VISUAL AGING - UNSPECIFIC DECLINE OF THE RESPONSES TO LUMINANCE AND COLOR

We have investigated whether ageing affects selectively the responses to equiluminant patterns of pure colour contrast, In two groups of sub jects (mean ages 29 and 72 yr) contrast thresholds were measured psych ophysically for the detection and for the discrimination of the direct ion of motion of drifting gratings, The gratings were modulated either in pure luminance contrast (and uniform colour), or pure chromatic co ntrast (red-green equiluminant gratings), In subjects of the same age groups, visual evoked potentials (VEP) were recorded in response to gr atings with either pure luminance contrast or pure colour contrast sin usoidally reversed in contrast at various temporal frequencies, It was shown that psychophysical contrast sensitivity for equiluminant patte rns deteriorates significantly with age, and VEP latency increases, Ho wever, these effects of ageing on the responses to patterns of pure co lour contrast are substantially the same as those observed in the same subjects for stimuli with pure luminance contrast. The results sugges t that ageing causes a small and unspecific decline of the response of the visual system to luminance and colour contrast. Copyright (C) 199 6 Elsevier Science Ltd.