Avoiding bright light might be wise for children with Stargardt’s disease, and also for adults with age-related macular degeneration, according to Dr. Gabriel Travis of the University of Texas Southwestern in Dallas.

Dr. Travis and his colleagues studied the effects of the ABCR gene, which is associated with both diseases, by altering the genetic makeup of 17 lab mice. The genetically altered mice’s eyes took twice as long to adapt to darkness as the eyes of unaltered mice, just as occurs in children with Stargardt’s disease. The altered mice also lost their vision within a few weeks of birth.

The researchers determined that the genetic disruption in Stargardt’s disease causes the buildup of natural compounds in the retina by affecting the rim protein that normally clears impurities. The compounds are released only in the presence of light, so Dr. Travis suggests that children with Stargardt’s disease wear dark glasses and limit their exposure to bright light.

Because 10% of people with age-related macular degeneration suffer from some defect in their ABCR genes, they might also benefit from taking these precautions.