Prevalence of Charles Bonnet syndrome in patients with age-related macular degeneration: systematic review and meta-analysis

Age-related macular degeneration (AMD) is the most common cause of visual impairment in the developed world. A number of patients experience complex lifelike visual experiences-Charles Bonnet syndrome (CBS). In this systematic review, our aim was to provide an overview of the CBS literature in relation to AMD, to determine the prevalence of CBS in patients with AMD and to provide an overview of associated demographical and clinical aspects. We searched the literature databases PubMed/MEDLINE, EMBASE, Web of Science, the Cochrane Central, and PsycINFO on 22 March 2019 for studies evaluating the prevalence of CBS in patients with AMD. Two independent authors extracted the data and evaluated risk of bias. Studies were reviewed qualitatively in the text and quantitatively in a meta-analysis including subgroup analyses for differences between demographic and clinical factors. We identified 18 studies with data on >4303 patients with AMD. We found an overall prevalence of CBS of 15.8% (95% confidence interval: 11.0%-21.2%). When looking at consecutively recruited patients with neovascular AMD from the clinic, prevalence of CBS was 7.2% (95% confidence interval: 4.3%-10.6%). Among visitors to visual rehabilitation centres, prevalence of CBS was 31.6% (95% confidence interval: 21.7%-42.3%). Taken together, we find that CBS is rather common in patients with AMD.