Age-Related Macular Degeneration (ARMD): Overview and Risk Factors

Age-related macular degeneration is a degenerative disease of the macula, the central part of the retina. It results in loss of central vision, which is necessary for most daily activities, and can cause legal blindness. This disease is the most common cause of poor vision among elderly persons

There are two forms of macular degeneration: The "dry" form is marked by changes in the macula without bleeding or leakage of fluid. The "wet" form includes leakage and/or bleeding from new blood vessel growth beneath the retina.

Macular degeneration is thought to be due to destruction of the fatty acids in the rods and cones of the eyes. Thus, antioxidant nutrients have long been thought to be protective (see Nutritional Considerations).

The disease is characterized by gradual vision loss. However, "wet" macular degeneration can result in blindness within weeks. Other symptoms include distortion of straight lines, slow recovery of vision after leaving sunlight and going indoors, and changes in color vision.

Risk Factors

• Age: Macular degeneration rarely occurs in persons under age 55. The prevalence is nearly 1 percent in those aged 70 and older, and increases to more than 15 percent in those over 90.
• Smoking: Individuals who smoke have more than double the risk, compared with those who have never smoked. Risk may remain elevated for 15 or more years after smoking cessation.

Additional probable risk factors include nutritional deficiencies (see Nutritional Considerations) and family history of the disease. Some studies suggest that hypertension, sunlight exposure, and cataract surgery also increase the risk of macular degeneration. However, further study is necessary to define these risks.