Charles Bonnet Syndrome: Epidemiology, Clinical Recognition, and Management of an Overlooked Condition

Charles Bonnet syndrome (CBS) is an important cause of visual hallucinations in people with sight loss, yet fear of stigma and limited clinical awareness can prevent disclosure. This narrative review examines its epidemiology, clinical recognition, mechanisms and management, with particular attention to older adults. The working definition follows visual hallucinations in the International Classification of Diseases, 11th Revision (ICD-11): complex, exclusively visual hallucinations associated with partial or complete visual loss and not explained by a mental or behavioural disorder. Published prevalence estimates vary substantially with recruitment setting, visual function and case definition; rates from low-vision and rehabilitation services should not be applied to unselected ophthalmology populations. Mechanistic studies support involvement of visual cortical activity but do not establish a single causal pathway. Clinical assessment should consider delirium, neurodegenerative disease, medication effects and focal neurological causes before reassurance is offered. Direct enquiry, a clear explanation, treatment of reversible visual impairment and access to rehabilitation form the basis of care, although evidence for their effects on hallucinations is limited. No pharmacological treatment has robust controlled evidence for routine use, and neuromodulation remains experimental. Consistent diagnostic criteria, adequately powered trials, and follow-up that addresses distress and daily functioning are needed.