Abstract
Charles Bonnet syndrome (CBS) is a condition where cognitively normal individuals with sight impairment experience simple and/or complex visual hallucinations. The exact pathogenesis of CBS is unknown; however, deafferentation is often recognised as a causal mechanism. Studies have provided insight into the multifaceted impact of CBS on wellbeing. Onset of CBS may cause distress among those believing visual hallucinations are indicative of a neurological condition. Hallucinatory content is often congruent with the emotional response. For example, hallucinations of a macabre nature typically result in a fearful response. Visual hallucinations may be highly disruptive, causing everyday tasks to become challenging. Clinical management relies on forewarning and pre-emptive questioning. Yet, knowledge and awareness of CBS is typically low. In this review, we provide a summary of the social and psychological implications of CBS and explore recent developments aimed at raising awareness and improving patient management.
Highlights
Swiss neurologist Georges de Morsier is credited with coining the term Charles Bonnet syndrome (CBS) recognising the occurrence of visual hallucinations among individuals with impaired vision
The condition is characterised by the presence of simple or complex visual hallucinations in patients with some form of sight impairment, occurring without conscious volition and with retained insight that what is observed during an episode is not real.[1]
Accurate diagnosis of CBS relies on detailed elucidation of the clinical features and an understanding of alternative phenomena such as peduncular hallucinosis, a rare form of visual hallucinations often described in relation to both vascular and infective lesions of the mesencephalon and thalamus
Summary
Swiss neurologist Georges de Morsier is credited with coining the term Charles Bonnet syndrome (CBS) recognising the occurrence of visual hallucinations among individuals with impaired vision. CBS has been estimated to occur in 11–15% of those with sight loss.[2] these estimates vary widely depending on the study, with more recent evidence indicating that as many as one in five low vision patients experience visual hallucinations.[3] This variability reflects some the clinical challenges associated with CBS; for example, there has been a long-standing lack of consistency regarding diagnostic criteria.[1] Visual hallucinations have a broad differential diagnosis, for instance, photopsia (presence of flashes or floaters) may precede other serious ocular conditions, such as retinal tears or detachment. Old age and significantly reduced visual acuity are often regarded as contributing factors;[4,5] a number of studies have observed visual hallucinations in the absence of these factors.[6,7,8,9,10,11,12]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
