Abstract
Abstract: :
Purpose:To evaluate the effect of high–dose vitamin C and E, beta carotene, and zinc supplements in the Age–Related Eye Disease Study (AREDS) on the progression of further vision loss in eyes with advanced AMD. Methods: Repeated–measures logistic regression to model progression to vision loss (at least a 15 letter loss) for 294 participants with advanced AMD in one eye at baseline and visual acuity 20/100 or better in that eye. A similar analyses for 540 participants with an eye that progressed to advanced AMD during the course of the study and with visual acuity 20/100 or better in that eye at the time of the advanced AMD event. Results: Compared with persons assigned to placebo, in a model controlling for age, gender, race, smoking status and baseline visual acuity in the eye with advanced AMD, persons assigned to the antioxidants alone group had a reduced risk of progression to further 3–line visual acuity loss (Odds ratio [OR] 0.36, 95% confidence interval [CI] 0.19, 0.67). Treatment effect estimates in persons in the zinc alone and the antioxidants with zinc groups were in the protective direction compared with placebo but were not statistically significant (OR 0.61, 95% CI 0.34, 1.12 and OR 0.66, 95% CI 0.36, 1.21, respectively). Similarly, for those eyes that progressed to advanced AMD during the course of the study (median follow–up 3.8 years after developing advanced AMD), the treatment effect was in the direction of benefit but not statistically significant for each of the treatment arms in a model controlling for age, gender, race, smoking status and visual acuity at the time of development of advanced AMD (antioxidants alone: OR 0.89, 95% CI 0.58, 1.37; zinc alone: OR 0.91, 95% CI 0.59, 1.38 and antioxidants with zinc: OR 0.71, 95% CI 0.46, 1.10). Conclusions: For persons with unilateral advanced AMD, the AREDS supplement not only reduced the risk of developing advanced AMD in the fellow eye, but also may reduce the 5–year risk of further 3–line visual acuity loss in the affected eye, provided that eye’s visual acuity was 20/100 or better at the time supplements were started.
Keywords: visual acuity • age-related macular degeneration • clinical (human) or epidemiologic studies: treatment/prevention assessment/controlled