Restoring Sight to the Blind
Hope may be at hand for people with age-related macular degeneration (AMD) as well as those with the inherited form of blindness called retinitis pigmentosa. Scientists led by neurobiologist Richard Kramer of the University of California, Berkeley were able to temporarily restore some vision to blind mice by injecting a chemical called AAQ that makes the retina sensitive to light. The findings will be published on Thursday, July 26, 2012 in the journal Neuron.
A release from the university quoted Kramer as saying that the reason a temporary fix is valuable is that "you can turn it on and off and turn on or off neural activity." Kramer continued by saying, "The advantage of this approach is that it is a simple chemical, which means that you can change the dosage, you can use it in combination with other therapies, or you can discontinue the therapy if you don't like the results. As improved chemicals become available, you could offer them to patients. You can't do that when you surgically implant a chip or after you genetically modify somebody.
When the team injected small amounts of AAQ into the eyes of the blind mice, they knew that they had restored light sensitivity to the mice because pupils contracted in bright light. Also, the mice avoided light, which is a typical rodent behavior that's impossible unless the animals can see some light.
"We still need to show that these compounds are safe and will work in people the way they work in mice," Van Gelder said. "But these results demonstrate that this class of compound restores light sensitivity to retinas blind from genetic disease."