Charles Bonnet Syndrome

The Charles Bonnet Syndrome (CBS) is a condition that causes patients with visual loss to have complex visual hallucinations, first described by Charles Bonnet (1720-1792) in 1760 and first introduced into English-speaking psychiatry in 1982.

Patients, who are mentally healthy people with often significant visual loss, describe vivid, complex recurrent visual hallucinations. One characteristic feature of these hallucinations is that they usually are ‘lilliputian’ in nature[1], which means that the hallucinations in which the characters or objects are smaller than normal. The most common hallucination is of faces or cartoons. Others report images of complex coloured patterns and images of people or animals. The hallucinations also often fit into the person's surroundings.

Sufferers understand that the hallucinations are not real, and the hallucinations are only visual, that is, they do not occur in any other senses, e.g. hearing, smell or taste.

Among older adults with significant vision loss, the prevalence of Charles Bonnet syndrome has been reported to be between 10% and 40[2].

[1] Schneider et al: Strange sightings: is it Charles Bonnet syndrome? in Nursing - 2013
[2] Vukicevic et al: Butterflies and black lacy patterns: the prevalence and characteristics of Charles Bonnet hallucinations in an Australian population in Clinical Experimental Ophthalmology - 2008