Background: As a cause for severe visual loss, geographic atrophy of the retinal pigment epithelium is about half as common as choroidal neovascularization in patients with advanced age-related macular degeneration. To assess symmetry, we determined intraindividual variations of various features of bilateral geographic atrophy in patients with atrophic age-related macular degeneration in a cross-sectional study.
Methods: Patients were examined with the use of a confocal scanning laser ophthalmoscope (Heidelberg Retina Angiograph; Heidelberg Engineering, Heidelberg, Germany). Digital infrared reflection images (excitation, 830 nm) and fundus autofluorescence images (excitation, 488 nm) were recorded. The eyes of each patient were compared regarding number, size, and convex hull of the atrophic areas with the use of image analysis software and with respect to fundus autofluorescence changes in the junctional zone.
Results: Seventy-two patients (mean +/- SD age, 76.3 +/- 7.9 years) were examined. The number of atrophic areas ranged from 1 to 23 (mean +/- SD, 4.9 +/- 4.6); the size of geographic atrophy, from 0.18 to 30.20 (mean +/- SD, 7.0 +/- 6.6) mm(2); and the size of the convex hull, from 0.18 to 39.20 (mean +/- SD, 11.7 +/- 8.4) mm(2). No statistically significant difference was found when comparing these variables between each left and right eye: number, P =.62; size, P =.81; and convex hull, P =.78. Identical patterns of fundus autofluorescence were observed in 43 (80%) of 54 patients.
Conclusions: There is intraindividual symmetry in eyes with bilateral geographic atrophy in the presence of a wide range of interindividual variability. The findings are in accordance with the view that age-related macular degeneration is not merely the result of a nonspecific aging process. Symmetric manifestations, rather, reflect specific individual determinants in the pathogenesis and manifestation of the disease.