Spectral sensitivity and color vision tests were performed on a subject who was totally color blind at low photopic luminances, but exhibited hue discrimination at relatively high photopic levels. Chromaticity confusion loci showed that the residual color vision was abnormal; a tritan defect was superimposed on the generalized reduction of cone sensitivity. Although cone function was markedly depressed, a photopic spectral sensitivity curve was obtained for the light-adapted fovea. Dark-adapted foveal measurements, on the other hand, gave a scotopic function almost identical to that of the dark-adapted periphery. However, it was possible to demonstrate objectively that this subject shifts fixation to an eccentric position under scotopic conditions, i.e., the dark-adapted “foveal” results were, in fact, for a para-macular region. Irrespective of the degree of light adaptation, cone function was not detectable in the peripheral measurements.
© 1966 Optical Society of AmericaFull Article | PDF Article
OSA Recommended Articles
Louise L. Sloan
J. Opt. Soc. Am. 44(2) 117-128 (1954)
J. Opt. Soc. Am. 57(11) 1289-1301 (1967)
Lothar Spillmann and Jane E. Conlon
J. Opt. Soc. Am. 62(2) 182-185 (1972)