1、LETS TALK LOW VISIONSuleiman Alibhai,O.D.Retina Group of WashingtonKrista M.Davis,O.D.,F.A.A.O.Columbia Lighthouse for the Blind.Eye Anatomy.DefinitionsLegal Blindness Best corrected distance visual acuity of 20/200 or worse in better eye Horizontal visual field of 20 degrees or less at widest point
2、 in the better eyeLow Vision Worse than 20/60 in the better eye Significant field loss Impaired function.Goals of Low VisionManagementIncrease functionality Make the most of the remaining visionProvide link to community resources and support servicesEducation.Common ConditionsMacular DegenerationGla
3、ucomaDiabetic RetinopathyStroke/brain injuryRetinitis pigmentosaOptic Nerve diseaseAlbinism NystagmusCortical Visual Impairment.Functional Effects of Low VisionLoss of central vision(visual acuity)Loss of peripheral vision(visual field)Glare and contrast.Issues Related to Decreased AcuityDifficulty
4、readingProblems writing/completing paperworkInability to recognize distance objects and faces.Issues Related toVisual Field LossLocation of scotoma important!Generalized loss of visual field difficult to compensate forMobility and independent travelReading may require adaptations.Issues Related to C
5、ontrastNeed for additional lightingProblems with glareIncreased adjustment to changes in illuminationVisual discomfort and fatigue.Exam SequenceHistory/intakeVisual acuityVisual field testingPupilsExtraocular muscle testingRefractionColor vision and Contrast TestingOcular Health.Types of Acuity Char
6、tsDistance Snellen(projection)Feinbloom/SOSH ETDRS Lea SymbolsNear Single letter Continuous text.Distance Charts.Near Charts.Interpreting Near AcuityThreshold acuity Difference between single letter and continuous text1.0 M=20/50=8-10 point font Need to look at working distance Jaeger charts nonstan
7、dardTypical sizes Newspaper=1.0M Childrens books=1.2 1.6M Large print=1.6 2.0M Newspaper headlines=4.0 5.0 M.Visual Field TestingConfrontationArc perimeterVision DiscAutomated perimetryGoldmann perimetry.Color and Contrast TestsIshiharaColor Vision Testing Made EasyD-15Pelli-RobsonVistech Contrast S
8、ystemMr.HappyHiding Heidi.Color Vision Tests.Contrast Tests.MagnificationEnlarges image on retina to stimulate more retinal cellsCan be achieved in many ways Relative Distance Relative Size Optical/Angular Electronic.Low Vision DevicesDistanceNearField enhancementNon-optical.Distance DevicesHand hel
9、d telescopesMounted telescopesElectronic systems.Telescopes.Electronic Distance Systems.Near DevicesSpectacles Prismatic eyes Full-field microscopesMagnifiers Hand held vs.stand Illuminated vs.non-illuminatedTelemicroscopesElectronic Devices.Spectacle Microscope.Near Loupe.Hand Held Magnifiers.Stand
10、 Magnifiers.Electronic Magnifiers.Non-optical DevicesGlare reduction devicesContrast enhancement devicesComputer softwareAccessory devices Talking watches,clocks,etc Writing guides Tactile markers.Glare and Contrast.Lighting.Other Non-optical Devices.Adaptive Computer Equipment.Additional ServicesOr
11、ientation and mobility trainingIndependent living skills trainingSupport groupsBraille instructionComputer trainingGenetic counseling.Community ResourcesSupport groupsParatransit ServicesBooks on tapeAudio described performancesTactile toursLarge print publicationsEducational services.Communication
12、GoalsEducate patient on eye conditionHelp them to understand what options are available and how to use/care for tools Glasses Low vision devices Technology Community resourcesEducate parents and teachers/professionals on functional implications.Functional ImplicationsPrint sizeVisual efficiency and fatigueMobility issuesPositioning/classroom placementLighting/glare reduction needs.
