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Donna Welch, Divya Narayanan, John David Rodriguez, Matt J Chapin, Garrick Wallstrom, Mark B Abelson; Macular Recovery Following Photostress in Low Luminance Conditions in Young and Old Subjects. Invest. Ophthalmol. Vis. Sci. 2019;60(9):5933.
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© ARVO (1962-2015); The Authors (2016-present)
Impaired adaptation to changes in lighting levels as well as low luminance visual function is a common complaint in the elderly. The use of photostress is a well established method to test adaption rate and the response of the visual cycle. Most studies have been concerned with recovery in mid-phototopic luminance conditions. In this study we test visual function recovery to low luminance stimuli following a long duration photostress in young and elderly subjects.
A group of 14 older normal subjects (mean age 71.9 ± 8) and a control group of 8 younger normal subjects (mean age 29.1 ± 7) were subjected to macular photostress using the OraLux photostress System. The OraLux System provides a diffuse light source bleaching 84% of cone photopigment while maintaining an exposure safety factor of 200 times less than maximum safe exposure. After each photostressing session, macular recovery was tracked using a foveal, variable contrast, flickering stimulus of mean luminance in the high mesopic range. Recovery was tracked for 300 seconds. Endpoint was time to recovery to baseline sensitivity as evaluated by two static sensitivity trials prior to photostress.
50% of the younger group recovered baseline sensitivity in under 180 seconds. 88% of younger subjects recovered in under 240 seconds. One younger subject failed to return to baseline after 300 seconds. In the older group, only 29% returned to baseline in under 240 seconds. Ten older subjects failed to return to baseline by 300 seconds.
Photostress recovery under low luminance conditions is considerably prolonged in older subjects. This agrees with subject reported complaints in low luminance conditions after exposure to bright lights such as night driving.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.
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