Blind man's hallucinations

NPR has an interesting audio and written feature on David Stewart, a blind man who also has Charles Bonnet syndrome, a condition marked by incredibly vivid hallucinations. He first recognized that something wasn't quite right while listening to the book 1776 on tape. He suddenly "saw" one of the sailors described in the book in a "highly detailed, very real-like hallucination." The sailor winked at him. From NPR:

A surprisingly large percentage of people who lose sight start seeing things, says ophthalmologist Jonathan Trobe of the University of Michigan.

"The brain is doing a mash-up of stored visual memories," says Trobe. When visual cells in the brain stop getting information – which happens when your rods and cones stop working – the cells compensate, he explains. If there's no data coming in, they make up images. They hallucinate.

Trobe thinks maybe 10 percent of all people who go blind will have this experience. "It's very common," he says.

Link to NPR, Link to 2004 Fortean Times article "Eye Spirits and Macular Degeneration" (via Mind Hacks)