Health Watch -- Finding Causes of Blindness

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Researchers are trying to find the genetic root of one of the most common causes of blindness.

Eyesight tends to weaken with age, but millions of older Americans lose their eyesight as they get older, due to a disease called macular degeneration. The macula is the area in the center of the retina where light is focused. That's where light is translated into nerve signals that send an image to the brain. You use your macular vision when you look straight ahead or perform tasks that require sharp vision, such as reading or driving.

When the macula starts to fail, people begin to lose that straight-ahead vision and have to rely more on peripheral vision. It's estimated that by age 75, 30 percent of Americans have some degree of macular degeneration. It's the leading cause of blindness in older adults.

The risk is much higher for people who have a family history of the disease. Because of this, researchers at UT Southwestern Medical Center at Dallas are conducting a study of families with multiple members who have been diagnosed with macular degeneration. Researchers hope to find the genes responsible for the disease. Dr. Albert Edwards, the UT Southwestern ophthalmologist who's leading the study, says once they know this, they may be able to screen for the disease and develop treatments by manipulating the biological pathways associated with the disease.

In addition to heredity, risk factors include smoking, high blood pressure, heart disease and sun exposure.


Feb. 2004