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

Abstract

Studies suggest a link between visual acuity and visual hallucinations in dementia, but links with specific eye pathologies have not been evaluated. 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 ophthalmological examinations included standardized assessments for cataracts and macular degeneration. Impaired visual acuity and the severity of cognitive impairments were significantly associated with visual hallucinations. No 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. Descriptive follow-up information suggests that an optician's assessment for glasses improves outcome. Glasses and cataract surgery need evaluation as prophylactic or adjunctive treatments for visual hallucinations in patients with probable Alzheimer's disease.