Health Team

Genetic test measures risk of eyesight loss

Posted June 6, 2011 5:30 p.m. EDT
Updated June 6, 2011 6:28 p.m. EDT

— A genetic test can help people learn their risk of contracting macular degeneration, the most common cause of vision loss in people over age 65.

Teresa Kirby, 56, gets regular eye exams, partly because her mother had macular degeneration.

"She was in good health, but because of that disease, she was no longer able to look after herself," Kirby said.

Macular degeneration occurs in the central part of the eye's retina, and risk for the disease can be inherited.

"If one of your parents had macular degeneration, you have a 50 percent chance of developing macular degeneration," said Dr. Susan Durham, an optometrist with Doctors Vision Eye Center in Raleigh.

Simple cheek swabs find genes associated with the disease, and the test results, which take several weeks to get back, show a person's level of risk for developing an advanced stage of the disease.

Eighty percent of patients are at average or less than average risk. 

Lifestyle changes can cut that risk.

"Encourage them, say, for instance, if they are a smoker, to stop smoking," Durham said.

Patients can also eat more leafy green vegetables and fish oil, control their blood pressure, lower their blood pressure and lose excess weight.

People at a higher risk of the disease are referred to retina specialists.

"With early intervention, we have a very good chance of saving one's vision and maintaining their quality of life," Dr. Nitin Gupta, a retina specialist and ophthalmologist, said.

Kirby was diagnosed with traces of macular degeneration in one eye and took the genetic test to find out more about her risk.

"I might not be able to make those traces go away, but hopefully I can stabilize it so it doesn't go any further," she said.

The test costs $700, and insurance companies might pay for it if the results are positive. One testing company has offered to cover the costs if the results are negative.