Grotesque faces linked to eye disease

By BBC Science's Fiona Roberts

Ghostly visions and so-called night terrors could be linked to eye disease, according to new research.

Individuals who have lost their sight through eye disease or have had eyes removed often report a frightening array of hallucinations including faces and costumed figures, said Dr Dominic Ffytche of the Institute of Psychiatry, London.

Brain scans carried out while the patients were hallucinating showed activity in specialised regions of the visual cortex.

In 60% of cases, patients reported seeing distorted faces with prominent eyes and teeth, said Dr Ffytche.

"They often see grids, lattices and brickwork, and then plenty more complex forms, often a face, that's characteristically distorted in some way with prominent eyes, prominent teeth and then beyond that whole landscapes, little tableaux populated by people often in costumes," he told the British Association's Festival of Science.

Specialised maps

Forty per cent of patients saw figures in costumes, including people in Edwardian clothes and Napoleonic uniforms, as well as knights in armour.

Dr Ffytche suggested that sightings of ghosts and near-death experiences could have the same biological cause.

He believes the narrow repertoire of images seen in hallucinations is related to the way visual systems are organised in the brain.

"Our visual brains are organised as a series of specialised maps, each map specialised for a different attribute," he said.

"It seems that activities within one of these maps leads to an hallucination of that particular specialised attribute and since our visual brains are all the same, we all seem to have the same sort of hallucinations."

Dr Ffytche hopes now to investigate whether people of different ages, sexes and cultures see the same sorts of things too.