NOV 08, 2011
Researchers evaluated the role of fellow-eye status in determining geographic atrophy (GA) progression in patients with age-related macular degeneration (AMD). They found that AMD manifestation of the fellow eye may serve as an indicator for GA progression even after adjustment for GA baseline size.
They classified 193 patients (300 eyes) with GA from the prospective, longitudinal, natural history FAM Study into three groups according to baseline fellow-eye AMD manifestation: (1) bilateral GA, (2) early/intermediate AMD, and (3) exudative AMD. GA areas were quantified based on fundus autofluorescence images using a semiautomated image-processing method, and progression rates were estimated using two-level, linear, mixed-effects models
The crude progression rate in the bilateral GA group (mean, 1.64 mm2/y) was significantly higher than in the fellow eye early/intermediate AMD group (0.74 mm2/y). However, this difference was only significant when GA size was ≥1 DA at baseline with a progression rate of 1.70 mm2/y in the bilateral and 0.95 mm2/y in the early/intermediate group. The progression rate was similar between the bilateral GA and exudative AMD groups.
This study suggests that the disease stage and phenotypic manifestation of the fellow eye can serve as an indicator of the pace of atrophy enlargement and thus the expansion of corresponding absolute scotoma over time. Predictive characteristics not only contribute to the understanding of pathophysiological mechanisms, but also are useful for the design of future interventional trials in GA patients.