaL the mac%la is responsible for good vis%al
ac%it#F color visionF and central visionB
Macular egeneration H ;he deterioration of the
most sensitive and important region of the retinaF
the mac%laB ;his degeneration ca%ses significant
bl%rring of the central vision and can lead toblindnessB
Magnesium +luoride H ( metal oxide commonl#
applied to the s%rface of ophthalmic lenses to
red%ce and eliminate spec%lar reflectionsB
Magni(ication H ;he increase in the apparent or
perceived si*e or s%btended angle of an image in
relation to act%al si*e of ob@ectB
Ma&or Meridians H ;hese are the t!o meridians
made %p of the meridian of axis po!er and the
meridian that is 80 degrees from the axisB
Ma&or Re(erence "oint $MR"% H ;he point on alens that satisfies all optical D%alitiesB ;he point on
a !here the complete meas%re of a prism reD%ired
is presentB
Marginal Astigmatism H Ghen a narro! beam of
parallel ra#s stri6es a lens obliD%el#F ra#s in the t!o
opposite meridians foc%s at different pointsB ;he
distance bet!een the t!o foc%s points eD%als the
degree of astigmatism ca%sedB ;his tro%blesome
error ca%sed lens man%fact%rers to develop a
corrected c%rve lens seriesB ;he idea is if specific
c%rvat%res are controlled for specific correctionsFthen marginal astigmatism can be controlledB
Mar1ing evice o( Lensometer H ( device
mo%nted on a lensometer that is %sed !ith an in6
pad to mar6 the center and the direction of the axis
of the c#linder in a lensB
Mar1ing "ins H Cmall metalF spring&mo%nted
pointed pins on a lensometerF in6ed and %sed to
mar6 the ma@or reference point and hori*ontal lens
bisector on an ophthalmic lensB
Mar1)up H ?ar6ing of a reference line on a lens
d%ring the s%rfacing process to define ho! optical
characteristics are to be gro%nd into a lensB
Mastoid Bend H ;he c%rvat%re in the do!n bend ofthe temple ,earpiece- adapting to the mastoid
c%rvat%re ,depression- be#ond the earB
Mecanical Center H the geometric center of an
optical lensB
Medium H (n# material thro%gh !hich light passesB
Meibomian 6lands H ( variet# of glands located in
the e#elidB ;he# secrete an oil# s%bstance to 6eep
the e#e l%bricated and the tears from overflo!ing
the lid marginsB
Melanin H ( pigment that gives hairF s6in and e#es
its colorB Aat%re %ses melanin to protect the tiss%eof the e#e from s%nlight damageB ?elanin absorbs
the color in preportion to their potential damageB 1t
is lost !ith agingB
Meniscus H ( lens !ith a crescent&shaped profile
that is a combination of a concave and a convex
s%rfaceB
Meridian H phthalmic lens po!er is specified
according to a pattern similar to the face of a cloc6B
;he hori*ontal ,KP0- merdian !o%ld be a line
passing thro%gh the three and the nineB ;he vertical
,080- meridian !o%ld be a line passing thro%gh sixand t!elveB ;he one to seven line !o%ld be the 0I0
meridian and the ten to fo%r line is the KO0
meridianB
Metallic $Re(lexive% Mirrors H ;hese coated
lenses red%ce visible light b# 2OS to 7OS %sing K
to 7 la#ers of metalB ?etallic mirrors sho%ld be
applied to lenses !ith a base tint of at least O0S
densit# for maxim%m effectB
Mid)Range Vision H 3s%all# from 70 inches to O0
inchesL arms&length rangeB
Millimeter H ( s%b%nit of linear meas%rementL onetho%sandth of a meterL abbreviated mmB
Miniaturi.ation H Ghen an image is smaller
thro%gh the lens than its original ob@ect si*eB
Minimum Lens ,ic1ness H ;here is a limit to
ho! thin a lens can be s%rfacedB ;his minim%m
thic6ness is determined b# practicalit# and b#
established standards s%ch as (AC1 TP0&K888B
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Minus H ;erm %sed to indicate the po!er of a
concave s%rface of po!er of a lens !hose concave
s%rface is stronger than its convexB 3sed to correct
m#opiaB
Mires o( Lensometer H;he bars and dots that go
in and o%t of foc%s as #o% t%rn the po!er !heel ofthe lensometerB
Mirror Mirror 6radient Mirror ouble 6radient
H ( vac%%m applied mirror&t#pe coating placed on
the front of the lensB
Miter oint H ( @%nct%re bet!een front and temple
!here both mating s%rfaces are ang%larl# c%tB
Moisture Camber H ( thin plastic sheet attached
to the e#e!ire of a frame and shaped to fit li6e a
safet# c%p st#le side shieldB elps to create a
chamber of moist%re for a dr# e#e conditionB
Monocle H ( single e#eglass lens designed to be!orn or hand&held in front of one e#eL %s%all#
provided !ith an attached cord or chainB
Monocular H 5ertaining to one e#e onl#B
Monocular Vision H 4ision res%lting from the %se
of one e#e onl#B
Mono)esign H ;his progressive lens t#pe %ses a
single design for a given distance base c%rve to
!hich all add po!ers are appliedB
Mounted Lens H 9ens that has been inserted into a
spectacle frame frontB
MR)=0 H 3niD%e KBIN high index resin %sed in lensman%fact%rerJs mix !ith best tensile strength for
rimless mo%ntingsB
MR" H ;he ?.5 ,ma@or reference point- is that
point in the lens that gives the prescriptionB
Multi)esign H ;his progressive lens is c%stom
designed for each base/add po!er combinationB
9ens variables are selected and controlled for all
designs maximi*ing vis%al performanceB
Multi(ocal H( lens incorporating t!o or more
different po!ers ,incl%des bifocalF trifocalF or
progressive lenses-BMulti)la!er AR H (ll modern (. coatings consist of
m%ltiple la#ers on each side of the lensF %s%all# five
or moreB
M!driatic H (n# dr%g that dialates the p%pilB
M!odisc H ( strong min%s lens that limits thic6ness
b# lentic%lari*ing the min%s po!er into a small 2O to
7O mm concave bo!l in the center of a 5lano or
pl%s lens blan6B ften an option for a ver# high
min%s patientB
M!opia H AearsightednessL abilit# to see close
ob@ects more clearl# than distant ob@ectsL a
refractive condition in !hich the point of foc%s falls
in front of the retinaL ma# be corrected b#e#eglasses or contact lensesB
N
' H ;he variable %sed to represent a materialJs
index of refractionB
'anometer $nm% H ( %nit of length eD%al to one&
millionth of one millimeter or K0 (ngstrom %nitsL
%sed to meas%re the !avelength of lightB
'arro#/stretc Bridge H ;o change the bridge
si*e b# modif#ing the shape of a lens b# c%ttinga!a# the bridge
or filling the bridge area !ith extra frame material
on a *#l frameB
'asal -dge H ;he side of a spectacle lens closest
to the noseB
'ear Acuit! H ;he e#eJs abilit# to disting%ish an
ob@ectJs shape and details at a near distanceB
'ear "oint o( Convergence $'"C% H ;he closest
point at !hich the t!o e#es can maintain a single
%nit imageB
'earsigtedness H ( condition in !hich the opticsof the e#e are too strong and foc%s in front of the
retinaF res%lting in bl%rred distance visionB (lso
referred to as m#opiaB 1t is corrected !ith min%s
po!er lensesB
'ear Vision H 3s%all# from KK inches to !ithin arms
reach ,approxB 70 inches-B
'ear Done 8idt H ;he meas%rement of the near
*one ta6en at a specified point belo! the fitting
crossB
'egative Relative Accommodation $'RA% H (
meas%re of the maxim%m abilit# to relaxaccommodation !hile maintaining clearF single
binoc%lar visionB
'eutrali.ation H 3tili*ing a lensometer to
determine the dioptric po!er of an ophthalmic lensB
'eutrali.er H ( combination of chemicals %sed to
'sta#) a color of tint on a lens s%rfaceB
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'igt Vision H ;he e#eJs abilit# to adapt to lo!
light conditionsB 3nder lo! light levelsF the p%pil
enlarges and the e#e %ses different light receptors
,rods-B +ifferent e#e conditions res%lting in night
blindness or poor night vision incl%de p%pils that
become smaller !ith ageF cataractsFnearsightednessF retinitis pigmentosaF or 4itamin (
deficianciesB
'odal "oint H ;he point on the optical axis to
!hich entering and emerging ra#s are directedB
'ominal "o#er H ;he nominal c%rve of a semi&
finished lens mar6ed in diopters b# the
man%fact%rerB ;he difference bet!een mar6ed and
act%al tool c%rve of the s%rface represents the
man%fact%rerJs compensation for the base c%rveB
;his compensation allo!s standard tooling to be
%tili*ed over a range of prescriptions !ith little or nof%rther compensation b# the laborator#B
'ormal Retinal Correspondence $'RC% H ;he
foveas of the t!o e#es are corresponding ne%ral
points in the vis%al cortex and binoc%lar vision can
occ%rB
'ormal Vision H 4ision is clear and sharp !hen
the e#e is able to foc%s on images correctl# onto
the retinaB
'ose "ad H ;he nasal bearing s%rface member of
a frontL also called padB
'!ctalopia H Aight blindnessL impaired vision%nder red%ced lightB
'!stagmus H ;he rapid fl%ct%ation of the e#es in a
rotar# or side to side directionB ( fl%ttering of the
e#esB
O
5b&ect isplacement H ?ovement of ob@ects seen
thro%gh a prism to!ard the apex of the prismB
5b&ective Re(raction H +etermination of the
prescription %tili*ing the response of the patient todetermine the acc%rac# of the prescriptionB
5bli3ue H 1n referring to optical axisF an# axis that
is not perpendic%lar ,80- or parallel ,KP0-B
5bli3ue -rrors H bliD%e astigmatism and obliD%e
spherical po!er errorB
5ccluder H (n opaD%e plastic spat%la device %sed
to cover one e#e d%ring examinationB
5ccular 6lobe H ;he e#eballB
5ccular 4!pertension H (n increase in press%re
above the normal range !ith no detectable changes
in vision or damage to the e#eB ommon in ver#
nearsighted or diabetic patientsB
5cculist H (n earl# term for a ph#sicianspeciali*ing in the st%d# and treatment of affects
and diseases of the e#eB
5cular e(ects H ;he end res%lt of vis%al
problemsB
5ccupational egment H ( segment that is
prescribed and fit to ans!er a specific tas6B
5EE H ,K- (n abbreviation of +octor of optometr#L
,2- oc%l%s dexter in latin H meaning 'right e#e)B
5(( Center $Marginal% Astigmatism H l%rred
vision d%e to po!er error and ind%ced c#linder in
the peripher#F corrected b# introd%cing asphericit#into lens designB
5leopobic Coating H ( chemical composition top
coat consisting of h#drophobic chemicals and
oleophobic chemicals to repel dirtF d%stF s6in oilsF
and ma6e %p for effortless cleaning and sm%dge
resistanc#B
5pa3ue H 1mpenetrable b# lightF does not refract
lightB
5ptalmometer H (n instr%ment %sed to
meas%re the c%rvat%re of the corneaB
5ptalmoscop! H ;he doctor examines the insideof the e#es !ith an ill%minates and magnifies the
interior of the e#eB
5ptalmoscope H (n instr%ment containing a
perforated mirror and lenses to examine the interior
of the e#eB
5ptalmologist H ( medical doctor ,?B+B- !ho is
an e#e specialist that can diagnose and treat e#e
diseasesF perform e#e s%rger#F and prescribe
prescriptions and medicationsB
5ptical Correction H ombination of c%rvat%res of
the front and rear s%rface of the lensF meas%red indioptersB
5ptic isc H ead of the optic nerve in the e#eballB
5ptical Axis H (n imaginar# line at right angles to
the s%rfaces of a lens and passing thro%gh its
optical centerB
5ptical Center H ;he point on an optical lens
!here the light passes directl# thro%gh !itho%t
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bendingB ;he thic6est point of a pl%s lens and the
thinnest point of a min%s lensB
5ptical Cross H ( diagram consisting of t!o
straight lines crossing each other at right angles
orientated to represent the principal refractive
meridians of an ophthalmic prescription lensL %sedto chart the axis and refractive po!ers in the
principal meridiansB
5ptic Cup H ;he !hiteF c%p&li6e area in the center
of the optic discB
5ptic isc/5ptic 'erve 4ead H ;he circ%lar area
,disc- !here the optic nerve connects to the retinaB
ptic nerve has the b%ndle of over one million
nerve fibers that carr# vis%al messages from the
retina to the brainB
5ptician H ( person trained in the dispensing and
fitting of prescription e#e!ear and/or contact
lensesB
5ptical Axis H ;he line that passes thro%gh the
center c%rvat%re of optical s%rfacesB
5ptical Center H ;he point on a lens thro%gh !hich
light can pass !itho%t being deviatedB
5ptimi.ation H ( method of manip%lating a given
progressive lens %sing complex mathematical
algorithms in order to preserve the desired optical
characteristics of the 'ideal) or 'target) lens design
in the final lensB
5ptometric Assistant H ffice staff primaril#
involved in front&office proced%resF optical
dispensing and contact lens patient ed%cationB
5ptometric ,ecnician H ;echnicians !or6
directl# !ith optometrists in the areas of patient
examination and treatment incl%ding contact
lensesF lo! visionF vision therap#F and optical
dispensing and office managementB
5ptometrist $5EE% H ( doctor of optometr# !ho
speciali*es in vision examinations and treatmentF
prescribes spectacle and contact lensesF and also
diagnoses and treats some e#e diseasesB
5pt!l H ;he trade name for a thermo&setting epox#
resin of high stabilit# %sed in e#eglass framesB 1t
!ill ret%rn to its original shape !hen heatedB
5rbital Cavit! H on# orbits that serve as soc6ets
!hich contain the e#eballsB
5rto1eratolog! H ;he practice of correcting or
red%cing prescription needs s%rgicall# altering the
shape of the corneaB