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Russell J Adams, Stephanie M Scott, James R Drover, Michele E Mercer; Spatial and Temporal Vision Across Retinal Eccentricity: Individual Variation. Invest. Ophthalmol. Vis. Sci. 2014;55(13):768.
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© ARVO (1962-2015); The Authors (2016-present)
Despite the well-known differences in both the distribution and the relative ratios of magno- and parvo-cells across the primate retina, there has been little direct comparison of the corresponding spatial and temporal visual functions across eccentricity. Such information is also of clinical importance, as different ophthalmic, neurological, and systemic diseases target central vs. peripheral and temporal vs. spatial vision selectively. Here, we evaluate in the same adults, both spatial contrast sensitivity (CS) and flicker fusion thresholds across a broad range of retinal eccentricities.
Right eyes from 20 healthy adults (16-55 years; 11 female, 9 male) were tested with stationary sinusoidal Gabor patches that ranged logarithmically in spatial frequency (SF) from 0.38 to 18.0 cy/deg and in Michelson contrast from 0.001 to 0.30. Contrast thresholds (>75% correct) at each SF were obtained foveally and at 10 deg, 20 deg, 40 deg, and 60 deg within the temporal visual field. At the same eccentricities, critical flicker fusion (CFF) thresholds were also obtained from the same subjects.
As expected, CS was best with central vision (M = 145.9) but declined progressively at 10 deg (M = 57.1), 20 deg (M= 37.4), 40 deg (M=15.3), and 60 deg (M= 5.6). Although CSFs did retain their typical inverted-U shape across eccentricity, they show a relatively greater decline with increasing SF. In contrast, temporal sensitivity declined more gradually, with CFFs decreasing from about 38 Hz at 0 deg to about 31 Hz at 60 deg. Individual performance across both tasks was very consistent (r = 0.68) . Specifically, those who maintained better CS with increasing eccentricity also showed relatively higher CFFs as well.
These data are the first to evaluate both spatial and temporal resolution across eccentricity in the same subjects. With increasing peripheral vision, the rate of reduction in spatial vision (~ 0.24 log units per 10 deg) is much more rapid (especially at higher SF) than the rate of temporal loss (~0.018 log units per 10 deg), on average a 13-fold difference in the relative decline. Individuals also show corresponding rates of decline in their spatial and temporal performance. Overall, these psychophysical data are consistent with anatomical and physiological data describing the relative ratios and the cortical efficiency of M- and P-cells in the central and peripheral primate retina.
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