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Kristine Dalton, Rianne Ravensbergen, James Roberts, Arijit Chakraborty, Susan Leat, Benjamin Thompson, David Mann; Global Motion Perception with Low Vision. Invest. Ophthalmol. Vis. Sci. 2017;58(8):4693.
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© ARVO (1962-2015); The Authors (2016-present)
Low vision is typically characterized by deficits in spatial vision, such as visual acuity and contrast sensitivity. However, motion perception, which is particularly important in dynamic environments such as street crossings or the sports arena, has not been widely assessed in this population. Therefore, we conducted a cross-sectional clinical study to determine if individuals with low vision could complete a global motion task, and to compare their performance to that of normally sighted individuals.
We assessed global motion perception in 31 individuals with low vision (23.9 ± 6.5 yr; range 13 to 37 yr) and 19 controls (30.0 ± 4.6 yr; range 24 to 37 yr) using random dot kinematograms that were scaled in size to account for visual acuity deficits in the low vision group. Vertical translation and radial global motion coherence thresholds were measured using a dot size of 2.0 logMAR in both groups. A subset of participants also completed the vertical translation motion measurements with 1.0 logMAR dots (Low Vision, n=15; Controls, n=19). All global motion tasks were displayed within a 25° field. Binocular visual acuity (VA) was measured using ETDRS and Berkley Rudimentary Vision charts; CS was measured with the MARS chart. As the data were normally distributed, comparisons between groups were made with independent sample t-tests and correlations were examined using Pearson’s r.
17 of 21 low vision participants with measureable VA and CS were able to complete the 2.0 logMAR global motion tasks. Mean VA in the low vision group (n=17) was 1.50 ± 0.44 logMAR (range: 0.70 to 2.60). CS (n=16) was 1.08 ± 0.40 logCS (range: 0.36 to 1.76). Motion coherence thresholds in the low vision group (Translation 2.0: 60.07 ± 26.2; Radial 2.0: 38.6 ± 25.8, Translation 1.0: 52.7 ± 29.4,) were worse than the controls (Translation 2.0: 16.6 ± 6.5, Radial 2.0: 16.5 ± 2.6, Translation 1.0: 18.1 ± 7.1; all p < 0.01). In the low vision group, motion coherence thresholds were not significantly correlated with VA or CS (r < 0.5, p > 0.05).
The neural mechanisms supporting motion integration remain functional in most individuals with low vision who have measurable VA and CS, despite motion coherence thresholds being higher in this group than in controls. Measures of motion perception may provide useful additional information when assessing visual function in individuals with low vision.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.
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