第二章视功能检查ChapterTwoVisualFunctionExamination68课件.pptx

第二章视功能检查

ChapterTwoVisualFunctionExamination

五、眩光检查Ⅴ.GlareExamination标准视力表所釆取的是具有高度对比度的黑白对比视标，并不能反映患者生活中的真实视力。当患者存在角膜斑翳、圆锥角膜、角膜水肿、白内障、玻璃体混浊时，标准视力表所查得的视力可能是在正常范围内，但在白天较亮或夜间较暗的光线下，由于眩光的出现导致视力明显下降。原因在于眼屈光间质不均一，使得眼内光线散射，从而减低了实际到达视网膜的光线的对比度。Adoptingablackandwhitecontrastindexwithhighcontrast,thestandardvisionchartcannotreflecttherealvisionofthepatientinlife.Whenapatientsuffersfromcornealplaque,keratoconus,cornealedema,cataract,orvitreousopacity,thevisionmaybewithinthenormalrangebyexaminationonthestandardchart,butthevisiondecreasessignificantlyduetotheglareinbrightlightatdayordarklightatnight.Thisisbecausethelightscattersintheeyesduetonon-uniformrefractivestromaoftheeye,whichreducesthecontrastoflightactuallyreachingtheretina.

由于各种原因引起低视力患者的眩光，将造成患者的不适或视力下降。特别是物品之间对比度的降低，将导致低视力患者在室内活动的困难。Glareinlowvisionpatientsduetovariousreasonswillcausediscomfortorreductionofvision.Inparticular,areductionincontrastbetweenitemswillmakelow-visionpatientshavedifficultiesinmovingindoor.眩光分为：不适眩光和失能眩光。前者是指由于散射光线导致视觉不适，而不影响分辨率或视力的情况。后者是指由于散射光线在眼内使视网膜成像重叠、视网膜成像的对比度下降，降低了视觉效能和清晰度，甚至不能视物。Glareisdividedinto：discomfortglareanddisabilityglare.Theformerreferstovisualdiscomfortduetodivergencelight,whichdoesnotaffectresolutionorvision.Thelatterreferstothecasewhenvisualefficiencyandclarityarereducedandthepatientisevenunabletoviewobjectsbecausethedivergencelightcreatesoverlappingretinalimagingintheeye,andthecontrastofretinalimagingisreduced.

眩光的检查：常用眩光测试仪,如InnomedTerry视力分析仪、多种视觉敏感度测试仪和Miller-Nadler眩光测试仪等。自动型眩光检查仪及对比敏感度检查仪，能同时进行对比敏感度和眩光敏感度两项检查。Theglareexaminationiscommonlyconductedwithglaretesters,suchasInnomedTerryVisionAnalyzer,MultipleVisualSensitivityTesterandMiller-NadlerGlareTester,etc.Takaci-CGT-1000automaticglareandcontrastsensitivitytestercancheckcontrastse