Chromatic discrimination in subjects with both congenital and acquired colour vision deficiencies

Abstract

We have isolated the processing of chromatic signals using spatiotemporal background perturbation techniques. Two stimulus configurations were designed and chromatic discrimination thresholds were measured in a subject with both congenital and acquired colour vision deficiency and in subjects with optic neuritis. In the first test, the subject's task is the detection of vertical bars that are presented suddenly in the visual held and can be de fined only by means of chromatic signals. The second test involves the detection of colour changes in a large object that is already defined by luminance contrast. The results show that although no great differences exist between these two thresholds in normal trichromats or in dichromats, pattern thresholds, in particular, can be affected significantly in subjects with diseases of the retina and/or the optic nerve.