_adaptations in strabismus在斜视感觉适应课件

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1、SensoryAdaptationsinStrabismusToavoidconfusionanddiplopia,thevisualsystemcanusethemechanismsofsuppressionandARC.ItisimportanttorealizethatpathologicsuppressionandARCdeveloponlyintheimmaturevisualsystem.SuppressionSuppressionisthealterationofvisualsensa

2、tionthatoccurswhentheimagesfrom1eyeareinhibitedorpreventedfromreachingconsciousnessduringbinocularvisualactivity.Pathologicsuppressionresultsfromstrabismicmisalignmentofthevisualaxes,Suchsuppressioncanbeseenasanadaptationofavisuallyimmaturebraintoavoid

3、diplopia,Physiologicsuppressionisthemechanismthatpreventsphysiologicdiplopia(diplopiaelicitedbyobjectsoutsidePanum'sarea)fromreachingconsciousness,SuppressionclassificationCentralversusperipheral.Centralsuppressionisthetermusedtodescribethemechanismtha

4、tkeepsthefovealimageofthedeviatingeyefromreachingconsciousness,therebypreventingconfusion,Peripheralsuppressionisthemechanismthateliminatesdiplopiabypreventingawarenessoftheimagethatfallsontheperipheralretinainthedeviatingeye,theimagethatresemblestheim

5、agefallingonthefoveaofthefixatingeye.Thisformofsuppressionisclearlypathologic,developingasacorticaladaptationonlywithinanimmaturevisualsystem,Adultsmaybeunabletodevelopperipheralsuppressionandthereforemaybeunabletoeliminatetheperipheralsecondimageofthe

6、objectviewedbythefixatingeye(theobjectofregard)withoutclosingoroccludingthedeviatingeye,SuppressionclassificationNonalternatingversusalternating.Ifsuppressionisunidirectionaloralwayscausestheimagefromthedominanteyetopredominateovertheimagefromthedeviat

7、ingeye,thesuppressionisnonalternating.Thistypeofmechanismmayleadtotheestablishmentofstrabismicamblyopia.Iftheprocessisbidirectionalorswitchesovertimebetweentheimagesofthe2eyes,thesuppressionisdescribedasalternating.SuppressionclassificationFacultativev

8、ersusobligatory.SuppressionmaybeconsideredfacultativeifPresentonlywhentheeyesareinthedeviatedstateandabsentinallotherstates.Patientswithintermittentexotropia,forinstance,oftenexperiencesuppressionwhentheeyesaredivergentbutmayenjoyhigh-g