Charles Bonnet Syndrome

Visual hallucinations in people with vision loss

Overview

Charles Bonnet syndrome refers to vivid visual hallucinations experienced by people who have significant vision loss, without psychiatric illness or cognitive impairment. Images can be simple patterns or complex scenes of faces, people, animals, or buildings, and people typically recognize that they are not real. It is thought to arise because the visual parts of the brain, deprived of normal input, generate their own images. It is named after the Swiss naturalist Charles Bonnet, who described the experiences of his grandfather in the eighteenth century. Reassurance that the hallucinations are not a sign of mental illness is considered an important part of care.