What causes macular degeneration?

What causes macular degeneration? I heard a rumor it can be caused by being outside in bright sunlight without sunglasses. Is that true? If so, it it the bright visible light or ultraviolet light doing the damage?

people develop macular degeneration as part of the body's natural aging process. Less commonly, macular degeneration may be an inherited condition, as in the case of juvenile macular degeneration. Injury, infection, inflammation or extreme nearsightedness may also damage the delicate tissue of the macula.

The two most common types of age related macular degeneration are "dry" (atrophic) and "wet"(exudative):

"Dry" macular degeneration (also called atrophic or invilutional macular degeneration):

By far the most common type, "dry" macular degeneration is caused by aging and thinning of the tissues of the macula. Vision loss is usually gradual.

"Wet" macular degeneration (also called exudative or hemorrhaging macular degeneration):

Accounting for about 10% of all cases, "wet" macular degeneration results when abnormal blood vessels form at the back of the eye. These new blood vessels leak fluid and blood. Leaking fluid distorts and blurs central vision, often resulting in dense scar tissue in the macula. Vision loss may be rapid and severe.

No one knows the causes of age-related macular degeneration. Causes are likely to be genetically inherited, but environmental factors also contribute. Macular degeneration often runs in families. A recent study of twins showed that genetic factors play a significant role in the cause.

Many of the following risk factors have been found to be associated with age-related macular degeneration:

* Age: The likelihood to develop macular degeneration increases with age.


* Race: Macular degeneration is more common in whites but occurs in all races.


* Smoking


* High blood pressure


* Vascular disease


* High intake of saturated fat and cholesterol


* High blood cholesterol level


* Farsightedness (hyperopia)


* Exposure to sunlight


* Family history