By manipulating a virus to carry genetic material for L-opsin production, researchers were able to give red-green sight to two adult male monkeys. The particular type of monkey used in the experiment is known to be unable to see red-green distinction in the natural environment.

From Wired:

Neitz was quick to caution that “there’s a lot of steps before we actually cure a real blindness in people.” Except for the LCA trials, proposed gene therapies for blindness are still in animal-testing stages, if they’ve even progressed that far. The monkeys appear free of any side effects, but safety still needs to be proven. Williams, however, was quicker to speculate. “Ultimately we might be able to do all kinds of interesting manipulations of the retina,” he said. “Not only might we be able to cure disease, but we might engineer eyes with remarkable capabilities. You can imagine conferring enhanced night vision in normal eyes, or engineering genes that make photopigments with spectral properties for whatever you want your eye to see.”

I’ll certainly be interested to see where this technology goes. I remember hearing a bit on NPR a few weeks ago about birds having a 4th color receptor (beyond human’s red, green, blue) in the UV spectrum. I’d like to be able to see a bit more detail in my world…