Ocular Risk Factors for Developing Neovascular AMD in the Fellow Eyes of Patients with Unilateral Neovascular AMD

Abstract

Abstract: : Purpose: To determine ocular risk factors and progression rates for the development of neovascular AMD in the second or fellow eye of AREDS clinical trial participants having one eye with neovascular AMD at baseline. Methods: Repeated–measures logistic regression was used to model progression to neovascular AMD with the severity of selected ocular risk factors (drusen area, maximum drusen size, pigment abnormalities) present at baseline in the study eye, for 714 AREDS participants with neovascular AMD in the non–study (first affected) eye. Models were adjusted for age, gender and AREDS treatment. Probability of progression to neovascular AMD was estimated for two models: 1) Drusen size/Hyperpigmentation and 2) Drusen area/Hyperpigmentation. Results: A total of 262 (37%) fellow eyes progressed to neovascular AMD in the AREDS clinical trial during an average follow–up period of 6.2 years. Three ocular characteristics were associated with an increased risk of progression to neovascular AMD. The association increased with increasing severity level of each factor: drusen area scale (OR : 4.6, 7.8, 11.8, 15.8 and 18.9), maximum drusen size scale (OR : 3.9, 8.2, 12.0) and increased pigmentation scale (OR : 1.8, 2.5). Using either drusen area or size combined with the degree of hyperpigmentation yields 5–year rates of developing advanced AMD that range from about 5% for fellow eyes in the lowest categories of drusen area (<125 µ total drusen area) or size (none or < 63µ size) and hyperpigmentation (none) to almost 50% for those in the highest categories of drusen area (> 1 DA drusen) or size (>250 µ drusen) and hyperpigmentation (hyperpigmentation >125 µ). In the models, drusen area was somewhat more associated with the development of advanced AMD than drusen size; however, drusen size and area are correlated with one another and they each are strongly associated with the development of advanced AMD. Conclusions: The risk of progression to neovascular AMD in the fellow eye of patients with unilateral neovascular AMD is associated with drusen area or size combined with the degree of focal hyperpigmentation.

Keywords: age–related macular degeneration • choroid: neovascularization • clinical (human) or epidemiologic studies: risk factor assessment