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John David Rodriguez, Divya Narayanan, Garrick Wallstrom, Matt J Chapin, Donna L Welch, Mark B Abelson; Recovery of Macular Contrast Sensitivity Following Photostress in non-advanced AMD Subjects. Invest. Ophthalmol. Vis. Sci. 2020;61(7):3008.
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Visual adaptation to reduced lighting levels following photostress has been shown to be impaired in early and intermediate AMD in several studies. The use of a foveal Gaussian blob stimulus to track recovery is often used but may result in false positives in some subjects. In this study, we test post-photostress recovery of contrast sensitivity in early/intermediate AMD subjects and controls using a rotating Landolt-C as the target stimulus. Endpoint was time to recovery to 2.5 times baseline contrast sensitivity as evaluated by two static sensitivity trials prior to photostress.
A group of 9 early/intermediate AMD (1-4 AREDS simplified grading) subjects (mean age 72.3 ± 6.6) and a control group of 9 normal subjects (mean age 77.3 ± 4.0) were subjected to macular photostress using the OraLux™ Photostress System which provided a diffuse light source of 40,000 cd/m2 viewed from a distance of 12 inches. After each photostress session, macular recovery was tracked using a foveal, variable contrast, rotating Landolt-C stimulus against a constant background of mean luminance in the low photopic range. Recovery was tracked for up to 900 seconds.
BCVA for normal subjects was 0.167 ± 0.14 and 0.122 ± 0.20 for AMD (p=0.60). Mean baseline contrast threshold sensitivity was 0.064 ± 0.050 for the AMD group and 0.058 ± 0.023 for the control group (p=0.73). Mean time to recover 2.5 times baseline sensitivity was 178.2 ± 93.2 seconds for the AMD group and 212.0 ±.73.9 seconds for the control group (p=0.41).
This study failed to find an expected impairment of contrast sensitivity recovery following photostress in AMD subjects. These results may be due to limitations of the small sample size or other confounding factors in the populations. Larger studies are required to reconcile the results presented here with previous results.
This is a 2020 ARVO Annual Meeting abstract.
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