Following up on my previous comments here, scientists have cured color blindness in monkeys:
Neitz’s team injected their monkeys’ eyes with viruses carrying a gene that makes L-opsin, one of three proteins released when color-detecting cone cells are hit by different wavelengths of light. Male squirrel monkeys naturally lack the L-opsin gene; like people who share their condition, they’re unable to distinguish between red and green.
At first, the two monkeys behaved no differently than before. Though quick to earn a grape juice reward by picking out blue and yellow dots from a background of gray dots on a computer screen, they banged the screen randomly when presented with green or red dots.
But after five months, something clicked. The monkeys picked out red and green, again and again. At the biological level, Neitz can’t say precisely what happened — the monkeys, named Sam and Dalton, are alive and healthy, their brains unscanned and undissected — but their actions left no doubt.
They think it will work identically in humans. If so, this means that we could do the same thing for the mutant version of L-opsin that tetrachromat women have, and make anyone (even a man) into a tetrachromat. Or, even more excitingly, a gene for infrared or ultraviolet light.