Characteristics of Geographic atrophy in an elderly UK population-The Bridlington Eye Assessment Project (BEAP): a cross-sectional study (2002-2006).

Background/objectives: Geographic atrophy (GA) is a common cause of visual loss. The UK population prevalence is unknown. We studied GA prevalence, characteristics, and associations in an elderly UK population.

Methods: Masked grading of colour fundus photographs from 3549 participants in the cross-sectional study of Bridlington residents aged ≥65 years. GA size, shape and foveal involvement were correlated with demography and vision.

Results: GA was detected in 130 eyes (101 individuals) of 3480 participants with gradable images (prevalence 2.90%; 95% CI 2.39-3.52 either eye), was bilateral in 29/3252 subjects (0.89%, 95% CI 0.62-1.28) with bilateral gradable photos, with mean age of 79.26 years (SD 6.99, range 67-96). Prevalence increased with age, from 1.29% (95% CI 0.69-2.33) at 65-69 to 11.96% (95% CI 7.97-17.50) at 85-90 years. Mean GA area was 4.51 mm (SD 6.48, 95% CI 3.35-5.66); lesions were multifocal in 47/130 eyes (36.2%; 95% CI 28.4-44.7). Foveal involvement occurred in 41/130 eyes (31.5%; 95% CI 24.2-40.0). In eccentric GA, mean distance from circumference to fovea was 671μm (SD 463; 95% CI 570-773). Older age (OR 1.10/year increase; 95% CI 1.06-1.14), RPD (OR 1.87; 95% CI 1.10-3.19) and large drusen/RPD ≥ 125 μm (OR 6.16; 95% CI 3.51-10.75) were significantly associated with GA in multivariate analysis. GA lesions (18/31 eyes; 58%; 95% CI 40.7-73.6) had U-shape configuration more frequently in RPD subjects than those without (9/99 eyes, 9.1%; 95% CI 4.66-16.6) (p = 0.0001).

Conclusion: GA, commonly solitary and eccentric, occurred in the perifovea. However, one third of GA eyes had foveal and bilateral involvement. Possible association of RPD with GA phenotype exists. Population multimodal imaging studies may improve understanding further.