Age-related macular degeneration (AMD) is damage to or breakdown of the central part of the retina, called the macula, which allows us to see details clearly. Macular degeneration can impair both distance and close vision, but does not affect peripheral (side) vision. Macular degeneration by itself does not cause total blindness, but can result in complete loss of central vision.
There are two types of macular degeneration: dry and wet. “Dry” (atrophic) macular degeneration is the result of drusen (protein and lipid deposits) forming in the macula and is the more common form of the disease. Vision loss is gradual. The most advanced form of the dry type is called geographic atrophy. “Wet” (exudative) macular degeneration occurs when abnormal blood vessels form underneath the retina and leak fluid or blood. This type accounts for about 10 percent of macular degeneration, and vision loss can be rapid and severe.
Many people, including Georgia O’Keeffe, Judi Dench, and Stephen King have experienced the telltale sign of seeing an area of darkness in the middle of their vision, making even the simplest tasks—driving, reading, recognizing faces—difficult to impossible. Although the disease can strike patients of any age (a rare form of the disease affects children), macular degeneration is often related to aging, and the percentage of the American population over 65 is increasing rapidly. Experts predict the elderly population will be six times greater in 2025 than in 1990; thus the disease is likely to approach epidemic proportions.