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Amblyopia Update for the Primary Care OD 2018 1| Page www.EyeCodeBlog.com Christopher Wolfe, OD, FAAO, Dipl. ABO Amblyopia Amblyopia is a unilateral or bilateral condition that causes the in which the best corrected visual acuity (VA) is worse than 20/20 in the presence of a normal healthy eye (no structural abnormalities or ocular disease) [1]. Amblyopia develops during the critical period, typically in patients <6-8 years old (critical period) [2]. Depending on the level of VA reduction the prevalence changes: Using VA of 20/40 or worse – prevalence is 1.4% of the population [3] Using VA of 20/30 or worse – prevalence is 3.5% of the population [3] In addition to a reduction in BCVA, patients with amblyopia can also have: crowding effect, unsteady fixation, poor tracking, reduced contrast sensitivity and inaccurate accommodative responses [4]. Below we will classify amblyopia based on the condition that leads to the reduction in best corrected VA. Form Deprivation Amblyopia Form deprivation amblyopia occurs when there is an obstruction in the visual axis that precludes a clear image on the retina. Common conditions that can lead to form deprivation amblyopia include [5] [6] [7] [8]: Congenital cataract (most common) Traumatic cataract Corneal opacities Congenital ptosis Vitreous opacification Prolonged uncontrolled patching Prolonged unilateral blepharospasm Prolonged unilateral atropinization Refractive Amblyopia Refractive amblyopia results from a blurred image on the retina in one or both eyes that prevents the normal development of the visual pathway resulting in a reduction in VA at the level of the visual cortex [1]. Refractive amblyopia can be classified as either isoametropic or anisometropic. Isoametropic Isoametropic refractive amblyopia occurs when there is an equal but high uncorrected refractive error in both eyes that leads to significant retinal blur and reduced VA. Anisometropic Anisometropic refractive amblyopia occurs when there is an unequal uncorrected refractive error between the two eyes that leads to significant retinal blur and reduced VA. CROWDING Patients impacted by the crowding effect will perform better with lines of letters than blocks of letters and better with single letters than lines of letters.

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Page 1: Amblyopia Update for the Primary Care OD...Amblyopia Update for the Primary Care OD 2018 4 | Page Exotropia (XT) Exotropia occurs when the eyes are too divergent for the object of

AmblyopiaUpdateforthePrimaryCareOD2018

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ChristopherWolfe,OD,FAAO,Dipl.ABO

AmblyopiaAmblyopiaisaunilateralorbilateralconditionthatcausestheinwhichthebestcorrectedvisualacuity(VA)isworsethan20/20inthepresenceofanormalhealthyeye(nostructuralabnormalitiesoroculardisease)[1].Amblyopiadevelopsduringthecriticalperiod,typicallyinpatients<6-8yearsold(criticalperiod)[2].DependingonthelevelofVAreductiontheprevalencechanges:

• UsingVAof20/40orworse–prevalenceis1.4%ofthepopulation[3]

• UsingVAof20/30orworse–prevalenceis3.5%ofthepopulation[3]

InadditiontoareductioninBCVA,patientswithamblyopiacanalsohave:crowdingeffect,unsteadyfixation,poortracking,reducedcontrastsensitivityandinaccurateaccommodativeresponses[4].

BelowwewillclassifyamblyopiabasedontheconditionthatleadstothereductioninbestcorrectedVA.

FormDeprivationAmblyopiaFormdeprivationamblyopiaoccurswhenthereisanobstructioninthevisualaxisthatprecludesaclearimageontheretina.Commonconditionsthatcanleadtoformdeprivationamblyopiainclude[5][6][7][8]:

• Congenitalcataract(mostcommon)• Traumaticcataract• Cornealopacities• Congenitalptosis

• Vitreousopacification• Prolongeduncontrolledpatching• Prolongedunilateralblepharospasm• Prolongedunilateralatropinization

RefractiveAmblyopiaRefractiveamblyopiaresultsfromablurredimageontheretinainoneorbotheyesthatpreventsthenormaldevelopmentofthevisualpathwayresultinginareductioninVAatthelevelofthevisualcortex[1].

Refractiveamblyopiacanbeclassifiedaseitherisoametropicoranisometropic.

IsoametropicIsoametropicrefractiveamblyopiaoccurswhenthereisanequalbuthighuncorrectedrefractiveerrorinbotheyesthatleadstosignificantretinalblurandreducedVA.

AnisometropicAnisometropicrefractiveamblyopiaoccurswhenthereisanunequaluncorrectedrefractiveerrorbetweenthetwoeyesthatleadstosignificantretinalblurandreducedVA.

CROWDING

Patientsimpactedbythecrowdingeffectwillperformbetterwithlinesoflettersthanblocksoflettersandbetterwithsinglelettersthanlinesofletters.

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Typicallyamblyopiaislarger(deeperwithworseVA)forlargerdifferencesinrefractiveerror[9].

AmblyogenicRefractiveErrors[9][10][11][12] Myopia Hyperopia AstigmatismIsoametropic >8.00D >5.00D >2.50D

Anisometropic >3.00D >1.00D >1.50D

TABLE1:COMMONREFRACTIVEAMBLYOGENICRISKFACTORS

HyperopicAnisometropiaSincepatientswithhyperopiawillaccommodatetheleastamountnecessaryatdistanceandneartoseeclearly,lessanisometropiaisrequiredtocauseamblyopiasincethelesshyperopiceyewillbeusedforbothdistanceandnear.MyopicAnisometropiaSincepatientswithmyopiawillusethelessmyopiceyefordistanceandthemoremyopiceyefornearamblyopiawilltendnottooccuruntilthereismorethana3diopterdifferencebetweentheeyes.

StrabismicAmblyopiaStrabismicamblyopiamostcommonlyoccurswhenthereisconstant,unilateralstrabismusduringthecriticalperiod.Sincethereisnobifoveation,eacheyeseesdifferentimages,whichcanleadtoconfusion(centralretina)anddiplopia(peripheralretina).Ifconfusionand/ordiplopialastsforlongenough,thepatientwillactivelysuppressthenon-correspondingretinalimageswhichwillleadtoamblyopia[13].Additionalsensoryadaptationscanoccurtoeliminateconfusionanddiplopia.Theseinclude:

• Eccentricfixation–occurswhenapatientusesanon-fovealpoint(typicallyofthestrabismiceye)whenfixatingmonocularly)[14]

• AnomalousCorrespondence–isabinocularconditionthatlinksanon-fovealpointofthestrabismiceyewiththefoveaofthefixatingeye.

Esotropia(ET)Esotropiaoccurswhentheeyesaretooconvergentfortheobjectofregard.

Congenital/InfantileEsotropia

Congenital(Infantile)esotropiaisaconstantlargeangleesotropiathatoccurspriorto6monthsofage.Additionalclinicalfeaturesthatcanbeseeninclude:

1. Inferiorobliqueoveraction(70%)–thisclinicallysimilarlytoasuperiorobliquepalsy(hyperdeviationduringADduction)

2. Disassociatedverticaldeviation(75%)–elevationofthestrabismiceyewhencovered

INTERMITTENTStrabismuscanbeintermittentoralternatingbutthistypeofstrabismusleadstoamblyopialessfrequentlythanconstantstrabismus.

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3. Latentnystagmus(50%)–typicallyahorizontaljerknystagmusthatmanifestswheneithereyeiscovered,thefastphasewillbeAWAYfromthesideoftheoccludedeye[15]

Thelargeangleofthetropiaprecludesbinocularvisionatanydistancesosurgeryisthemostcommoninitialtreatment.

AccommodativeEsotropiaAccommodativeesotropiaoccurswhenthereiseitherahighAC/Aratioorasignificantamountofhyperopia(>+2.00).Theinitialtreatmenttypicallyincludesspectacleprescriptionwithpossiblebifocalwithaddtoneutralizetheneartropia/phoria.

MechanicalEsotropiaMechanicalEsotropiaoccurswhenthereisarestrictionorobstructionofanextraocularmuscle.Causesinclude:

• Extraocularmusclefibrosisinthyroidorbitopathy• Blowoutfracture• Duanesyndrome-iscongenitalandnon-progressiveand

duetoanabsenceofCNVIandaberrantinnervationofabranchofCNIIIintothelateralrectus[16].Additionally,globeretractionoccurswhenboththelateralandmedialrectusarestimulatedatthesametime[17].Thethreetypesinclude[18]:

o Type1(75-80%)-esotropiainprimarygazewithacompensatoryheadturntotheinvolvedside

o Type2(5-10%)-exotropiainprimarygazewithacompensatoryheadturntotheuninvolvedside

o Type3(10-20%)-eitheranesotropiaorexotropiainprimarygaze,andwillhaveacompensatoryheadturntowardstheinvolvedside.Additionally,thereisnoabilitytoadducttheeye

MicroesotropiaMicroesotropiahasanonsetinchildrenunder3yearsandistypicallyaconstant,unilateralesotropiawithanangleoflessthan10∆.Sincetheangleofthetropiaissmall,itcanbechallengingtodiagnosewithacovertest.Patientswithmicroesotropiacanhaveasmallcentralsuppressionscotomathatleadstonorandotstereopsis,additionally,a4baseout(BO)testcanbeutilizedtoaiddiagnosis.

• Inapatientwithnormalfixationandnomicrotropia,wewillseetwodistinctmovementsona4BOtest.Thesemovementsinclude:

1. Versionalmovementofbotheyestowardtheapexoftheprism2. Convergencere-fixationoftheeyethatisnotcoveredbytheprism

• Inapatientwitharightmicroesotropiaandasmallcentralsuppressionscotoma,wewouldexpecttoseethefollowingona4BOtest:

1. Prismplacedoverrighteye–NOmovement2. Prismplacedoverthelefteye–versionalmovementofbotheyestowardtheright,NO

convergencere-fixation

BLOWOUTWetypicallythinkofinferiorrectusentrapmentassociatedwithblowoutfracturesbutwecanalsoseelateralormedialrectusentrapmentsthatleadtoesotropia[29][30].

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Exotropia(XT)Exotropiaoccurswhentheeyesaretoodivergentfortheobjectofregard.

CongenitalExotropiaCongenitalexotropiaistypicallyconstantandoccurspriorto6monthsofage.Patientswithcongenitalexotropiahaveanincreasedincidenceof[19]:

• cerebralpalsy• neurologicdisorders• craniofacialdisorders• ocularalbinism

SensoryExotropiaSensoryexotropiaoccursinpatientswithseverelyreducedVAorablindeye.Inpatientswhoaretypicallyolderthan2-4yearsoldiftheybecomeblindorseverelylowvisioncanalsobecomeexotropicduetoaninabilitytodisparateimages[20].

IntermittentExotropiaIntermittentexotropiatypicallyoccurswhenviewingdistanceobjectswhenpatientsaretired,sickorinsomewayataloweredmentalstate(eg.intoxicated)andunderbrightlyilluminatedsituations.The3subtypesofintermittentexotropiaare:

1. BasicIntermittentXT–distanceandnearphoria/tropiameasurementsarewithin10∆ofeachotherandconvergenceisnotimpacted.

2. Pseudo-divergenceexcess–characterizedbyanexotropiathatislargeratdistancebutresolvesafteraperiod(30-60minutes)ofocclusionofthenon-fixatingeye.Thesepatientstypicallycompensatebyincreasingtonicfusionalconvergence.

3. Divergenceexcess–characterizedbyanexotropiathatislargeratdistancethannearbutdoesnotresolveafterocclusionofthenon-fixatingeyeandtypicallyahighAC/Aratio.

DifferentialDiagnosisofAmblyopiaIntheassessmentofpatientswithamblyopiaitisimportanttoconsiderotherconditionsthatcanmasqueradeasrefractiveorstrabismicamblyopia.Someconditionshaveobviousclinicalfindingsandothersaremoresubtle.Theseconditionsinclude[21]:

• Duane’ssyndrome(XT/ET)• CNIIIpalsy(XT)• CNVIpalsy(ET)• Internuclearophthalmoplegia(XT)–affectedeyehaslimitedAdductionand“normaleye”

appearstoexotropicandexhibitsnystagmusonABduction• Orbitalfibrosis/thyroideyedisease(XT/ET)–exotropiceyewillnotmoveinonADductionand

therewillberesistancetoADductiononforcedductiontesting• Moebiussyndrome(XT/ET)–anonprogressivecraniofacialandneurologicaldisorderthat

manifestsasprimarilyasfacialparalysiswithlackoflateraleyemovements• Myastheniagravis(XT/ET)• Achromatopsia

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• Coloboma• Myelinatednervefibers• Retinopathyofprematurity• Degenerativemyopia• Hypoplasticopticnerve• Keratoconus• Mediaopacities• Macular,perimacularchorioretinalscar• Macularpathology(e.g.,Stargardt'sdisease)• Opticatrophy• Retrobulbarneuritis• Nystagmus(congenital,latent,manifestlatent)• Craniopharyngioma

TraditionalTreatmentandManagementAsdiscussedabove,therearemanysubsequentsequelaeforthevisualsystemthatcanoccurinpatientswithamblyopia.Traditionaltreatmentoptionsinclude:

1. Refractive error correction 2. Patching 3. Penalization 4. Vision therapy 5. Surgery UpdateontheLiterature–AmblyopiaTreatmentStudies(ATS)Becauseoftheabovevariables,itcanmakedesigningalargestudychallengingtotractimprovementineachoftheareassinceimprovementcouldbemonitoredbasedonVA,binocularvision,accommodativeaccuracy,andevencosmesis.TheadvantageoftheAmblyopiaTreatmentStudiesisthattheyarelargemulti-centerprospectivestudiesthatcanhelpguideusonhowtoimproveVAwithdifferenttreatmentoptionsinpatientswithamblyopia.ThedownsidewiththestudiesisthattheydealalmostexclusivelywithimprovementsinVAandtheyhavehadadifficulttime,duetomanypotentialfactors,evaluatingtheimpactofvisiontherapyandsurgery. ATS-1:Inpatientswithmoderateamblyopiaispatchingorpenalizationmoreeffectiveinpatientsaged3-7yearsold?[22]

• 419childrenwithamblyopia(20/40to20/100)wererandomizedto:o 215patching(6hourstofulltime)o 204atropine(1%QD)

• BaselinemeanVAintheamblyopiceye:20/63• Baselinemeandifferenceinacuitybetweeneyes:4.4lines• VAImprovement:

o SixMonthsMeanVA:§ Patching:20/32§ Atropine:20/32-2

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§ Improvementinitiallywasfasterinthepatchinggroup,butaftersixmonths,thedifferenceinacuitybetweentreatmentgroupswassmall

o TwoYearMeanVA:§ Patching:+3.7lines§ Atropine:+3.6lines

ATS-2A:Inpatientswithsevereamblyopiais6hoursofpatchingaseffectiveasfull-timepatchinginpatientsaged3-7yearsold?[23]

• 175childrenwithsevereamblyopia(20/100to20/400)wererandomizedtoeither6hoursperdayorfull-timedailypatching.

• Allpatientswereprescribedatleastonehourperdayofnearvisualactivitieswhilepatching

• VAImprovement:o 6hoursperdayofpatching: +4.8lineso Full-timedailypatching: +4.7lines

ClinicalPearlsATS-1

• Bothtreatmentswerewelltolerated,althoughatropinehadaslightlyhigherdegreeofacceptabilityonaparentalquestionnaire

• At6monthsitisslightlymorelikelyforpatientstakingatropinetohavereducedacuityinthesoundeyeatsixmonthsbutthisdidnotpersistwithfurtherfollowup

• Patchingadvantage:morerapidimprovementinVAandpossiblyaslightlybetteracuityoutcome

• Atropineadvantage:easieradministrationandlowercost• Ifonetreatmentdoesn’tworkconsiderswitchingtotheother• Initialchoiceofpatchingoratropinecanbemadebytheproviderandparent

ClinicalPearlsATS-2A

• Forpatientswithsevereamblyopia,startwith6hoursofpatchingdaily•

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ATS-2B:Inpatientswithmoderateamblyopiais2hoursofpatchingaseffectiveas6hoursofpatchinginpatientsaged3-7yearsold?[24]

• 189childrenwithsevereamblyopia(20/40to20/80)wererandomizedtoeither2hoursor6hoursdailypatching.

• Allpatientswereprescribedatleastonehourperdayofnearvisualactivitieswhilepatching

• VAImprovement:o 2hoursperdayofpatching: +2.4lineso 6hoursperdayofpatching: +2.4lines

ATS-2C:Howoftenwillamblyopiaregressaftertreatmentisstopped?[25]• 156children(<8yearsold)withsuccessfullytreated(improvementinVAwithpatchingor

atropine)anisometropicorstrabismicamblyopia8yearsofage,• Followedwithouttreatmentfor52weekstoassessrecurrenceofamblyopia,

o Recurrencedefinedaseither:§ 2ormorelogMARlevelreductionofVAfromenrollment§ Treatmentisrestarted

• Recurrenceo Patientswhowerepenalized: 21%o Patientswhowerepatched: 25%

• Ifpatchingis≥6hoursandNOtaper: 42%• Ifpatchingis≥6hoursandthentaper: 14%

ClinicalPearlsATS-2B

• Forpatientswithmoderateamblyopia,startwith2hoursofpatchingdaily•

ClinicalPearlsATS-2C

• ~1/4ofsuccessfully-treatedamblyopeswillhavearecurrenceinthefirstyearofstoppingtreatment.

• Forpatientstreatedwith6+hoursofdailypatching,theriskofrecurrenceisgreaterwhenpatchingisstoppedabruptlyratherthanwhenitisreducedto2hoursperdaypriortocessation.

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ATS-3:Istreatment(patchingorpenalization)effectiveatimprovingVAin7-18yearoldswithamblyopia?[26]

• 507patientswithamblyopia(20/40to20/400)wererandomizedtobetreatedwithspectaclesonlyorspectaclespluspatching/penalization(2-6hours/daydependingonseverity)

• Numberofpatientswhorespondedtoeachtreatmentarmareasfollows:o Patients7to<13yearsold:

§ Spectaclesonly: 25%§ Spectacles+p/p: 53%

o Patients13to<18yearsold:§ Spectaclesonly: 25%§ Spectacles+p/p: 23%

• PatientsPREVIOUSLYtreatedwithp/p: 20%• PatientsNOTPREVIOUSLYtreatedwithp/p: 47%

ATS-4:Isweekendonlyatropineaseffectiveasdailyatropineattreatingpatientswithmoderateamblyopia(20/40to20/80)?[27]

• 168 children (3 to < 7 years old) with moderate amblyopia (strabismus, anisometropia, or mixed) were randomized to be treated with either daily atropine or to weekend atropine

• Improvement in VA of the amblyopic eye from baseline to 4 months averaged 2.3 lines in each group.

• Additionally, VA was either better than 20/25 or better than or equal to the sound eye in: o Daily group: 47% o Weekend group: 53%.

• Stereoacuity outcomes were similar in the two groups. • Patients were more compliant with the daily dosing

ClinicalPearlsATS-3

• Forpatients7to<13yearsold,prescribe2to6hoursperdayofpatching/atropineeveniftheamblyopiahasbeenpreviouslytreated.

• Forpatients13to<18yearsold,prescribe2to6hoursperdayofpatching/atropineifamblyopiahasnotbeenpreviouslytreatedandspectaclesONLYifamblyopiawaspreviouslytreatedwithp/p.

ClinicalPearlsATS-4

• Inpatientswithmoderateamblyipiawhenusingatropine,startwithdailydosingtoimprovecomplianceandthentapertoweekenddosingaftertheinitialfollowup.

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ATS-5:HowmucheffectdoesspectaclecorrectionhaveonimprovingVAinpatientswithanisometropicamblyopia?[28]

• 84children(3to<7yearsold)withpreviouslyuntreatedanisometropicamblyopia(20/40to20/250)wereevaluatedforimprovementinBCVAafterspectaclecorrectionoftheirametropia

• Amblyopiaimprovedwithspectaclecorrectionaloneby2ormorelinesin77%ofthepatients• Amblyopiaresolvedwithspectaclecorrectionalonein27%ofpatients• StabilizationofVAtookupto30weeksbutaveragedabout6months• Follow-upoccurredevery5weeksuntilstabilization

ATS-6:Whenpatching,does“distance”or“near”activitieshaveanimpactontheresolutionofamblyopia?[29]

• 425children(3to7years)withamblyopia(20/40–20/400)thatwascausedbyanisometropia,strabismus,orboth,andthatpersistedaftertreatmentwithspectacleswererandomizedto2hoursofpatchingperdaywithEITHERnearordistanceactivities.

• VAimprovementat8weekso Distancegroup: averaged2.6lineso Neargroup: averaged2.5lines

• Childrenwithsevereamblyopia(20/100to20/400)improvedbyameanof3.6lineswith2hoursofdailypatching.

ClinicalPearlsATS-5

• Whenstartingtreatmentforanisometropicrefractiveamblyopia,startwithspectaclecorrectionalonethiscanmakepatchingorpenalizationeasier(ifneeded)sincetheamblyopiceyeVAisbetter.

ClinicalPearlsATS-6

• Whenstartingpatchingtreatmentbothdistanceandnearactivitiesareequallyeffective• Encouragepatientstodoactivitiestheyenjoy(iPad,Wii,etc.)• Patientswithsevereamblyopiawillrespondwith2hoursofpatching

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ATS-7:HowlongeffectiveisspectaclecorrectionaloneatimprovingVAinpatientswithbilateralrefractiveamblyopiaandwhatisthetimeframeforVAimprovement?[30]

• 113children(age3to<10)withuntreatedbilateralrefractiveamblyopia(20/40to20/320)wereprescribedoptimalspectaclecorrection.

• After1yearoftreatmentVAimprovementwas:o Initialbinocularacuityof20/40to20/80was3.4lineso Initialbinocularacuityof20/100to20/320was6.3lines

• Cumulativeprobabilityofbinocularacuityof20/25orbetterwaso 21%at5weekso 46%at13weekso 59%at26weekso 74%at52weeks

ATS-8:Doesweekendatropinewithaplanolensinthesoundeyehelpimproveamblyopiabetterthanweekendatropinealone?[31]

• 180childrenwithmoderateamblyopia(20/40to20/100)wererandomizedtoweekendatropineplusplanolensoverthesoundeyeorweekendatropineusealone.

• Soundeyehadtobehyperopicof+1.50ormore• VAimprovement

o AtropineONLY: 2.4lineso AtropinePLUS: 2.8lines

• AmblyopiceyeVAof20/25orbettero AtropineONLY: 29%o AtropinePLUS: 40%

• PatientsintheatropineplusgroupweremorelikelytohavereducedVAinthesoundeyeat18weeks,however,thiseffectresolvedafterceasingtreatment.

ClinicalPearlsATS-7

• Within1year3/4ofpatientswithbilateralrefractiveamblyopiawithhavebinocularVAimproveto20/25orbetterwithspectaclecorrectionalone.

ClinicalPearlsATS-8

• AugmentingatropinetreatmentwithaplanolensoverthesoundeyedoesnotsignificantlyimproveamblyopiceyeVA

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ATS-9:Ispatchingoratropinemoreeffectiveatimprovingamblyopiainpatientswhoare7to<13?[32]

• 193childrenwithamblyopia(20/40-20/100)wereassignedtoreceiveweekendatropineorpatchingofthesoundeye2hoursperdayandfollowedfor17weeks

• VAimprovement:o Atropine: 7.6letterso Patching: 8.6letters

• VAof20/25orbetter:o Atropine: 17%o Patching: 24%

ATS-10:HoweffectiveareBangerterfiltersoverthesoundeyeatimprovingVAinpatientswithamblyopia?[33]

• 186children(3to<10yearsold)withmoderateamblyopia(20/40-20/80)wererandomizedtoreceive2hoursofdailypatchingoraBangerterfilter(blurtoBVAinamblyopiceye)overthespectaclelensofthesoundeyeandfollowedevery6weeksfor24weeks.

• AverageVAimprovement:o Bangertergroup: 1.9lineso Patchinggroup: 2.3lines

• Percentageofpatientswith3ormorelinesofVAimprovement:o Bangertergroup: 38%o Patchinggroup: 35%

• Percentageofpatientswith20/25VAorbetterinamblyopiceyeacuityo Bangertergroup: 36%o Patchinggroup: 31%,

• TherewasalowertreatmentburdenintheBangertergroup

ClinicalPearlsATS-9

• Treatmentwithatropineorpatchingledtosimilardegreesofimprovementamong7-to<13year-oldswithmoderateamblyopia

• ~20%achievedVAof20/25orbetterintheamblyopiceye

ClinicalPearlsATS-10

• WithasmallaveragedifferenceinVAimprovementbetweenpatchingandBangerterfiltersandlowertreatmentburden,Bangerterfiltertreatmentisareasonabletreatmentoptionforpatientswithmoderateamblyopia.

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ATS-13:HowmucheffectdoesspectaclecorrectionhaveonimprovingVAinpatientswithstrabismicorcombinedmechanismamblyopia?[34]

• 146children(3to<7yearsold)withpreviouslyuntreatedstrabismic(S)amblyopia(n=52)orcombined-mechanism(CM)amblyopia(n=94)weretreatedwithspectaclelensesonly

• AverageVAimprovement: 2.6lineso S: 3.2lineso CM: 2.3lines

• VAimprovementof≥2lines: 75%• VAimprovementof≥3lines: 54%• Resolutionofamblyopia: 32%

ATS-15:InpatientswhoseVAplateauedwhenpatchingasperATS-2BhavefurtherimprovedVAifpatchingtimeisincreased?[35]

• 169children(3to<8years)withstableresidualamblyopia(20/32-20/160)after2hoursofdailypatchingforatleast12weekswererandomizedtoeithercontinue2hoursofdailypatchingorincreasepatchingtimetoanaverageof6hours/day.

• AverageVAimprovement:o 2-hourgroup: 0.6lineso 6-hourgroup: 1.2lines

• Percentageofpatientswith2ormorelinesofVAimprovement:o 2-hourgroup: 40%o 6-hourgroup: 18%

ClinicalPearlsATS-13

• OpticaltreatmentaloneofSandCMamblyopiaresultsinclinicallysignificantimprovementinamblyopiceyeVA

• Amblyopiawillresolvein~33%ofpatientswithSorCMamblyopiawithspectaclesalone• Spectaclecorrectionaloneshouldbestronglyconsideredastheinitialtreatmentfor

patientswithS/orCMamblyopia

ClinicalPearlsATS-15

• WhenamblyopiceyeVAstopsimprovingwith2hoursofdailypatching,considerincreasingthedailypatchingdosageto6hours

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Bibliography

[1] L.D.S.A.CiuffredaKJ,Amblyopia,Boston:Butterworth-Heinemann,1991.

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