Abstract

Mixtures of monochromatic lights that appear achromatic were measured for fifty normal trichromats ranging in age from 11 to 78 years. Stimuli were presented to one eye as a 1-sec flash (10 sec interstimulus interval) in Maxwellian view. The achromatic locus was found by varying the intensity ratio of a mixture of unique blue and unique yellow while maintaining constant overall retinal illuminance. Measurements were obtained at three intensity levels (10, 100, 1,000 td) for each observer. Additional verification of the position of the achromatic locus in color space was obtained for twenty-three subjects using a mixture composed of 600 nm and its spectral complement. There were no significant changes in the achromatic loci as a function of age. The mean achromatic locus in CIE chromaticity space was x,y = 0.31,0.31, or u'v' = 0.21,0.46. These results imply that the three classes of cones undergo parallel losses in sensitivity (specified at the cornea) as a function of age.

© 1991 Optical Society of America