Hallucinations that are tied to eye disease

In recent days, both the Daily Mail and Wired.com looked at Charles Bonnet Syndrome, a disease characterized by bizarre and vivid visual hallucinations. Interestingly, people who suffer from CBS aren't mentally ill but have visual impairments such as macular degeneration. Even weirder is that the hallucinations often involve characters or things that are much smaller in size than reality. From the Daily Mail:

Following his wife's death six years ago, David Stannard has become accustomed to spending quiet evenings alone at his home in Walton-on-Thames, Surrey.

So it came as a surprise to the 73-year-old when he looked up from his television one evening to discover he was sharing his living room with two RAF pilots and a schoolboy.

'The pilots were standing next to the TV, watching it as if they were in the wings of a theatre,' he says.

An estimated 100,000 people in Britain have Charles Bonnet Syndrome (CBS), which leads to hallucinations. These can include visions of miniature people

'The little boy was in a grey, Fifties-style school uniform. He just stood there in the hearth looking puzzled. He was 18 inches high at most.'

"Visions of 'little people'"

Meanwhile, Wired.com interviewed famed neurologist Oliver Sacks, whose eye disease resulted in his own hallucinations. From Wired.com:

Why do hallucinations occur in people who lose their sight?

Oliver Sacks: When a part of the brain that is used to a sensory input, whether it is visual or auditory, isn't getting it, then it tends to become hyperactive and to generate activity on its own. In the case of musical hallucinations, with [people who go deaf], the brain delves into its memories of music, and so people hallucinate pieces of music, sometimes just a few bars.

The visual ones [in people who go blind] are different. People never recognize the figures or places they see. They're not like bits of memory. They're sort of strange inventions in a way, which the visual brain comes up with.

Q&A: Neurologist Oliver Sacks