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Macular Degeneration Macular degeneration is an incurable eye disease that is the leading cause of blindness in the United States. Macular degeneration affects more Americans than cataracts and glaucoma combined. Ten million Americans have macular degeneration with 1.6 million of those experiencing severe loss of vision. Macular degeneration has reached near epidemic levels in the United States. Since many people diagnosed with macular degeneration are over age 55, the number of cases of macular degeneration in the U.S. will increase significantly as baby boomers age. Age-related macular degeneration is a chronic eye disease that occurs when tissue in the macula, the part of the retina responsible for central vision, deteriorates. The retina is the layer of tissue on the inside back wall of the eyeball. The macula is made up of densely packed light-sensitive cells called cones and rods. These cells, particularly the cones, are essential for central vision. Degeneration of the macula causes blurred central vision or a blind spot in the center of the visual field. The specific factors that cause macular degeneration are not conclusively known.
Types of Macular Degeneration Macular degeneration occurs in two types: Dry macular degeneration--Most people with macular degeneration have the dry form. In fact, macular degeneration almost always starts out as the dry form. The dry form may initially affect only one eye but, in most cases, both eyes eventually become involved.
Wet macular degeneration: While it accounts for only about 15 percent of all cases, wet macular degeneration is responsible for the most severe vision loss. Developing wet macular degeneration in one eye greatly increases the odds of developing it in the other eye. Almost everyone with wet macular degeneration develops dry macular degeneration first.
Another form of wet macular degeneration, called retinal pigment epithelial detachment (PED), occurs when fluid leaks even though no abnormal blood vessels have started to grow. The fluid collects under the retinal pigment epithelium, causing what looks like a blister or a bump under the macula. This kind of macular degeneration causes similar symptoms to wet macular degeneration, but visual acuity may remain relatively stable for many months or even years before it deteriorates. This form of macular degeneration usually progresses to the more common wet form of macular degeneration that includes newly growing abnormal blood vessels. In either the dry or wet form of macular degeneration, the vision initially may falter in one eye but not the other. Since the good eye often compensates for the weak one, the symptoms of macular degeneration may not be recognized at its early stages. Vision and lifestyle are dramatically affected when macular degeneration develops in both eyes. More information about macular degeneration can be found at www.nei.nih.gov and www.macular.org.
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