第二章视功能检查ChapterTwoVisualFunctionExamination课件.pptx

第二章视功能检查

ChapterTwoVisualFunctionExamination

视力(visualacuity)即视锐度，它代表形觉功能。通常所说的视力是指中心视力，它反映功能最敏锐的视网膜黄斑中心凹的视力。世界卫生组织的标准规定，较好眼的矫正视力低于0.3为低视力，低于0.05为盲，称为低视力。Visualacuityistheacuityofvision,whichrepresentstheformfunctionoftheeye.Visualacuityisusuallyreferredtoascentralvisualacuity,whichreflectsthevisualacuityofthefoveacentralisoftheretina.AccordingtotheWHOstandard,correctedvisualacuityofstrongereyelessthan0.3islowvisionandlessthan0.05isblindness.一、视力Ⅰ.VisualAcuity

对于低视力患者，视力是低视力的诊断标准之一，是选择低视力助视器的主要依据，并可以评价常见眼病治疗前后的疗效，由于视力检查对于低视力患者的重要性，再加上低视力患者本身的眼病会影响视力检查，因此，最好由受过专门训练的技术人员进行检查，如验光师、视光师等。Forlowvisionpatients,visualacuityisoneofthediagnosticstandardsforlowvision.Itisthemainbasisforselectingvisualaidsforlowvision,anditcanbeusedtoevaluatetheeffectofcommoneyediseasesbeforeandaftertreatment.Becauseoftheimportanceofvisualacuityexaminationforlowvisionpatientsandthefactthatlowvisionpatientseyeconditionscanaffectvisualacuityexamination,itisbesttohavethemperformedbyaspeciallytraineddoctorornurse.

视力表是测定视力的主要工具，它是根据视角(指外界物体上两点在眼结点处所夹的角)原理设计的，视力检查的最终目的即是测出眼能辨别两点时的最小视角，用这最小视角的倒数值来表示视力。人眼能分辨出两点的最小视角是1视角，即1.0视力。Visionchartisthemaintoolformeasuringvisualacuity.Itisdesignedaccordingtotheprincipleofviewangle(theanglebetweentwopointsonanexternalobjectattheeyenode).Thefinalpurposeofvisionacuityexaminationistomeasuretheminimumviewanglewhentheeyecandistinguishtwopoints,andusethereciprocalvalueoftheminimumviewangletoexpressvision.Iftheminimumviewangleatwhichthehumaneyecandistinguishbetweentwopointsis1viewangle,thevisualacuityis1.0.

检查视力须两眼分别进行，一般先右后左。可用手掌或小板遮盖眼但不要压迫眼球。视力表须按标准亮度的光线照明。检查者用杆指着视力表的视标，嘱被检者说出或用手势表示该视标的缺口方向，逐行检查,找出被检者的最佳辨认行。戴眼镜者要先查裸眼视力，再查矫正视力。视力的计算公式为V=d/D,V为视力，d为实际看见某视标的距离，D为正常看见该视标的距离。VisualacuityexaminationforlowvisionVisualacuityex