The Charles Bonnet syndrome: a large prospective study in The Netherlands. A study of the prevalence of the Charles Bonnet syndrome and associated factors in 500 patients attending the University Department of Ophthalmology at Nijmegen

The aims were to determine the prevalence of the Charles Bonnet syndrome (CBS) in low-vision patients and analyse possible associated ophthalmic and sociodemographic factors. A semi-structured interview on visual hallucinations was given to 300 adult low-vision patients and 200 elderly general ophthalmic patients. Positive cases were examined with the Geriatric Mental State Schedule and the Mini Mental State Examination. Diagnostic criteria were as follows: complex, persistent, or repetitive visual hallucinations; full or partial retention of insight; no hallucinations in other modalities; and no delusions. Ophthalmic and sociodemographic data were gathered for all patients. The prevalence of CBS in low-vision patients was 11%. CBS was significantly associated with an age over 64 years and a visual acuity in the best eye of 0.3 or less. No significant associations with ophthalmic diagnoses, patient sex, marital status, or social circumstances were found. Our findings support association of CBS with sensory deprivation and advanced age.