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Katherine Grace Chen, Jason Alvarez, Wai T Wong, Henry Wiley, Emily Y. Chew, Frederick L Ferris, Catherine A Cukras; Longitudinal Study of Dark Adaptation as a Functional Outcome Measure for Age-Related Macular Degeneration. Invest. Ophthalmol. Vis. Sci. 2018;59(9):2423. doi: https://doi.org/.
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© ARVO (1962-2015); The Authors (2016-present)
To assess for correlation of changes in dark adaptation (DA) with age-related macular degeneration (AMD) severity, presence of reticular pseudodrusen (RPD), and progression of fundus features over 4 years.
Participants >50 years of age were assigned into groups based on fundus features: no large drusen (Group 0), unilateral large drusen (Group 1), bilateral large drusen (Group 2), late AMD in one eye with large drusen in fellow eye (Group 3), presence of RPD regardless of AMD status (Group RPD). Study eyes were also graded using the 9-step Age-Related Eye Disease Study (AREDS) Severity Scale. Study eyes underwent DA testing using a prototype AdaptDx™ device (MacuLogix, Hummelstown, PA) at baseline, 3, 6, 12, 18, 24, 36, and 48 months. The slope of the rod intercept time (RIT), or the rate of change in RIT (time for recovery to a stimulus intensity of 5 x 10-3 cd/m2), was calculated by linear regression fits of each individual’s RIT data. The slope RITs for AMD categories were compared using nonparametric statistical testing.
A total of 75 eyes in 75 participants (mean age 72±8.3 years, 53% female) were analyzed. All groups demonstrated a significantly positive slope RIT (p<0.0001 compared to the horizontal), indicating a prolongation of RIT over time. We found a trend of increasing rate of RIT change with increasing baseline AMD severity (mean rates for Groups 0-3 were 0.67, 0.72, 1.1, 2.2 min/year respectively) despite stable visual acuity. This trend was also present when study eyes were grouped using the AREDS Severity Scale. Eyes with RPD at baseline tested using an alternate testing protocol also demonstrated significantly positive slope RIT (mean RIT change = 2.83 mins/year). Study eyes without RPD at baseline that developed RPD during the study had a significantly greater mean baseline RITs (29.50 vs 14.65 mins, p<0.0001) and greater mean slope RITs (2.89 vs 0.74 mins/year, p<0.0001) than those that never develop RPD. Study eyes that exhibited progression of fundus changes (≥2 steps) on the AREDS Severity Scale trended towards a higher slope RIT but was not statistically significant.
DA as measured by RIT progressively worsens over the course of 4 years. Eyes with RPD at baseline and those that developed RPD demonstrate the greatest decrement in DA function. DA may be a useful functional parameter to understand AMD disease progression.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.
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