Macular degeneration is damage to the macula which results in central vision loss. The macula is in the center of the retina, the light sensitive tissue in the back of the eye. The macula allows you to read, drive, and do other activities requiring fine, sharp, and straight-ahead vision. It contains hundreds of nerve endings, packed closely together, and is responsible for the sharpness of the visual image in the center of your field of vision. If the macula is damaged, you no longer have crisp central vision.

Causes

The most common form of macular degeneration is involutional macular degeneration. This accounts for 70 percent of all cases and is associated with aging. It is caused by a breakdown or thinning of the tissues in the macula. Macular degeneration is thought to be caused by hardening and blocking of the arteries in the blood vessels that supply the retina. There are two forms of macular degeneration, wet and dry. With wet, also called exudative, macular degeneration, new, fragile blood vessels grow beneath the retina and leak blood and fluid. The leaks form a mound that is often surrounded by small areas of bleeding. This mound eventually shrinks, leaving a scar. The scarring and bleeding can quickly damage the macula. Dry, or atrophic, macular degeneration gradually breaks down the retina's dark-colored cell layer. There is no scarring, blood, or other fluid leakage.

Symptoms

If you have dry type, you may lose some of your vision gradually. You may have trouble reading or driving, or you may start to need a bright light or a magnifying glass to be able to do certain tasks, like needlepoint or reading small words on a page.
If you have wet type, you may start to see wavy lines. You might perceive a straight edge, such as a window blind, as wavy. The visual changes you are seeing may happen quickly, over several weeks.