The goal of the proposed research is to understand the differences in the visual mechanism which underly the differences in the color vision of normal and congenitally color deficient observers. Psychophysical experiments using methodologies designed to isolate the properties of the neural color coding channels will be used to study the spatial, temporal and opponent properties of these channels. The purpose of these experiments is to determine whether there are abnormalities in the neural coding of color information which accompany the abnormal visual pigments known to occur in the eye of color deficient observers. The proposed research should have direct significance for theories about the mechanisms of color vision as well as indirect impact of clinical psychophysical testing of visual defects, testing of color vision capabilities for practical applications, and the genetics of color deficiencies.