Association among visual hallucinations, visual acuity, and specific eye pathologies in Alzheimer's disease: Treatment implications

Objective: Studies suggest a link between visual acuity and visual hallucin ations in dementia, but links with specific eye pathologies have not been e valuated. Method: Fifty patients (20 with visual hallucinations, 30 without ) with probable Alzheimer's disease had an evaluation of psychotic symptoms . Visual acuity was measured before and after refractions, and ophthalmolog ical examinations included standardized assessments for cataracts and macul ar degeneration. Results: Impaired visual acuity and the severity of cognit ive impairments were significantly associated with visual hallucinations. N o patients with normal acuity (6/5 or 6/6 on the Snellen chart) experienced these symptoms. Impaired acuity improved with refraction in 60% (N=12) of the patients with visual hallucinations. Of specific eye pathologies, only cataracts were significantly associated with visual hallucinations. Descrip tive follow-up information suggests that an optician's assessment for glass es improves outcome. Conclusions: Glasses and cataract surgery need evaluat ion as prophylactic or adjunctive treatments for visual hallucinations in p atients with probable Alzheimer's disease.