Apparatus and method for testing visual accuity and contrast sensitivity

摘要

A vision testing apparatus and a method for testing vision in terms of contrast sensitivity and spatial frequency response are provided. The apparatus and method utilize a plurality light-polarizing optotypes which are provided on sheets of an oriented polymeric material. The optotypes are presented one at a time to a patient in conjunction with a polarizing filter such that rotation of the filter relative to the optotype will cause the contrast of the optotype to vary from a first condition wherein the pattern of the optotype is indistinguishable from its background to a second condition wherein the optotype is seen at a maximum level of contrast. The patient will indicate the point at which he or she first sees the optotype. The sequential presentation of a series of optotypes having patterns which vary in their spatial frequencies will provide a measure of both contrast sensitivity and spatial frequency response for each patient tested.