Contrast Sensitivity Measurement Tests and Methods

Abstract

Contrast is a measure of the amount of lightness or darkness an object has in relationship to its background. Usually, it is described as Contrast Sensitivity (CS), which actually is the inverse of the contrast threshold. More often than not, stimulus set includes grating patterns of various sizes that are presented in a stationary manner or are dynamically presented by reversing the contrast at different rates. A variety of tests were developed, in order to asses and evaluate contrast sensitivity, in many different ways. A classical method, to check for contrast sensitivity, is the Pelli-Robson contrast sensitivity chart. The Bailey-Lovie contrast sensitivity chart is another letter chart that deals with differences in the number of letters read on the high and low contrast charts, with a main drawback, the necessity to follow the size of the letters. The Functional Acuity Contrast Test is designed to identify vision loss from a variety of disorders, many of which are not detected by high or low contrast Snellen Acuity tests. The MARS Letter Contrast Sensitivity Test shows good agreement with the Pelli-Robson test and possibly it may be the alternative to the Pelli-Robson chart, in clinical practice and research.