In the new study, Neitz and colleagues inserted a missing gene into the eyes of red-green color-blind monkeys through an injection. The gene piggybacked on a virus that had been defanged so it no longer caused illness.
The findings appear in the Sept. 16 online edition of Nature.
The researchers then tested the monkeys by measuring their responses to colors. About 20 weeks after the treatment, the monkeys, which are still alive and doing well, were no longer color blind and could distinguish between red and green.
Researchers still need to make sure the procedure is safe for humans, Neitz said. Even if it's 99 percent safe, that's not enough because the eyes are involved, he noted.
Still, "we are confident that something is going to happen," he added.
Anand Swaroop, a senior investigator at the National Eye Institute, is color blind himself and uncertain about whether he'd undergo a treatment to fix the condition, especially considering that he's done fine so far.
"Sometimes if you don't know a color, you just don't know a color. Big deal," said Swaroop, who has trouble distinguishing between light green and light yellow.
"Will I let someone inject something into my eye with some viruses when I can otherwise see normally and I have absolutely no other problem? I'm not sure," he said.
The National Library of Medicine has more on color blindness.
SOURCES: Jay Neitz, Ph.D., professor, ophthalmology, University of Washington, Seattle; Anand Swaroop, Ph.D., senior investigator, National Eye Institute, Bethesda, Md.; Sept. 16, 2009, Nature, online
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