WHEN Delvin Kehoe looked at himself in the mirror earlier this year, he was appalled by what he saw. Instead of the smiling face of a man in his 30s, he was greeted instead by the grimace of a 59-year-old. But Kehoe was not suddenly feeling his age, nor even reviving from a long coma. He was simply seeing his reflection for the first time in 20 years.
His is one of several miracle tales sweeping the ophthalmological community. Years after losing their sight to a degenerative disease – in Kehoe’s case, retinitis pigmentosa – patients have been given an eye implant that restores their vision. These “visual prosthetics” work by artificially stimulating the retina with electrical signals that are fed down the optic nerve into the visual cortex. Of the 20 people who have received such implants worldwide, some claim that they deliver such clear and detailed images that they can not only see their reflections, but can make out objects as tiny as ants on a pavement. One man even felt confident enough to drive his car, albeit on private property.
But if the implants really work that well, why aren’t millions of blind people lining up for them? The truth is that, despite the compelling stories, many researchers are starting to question how well the current technology really works. For every Delvin Kehoe, there are several others whose visual prosthetics deliver little more than dots and fuzzy patches. For these people, the environment around them resembles at best a game of space invaders, full of grainy, dotted images that bear little resemblance to reality.
Now one researcher is proposing