LowvisionAid：低视力辅助课件

LowVisionAids...WhoarealllowvisionpatientHavingvisionlessthan6/18inbettereyeHavingvision6/6butfieldofvisionislessthan20Havingvision6/6,fieldofvisionisnormal,butcontrastsensitivityispoor...Whoneedrehabilitation?PatienthavingsomevisionthatpatientsneedLVdevicePatienthavinglessthan3/60,thatpatientwantsmobilitytraining...CausesMaculardegenerationDiabeticRetinopathyGlaucomaCornealdiseaseNeurologicaldisordersAlbinismRPOpticatrophyAchromatopsiaRetinalproblems...LowvisionExaminationCaseHistoryRRFieldContrastsensitivityGlareTrialoflowvisiondeviceInstructionPrescriptionFollow-up...TreatmentOpticalaidsNon-opticalaidsElectronicaids...MagnificationRelativesizemagnificationPhysicallyenlargingthesizeofanobjectoftheretinaRelativedistancemagnificationMovingtheobjectofregardstowardsthepatient...AngularmagnificationRatiooftheangleofsubstanceoftheimageformedbyanopticalinstrumentcomparedtotheactualobject.E.g..Telescope...OpticalAidsTelescopeSpectacleHandMagnifierStandMagnifierPocketMagnifierPrismosphere...Distancevision

TelescopesGalileanKeplerian...Galilean+Objective,-eyepieceLowpower(2xto4x)Lighter,lessexpensiveLargeexitpupil...Keplarian+objective,+eyepiecePrismtoinvertimageHigherpowersavailablePoorlightgathering...TypesHandheldtelescopesClipontelescopesSpectaclemountedtelescopes...HandheldPortableSpottingintermediate&distanceMonocularInexpensive...Clipon2.5xto4xDistanceandnearSomehandheldcanbeplacedinflip-upclip...Spectaclemounted1.7xto8xSpecialorderBiopticFulldiameterWideangleExpandedfieldwhencomparedtoothersItisalsoavailableheaddowntype...AdvantagesoftelescopesDistance,intermediateornearVariableworkingdistanceMonocular&binocularSpectaclemountedandhandheldIdealrange-2xto4x...DisadvantageinTelescopeDisadvantagesRestrictedfield ReducedlightgatheringLimiteddepthoffocusRequiresco-ordinationAppearanceandcostfactor...ProblemswithopticalsystemSmallfieldofviewWhenmagnificationincreasescontrastwillbedecreaseCloseworkingdistanceLightingandglareMoreaberrations...OpticalaidsavailablehereTelescope3x;4x2xhandheldmagnifier2xbarmagnifier3xhandheldilluminatedmagnifierPocketmagnifier(3x,6x)5.0dshandheldilluminatedmagnifier4xwidefieldstandmagnifier6xcutawaystandmagnifier...Kestenbaum’sruleTheinverseofthevisualacuity=theaddrequiredtoread1mpoint6/60=+10.0ds...SpectacleAdvantagesHandsfreeWidefieldProlongedreadingMonocularorbinocular...DisadvantagesFixingreadingdistanceClosereadingdistancePositioningandpostureHeadpain...HandMagnifiersAdvantagesVariableeyelensdistanceNormalreadingdistanceAllowsforeccentricviewingMayhaveownlightsourceIdealrange10to20dpts...HandMagnifier

DisadvantagesReducedfieldofviewBothhandsoccupiedCriticalfocusdistanceMotionmagnified(tremor,arthritis)Illuminationreflected...StandMagnifiersAdvantagesMayhaveownlightsourceLensdistancestabilizedonpageIdealforstroke,tremor,arthritispatientsIdealstandrange12–24dptsIlluminatedstandrange16to28dpts...StandMagnifiers

DisadvantagesReducedfieldofviewRequiresco-ordinationNeedtouseappropriateglassesIlluminationblockedandreflectedbylensNotbeaportable...PrismsphereglassesAdvantages+5.0ds&6.0ds,8.0dsprismospheres4xdomemagnifierAspheric,+16.0ds,+22.0ds,+24.0ds2.5standmagnifier...DisadvantagesVerycloseReadingStandardreadingdistance...NonOpticalAidsTintsIlluminationfluorescentlampIncandescentNeodymiumbulbHalogenlightContrastBlackpenTyposcope(black&whitecontrast

)Moneyfinder...ElectronicaidsCTV–closedcircuittelevisionsallowprintedhandwrittenandgraphicmaterialtobeelectronicallydisplayed,magnifiedandenhancedonatelevisionmonitor.Contrastcanbeincreasedandtheimagepolarityreversedallowingwhiteletterstobedisplayedonablackbackgroundorthereverse.Patientsalsohaveachoiceofcolordisplatts....HowtoprescribereadingglairsBestrefractionGivecorrectaddpowerfornearMakesurepatient