This large long-term prospective study found that the major risk factors associated with progression to advanced AMD include increasing age, severity of drusen, retinal pigment epithelium (RPE) abnormalities, and advanced AMD in the fellow eye. Overall, the researchers found that the natural history of AMD demonstrates continual vision loss in people with advanced AMD.
They describe in this study the 10-year progression rates to intermediate or advanced AMD in a large cohort of participants in the Age-Related Eye Disease Study (AREDS) trial.
Patients with no AMD or with AMD of varying severity (n=4,757) were followed for a median of 6.5 years. The majority of survivors were followed for an additional five years after the trial ended (3,549 of 4,209 surviving participants).
Increasing drusen severity at baseline, the presence of large drusen within one disc diameter of the fovea or the central zone, the presence of bilateral medium drusen, the presence of advanced AMD in the fellow eye, and the simultaneous presence of large drusen and AMD RPE abnormalities all increased the risk of progression to advanced AMD. Median visual acuity at 10 years in eyes that had large drusen at baseline but never developed advanced AMD was 20/25 while eyes that developed advanced AMD had a median visual acuity of 20/200.
Women and current smokers were at greater risk of neovascularization. Supplementation with antioxidant vitamins and minerals given during the AREDS trial decreased the risk of wet AMD but not of geographic atrophy.
The researchers say that the long-term visual acuity results are of interest because AREDS participants may constitute one of the last cohorts in whom the natural history of wet AMD is not affected by the administration of intravitreal injections of anti–vascular endothelial growth factor agents. Visual acuity changes are evident one year before the diagnosis of AMD.
They conclude that these clinic-based data provide important information for investigators who are interested in designing controlled clinical trials or epidemiologic studies of AMD in clinic-based populations. They say further research is needed to develop techniques for earlier detection and treatment of early disease so that final visual acuity results might be improved.