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James R. Drover, Karlah E. Noftle, Nikita-Rae C. Piercey, Kayla M. Dempsey; A Comparison of the Age-Related Declines in Grating Acuity and Vernier Acuity. Invest. Ophthalmol. Vis. Sci. 2012;53(14):4789.
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© ARVO (1962-2015); The Authors (2016-present)
The underlying mechanisms of vision are not completely understood. However, an investigation of the age-related changes that occur in functional vision may reveal the role of the optical/neural components of the visual system. Specifically, a comparison of age-related declines in different visual functions might allow one to infer whether these functions are mediated by the same or different underlying optical/neural mechanisms. Furthermore, the rate of change of these functions can be compared to the optical and neural changes that occur in the senescent visual system. In the present study, we compare the age-related changes that occur in grating acuity and vernier acuity.
Participants included 105 adults from three separate age groups (Young Adults: N=82, Mean Age=22.6±5.0y; Middle-Aged: N=12, Mean Age=51.2±5.7y; Seniors: N=11, Mean Age = 71.5±5.9y). All participants had normal healthy vision and were tested binocularly while wearing best optical correction. Grating acuity was measured using the well-established Teller Acuity Cards (TAC). Vernier acuity was measured using the vernier acuity cards, a newly designed test modeled after the TAC. To determine the rates of the age-related declines of each visual function, the scores of the three age groups were compared. In addition, a bilinear model was fit to the raw data using maximum likelihood analysis.
Overall, both grating acuity and vernier acuity declined with age (both p<0.05). Age group comparisons indicated that middle-aged adults had poorer grating acuity than young adults, and that seniors had poorer grating acuity than middle-aged adults (both p<0.05). Maximum likelihood analysis revealed that the decline in grating acuity began at 38 years of age. Conversely, young and middle-aged adults did not differ on vernier acuity (p=0.68), but seniors had poorer vernier acuity than middle-aged adults (p=0.04). According to the maximum likelihood analysis, the decline of vernier acuity began at 58 years of age.
Collectively, our results suggest that grating acuity follows a gradual pattern of decline that begins late in young adulthood, whereas vernier acuity remains relatively stable and then begins to decline during middle age. This difference in age-related declines suggests that grating acuity and vernier acuity are mediated by different optical/neural components.
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