Charles Bonnet syndrome in patients referred for cataract surgery

PURPOSE: To investigate the prevalence and clinical characteristics of Charles Bonnet Syndrome (CBS) in patients referred for bilateral cataract surgery. METHODS: This prospective, cross-sectional clinical trial included 391 patients attending cataract assessment at a single-center tertiary cataract clinic. After clinical examination, participants were screened for presence of visual hallucinations (VHs). Participants experiencing complex VHs were further questioned regarding characteristics of their hallucinatory experiences to properly determine if they were attributable to CBS. CBS was defined as complex visual hallucinations with retained insight, no medical history or medication known to cause hallucinations and not limited to hypnagogic or hypnopompic states (hallucinations happening shortly before falling asleep and/or shortly after waking up). RESULTS: Nineteen (4.9%) patients experienced complex VHs. Of these, 11 (2.8%) were diagnosed with CBS while 8 (2.1%) had complex hypnagogic and/or hypnopompic VHs. Multivariable logistic regression analysis identified lower best-corrected visual acuity (BCVA) in the better seeing eye as a significant predictor of CBS. When excluding participants with a BCVA>0.3, prevalence of complex VHs rose to 10.0%. Three of the patients with CBS (27.3%) had ocular comorbidities: two had exudative age-related macular degeneration (AMD), and one had drusenoid AMD. In the overall cohort, twenty-four patients (6.1%) reported prior knowledge of CBS. CONCLUSION: CBS was observed in a clinically relevant minority of cataract patients requiring bilateral surgical intervention. Given the high prevalence of cataract among the elderly, this study highlights the importance of healthcare personnel being aware of CBS and other complex VHs and their potential consequences for cataract patients.