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Stacy M Meuer, Kristine E Lee, Barbara E K Klein, Ronald Klein; The Characteristics of Geographic Atrophy From 25 Years of The Beaver Dam Eye Study (BDES). Invest. Ophthalmol. Vis. Sci. 2018;59(9):6011. doi: https://doi.org/.
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© ARVO (1962-2015); The Authors (2016-present)
To describe the characteristics of pure geographic atrophy (GA) and changes over time in a large population-based study.
As part of the BDES, stereo fundus photographs of the macula were collected every 5 years over 6 examination phases beginning in 1988. Images were graded according to the Wisconsin Age-Related Maculopathy grading scheme, and eyes with pure GA were identified for further measurements. Digitized images were put into an imaging database and calibrated according to a microns per pixel calculation. The center of the fovea (CPT) was identified and a tracing was made around the perimeter of each atrophic area. The GA lesion total area and proximity to the fovea were calculated.
Pure GA was identified in 139 persons at any of the six examinations. Persons with GA have up to 4 visits with measures, resulting in 269 eye-visits with pure GA measurements. At baseline 35 people (7 binocular) presented with pure GA, mean area of 3.29 disc areas (DA=2.54x106µm2) of involvement (SD 3.17), mean age 79 (SD 6). The CPT was involved in 69% of the eyes with pure GA and 44% had severe visual impairment (SVI) (20/200 or worse). In follow-up, 5 of those with unilateral GA went on to develop GA in their other eye and 104 people had incident GA in one (N=70) or both (N=34) eyes yielding incident disease in 143 eyes (mean age 83). The mean area of involvement was 1.71 DA (SD 2.27). The CPT was involved in 35% of the eyes and 9% had SVI. Of the 143 eyes with new GA, 41 (29%) had at least one 5 year follow up visit. These eyes had a mean 5 year increase in DA of 3.31 (SD 3.18). New CPT involvement developed in 57% (16/28) of the eyes at 5 years. In those eyes without CPT involvement (N=28) the increase in DA was 3.77 vs 2.35 with CPT involvement (N=13), P=0.10. There are no significant differences in increases in GA area by age, smoking, hypertension, body mass index, or distribution of the risk allele for CFH or ARMS2. Women have larger increases in DA (4.26 vs 2.23, p=0.03 with age adjustment).
Women appear to have larger increases in area of GA over 5 years and there is a suggestion the growth of GA may slow once it reaches the center of the fovea. Despite the long follow-up in this population, there are few eyes with pure GA that have multiple visits. Meta analyses with other similar populations are needed.
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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