Geographic atrophy

Geographic atrophy (GA) of the retinal pigment epithelium (RPE) is the advanced form of nonneovascular age-related macular degeneration (AMD) and is associated with gradual, progressive loss of central vision. Dense scotomas have been shown to correspond to the retinal areas affected by GA (1). These scotomas involve the parafoveal and perifoveal retina early in the course of the disease, sparing the foveal center until late in the course of the disease (2–5). Consequently, GA is responsible for approximately 20% of the legal blindness secondary to AMD, compared to choroidal neovascularization (CNV), which tends to involve the foveal center much earlier in the course of the disease and accounts for nearly 80% of the legal blindness secondary to AMD (6). However, the parafoveal and perifoveal scotomas in the early stages of GA compromise the patient’s ability to read and to recognize faces, often despite the retention of good visual acuity, and account for a much larger percentage of moderate visual loss in those affected (7). In addition, GA is present binocularly in most patients. The prevalence of GA in the population 75 years of age or older is approximately 3.5%, half that of neovascular AMD (8,9), and increases to 22% in those 90 years of age or older (10). While there are treatments for CNV, there is presently no definitive treatment available for GA. As our understanding of GA grows, it is hoped that medical and surgical interventions will be developed to completely halt its progression rate and to prevent subsequent moderate and severe visual loss.