Senescence of spatial chromatic contrast sensitivity. I. Detection under conditions controlling for optical factors.
Chromatic contrast thresholds for spatially varying patterns of various spatial frequencies (0.5, 1, 2, and 4 cycles per degree) were measured for ten older (65-77 yr of age) and ten younger (18-30 yr of age) observers. The stimuli were Gabor patches modulated along S-varying or (L - M)-varying chromatic axes. Thresholds were determined for two sets of stimuli. For one set of stimuli, the mean chromaticity and luminance were equated at the cornea for all observers. The second set of stimuli was corrected for ocular media density differences to equate stimulation of each of the three cone types at the retina for each individual. Chromatic contrast thresholds were higher for older observers for all stimuli tested. The magnitude of this difference showed little dependence on spatial frequency. When stimuli were equated at the cornea, this difference was greater for S-varying stimuli. When stimuli were equated at the retina, the age-related difference in thresholds for S-varying stimuli was reduced. Both optical and neural factors contribute to these age-related losses in spatial chromatic contrast sensitivity.
Hardy
Joseph L
JL
Department of Ophthalmology and Section of Neurobiology, Physiology and Behavior, University of California, Davis Medical Center, Sacramento, California 95817, USA.
Delahunt
Peter B
PB
Okajima
Katsunori
K
Werner
John S
JS
D000293:Adolescent; D000328:Adult; D000368:Aged; D000375:Aging / Q000502:physiology*; D003116:Color; D003118:Color Perception / Q000502:physiology*; D004056:Differential Threshold / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D055095:Optics and Photonics; D010775:Photic Stimulation / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity