眼科-08屈光不正與弱視students

Refraction

Optometry?

眼視光學(xué)

沈潔副教授，副主任醫(yī)師上海交通大學(xué)醫(yī)學(xué)院附屬仁濟(jì)醫(yī)院眼科TheopticalsystemoftheeyeConsistsofCorneaaqueoushumorLensvitreoushumorDiopters屈光度:Powerofrefraction

Diopters=1/focallength(m)Focallength

焦距：注視物體和眼球表面的距離focallength=0.25m，R=4Dfocallength=0.50m，R=2DF前焦點(diǎn)H主點(diǎn)n結(jié)點(diǎn)F’后焦點(diǎn)Thereducedschematiceye：

1principalplane(H)主點(diǎn)

1singlenodalpoint(n)結(jié)點(diǎn)

Simplifytheopticalsystemofeye簡(jiǎn)化眼17mm22.5mmPower=60DodationmodationTheeyechangesrefractivepowertofocusonnearobjectsbyaprocesscalledmodationmodationresultsfromchangesinthecrystallinelens.Contractionofthecilliarymuscleresultsinthickeningandincreasedcurvatureofthelens調(diào)節(jié)odationPartThree

Refractiveerror

Emmetropia正視眼Reractiveerror

Myopia

Classification

按屈光成份axialmyopia

refractivemyopia

按近視程度mild

<-3.00Dmoderate-3.00D—-6.00Dsevere

>-6.00DmyopiaDegenerativeretinalchanges

inhighmyopiaMaculardegenerationPeripheralretinaldegenerationRetinaldetachment臨床表現(xiàn)FundusofhighmyopiaCorrection

concavespherical(minus)lenses近視Hyperopia遠(yuǎn)視遠(yuǎn)點(diǎn)

classification

按屈光成份axial

reducedaxiallength

refractive

aphakia

按遠(yuǎn)視程度mild

<+3.00Dmoderate

+3.00D—+5.00Dsevere

>+5.00Dhyperopiacorrection凸透鏡遠(yuǎn)視Astigmatism

定義：在調(diào)節(jié)靜止時(shí)，平行光線經(jīng)過(guò)眼屈光系統(tǒng)后，在不同的子午線上屈光力不同，形成前后兩條（不能在網(wǎng)膜上形成焦點(diǎn)）焦線，稱(chēng)為散光。

Regularastigmatism最大屈光力和最小屈光力主子午線相互垂直

病因：

角膜、晶體各經(jīng)線曲率半徑不同。

規(guī)則性不規(guī)則性單純近視散光單純遠(yuǎn)視散光復(fù)性近視散光復(fù)性遠(yuǎn)視散光混合性散光圓錐角膜角膜斑翳多發(fā)性角膜異物分類(lèi)散光

Cylindricallenses柱鏡矯正。CombinedwithsphericallensesCorrection散光Anisometropia

Differenceinrefractiveerrorbetweenthetwoeyes

Thedifferencebetweentwoeyesismorethan2.50D

RefractivecorrectionDifferenceinsizeoftheretinalimageSpectaclecorrection:<2.75DContactlenscorrection:≥3DPresbyopia

Thelossofmodationthatcomeswithaginginallpeople.。

Inabilitytoreadsmallprintordiscriminatefinecloseobjects老視Ataboutage44-46+1.50D；

age50

+2.00D；

age60+3.00Dcorrection：pluslens，bifocallens,progressivemultifocallensMethodsofrefraction

一、Objectiverefraction客觀驗(yàn)光法

二、Subjectiverefraction主覺(jué)驗(yàn)光法

三、cycloplegicrefraction

CorrectionofrefractiveerrorsA.Spectaclelenses

B.Contactlenses

Softcontactlensesragidgas-permeablecontactlens,RGPorthokeratology

C.keratorefractivesurgery角膜屈光手術(shù)RK:PRK（屈光性角膜切削術(shù)）LASIK（準(zhǔn)分子激光角膜原位磨鑲術(shù)）LASEK（準(zhǔn)分子激光上皮瓣下角膜磨鑲術(shù)）：EPI-LASIK飛秒IntraocularlensesPHACO+IOL,ICL鞏膜屈光手術(shù)后鞏膜加固術(shù)Amblyopia

Binocularvisualdevelopmentoccursinthebrain(nottheeyes)Amblyopia:DefinitionAbnormalvisualdevelopmentTypicallyonlycentralacuityisdecreasedUnilateralorbilateralDecreasedvisualacuityevenwhenallothereyeproblemshavebeencorrectedSeveritymild

visualacuity0.6-0.8moderate

visualacuity0.2-0.5severe

visualacuity≤0.1BinocularvisualdevelopmentTypesofproblemsNoimageBlurryimageConfusingimageTypesStrabismusAnisometropiaRefractiveerrorFormdeprivation弱視Amblyopia:CausesCause#1:Noimage“Formdeprivation”Visualimagecan’tgettotheretinaWilliamN.Clarke,MDAmblyopia:CausesCause#2:BlurryimageRefractiveerror=patientneedsglasses!UnequalrefractiveerrorsarepoorlytoleratedEqualrefractiveerrorsarebettertoleratedWilliamN.Clarke,MDAmblyopia:CausesCause#3:‘Confusingimage’PooraimTomakesenseofthevisualworld,theimagesfromeacheyemustmatchupAmblyopia:CausesCause#3:‘Confusingimage’TheimagesdonotmatchupwhentheeyesaremisalignedAmblyopia:CausesCause#3:‘Confusingimage’Misalignmentoftheeyes=strabismusAmblyopia:CausesCause#3:‘Confusingimage’=StrabismusThebrainignoresvisualinputfromoneeyeAmblyopia:SignificancePrevalence2-4%UsuallyunilateralMostcommoncauseofunilateralvisuallossinchildhoodSeverebilateralamblyopia=blindnessAmblyopiaScreening:ImportanceAlmostalwayspreventable/treatableEarlydetectioniskeyLife-treateningdisordersmaypresentasamblyopiaAmblyopiaTreatmentClearingthemediaTheimportanceofearlydetectionandtreatmentcannotbeoveremphasizedTimelyreferralisthekey!AmblyopiaTreatmentOpticaltreatmentshouldbethefirstlineoftreatmentFocusingtheimageAllpediatricpatientsrequireacycloplegicrefractiontoaccuratelydeterminerefractiveerrorAmblyopiaTreatmentOcculusionandPenalizationofthe