Light could be therapy against blindness - Biomedicine - Brief Article

Science News, March 8, 2003

Beaming red light at animals soon after they've drunk methanol partially protects their eyes against that chemical's blinding effects, research on rats suggests. Such light therapy might find applications in people who accidentally ingest methanol or who suffer from other forms of acquired blindness, such as age-related macular degeneration and glaucoma, says Janis T. Eells of the Medical College of Wisconsin in Milwaukee.

Strong, red light is high-intensity, low-frequency radiation. Eells and her colleagues chose to experiment with such radiation because other studies had shown that it can protect cells' energy-producing parts, the mitochondria, from some forms of chemical and metabolic injuries.

Methanol harms sight mainly by damaging mitochondria in cells in the eye's retina and optic nerve. People and animals can go blind within 2 days of ingesting methanol, an alcohol used in windshield-wiper fluid and other solvents.

Eells and her colleagues fed lab rats three doses of methanol over 2 days and exposed some of the animals to three periods of intense red light, each lasting almost 2.5 minutes. Cells in the light-treated animals' eyes were subsequently more responsive to normal light and suffered less structural damage from the methanol poisoning than eye cells in animals not treated with light therapy. The researchers report their findings in an upcoming Proceedings of the National Academy of Sciences.

Since mitochondrial damage may play a role in other sight disorders, light therapy could prove useful against multiple causes of blindness, Eells says. She cautions that commercially available red lights don't shine with the intensity that seems necessary to achieve therapeutic effects.--B. H.