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Lynnette Leone, Barbara Blakeslee, Mark McCourt; Effects of Normal Aging on Suprathreshold Contrast Perception. Journal of Vision 2011;11(11):463. doi: 10.1167/11.11.463.
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Thresholds for a number of visual capacities (motion, contrast, orientation) show significant age-related elevations. We assessed suprathreshold contrast perception across the lifespan. A total of 93 healthy subjects (16–74 years) participated. In Experiment 1 subjects adjusted the contrast of a matching grating (0.5° or 2° × 40°; 0.075 c/d) to equal that of both real (30% contrast, 0.075 c/d) and induced (McCourt, 1982) test gratings (100% inducing grating contrast; 0.075 c/d). Matching gratings appeared in the upper visual field and test gratings appeared in the lower visual field (eccentricity ±7.5°) or vice versa. For test gratings situated in the upper visual field matching contrast increased with age, whereas the opposite occurred for test gratings situated in the lower visual field, indicating a significant age-related reduction in perceived suprathreshold contrast for stimuli in the lower visual field. Regression analyses show significant age-related reductions in perceived grating contrast in the lower versus upper visual field for both real and induced gratings [Real (2°): F(92) = 24.67, p < 0.001; Induced (0.5°), F(92) = 20.94, p < 0.001; Induced (2°), F(92) = 11.65, p < 0.001. In Experiment 2 a quadrature-phase motion technique (Blakeslee & McCourt, 2008) was used to measure canceling contrast (in foveal viewing) for induced gratings at two temporal frequencies (1 and 4 Hz) at two test field heights (0.5° and 2°). Regression analyses show a significant age-related reduction in canceling contrast at 4 Hz [0.5° test field: F(92) = 14.51, p < 0.001; 2° test field, F(92) = 7.23, p < 0.001], but not at 1 Hz [0.5° test field: F(92) = 0.09, p = 0.761; 2° test field, F(92) = 0.50, p = 0.477]. These results are consistent with previous reports that age-related visual changes are largest at higher temporal frequencies, and are the first to disclose significant differential age-related changes in suprathreshold vision between the upper and lower visual fields.
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