The macula is a tiny circle in the middle of the retina, a light-sensitive membrane that lines the inside of the back of the eye. In older people, it sometimes begins to deteriorate or degenerate for unknown reasons. Women are believed to be more at risk than men. Macular degeneration is the leading cause of legal blindness in Canada, accounting for 34% of cases. However, macular degeneration rarely leaves you totally unable to see.

There are two types of this disease:

Dry macular degeneration accounts for about 90% of cases. The tissue of the retina shrinks and pigments accumulate inside of it. Dry macular degeneration can progress to the wet form.

Wet macular degeneration New blood vessels grow around and behind the macula. There's sometimes bleeding in or behind the macula. Material seeps into the retina and settles in the macula. This is called an exudate. Eventually the exudate disappears, but a scar takes its place. All people who have wet macular degeneration had dry macular degeneration first.

Causes of Macular Degeneration

The causes of macular degeneration are unknown, but the risk grows with age. Because it's extremely rare in people under age 50, the condition is usually referred to as age-related macular degeneration (AMD).

There are some known risk factors for macular degeneration. Smoking may increase your chances of developing the condition and seems to speed up its progress. High cholesterol levels, high blood pressure, obesity, and a diet lacking in dark green leafy vegetables and omega-3 fatty acids may also be associated with macular degeneration. Women seem to be at a higher risk than men.

Macular degeneration runs in some families but not in all. Recent studies of twins suggest that both genes and environment contribute to the onset of macular problems. Wet macular degeneration, at least, seems to be more common in people with poor cardiovascular health. Although it only accounts for about 10% of the cases, wet macular degeneration is responsible for 90% of the blindness caused by this disease.

Treating and Preventing Macular Degeneration

While there's little that can be done for dry macular degeneration, the disease progresses very slowly, and will probably never completely black out the central vision. Many people with this condition live full lives without serious disability.

Some studies have suggested a link between poor nutrition and faster degeneration of the macula. According to this evidence, fruit and dark green vegetables like spinach can slow the disease and contribute to better outcomes. For some people, a doctor will recommend a daily supplement that contains zinc, copper, vitamin E, vitamin D, and beta-carotene or vitamin A.

There is no cure for wet macular degeneration, but treatment may help to slow it down. Laser surgery destroys tiny, newly grown blood vessels that may be bleeding into the macula. Photodynamic therapy may also be used. This involves injecting a medication called into a vein. Then, a light is used to activate the medication to close abnormal blood vessels. Medications injected into the eye, may be used to slow down the growth of blood vessels. Daily supplements may also be recommended.

It's been shown that bright sunlight may speed up the progress of macular degeneration. Those with the condition should consider wearing UV-protective sunglasses when they are outdoors during daytime hours. People who have lost their vision may need magnifiers, strong reading glasses, and other devices to help them manage.