The different effects of aging on normal sensitivity in flicker and light-sense perimetry.

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Abstract

PURPOSE: To verify whether or not an accelerated loss at an older age for normal sensitivity in the central visual field is present when using the stimulus configuration of conventional white/white automated light-sense perimetry and the stimulus configuration of the automated flicker perimeter developed by one of the authors (BJL). METHODS: One hundred thirty eyes of 130 normal subjects aged 9 to 86 years were tested with the Humphrey-Field-Analyzer 640, program 30-2, and our automated flicker perimeter. In addition, short introductory learning programs were used for both techniques. All tests were performed in random order. RESULTS: Mean critical flicker fusion frequency shows a linear loss over the entire age range (r = -0.5546, P < 0.0001, slope a = -0.3820 dB/decade), whereas mean light difference sensitivity decreases only slightly up to 46 years of age (r = -0.0118, P = 0.9226, slope a = -0.0153 dB/decade), with a marked acceleration above 46 years of age (r = -0.7304, P < 0.0001, slope a = -2.0640 dB/decade). CONCLUSIONS: The absence of an accelerated loss at an older age for critical flicker fusion frequency (CFF) and the presence of such a loss for light-difference sensitivity (LDS) might be attributed to the independence of a flickering stimulus from distributing effects induced by the ocular media at an older age as proposed by one of the authors. The different age effects for CFF and LDS could also be explained by different age-related losses at different sites and for different neuronal populations throughout the visual pathways.