LUMINANCE NOISE AND THE RAPID-DETERMINATION OF DISCRIMINATION ELLIPSES IN COLOR DEFICIENCY

A computer-controlled test of; colour vision is described, in which luminance noise and masking contours are used to ensure that the subject's responses depend on chromatic signals. The test avoids the need-common to most computer-controlled tests-to define equiluminance for the individual subject before the colour test itself can be administered. The test achieves a good separation of protan and deutan subjects and reveals the large range of chromatic sensibilities among anomalous trichromats. As a population, dichromats had higher thresholds on the tritan axis of the test than did normals. In an extension of the test, full discrimination ellipses were measured for normal and colour-deficient observers. The nature of anomalous trichromacy is discussed and the possibility is raised that hybrid genes, resulting from genetic recombination, may code for incorrectly labelled or functionally impaired molecules.