Study: Antioxidants may slow vision loss

U.S. scientists say they've blocked the advance of retinal degeneration in mice with a form of retinitis pigmentosa by treating them with antioxidants.

"Much more work needs to be done to determine if what we did in mice will work in humans," said Peter Campochiaro, a Johns Hopkins University professor of ophthalmology and neuroscience and the leader of the study. "But these findings have helped to solve a mystery."

In patients with retinitis pigmentosa, or RP, rod photoreceptors die from a mutation but it has not been known why cone photoreceptors die. The Johns Hopkins scientists determined that, after rods die, the retina's level of oxygen increases and it's that high oxygen that gradually kills the cones.

Oxygen damage is also called "oxidative damage" and can be reduced by antioxidants such as vitamin E, alpha-lipoic acid and other antioxidant chemicals.

So, for the first time, Campochiaro said, a treatment target has been found for patients with RP.

The research is explained in the July online edition of the Proceedings of the National Academy of Sciences.

Copyright 2006 by United Press International