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Kara Quealy, Ethan Bensinger, Kelly Theberge, Mark B Abelson; Stride length in different luminance in non-advanced age-related macular degeneration. Invest. Ophthalmol. Vis. Sci. 2021;62(8):323.
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Detecting early stage age-related macular degeneration (AMD) needs clinical tests that correspond to impacts on activities of daily living. The purpose of this study is to determine if stride length is affected in early AMD subjects under different luminance levels.
Six participants with non-advanced AMD (grade 1 to 4 on AREDS simplified scale) and 9 age-matched normal controls (AREDS grade 0) with best visual acuity (VA) 20/25 or better during their baseline visit were included. Stride length was measured using the 16 feet long GAITRite electronic walkway system. The testing room was set up to test under 3 luminance levels, high (about 300 Lux), moderate (about 20 Lux) and low (mesopic, about 5 Lux). A practice session was done prior to recording the test conditions. For each luminance condition, foot falls were automatically detected, stride length was measured and averaged across 4 trials. Best corrected visual acuity (BCVA) was recorded.
For all light levels, stride length trended shorter in the non-advanced AMD group compared to the normal control group, although statistical significance was not reached. Stride length did not considerably alter with change in luminance for either normal or non-advanced AMD groups. For all subjects combined, the mean stride length was 105.5±14.6cm at high luminance, 104.8±15.6cm at moderate luminance and 104.3±14.7cm at low luminance (mesopic). Stride length at moderate and low luminance mesopic testing did not significantly differ from high luminance photopic testing (p=0.32 for moderate vs high, p=0.16 for low luminance vs high comparisons). LogMAR BCVA was also not significantly different between AMD (mean 0.05±0.10) and normal group (mean 0.02±0.12) (p=0.65).
Subjects with non-advanced AMD trend towards smaller stride length than age-matched normal controls. An effect of change in stride length in response to luminance was not observed in this small cohort, possibly due to a combination of small sample size and less challenging test conditions. An additional study with larger sample size and alterations in test conditions is currently in progress.
This is a 2021 ARVO Annual Meeting abstract.
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