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Lisa M. Renzi, Billy R. Hammond, Billy R. Wooten; Age-related changes in the temporal modulation transfer function, assessed foveally and parafoveally. Journal of Vision 2008;8(17):76. doi: 10.1167/8.17.76.
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© ARVO (1962-2015); The Authors (2016-present)
Purpose: The temporal modulation transfer function (TMTF) has been related to declines in visual processing speed with age and ocular disease. The precise nature of these declines (i.e., whether at high- or low-frequency) is often prognostic. The purpose of the current project was to characterize changes in the TMTF with age at a central and parafoveal location. The stimuli were designed to minimize confounding due to pupil size, head movements, and lenticular absorption. Methods: 57 subjects (range = 69 y., M = 40 ±19.8 y.) were selected from the UGA community. TMTF was assessed using an optical device with a 20-nm half-band pass LED that presented a one-degree, 660 nm disk on a 10-degree 660 nm surround with a 4-minute gap between center and surround. For parafoveal measures, subjects fixated on a point located nasally at 7-degrees. Subjects were asked to adjust the percentage of modulation across frequencies ranging from 0.4–1.5 log-Hz. Subjects viewed the stimulus through an eyepiece containing a 3 mm artificial pupil. Results: Central flicker sensitivity declined as a function of age (r = −0.31, p [[lt]] 0.02) across frequencies. This relation was more pronounced at high frequencies (r = −0.48, p [[lt]] 0.0001) vs. low frequencies (r = −0.25, p [[lt]] 0.03). Age declines were not significant in the parafovea (p [[lt]] 0.10). Conclusions: Age-related declines in temporal vision were confined to the central presented stimulus and were more pronounced at high frequencies. This suggests that losses in temporal vision with aging are driven by post-receptoral changes.
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