Contrast increment thresholds at different ages

Abstract

Previous research has shown that older observers have reduced contrast sensitivity at high spatial frequencies (e.g., Owsley et al., 1983). The present investigation extends this finding to include age-related changes in suprathreshold contrast perception. Contrast increment threshold functions were obtained for young (<40-years), middle aged (40-60-years) and older (>60-years) adults. A two-alternative forced-choice procedure was used to determine psychometric functions for contrast detection and discrimination of antisymmetric Gabor stimuli with a fundamental spatial frequency of 10.0 cpd. Thresholds were measured at three standard contrasts (0.0, 0.008, and 0.30) and at two levels of mean luminance (50 and 12.5 cd/m2). The results from all age groups show decreased contrast thresholds at the higher mean luminance level. Young and middle-aged observers showed the characteristic facilitation effect at the intermediate contrast. However, there was no evidence for this facilitation effect in the older age group.