Abstract
Purpose :
Several studies have investigated the progression rate of geographic atrophy (GA) lesions in nonexudative AMD but the reported progression rates vary widely across clinical trials.
Methods :
We searched in 5 databases up to September 12th, 2018 for studies that evaluated GA growth rates in at least two topographic regions in untreated eyes with nonexudative AMD. To account for the different entry times of the subjects into cohort studies, we added a horizontal translation factor to shift each data set until r2 was maximized for the cumulative trend line. We determined the GA linear growth rates in retinal zone 1 (central 0 to 0.75 mm), 2 (0.75 to 3.5 mm from the foveal center), and 3 (beyond 3.5 mm from the foveal center). We then determined the GA linear growth rate at different distances from the foveal center. We also performed random-effects meta-analyses to assess the GA linear growth rate of foveal-sparing and fovea-involving GA lesions.
Results :
We included 8 studies with data from 1806 eyes in the analysis. “Zone 1 spared” GA lesions had a significantly higher GA linear growth rate compared to “zone 1 involved” lesions (0.196 vs. 0.130 mm/year, p = 0.006). This trend was maintained when we compared “foveal center spared” versus “foveal center involved” GA lesions (0.201 vs. 0.160 mm/year, p < 0.001) (Fig. 1). We also found distinct linear GA growth rates depending on the distance to the foveal center, with the growth rate in the zone 2 (0.160 mm/year) being more than 2-fold faster than the growth rate in zone 1 (0.054 mm/year) and periphery (0.072 mm/year) (Fig. 2). We then determined the GA linear growth rate at 7 retinal locations and fit the growth rate as a Gaussian function of retinal eccentricity.
Conclusions :
The distance to the foveal center significantly affected GA progression. Our analysis may provide natural history data on the prognosis of GA and shed light on the underlying mechanism of GA expansion.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.