The causes of age-related macular degeneration are complex and incompletely understood. However, scientists believe that both genetic and environmental factors such as smoking and ultraviolet exposure may be involved. Many older people develop macular degeneration as a part of the aging process. In addition to age, there are characteristics that many people with macular degeneration share. These include family history, smoking, or having light-colored eyes.

Although many people with macular degeneration have common traits, it is unknown how and if these traits affected their risk of developing macular degeneration.