Colour Vision Deficiencies: Matching and Confusion of Computer Colours

摘要

The report compares current methods of testing congenital color deficiencies withtests designed to employ color video display units (VDUs). Twelve persons with congential color vision deficiencies were asked to judge and match colors presented on a full color VDU. Color stimuli were selected from different 'chromaticity-confusion lines' within the CIE 1931 chromaticity diagram; colors were chosen from one tritan, three protan, and three deutan confusion lines. The results show that the ability to discriminate VDU color stimuli is greatly impaired in protanopes and deutranopes, compared with both normal and deuteranomalous observers. When pairs of color stimuli lay on a protan or deutan confusion line, protanopes and deuteranopes frequently accepted them as equivalent even when the stimuli were separated by large distances in the chromaticity diagram. Protanopes performed slightly better on color stimuli from deutan lines than on those from protan lines. Similarly, deuteranopes showed better performance on protan than on deutan pairs. Deutranomalous observers performed better than dichromats but less well than normals. Color confusions shown by dichromats are in agreement with those shown in standard tests of color vision. Since a full color VDU has a larger chromaticity gamut than the pseudo-isochromatic plates or the Farnsworth D-15 test, it can be a powerful tool for screening dichromats from normals and for illustrating the difficulties persons with color deficiency will have in discriminating colors.