Geographic atrophy is the advanced form of atrophic age-related macular degeneration. It is present in 3.5% of people age 75 and over in the United States. It progresses gradually over time, often sparing the fovea until late in the course of the disease. Forty to fifty percent of eyes with geographic atrophy and good visual acuity at baseline lose three or more lines of acuity by two years and 27% become worse than 20/200 by four years. This article discusses the information known about age-related geographic atrophy at the present time.