February is Age-Related Macular Degeneration Awareness Month. Macular degeneration is the leading cause of legal blindness, affecting more Americans than cataracts and glaucoma combined. In macular degeneration, the light-sensing cells of the macula, which has our sharpest vision, malfunction and may over time cease to work. Macular degeneration occurs most often in people over 60 years old, in which case it is called Age-Related Macular Degeneration (ARMD). Much less common are several hereditary forms of macular degeneration, which usually affect children or teenagers.
Macular degeneration is caused by the deterioration of the central portion of the retina, the inside back layer of the eye that records the images we see and sends them from the eye to the brain. The retina's central portion is the macula and is responsible for focusing central vision in the eye. It controls our ability to read, drive a car, recognize faces or colors, and see objects in fine detail. Because only the center of your vision is affected, people will not go completely blind from the disease.
There are two forms of ARMD. The 'dry' type affects about 90 percent of those with the disease. It progresses more slowly. 'Wet' ARMD is the second type. Although only 10 percent of all people with ARMD have this type, it accounts for 90 percent of all severe vision loss from the disease. Damage in the wet type is caused by new blood vessels behind the retina that leak blood and fluid under the macula.
Age is a significant risk factor in ARMD. People in their 50's have about a two percent chance of getting ARMD, while people over 75 have a 30 percent chance. Other risk factors include being a female, smoking, having a family history of ARMD, and elevated cholesterol levels.
Neither dry or wet ARMD causes any pain. The most common symptom of dry ARMD is slightly blurred vision. An early symptom of wet ARMD is that straight lines appear wavy. Maintaining regular eye examinations is the best way to detect ARMD. The eye care professional can use visual acuity tests, field screenings, and dilated fundus examinations to look for ARMD.
For more information on ARMD, there are several informative web sites available. These include The American Optometric Association at www.aoa.org, the American Macular Degeneration Foundation at www.macular.org, the Macular Degeneration Foundation at www.eyesight.org, and the National Eye Institute at www.nei.nih.gov.