Charles-Bonnet syndrome (CBS) is characterised by persistent or recurrent complex hallucinations (usually visual or auditory), occurring in clear consciousness. This is generally against a background of visual impairment (although visual impairment is not mandatory for a diagnosis). Insight is usually preserved. This must occur in the absence of any other significant neuropsychiatric disturbance.


Risk factors include:
  • Advanced age
  • Peripheral visual impairment
  • Social isolation
  • Sensory deprivation
  • Early cognitive impairment

CBS is equally distributed between sexes and does not show any familial predisposition. The most common ophthalmological conditions associated with this syndrome are age-related macular degeneration, followed by glaucoma and cataract.

Clinical features

Well-formed complex visual hallucinations are thought to occur in 10-30 per cent of individuals with severe visual impairment. Prevalence of CBS in visually impaired people is thought to be between 11 and 15 per cent.


Around a third find the hallucinations themselves an unpleasant or disturbing experience. In a large study published in the British Journal of Ophthalmology, 88% had CBS for 2 years or more, resolving in only 25% at 9 years (thus it is not generally a transient experience).