Ehh...critical period, who needs it.

I'm not sure if this story will be available to people without a subscription to nature, but here's a part of the story. It's pretty interesting. Ohh and I've always loved Joe Paterno's glasses.

Doctors gave SK his first pair of glasses in July 2004. He had been too poor to afford a pair before — but then he was a 29-year-old blind man, what use were glasses to him? Had he been given glasses as a child they might have helped him overcome his congenital aphakia — an extremely rare condition in which the eyeball develops without a lens. Yet his chances of being diagnosed, let alone treated, in the poor Indian village in which he was born were slim. As a result, SK was living in a 'hostel for the blind' with no running water when the doctors arrived from New Delhi. SK's doctors weren't sure how much sight he would gain, or if he would comprehend what he saw. For the first year, he had only the most basic visual skills. He could recognize simple two-dimensional objects but anything three-dimensional, even an everyday object such as a ball, was beyond him. All this was consistent with the idea of a 'critical period' in vision: that if you haven't learned to see by a certain age, you never will. But 18 months after getting his glasses, SK surprised everyone. He had begun to make sense of his world, building his visual vocabulary through experience and recognizing more complex objects with varying colours and brightness. In doing so, he turned one of the most fundamental concepts in neuroscience on its head.