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S. M. Meuer, M. D. Knudtson, B. E. K. Klein, R. Klein; The Epidemiology of Progression of Geographic Atrophy; The Beaver Dam Eye Study. Invest. Ophthalmol. Vis. Sci. 2008;49(13):2455. doi: https://doi.org/.
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© ARVO (1962-2015); The Authors (2016-present)
To examine the change in size and location of geographic atrophy (GA) in a large population-based study.
95 persons (184 eyes) with pure GA at either baseline and/or one of the 3 5-year follow-up examinations were identified. A tracing around the perimeter of each atrophic area was done using Digital Healthcare’s Oculab IP tools and the lesion area and greatest linear dimension (GLD) were calculated. In eyes where multiple atrophic areas were present, the areas were added together and the GLD was determined using the largest atrophic area. 32 persons (53 multiple eye-visit pairs) were seen at multiple visits with pure GA in the same eye to evaluate changes in total area and GLD.
Of the 184 eyes, 63 (34%) had a single lesion, 32 (17%) were multi-focal and 89 (48%) had merged GA. Of the pure GA eyes, 106 (58%) involved the foveal center with an average total area of 4.6 Disc Areas (DA) (95% CI 3.8,5.4), average GLD of the largest lesion of 4,322 µm (95%CI 3,704-4,939), and an average of 3 letters (95% CI -4 to 10) read on the LogMar visual acuity chart. Area and GLD increased by 2.6 DA and 513 µm on average, respectively, and visual acuity declined on average of 22 letters over the 5-year period of follow-up. Of those eyes with GA not involving foveal center [n=78 (42%) eyes], the average total area was 1.2 DA (95% CI 0.6,1.7), average GLD of the largest lesion of 1,911 µm (95%CI 1,504-2,317), and an average of 42 letters (95% CI 36 to 48) read on the visual acuity chart. Area and GLD increased by 2.9 DA and 3,252 µm on average, respectively and visual acuity declined on average of 28 letters over the 5-year period of follow-up. Nine of 19 eyes that had GA not involving the center point at baseline moved into the center point at follow-up. In a multivariate model, older age and greater total area of involvement were associated with larger area changes at follow-up.
These data document the distribution and changes in pure GA in the Beaver Dam Eye Study population. This information is important in understanding the natural history of GA and will be useful estimating risks of progression in clinical trials of new interventions for GA.
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