macular degeneration (redirected from metamorphopsia)

macular degeneration, eye disorder causing loss of central vision. The affected area, the macula, lies at the back of the retina and is the part that produces the sharpest vision. The most serious visual impairment occurs when abnormal blood vessels form and leak serous fluid or bleed into the tissue of the macula, ultimately producing scar tissue. Peripheral (side) vision is unaffected. Onset may be acute with hemorrhage but usually is gradually progressive. Although some vision is retained, the ability to read, recognize faces, and drive a motor vehicle is greatly reduced. The condition is painless.

Macular degeneration is a major cause of vision impairment among elderly people. Although its underlying cause is unknown, it sometimes appears to run in families. Serious macular degeneraton, if diagnosed early, may have its progress stemmed by laser or photodynamic (cold laser and drug) treatment that closes leaking vessels. Antiangiogenic drugs, which inhibit the formation of new blood vessels, can be injected into the eye to stop degeneration and in some cases even improve vision. Sudden change in vision in someone over age 50 thus requires immediate medical attention.

Bibliography

See H. Grunwald, Twilight: Losing Sight, Gaining Insight (1999).

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macular degeneration

Degeneration of the macula (central part of the retina), with corresponding visual-field defect. It is the leading cause of blindness in old age. Probably due to reduced blood circulation, it is now known to have a genetic component. It is twice as common in smokers as in nonsmokers, and it is also correlated with lifelong sun exposure. Peripheral vision usually remains, but loss of central visual acuity makes reading or fine work difficult or impossible, even with special magnifying eyeglasses. Some forms of macular degeneration can be halted (but not reversed) by laser surgery.