眼科学-眼外肌病

DiseasesofExtraocularMuscles眼外肌病

Section1Introduction概述23Therearesixextraocularmuscleswhichacttorotateaneyeaboutitsvertical,horizontal,andantero-posterioraxes:themedialrectus(MR),thelateralrectus(LR),thesuperiorrectus(SR),theinferiorrectus(IR),thesuperioroblique(SO),andtheinferioroblique(IO).4Allsixmusclesworkinunisontomovetheeye.

Asonecontracts,theopposingmusclerelaxes,creatingsmoothmovements.

Inadditiontothemusclesofoneeyeworkingtogetherinacoordinatedeffort,themusclesofbotheyesworkinunisonsothattheeyesarealwaysaligned.5Ductionsaremonoculareyemovements.Movementoftheeyenasallyisadduction;temporalmovementisabduction.Elevationanddepressionoftheeyearetermedsursumduction(supraduction)anddeorsumduction(infraduction),respectively.Incycloduction(intorsion)isnasalrotationoftheverticalmeridian;excycloduction(extorsion)istemporalrotationoftheverticalmeridian.67891011121314Positionofgazetoisolatetheprimaryactions:15Binoculareyemovementsareeitherconjugate共轭运动(versions)ordisconjugate分离运动(vergences).Versionsaremovementsofbotheyesinthesamedirection(eg,rightgazeinwhichbotheyesmovetotheright).Dextroversionismovementofbotheyestotheright,andlevoversionismovementofbotheyestotheleft.Sursumversion(supraversion)anddeorsumversion(infraversion)areelevationanddepressionofbotheyes,respectively.1617FunctionsandinnervationsMedialrectusM:adductionLateralrectusM:abductionSuperiorRM:elevationintorsionadductionInferiorRM:depressionextorsionadductionSuperiorOM:intorsiondepressionabductionInferiorOM:extorsionelevationabduction1819SUPRANUCLEARCONTROLOFEYEMOVEMENTS

Themajorconjugateeyemovement共轭运动systemsaresaccades(sə’kɑ:d)扫视andpursuit.Thesaccadicsystemcontrolsrapideyemovementandmaintainsfixation(foveation)ontheobjectofregard.Horizontalsaccadesarecontrolledbycontralateralfrontaleyefieldsinthefrontallobe.Therightfrontallobecontrolssaccadestotheleft,andtheleftfrontallobecontrolshorizontalsaccadestotheright.20Thepursuitsystemcontrolssmoothtrackingtofollowslow-movingobjects.Thepursuitmovementsarecontrolledbytheipsilateralparietallobe顶叶(ie,rightpursuitisdrivenbytherightparietallobe,andleftpursuitisdrivenbytheleftparietallobe).Mostvoluntaryeyemovementsareacombinationofsaccadeandpursuiteyemovements.21Controlofthevergencesystemispresumedtobelocatedatthelevelofthebrainstem.Retinaldisparityisthoughttobethestimulusthatdrivesdivergenceorconvergence(motorfusion)tomaintainsensoryfusionandstereopsis.2223BinocularSingleVisionBSVistheabilitytousebotheyestocreateasingle,commonperception.双眼同时注视时，物体在视网膜上分别成像，但大脑皮层视觉中枢可将其融合为一个物像，使人们感觉到一个完整的立体形象，而不是两个相互分离的物体，这种功能称为双眼单视binocularsinglevision，是在出生后逐渐发育、完善的。24BinocularSingleVisionItcanbebrokendownintothreecomponentparts:1.simultaneousperception-witheacheyeseeingtheimageatthesametime(第一级：同时知觉:双眼能同时看到两个不同的画面)2.fusion-wheretheimagesfromeacheyearefusedtogiveasingleimageatthevisualcortex.(第二级：融合功能双眼能将大部分相同细节不同的图像看成一个图像。)25Binocularsinglevision的分级3.stereopsiswherefusionoftheslightlydifferentimagesfromeacheyeareinterpretedtoallowaperceptionofdepth(第三级：立体视将两个近似的图像看成一个有立体感的图像。)26有了fusion，就能综合双眼看到的物像，形成一个完整的印象。有了stereopsis,就能将两眼看到的物像形成有深度的知觉。人们可以赖以完成各种高级精细的工作。27TwoEyestotheSideherbivorous

animalsTwoEyesinFront

carnivorous

hunters28Naturehasgivenanimalsthephysicalattributesnecessaryforsurvival.Lateralplacementoftheeyesisessentialtothesurvivalofhuntedanimalsorherbivorous食草动物

animals(horse,rabbit,cow)asitallowthemtoincreasesideorperipheralvision.Sidevision(increasedbylateralplacement)isasensitivedetectorformotionormovement.Peripheralvisionallowscreaturestoeffectivelyscanfordanger.Therabbitmustbeconstantlyawareofitsnaturalenemieswhileiteatsyourgardengreens.Atthefirstsignofdanger,peripheralvision,themotiondetectorsystem,alertstherabbitthatthereisdanger.Theimmediatereflexiveresponseisfortherabbittorun.29Fastermovingcarnivorous肉食类

huntersdonotneedasmuchperipheralvisionasthehunted.Itismoreimportantforhunterstolocatetheirpreyandaccuratelydeterminethedistancefromthemselvestothatprey.Therefore,animalsthathunthavefrontalplacementofthetwoeyesinordertodeterminetheexactlocationoftheirprey.Thehunterssacrificethelargeperipheralmotiondetectionsystemaffordedbysideplacementoftheeyesinfavoroftheincrediblyaccuratedepthperceptionsystemcreatedbyfrontalplacementoftheeyes.Tomakeupforthelossofperipheralvision,mostcarnivorousanimalshavealsodevelopedasophisticated,pivotingsystemwhichextendstherangeofsidevision...thatis,theneck.30视觉空间和双眼差异通过视觉信息认识的空间为视觉空间，实际存在的外界空间叫实际空间。二者间有复杂的对应关系。我们都是通过视觉空间来认识实际空间。page23131两眼是从不同的角度看同一物体，角度不同，形成的视觉也不同，这就是双眼差异binoculardisparity.正是因为有了binoculardisparity，大脑将双眼不同的信息加工处理（融合），形成了立体视。32只有一只眼的人也并不是完全没有立体视。日常生活中可以根据光线照射物体的阴影、相对运动、物体移动时由大到小的变化等产生一定的立体视。33Stereopsisplaysaroleinmanyotherhumanactivites,suchas,catchingaball,parkingacar,threadinganeedle,performingsurgery,oranyotheractivitythatrequiresaccuratedepthperceptionatclosedistances.34双眼视觉的发生、发展刚出生的婴儿没有双眼视觉，眼球的运动与视觉无关。视力只有0.03～0.05，视皮质、视通路不成熟。6～8周婴儿出现明显的眼球运动，开始双眼注视。3个月时可随意注视，5个月时有较好的集合、调节及部分融合。1岁时有较好的融合，1岁半时调节、集合能很好地协同，3～4岁时立体视达成人水平，5～6岁时双眼视趋于完善和稳定。page23035双眼视觉是在正常的眼球结构和良好的视觉知觉基础上，通过反复适宜的视觉刺激和强化才逐渐建立的。形成条件：视觉知觉RCPmonofixationnormalbinocularmovement….36双眼视的关键期从出生几个月开始，至12岁左右。可塑性高峰期在2岁左右。6岁以前，特别是2岁以前，如果缺乏视觉经验，会造成视觉中枢功能受抑制、结构改变，形成弱视的不良后果。37Table1normalvisualDevelopmentpupillarylightreactionpresent–30wksgestationblinkresponsetovisualthreat—2-5monthsfixationwelldeveloped–2monthssmoothpursuitwelldeveloped—6-8wkssaccadeswelldeveloped—1-3wksaccommodationappropriatetotarget—4momthsstereopsiswelldeveloped–3-7monthscontrastsensitivityfunctionwelldeveloped–7monthsocularalignmentstabilized—1monthfovealmaturationcomplete—4monthsopticnervemyelinationcomplete—7monthsto2yrs38Visualmilestones1.1-2months—briefattentiontoobjectwithoutauditorystimulus2.3months—attentioncombinedwithabilitytofollowmovement3.4-5months—increaseddurationofattentionspan4.6months—reachesforandplaywithanobjectinhisorherhand5.1year—pointstodesiredobject6.Uptoage5—mayalteroflosevisualreflexes7.Afterage5—difficulttoalterorlosevisualreflexesasvisualsystemisfairlymature39视网膜的对应点视网膜对应：retinalcorrespondingpoints双眼单视时，用双眼的黄斑中心凹注视视物，因此两眼黄斑部是对应点。其他视网膜成分各依其与黄斑部的距离结成对应关系，一眼黄斑部鼻侧的一点必与另一眼黄斑部颞侧等距离的另一点相对应。双眼视觉的生理基础40Whenwelookatanobjectwithtwoeyes,weperceiveitassingular,likewedootherpartsofthevisualscenestimulatingpointsonourretinathatshareacommonvisualdirection.Thesepointsaretermed"retinalcorrespondingpoints"andfallonanareacalledthe"horopter".Pointsoutsidethehoropterfallonslightlydifferentretinalareasandsodonothavetheidenticalvisualdirectionandleadto"retinaldisparity",thebasisofourdepthdiscrimination.41Ourvisualworldcomprisesofmultiplepoints,hence,theneedtodevelopconceptstodealwiththewholevisualspace.Thisconceptiscalledthehoropter.Thehoropteristhelocusofpointsinspacethatstimulatescorrespondingpoints.Thatis,amultitudeofpointsinvisualspacethatleadtosinglevision.42Thisretinalimagedisparityoccursduetothelateraldisplacementoftheeyes.Theregioninvisualspaceoverwhichweperceivesinglevisionisknownas"Panum'sfusionalarea",withobjectsinfrontandbehindthisareabeinginphysiologicaldiplopia(i.e.doublevision).Ourvisualsystemsuppressesthisdiplopiaandhencewedonotperceivedoublevisionundernormalviewingconditions.43Physiologicaldiplopiaisanormalphenomenoninwhichobjectsnotwithintheareaoffixationareseenasdouble.Usually,itissuppressedcentrallyanddoesnotimpingeontheconsciousness.Occasionally,itis'discovered'byachildwhocomplainsofdoublevision.Diagnosisisbyabsenceofdefectiveeyemovementanddemonstrationofthephenomenonbyaskingthepatienttolookatadistantobjectwhilstattentionisdirectedtoanearobject.44主观感觉上视网膜某一点代表着空间一个固定的方位。两眼视网膜对应点的空间投射方向相同。一个物体的影象只有同时落在两眼视网膜的对应点上，才能被感觉为一个影像，形成双眼单视。落在非对应点的物像，将被感觉成为两个影像。45斜视患者双眼单视的改变复视diplopia：两眼的中心凹接收不同的像，无法将其融合成单一像，从而成像双重像，呈复视。斜视患者未出现单眼抑制时，往往会出现diplopia.Diplopiaistheperceptionofthesameimageintwodifferentvisualdirections.Doublevision(diplopia)isoneofthemosttroublesomevisualdisordersapatientcanexperience.Theabilitytoread,walkandperformcommonactivitiesissuddenlydisrupted.

Themanagementofdoublevisionmayincludeprisms,orthoptics,therapy,eyemusclesurgeryandocclusion.

Thegoalistoestablishclearbinocularsinglevision.46视混淆confusion：一眼偏斜时，有两个物体分别成像在双眼视网膜的中心凹上，此时感知为两个物像的重叠，称confusion.

Visualconfusion,theperceptionoftwodifferentimagessuperimposedontothesamespace,isalsoasymptomofocularmisalignment.

Thissymptomcanresultfromnewlyacquiredstrabismusorfromchangeinthedirectionoramountofocularmisalignmentinadultswithchildhoodstrabismus.

Visualconfusionisparticularlydebilitatingwhendriving.

Theaffectedindividualmaydescribeacar"crossingoverthecenterlineandcomingstraightatthem,"when,infact,thebrainisshiftingtheimageofthecarandsuperimposingitontheroadahead.

Surgicalcorrectionorreductionoftheoculardeviationwillusuallyrelievevisualconfusion.Confusionoccurswhentwodifferentobjectsareseeninthesamevisualdirection,commonlyasaresultofstrabismus.47抑制suppression：对斜视的适应。发生斜视后，若用双眼注视，则中心凹接收不同的像，会出现diplopia.为了消除diplopia，大脑自动关闭一眼视觉信息的传入，只接收另一眼的视觉信息。suppressionSuppressionisabinocularphenomenonresultingintheinhibitionatthecorticalleveloftheimagefromoneeye.Suppressiontypicallyoccursasanadaptationtoananomalyofbinocularvision,likestrabismus.48异常视网膜对应anomalousretinalcorrespondence，ARC:对斜视的适应。斜视者在双眼视的情况下，通过一眼中心凹与另眼中心凹以外的点建立点点对应关系，以消除diplopia,这种新建立的异常对应关系叫ARC。Anomalousretinalcorrespondence(ARC),anadaptationtostrabismus,isabinocularconditioninwhichthetwofoveasdonotcorrespondinthevisualcortex.Itoccurswhenanonfovealpointintheretinaofthedeviatingeyeis"associated"inthevisualcortexwiththefoveaofthefixatingeye.Itismorecorrectlyreferredtoasanomalouscorrespondencebecausecorrespondenceiscortical,ratherthanretinal.49中心旁注视eccentricfixation：用中心凹以外的点注视目标。可分为旁中心凹注视、黄斑注视，旁黄斑注视、周边注视、游走性注视。Eccentricfixationisanadaptationtostrabismus,andoccurswhenanonfovealretinalpointisusedforfixation.Thatis,thedeviatingeyedoesnotusethecentralfovealareaforfixation.Thisexplainswhyallpatientswitheccentricfixationareamblyopic.Eccentricfixationistestedundermonocularconditionsonly,becauseitisamonocularphenomena.弱视amblyopia50Illustrationofnormalcorrespondence.Illustrationofharmoniousanomalouscorrespondence.51Illustrationoftypicalunharmoniousanomalouscorrespondence.52眼外肌的运动受神经支配。眼球向任何方向运动都必须有几条眼外肌共同作用完成。

Agonist:

theprimarymusclethatmovesaneyeinagivendirectionisknownastheagonist.Amuscleinthesameeyethatmovestheeyeinthesamedirectionastheagonistisknownasasynergist,whilethemuscleinthesameeyethatmovestheeyeintheoppositedirectionoftheagonististheantagonist.单眼某一条眼外肌行使其主要作用，使眼球向某一方向转动时，同一眼起辅助作用的眼外肌称为协同肌,起制约作用的眼外肌称为拮抗肌。page24053Accordingtosherrington’s

Law,increasedinnervationtoanyagonistmuscleisaccompaniedbyacorrespondingdecreaseininnervationtoitsantagonistmuscle(s).Ineachpositionofgaze,onemuscleofeacheyeistheprimarymoverofthateyeandisyokedtotheprimarymoveroftheothereye.

54双眼同方向、同角度运动时，双眼的同时、同角度收缩的眼外肌称配偶肌yokemuscles。例如向右侧注视，右眼外直肌与左眼内直肌等量收缩，为一对yokemuscles.Below,eachofthesixcardinalpositionsofgazeisshown,alongwithupwardgaze,downwardgaze,andconvergence:55Sherrington'slawofreciprocalinnervationstatesthat:Whenamusclecontracts,it'sdirectantagonistrelaxestoanequalextentallowingsmoothmovement.Hering'slawofequalinnervationisusedtoexplaintheconjugacyofeyemovements(saccades)instereopticanimals.ThelawwhichwasproposedbyHeringinthe19thcenturyproposesthatconjugacyofsaccadesisduetoinnateconnectionsinwhichtheeyemusclesresponsibleforeacheye'smovementsareinnervatedequally.Thelawalsostatesthatapparentmonoculareyemovementsareactuallythemathematicalsummationofconjugateversionandvergenceeyemovements

5657第二节相关基础研究－眼球运动基础一.转动中心与转动轴眼球的旋转中心在角膜中央后方13.5mm处。可以设想眼球沿Fick氏三轴的转动：沿水平轴（X轴）作上转、下转运动沿前后轴（Y轴）作内旋、外旋运动沿垂直轴（Z轴）作内转、外转运动58二眼球运动法则Hering氏法则：如一眼转向某一方向，其作用肌所接受到的神经冲动，同时也以相应的比例量到达其配偶肌。InnervationtoyokemusclesisdescribedbyHering'sLawofsimultaneousinnnervation.

TheRMRandtheLLRareyokemusclesbecausetheycontractsimultaneouslytomovethegazetotheleft.

Hering'sLawstatesthattheinnervationtotheyokemuscleinthenon-fixingeyemustequaltheinnervationtothecorrespondingagonistmuscleinthefixingeye.59InnervationtoagonistandantagonistmusclesisdescribedbySherrington'sLawofreciprocalinnervation.

RememberthattheRMRandtheRLRareantagonistsofoneanother.

Asonecontracts,theothermustrelax.

Sherrington'sLawstatesthatfortheamountofcontractioninnervationgiventotheRMR,anequalamountofrelaxationinnervationmustbegiventotheRLR.

Thatmakessense.

Otherwise,theiractionswouldnotbecoordinated.Sherrington氏法则：眼外肌收缩时，其拮抗肌同时以相应比例量松弛。60三.两眼运动的协调性人的眼球具有偏斜的倾向，但在融合功能的控制下，能够调整眼位，使物体成像于双眼的黄斑中心凹，成为一个物像。双眼看近物时，会同时出现集合(辐辏convergence:两眼视轴转向注视物体)、调节(accommodation:晶状体变凸，增加屈光度)、瞳孔缩小，称为近反射。61第三节斜视strabismus两眼不能同时注视目标，其中一眼注视目标，另一眼的视轴偏离目标，称为strabismus.Heterotropia,strabismus,tropia,squint:amanifestdeviationofthevisualaxesofthetwoeyes..分类：共同性斜视concomitantstrabismus非共同性斜视（麻痹性斜视）non-concomitantstrabismus特殊类型斜视specialtypes62strabismusClinically,strabismusmustbeproperlycharacterized,usingthefollowingcategories:Unilateralstrabismus:Strabismusinwhichonlyoneeyedeviates.Alternatingstrabismus:Strabismusinwhichthedeviatingeyecanchange.Intermittentstrabismus:Strabismuswhichisnotpresentatalltimes.Constantstrabismus:Strabismuswhichispresentatalltimes.Periodicstrabismus:Strabismuswhichoccursatonetestingdistancebutnotatanother.63orthophoria/orthotropiaOrthophoriaoccurswhenthetwovisualaxesaredirectedtowardthepointofbinocularfixationintheabsenceofanadequatestimulustofusion.Thatis,themagnitudeoftheheterophoriaiszero.Orthotropiaoccurswhenthetwovisualaxesaredirectedtowardthepointofbinocularfixationwhilestimulustofusionexists.64heterophoriaHeterophoria,alsoreferredtoas"phoria"or"dissociatedphoria,"isalatentdeviationofthevisualaxesoftheeyes.Itismanifestedbyeliminatingallstimulitofusion,suchasinthecovertestorwithastereoscope.Themagnitudeoftheheterophoriaisaresultofthecombinedeffectsoftonic,accommodative,andproximalvergences.65esophoria/esotropiaEsophoriaoccurswhenthevisualaxesoftheeyesconvergeatapointbetweenthepatientandtheobjectofregardwhenfusionissuspended.Esotropiaoccurswhenthevisualaxesoftheeyesconvergeatapointbetweenthepatientandtheobjectofregardundernormal,binocularviewingconditions(i.e.aconvergentstrabismus).66exophoria/exotropiaExophoriaoccurswhenthevisualaxesoftheeyesconvergeatapointbeyondtheobjectofregard(ordivergeinthecaseofanobjectofregardlocatedatopticalinfinity)whenfusionissuspended.Exotropiaoccurswhenthevisualaxesoftheeyesconvergeatapointbeyondtheobjectofregard(ordivergeinthecaseofanobjectofregardlocatedatopticalinfinity)undernormal,binocularviewingconditions(i.e.,adivergentstrabismus).672.Esophoria:Eyesarestraightuntilthelefteyeiscoveredandturnsinward1.Exophoria:Eyesarestraightuntilthelefteyeiscoveredandturnsoutward1268一.斜视检查法（一）询问病史发病时间、年龄、诱因、病情变化发展情况、治疗史及家族史等。（二）视力检查及屈光检查婴幼儿可作遮盖试验,三棱镜诱发眼斜试验；学龄儿童可使用E字视力表，必要时可检查对比敏感度和视觉诱发电位VEP。7岁以下儿童使用睫状肌麻痹剂以消除调节。（三）眼球偏斜方向

注意有无代偿头位6970（四）眼球运动检查在六个方向（左、右、左上、左下、右上、右上）上观察每条肌肉有无异常。双眼对比。71（五）斜视的定量检查1.角膜映光法corneallightreflectiontest患者注视33厘米处的点光源，观察角膜上反光点的位置，若双眼角膜反光点位于瞳孔中央则为正位眼，若一眼角膜反光点偏鼻侧则为外斜视exotropia；位于颞侧则为内斜视esotropia.10°~15°25°~30°45°角膜缘瞳孔缘722.三棱镜加遮盖试验

患者分别注视33cm和6m处目标，将三棱镜置于注视眼前，三棱镜的尖与斜视方向相同。交替遮盖两眼，观察三棱镜后的眼球是否移动。增减三棱镜度直至眼球不再移动，所得的三棱镜度即为该眼的斜视度。737475Description:Aneyecareprofessionalusesaprismtocheckforstrabismus,achildhoodeyedisorderthataffectstheeyemuscles.763.视野弧法

注视眼通过视野弧上的注视孔注视视标，检查者手持点光源在视野弧上移动，至角膜反光点位于被检眼瞳孔中央时，光源对应的视野弧刻度即为斜视度。774.三棱镜加马氏杆（Maddoxrod）法Maddoxrod由数根并排的玻璃圆柱组成，嵌于金属小框内。通过Maddoxrod看点光源，会看到成条的光线，方向与rod的方向垂直。暗室中设置小灯为注视目标，马氏杆置于一眼前，则双眼视网膜上形成截然不同的影象，从而干扰融象。若看到线条光通过点光源，则为正位眼，否则有斜视或隐斜。785.同视机检查

可查出主观斜视角和客观斜视角79808182concomitancy(comitancy)Concomitancy(comitancy)meansthattheangleofdeviationofthevisualaxesremainsthesameinallpositionsofgaze.Therearenoabnormalunder-oroveractionsoftheextraocularmuscles.Perfectconcomitancyisraresincetheangleofdeviationformostpeoplevariesslightlyfromonedirectionofgazetoanother.Clinically,iftheanglechangesbylessthan5prismdiopters,itisconsideredtobeconcomitant.83二.共同性斜视

concomitantstrabismus健眼注视目标，斜眼的偏斜度为第一斜视角；

斜眼注视目标，健眼的偏斜度为第二斜视角。眼球运动无障碍，各注视方向斜视度无明显差异的眼位偏斜，叫concomitantstrabismus.84分类根据偏斜持续的方向分共同性内斜视共同性外斜视共同性垂直斜视（极少见）(图)根据偏斜时间分：单眼恒定性斜视：经常一眼注视，另一眼恒定偏斜，斜视眼视力显著减退。交替性斜视：两眼主动（或遮盖后）交替注视目标，另眼交替偏斜，两眼视力相等或相近。间歇性斜视：一眼有时偏斜，有时正位，或只在视近、视远时出现偏斜。85

86共同性内斜视concomitantesotropia儿童斜视中发病率最高，随年龄增长逐渐降低。病因：不清，主要有神经支配因素：注视反射、融合反射、大脑皮层及皮层下眼球运动中枢功能障碍。机械因素：眼球大小、形状、眼外肌的解剖变异。临床表现：一眼偏向鼻侧，起病时多为间歇性，逐渐转为恒定性。多无复视，眼球运动基本正常。第一斜视角与第二斜视角相等，各方向斜视度相等。8788根据偏斜与调节的关系分:调节性内斜：因存在远视屈光不正，视近时过度使用调节，引起调节性集合过量所致。（视近时调节、集合、瞳孔缩小同时存在）部分调节性内斜：部分由调节因素，部分由其它因素引起。非调节性内斜：非调节因素所致的内斜。89convergenceexcess(CE)

Convergenceexcess(CE)isaconditioninwhichthepatientexhibitsapproximateorthophoriaatdistanceandhasanesotropiaatnear.ItisassociatedwithahighAC/Aratio.Patientsymptomsmayincludevisualfatigue,drowsiness,andtransientdiplopiaaccompanyingprolongednearwork.Effectivetreatmentincludesaplusaddfornearoruseofbase-outprismforcloseworktoreducesymptoms.90divergenceinsufficiency(DI)

Divergenceinsufficiency(DI)ischaracterizedbyesotropiaatdistanceandanapproximateorthophoriaatnear.ItisassociatedwithalowAC/Aratio.Effectivetreatmentincludesbase-outprism91继发性内、外斜视常见于肌肉或神经有轻度麻痹继发于术后欠矫或过矫知觉性斜视：一眼视力严重障碍，感知丧失发生眼位偏斜92InfantileEsotropiaEsotropia93治疗目的：恢复双眼视功能、获得正常眼位。因此，必须提高斜视眼的视力，恢复正常视网膜对应。矫正屈光不正，尤其在调节性内、部分调节性内斜患者治疗弱视眼正位训练手术治疗斜视眼戴镜半年至一年，斜视度不变者可手术治疗94矫正屈光不正9596共同性外斜视concomitantexotropiaConcomitantexotropia与屈光不正、调节关系不大，发病年龄较分散。常有一间歇期，逐渐转为恒定性外斜视。Exotropia的度数有逐渐增加的趋势。97病因可能与中枢性辐辏兴奋、分开兴奋不平衡有关。调节、集合不平衡。如近视屈光不正时，视近不需调节，使调节性集合低下，导致外斜。屈光参差使双眼成像不等，影响融合。9899Exotropia--straightExotropia--deviatedExotropiaVisiontrainingisaneffectivewaytomanagethiscondition100divergenceexcess(DE)Divergenceexcess(DE)ischaracterizedbyhighexotropiaatdistanceandlowexophoriaororthophoriaatnear.ItisassociatedwithahighAC/Aratio.Divergenceexcesscasescanbetreatedwithvisiontraining,BIprismfordistance,oradecreaseinpluspoweroranincreaseinminuspowerfordistance.101convergenceinsufficiency(CI)Convergenceinsufficiency(CI)isaconditioninwhichthepatientexhibitsapproximateorthophoriaatdistanceandhasamoderatetohighexotropiaatnear.ItisassociatedwithalowAC/Aratio.Typically,theNPCisreceded,andthereislikelytobealowpositivefusionalvergencereserve.Patientsymptomsmayincludevisualfatigue,drowsiness,andtransientdiplopiaaccompanyingprolongednearwork.102临床表现发病年龄分散间歇性外斜的斜视角变化较大少数人早期有复视，多数人因单眼抑制无复视幼年发病，视功能预后差；成年发病，因保留一部分融合功能，术后双眼单视功能较好可有异常视网膜对应和弱视103治疗矫正屈光不正小角度斜视或术后残留斜视可用三棱镜矫正。正位训练手术治疗104noncomitancy/incomitancyNonconcomitancyoccurswhenthedeviationchangeswithdifferentpositionsofgaze.Therefore,thereiseitherabnormalrestrictiontomovementoroveractionofoneormoreoftheextraocularmuscles.Clinically,ifthechangeindeviationismorethan5prismdiopters,thedeviationisconsideredtobenonconcomitant.105非共同性斜视

non-concomitantstrabismus指麻痹性斜视，是由于神经核、神经、眼外肌本身器质性病变，引起单条或多条眼外肌完全或部分麻痹，导致的眼位偏斜。偏斜角度在不同注视方向和距离有所不同，伴不同程度的眼球运动障碍。106病因先天性出生时或生后早期发生。由于先天发育异常、产伤、眼外肌缺如等。常有代偿头位。后天性发病急，有确切发病时间。外伤：头部外伤可累及眼球的运动神经。炎症：脑炎、脑膜炎常累及展神经、滑车神经。眶尖脓肿、海绵窦血栓可引起多发性神经麻痹。血管性疾病：高血压可致展神经麻痹。脑血管意外可损伤眼球运动神经及核上联系。肿瘤：直接压迫、颅内高压、肿瘤浸润使神经麻痹。代谢性疾病：糖尿病血管病变，血供不足，使神经麻痹。机械性眼球运动障碍眶底骨折使眼外肌嵌顿，术后组织粘连限制眼外肌运动等。107临床表现复视diplopia、眩晕代偿头位108眼位偏斜运动受限麻痹肌行使作用不足第二斜视角大于第一斜视角，即以麻痹眼注视时，健眼的偏斜度大109110治疗病因治疗药物治疗维生素B1、B12、三磷酸腺苷糖皮质激素、抗生素治疗神经炎肌肌炎肉毒杆菌毒素A注射麻痹肌的直接拮抗肌，使之与麻痹肌间建立新的平衡，缓解症状并防止拮抗肌发生挛缩三棱镜

小于10△的斜视，可用三棱镜中和法消除复视。手术病因被去除，病情稳定，但仍不恢复，可手术治疗。一般需等待6个月，观察斜视角确无变化。时间太长麻痹肌的拮抗肌会发生挛缩，影响效果。111112113DifferentialDiagnosisofcomitantandincomitantstrabismus

麻痹性（非共同性）共同性发病骤然逐渐进展眼球运动向麻痹肌运动方向障碍无异常斜视角第二斜视角>第一斜视角

第二=第一复视有无代偿头位有无114特殊类型斜视一.眼外肌广泛纤维化综合征先天性眼外肌、筋膜发育不正常。单眼或双眼发病。第一眼位偏斜，运动受限，各方向程度不等。可有上睑下垂。被动转眼试验阳性，甚至眼球完全不能离开斜位。115二.Duane眼球后退综合征第一眼位可正位或偏斜。眼球运动受限，企图内转时，患眼睑裂变窄，眼球后退。病因可能有：肌肉和筋膜纤维化节制韧带和肌肉附着点异常神经错位支配116117Duane'sRetractionSyndrome118三.垂直后退综合征当眼球向患侧转动时再向上或向下转，会出现眼球后退。上转有明显障碍者，外下转也可能受限。因此两眼向患侧外上方看时，患眼眼位低；向患侧外下方看时，患眼眼位高。第一眼位可无偏斜。119四.Brown上斜肌鞘综合征上斜肌鞘有节制韧带的作用，上斜肌鞘缩短或纤维化就会出现Brown综合征。患者第一眼位正位或轻度下斜，有代偿头位。患眼内上转显著受限，被动牵引内上转也很困难。aBrown'sSyndromeofthelefteye.120例1.房某，男，10岁。V外斜。术前（2002，7，16）照片号：109—967-76。

房某，术后1个月随访照片。121例3.和某,女，4岁。V内斜。术前照片

和某，术后3天照片。122第四节弱视amblyopiaAmblyopia:Amblyopiaisreducedvisualacuity(poorerthan20/20)whichisnotcorrectablebyrefractivemeans,andisnotattributabletoobviousstructuralorpathologicalanomalies.

凡眼球内部、外部无任何器质性病变，而矫正视力不能到正常者。123Amblyopia是由于视觉系统发育关键期，进入眼内的视觉刺激不够充分，剥夺了形成清晰物像的机会（形觉剥夺），或者两眼视觉输入不同，引起清晰物像与模糊物像间发生竞争（双眼相互作用异常），造成单眼或双眼视力发育障碍。一般矫正视力≤0.8。124双眼视觉关键期：出生～12岁，视觉功能脆弱，易受异常视觉条件的影响可塑高峰期：2岁M通道低空间频率（粗大目标）P通道高空间频率（细小目标）弱视与P通道125Table1normalvisualDevelopmentpupillarylightreactionpresent–30wksgestationblinkresponsetovisualthreat—2-5monthsfixationwelldeveloped–2monthssmoothpursuitwelldeveloped—6-8wkssaccadeswelldeveloped—1-3wksaccommodationappropriatetotarget—4momthsstereopsiswelldeveloped–3-7monthscontrastsensitivityfunctionwelldeveloped–7monthsocularalignmentstabilized—1monthfovealmaturationcomplete—4monthsopticnervemyelinationcomplete—7monthsto2yrs126Visualmilestones1.1-2months—briefattentiontoobjectwithoutauditorystimulus2.3months—attentioncombinedwithabilitytofollowmovement3.4-5months—increaseddurationofattentionspan4.6months—reachesforandplaywithanobjectinhisorherhand5.1year—pointstodesiredobject6.Uptoage5—mayalterorlosevisualreflexes7.Afterage5—difficulttoalterorlosevisualreflexesasvisualsystemisfairlymature127Amblyopiarepresentsasyndromeofcompromisingdeficits(ratherthansimplyreducedvisualacuity)including:increasedsensitivitytocontourinteractioneffects轮廓交互作用效应abnormalspatialdistortionsanduncertaintyunsteadyandinaccuratemonocularfixationpooreyetrackingabilityreducedcontrastsensitivityinaccurateaccommodativeresponse128Asceneasitmightbeviewedbyapersonwithmyopia(nearsightedness).Normalvision129分类及病因

classificationandetiology

斜视性弱视strabismicamblyopia

斜视患者物像不能成像在双眼的正常视网膜对应点上，引起复视和视混淆，大脑会主动抑制斜视眼传入的视冲动，斜视眼的黄斑功能长期被抑制，形成弱视。130屈光参差性弱视

anisometropicamblyopia双眼屈光参差相差2.5D以上，导致双眼视网膜成像大小不等，融合困难。屈光不正较重的眼受到抑制，形成弱视。131屈光不正性弱视

ametropicamblyopia多为双眼，发生在屈光不正未矫正者，视觉系统未得到清晰的视觉影像刺激，发育障碍，形成弱视。132形觉剥夺性弱视

formdeprivationamblyopia婴幼儿早期，由于角膜混浊、先天性或外伤性白内障、上睑下垂或遮盖一眼过久，因缺少视觉刺激，视功能发育不良，形成弱视。133其它微小眼球震颤，急、难产新生儿视网膜、黄斑、视路出血等。134分度轻度弱视矫正视力0.6～0.8中度弱视矫正视力0.2～0.5重度弱视矫正视力≤0.1135临床表现视力不良最佳矫正视力达不到该年龄段正常视力拥挤现象crowdingphenomenon对排列成行的视标分辨力较单个视标差，对比敏感度功能降低。异常固视弱视眼可有旁中心注视双眼单视功能障碍VEP排除心因性、中枢性、幼稚性等类型的视功能不良。136治疗1.去除形觉剥夺因素：早期治疗先天性白内障、上睑下垂，去除可引起弱视的因素。2.矫正屈光不正：配戴