E EM ? C § S E CQ N D LASERS I N CATARACT SURGERY a FE’IPECTED RESULTS FROM PRK OVER PRIOR LASH<

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Catarac fiRefrac ive BurgerApril 2010 -VolumE 10,No.4 I 0

TOUGIIEATARACT CASESTechmques f0r success in the face of difficulty.

Emrwpcmtéve FEGppy Catamct Swgecyflr‘és Sysiem in an EyeWéth a ShaémwBySamuel Masket:MD, AnterfimChamberand David F.Chang,MD ByUday DevganIMDl

Ca tag ‘ a fi and Alan S.Cranda||,MDByRoger F.Steinert,MD,andYRaIPh Chu MD A

_ ByPaul S.Koch,MD,Catafi’act and RichardJ.Mackool,MD

ByBarry 5.Seibei,MD,and Robert J.Cionni, MD

A D V A N C E D FOR QATAR/ACT - OPTiCS, VESUAL QUAUTY, AND ACUITY

HowDoYouUnexpected

TODAY'STOPiCSSection Editor:John F.Doane,MD

ApproachResults From

PRKOver Prior LASIK?BY STEPHEN COLEMAN, MD ; STEVEN J. DELL,MD; MARK A. KONTOS, MD;ROBERT K. MALONEY, MD ; LOUIS E. PROBST,MD ; AND STEPHEN A. UPDEGRAFF, MD

Haveyou everperformed a -1.00 Dspherical enhancement wi th PRK af te rp r i o r myopic LASIK only to achieve asurgical outcome of -2.50 D sphere?Alternatively, have you ever treated apat ient for a -1.00 D refract ion wi thPRK over p r io r myopic LASIK only toobtain a postoperative refract ion of2.25 D? Why do these unusual resultsoccur, a nd how do you resolve them?

STEPHEN COLEMAN, MDLaser technology isvery precise,but it is lessexact on

previously operatedeyes. Ingeneral, truly unexpectedresults followingaprimary procedureare relativelyuncommon,whereas littlesurprises after enhancementsaremuchmore likely.This motivatesmany surgeons tostrive to maintain a lowenhancement rate.Myopic LASlK commonly inducesasmall amount of

spherical aberration (lesssotoday comparedwith yearspast).The postoperative shapeof the cornea istypicallymore oblate,makingretreatments morechallenging, par‑ticularly considering the new relationship betweentheperipheral andcentral cornea after LASlK.One pearl thatl have found helpfulwhen performingPRK over previousLASIK isto use the preoperativecentral keratometricvaleues.They initially dictate the peripheral shot pattern andcompensate for the cosine effect‐a significant factor that

"The role of the epithelium afterLASIK is a significant variable,

because it is responding to a newand different corneal shape. ”

‐Stephen Coleman,MD

affects enhancement outcomes. Additionally, the roleofthe epithelium after LASIK isasignificant variable,because it isrespondingto anewanddifferent cornealshape.Optical coherence tomography technology will bevery useful in furtheringour understanding in this area.

STEVEN J. DELL.MDMany corneal irregularitiesareminimized by the natu‑

ral tendency of the epithelium to smooth over underlyingproblems.Forexample, in a keratoconic eye, the epitheli‑um over the apex thins, which reduces the steepness inthat area andmaymask early forme fruste keratoconus.Theepithelium isalsoanexcellent apologist for iatrogenicinsults to the cornea. An oblate cornea after myopicLASIK may haveavery thick central epithelial cellularlayerasaresult of the epithelium’s attempt to deal withthe abnormal shape.After anenhancement in an eye thathas undergonemyopic LASlK or PRK,the epitheliummayregrowwith a similar, greater, or smaller number of cellu‑lar layerscomparedwith its pie-enhancement state. Thisusualiy results in emmetropia, but occasionally, it resultsin under- or overcorrections. Inmyexperience, this phe‑nomenon ismuchmore common after hyperopic LASlKcorrections, where peripheralepithelial hypertrophywillcause hyperopic regression.Epithelialdebridement issometimes helpful in dealingwith the hypertrophicepithelium.

APRIL 2010 CATARACT & REFRACTiVE SURGERY TODAY 17

TODAY’S TOPlCS

MARK-A”. KONTOS,MDAlthough PRKover prior LASIK has

advantages,it carries adegree ofuncertainty regardingthe surgicaloutcome.Multiple factors probablycausevariable outcomes.Mitomycin, C(MMC)may havea less predictable.effect in this setting,andepithelialhyperplasiaisalsoasignificant factorin many of thesecases.When I lookedthrough mypast cases, I noticed thatthe patientswho hadahyperopicovercorrection tendedalso to havemoderate‐to-highmyopiaat the timeof their primary LASIK.The patientswho had littleor noeffect after PRKoften had lowermyopiaat the time oftheir primary LASIK.I try to keep thisin mindwhen planningtreatments.Becauseof the unpredictable natureof this type of enhancement, adetailed discussionwith the patientabout all possible outcomes iscritical.Sometimes, the best plan of action isto leave things asthey are.

ROBERT K. MALONEY, MDReoperationscan producestrange

refractive results,and it isoften hardto determinewhy they occur.Thesurgeon should beaware of the possi‑bility of map regions from basementmembranedystrophy.These areas ofthickenedepithelial cells affect refrac‑tion, and their removal duringPRKcan producesignificant refractiveshifts.These thickened areas ofepithelial cells are best seen with fluo‑rescein and by lookingfor areas ofnegative staining.Another problemoccurswith PRK enhancements afterPRK,particularly if corneal haze ispresent.Accidental or intentionaldebridement of the hazeproducesalargehyperopicshift, even beforelaser retreatment.Subepithelial tissuefrom prior surgery ismore likely to beinadvertently removed if a rotatingbrush isused to remove the epitheli‑um for the enhancement. For thisreason, I usealcohol to remove theepithelium for PRKenhancements.

*4 k W STERILEOPHTHALMICSUSPENSIONBauschaLomb m a mlotemax. “ m mm,maloteprednoletabonate LOTEMAXisindicatedforthe treatmentofsteroidresponsiveinflammatoryconditionsofthepalpebralandbuybar

' "spa ~ coniunctiva,corneaandanteriorsegmentof theglobesuchasallergicconjunctivitis,acnerosacea,superficiapunctateOphthalmic5 “3'0" 05% keratitis,herpeszosterkeratitis,iritis, cyclitis,selectedinfectiveconiunctivitides,whenthe inherenthazardofsteroiduse

isacceptedtoobtainanadvisablediminutioninedemaandinflammation.

IOTEIIIAXis lesseffective thanprednisoloneacetate1%in two23-daycontrolledclinical studiesin acuteanterioruveitis,where72%of patients treatedwithtOTEMAXexperiencedresolutionofanteriorchambercells,comparedto87%ofpatientstreatedwithprednisoloneacetate1%. Theincidenceofpatientswith clinicallysignificantincreasesin IOP(:10mmHg)was1%withIOTEMAXand6%with prednisoloneacetate 1%.LOTEMAXshouldnot beusedin patientswhorequireamorepotentcorticosteroidfor this indication.

lOTEMAXisalsoindicatedfor thetreatmentofpost-operativeinflammationfollowingocularsurgery.

( M O N I T O R S :lOTEMAx,aswithotherophthalmiccorticosteroids,iscontraindicatedinmostviraldiseasesof thecorneaandconjunctivaincludingepithelialherpessimplexkeratitis(dendritickeratitis),vaccinia,andvaricella,andalsoinmycobacierialinfectionof theeyeandfungaldiseasesofocularstructures.LOTEMAXisalsocontraindicatedinindividualswithknownorsuspectedhypersensitivityto anyof theingredientsof thispreparationandtoothercorticosteroids.

WARNINGS:Prolongeduseoicorticosteroidsmayresultinglaucomawithdamageto theopticnerve,defectsinvisualacuityandfieldsof vision,andinposteriorsobcapsularcataractformation.Steroidsshouldbeusedwithcautioninthepresenceofglaucoma.

Prolongeduseoi corticosteroidsmaysuppressthehostresponseandthusincreasethehazardofsecondaryocularinfections.Inthosediseasescausingthinningofthecorneaorsclera,perforationshavebeenknowntooccurwith theuseof topicalsteroids.in acutepurulentconditionsof theeye,steroidsmaymaskinfectionorenhanceexistinginfection.

Useofocularsteroidsmayprolongthecourseandmayexacerbatetheseverityofmanyviral infectionsof theeye(includingherpessimplex).Employmentofacorticosteroidmedicationinthetreatmentof patientswithahistoryofherpessimplexrequiresgreatcaution.

Theuseofsteroidsaltercataractsurgerymaydelayhealingandincreasetheincidenceofblebformation.

PRECAUTIONS:General:Forophthalmicuseonly. The initial prescriptionandrenewalof themedicationorderbeyond14daysshouldhemadebyaphysicianonlyafterexami‑nationof the patientwiththeaidofmagnification,suchasslit lampbiomicroscopyand,whereappropriate,iluoresceinstaining.If signsandsymptomsfail toimproveaftertwo days,thepatientshouldbere-evaluatad.

If thisprodticlisusedfor 10daysor longer,intraocularpressureshouldbemonitoredeventhoughIt maybedifficult in childrenanduncooperativepatients(seeWARNIW‘

fun corneaareparthe corneaareparticularly prone todevelopcoincidentally with long-termlocal steroidapplication, Fungusinvasionmustbeconsid‑..y persistent cornealulcerationwhereasteroidhasbeenusedor is in use.Fungalculturesshouldbetakenwhenappropriate.

nationfor Patients: Thisproductissterile whenpackaged.Patientsshouldbeadvisednottoallowthedroppertip to touchanysurface,asthismayuminatethesuspension.It paindevelops,redness,itchingor inflammationbecomesaggravated,the patient shouldbeadvisedto consultaphysician.Asall ophthalmicpreparationscontainingbenzallroniumchloride,patientsshouldbeadvisednot towearsoft contact lenseswhenusingtOTEMAXI.

.rcinogenesis,mutagenesis,impairmentof fertility: long-termanimalstudieshavenotbeenconductedtoevaluatethecarcinogenicpotentialoi Ioteprednol.tabonate. toteprednoletabonatewasnotgenotoxicin vitro intheAmestest, themouselymphomatkassay,orinachromosomeaberrationtest inhumanlymphocytes,orin vivo in thesingledosemousemicronucleusassay.treatmentofmaleandfemaleratswithupto50mg/kg/dayand25mg/kg/dayof Ioteprednol:tabonate,respectively,(600and300timesthemaximumclinicaldose,respectively)prior toandduringmatingdidnot impairfertility in eithergender.Pr :‘ieratogenic effects:PregnancyCategoryc. loleprednoletabonatehasbeenshowntobeembryotoxic(delayedossification)andteratogenic(increasedinci enceofmeningocele,abnormallelt commoncarotidartery, andlimbflexures)whenadministeredorally torabbitsduringorganogenesisatadoseof3mg/kg/day(35times themaximumdailyclinicaldose),adosewhichcausednomaternaltoxicity. Theno-observed-effect-Ievel(NOEL)for theseeffectswas0.5mg/kg/day(6timesthemaximumdaiiyclinicaldose). oraltreatmentof ratsduringorganogenesisresultedin teratogenicity(absentinnominateartery at :5 mg/kg/daydoses,andcleftpalateandumbilicalherniaat :50mg/kg/day) andembryotoxicity(increasedpost-implantationlossesat too or /kg/day anddecreasedfetalbodyweightandskeletalossificationwith :50mg/kg/day).Treatmentof ratswith0.5mg/kg/day(6timesthemaximumclinicaldosegduringorganogeneslsdidnotresultinanyreproductivetoxicity. loteprednoletabonatewasmaternallytoxic(significantlyreducedbodyweightgainduringtreatment)whenadministeredto pregnantratsduringorganogenesisatdosesof 25mg/kg/day.

Oralexposureof femaleratsto50mg/kg/dayof loleprednoletabonatefromthestartof the fetalperiodthroughtheendof lactation,amaternallytoxictreatmentregimen(significantlydecreasedbodyweightgain),gaverise todecreasedgrowthandsurvival,andretardeddevelopmentin theoffspringduringlactation;theNOELfor theseeffectswas5mg/itg/day. toteprednoletabonatehadnoeffectonthedurationofgestationorparturitionwhenadministeredorally topregnantratsatdosesupto50mg/kg/dayduringthefetal period.

NursingMothers:It isnotknownwhethertopicalophthalmicadministrationofcorticosteroidscouldresultinsufficientsystemicabsorptiontoproducedetectablequantitiesinhumanmilk.Systemicsteroidsappearinhumanmilkandcouldsuppressgrowth,interferewithendogenouscorticosteroidproduction,orcauseotheruntowardeffects.CautionshouldbeexercisedwhenLOTEMAXisadministeredtoanursingwoman.

Manicuse:Safetyandeffectivenessinpediatric patientshavenotbeenestablished.AOVERSEREACTIONS:Reactionsassociatedwithophthalmicsteroidsincludeelevatedintraocularpressure,whichmaybeassociatedwithopticnervedamage,visualacuityandfielddetects,posteriorsubcapsularcataractformation,secondaryocularinfectionfrompathogensincludingherpessimplex,andperforationof theglobewherethere isthinningof thecorneaorsclera. '

Ocularadversereactionsoccurringin545%ofpatientstreatedwithIoteprednoletabonateophthalmicsuspension(Olin-0.5%)inclinicalstudiesincludedabnormalvision/blurring,burningoninstillation,chemosis,discharge,dryeyes,epiphora,foreignbodysensation,itching, injection,andphotophobia.otherocularadversereactionsoccurringin lessthan5%ofpatientsincludeconjunctivitis, cornealabnormalities,eyeliderythema,keratoconjunctivltis,ocularirritation/pain/discomfort,papillae,anduveitis. Someof theseeventsweresimilarto theunderlyingoculardiseasebeingstudied.Non-ocularadversereactionsoccurredin lessthan15%of patients.Theseincludeheadache,rhinitis andpharyngitis.

Inasummationof controlled,randomiledstudiesof individualstreatedfor 28daysor longerwith Ioteprednoletabonate,the incidenceofsignificantelevationofintraocularpressure(210mmHg)was2%(15/901)amongpatientsreceivingloleprednoletabonate,7%(11/164)amongpatientsreceiving1%prednisoloneacetateand0.5%(3/583)amongpatientsreceivingplacebo.

DOSAGEANDW W W " :SHAKEVIGOROUSLYBEFOREUSING.

stgrgjd ggmsive Qts'gaseTreatmentApplyoneto two dropsof LOTEMAXinto theconjunctivalsacof theaffectedeyets)four timesdaily. Duringthe initial treat»mentwithinthefirstweek,thedosingmaybeincreased,upto I dropeveryhour,if necessary.Careshouldbetakennot todiscontinuetherapyprematurely.11signsandsymptomsfail to improveafter twodays,thepatient shouldbe reevaluated(SeePRECAUTIONS).

Post-operativenfiammatign: Applyoneto twodropsof tOTEMAXinto theconjunctivalsacof theoperatedeye(s)four timesdailybeginning24hoursafter surgeryandcontinuingthroughoutthefirst 2weeksof thepost-operativeperiod.

Storage: Storeuprightbetweenrs=»25°c(59°-77°r). no norrecur.KEEPOUTof REACHOFCHILDREN.RevisedApril 2006Bausch8 LambIncorporated,Tampa,Florida33637Us. Patent No. 4,996,3350.5. Patent No. 55110330U.S.Patent No. 5,747,061©8ausch8 tomb IncorporatedLotemax is a registered trademark of Bausch8 tomb Incorporated. 9071800

Basedon full prescribinginformation revisedApril 2006

TODAY’S TOPiCS

"Surgeons need to carefullymonitor the amount of higher‑

‘ order aberrations and the depthof ablation for enhancements."

‐Louis E.Probst,MD

LOUIS E. PROBST,MDAlthough the resultsof lifting the flap for LASIK retreat‑

ments for myopic regression are potentially more preciseanddefinitely moreconvenient than PRKenhancements,it ishas beenshown that there isan increasingrisk ofepithelial ingrowth associatedwith liftingthe flap asthepostoperative time increases.‘ Therefore, PRK ismy pre‑ferred enhancement method,particularly in the eyes ofolder patients that may have looser epithelial attachments.In myexperience, amyopic outcome after anenhance‑

men t for myopic LASIK regression is rare.When this doesoccur, it is likely the result of epithelial hyperplasia.A rea‑SOnableadditional treatment would beepithelial removalwith no laser treatment and the application ofMMCtoprevent further epithelial hyperplasia.Surgeonsshouldalwaysbecareful about chasingprogressivemyopiawithadditional procedures,asthis may indicate other ocularpathologyIatrogenic hyperopia after a customizedmyopic

enhancement for myopic LASIK regression ismore c o m ,mon.This outcome isdue to the combinedeffect of thetreatment of the myopia and higher‐order aberrations,which result in an excessive ablation depth. Surgeonsneed to carefully monitor the amount of higher‐orderaberrations and the depth of the ablation for enhance‑ments.With customized treatments, 18 um per spheri‑cal equivalent diopter would be the expected depth ofthe ablation (a ‐1.00 Denhancement should haveanablation depth of only 18pm). If the treatment planshows aproposeddepth of 30pm, this isbecauseof theadditional treatment of the higher‐order aberrations,which are probably greater than 0.50 pm.The treatmentsphere should be reducedwith the surgeon’s adjust‑ments until the ablation depth iscloser to 18pm toavoidovercorrection. Obviously, these adjustments arecritical for patients in the presbyopic agegroup.Withthese adjustments, customizedmyopic enhancementsyield excellent resultswith an improvement in uncor‑rectedvision andquality of vision.

STEPHEN A. UPDEGRAFF,MDI think that unusual results are directly related to

wound healingafter surface treatments. In the case of

20 CATARACT ti: REFi€!\CTi\I’E SURGERY TOBAY APRIL 2010

amyopic result, epithelial hyperplasia is the mos t likelyculprit and typically would be associatedwith cornealhaze but n o t always. I would wait aminimum of6 months before considering the next step. If appropri‑ate, corneal segments may be the safest and mos t reli‑able next enhancement. A hyperopic result is typicallyrelated to subclinical stromal melting from MMC,which creates aflatter-than‐intended cornea. If youpan the slit beam obliquely, you may pick up another‑wise imperceptible divot. l have reduced the concen‑tration of MMC that I use to 0.01%, and I do n o texceed 30seconds of application. I also rinse the eyewith continuous irrigation (50mL).Surface treatmentsare easy until you are faced with these outcomes. Thatiswhy it isbest n o t to plan aLASIK case with surfaceretreatment asyour sole fallback for fine-tuning. I

Section editorjohn F.Doane,MD, is in privatepracticewith Discover Vision Centers in Kansas City, Missouri, andhe isa clinicalassistant professorwith the Department ofOphthalmology, Kansas UniversityMedicalCenter inKansas City, Kansas. Dr. Doanemay be reachedat(816)478-1230;jdoane@discovervision.com.Stephen Coleman,MD, is the director of

Coleman Vision inAlbuquerque,NewMexico.Di: Colemanmaybe reachedat (505) 821-8880;stephen@colemanvisioncom.Steven1.Dell,MD, isthe director ofrefrac‑

tive andcornealsurgeryfor Texan Eye inAustin. Dr Dellmay bereachedat(512)327-7000.MarkA. Kontos, MD, is a partner of Empire

EyePhysicians, P5, of Washington and Idaho.Dr.Kontosmay be reachedat (509) 928-8040;mark.kontos@empireeye.com.RobertK.Maloney,MD, is in privatepractice

with and the director of theMaloney VisionInstitute in LosAngeles. Dr.Maloneymay bereachedat (310)208-3937;info@maloneyvision.com.Louis E.Probst, MD, is the nationalmedical

director of TLC The Laser EyeCenters inChicago;Madison, Wisconsin; andGreenvi/Ie,South Carolina. Dr. Probstmay be reachedat(708)562-2020.StephenA. Updegraff,MD, is themedical

director of Updegrafi‘Vision in St. Petersburg,Florida.Dr. Updegraflmay be reachedat(727)822‐4282apdegrafimd®upvisioncom.

I. (aster AI, hiessDW,Schwendemanflilntldcnceofepillielidlingitiwthinprimaryandretreatmentlaserinsitukeratomileusis.lfaramrrEthanSim}.2010;36(1I'97-101.

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