Visual Impairment and Risk of Dementia: the UK Biobank Study.

ABSTRACT Purpose : The association between visual impairment (VI) and the risk of dementia has been poorly understood. We sought to investigate the VI-dementia relationship in the UK Biobank Study. Design : Prospective cohort study Methods : A total of 117,187 volunteers (aged 40-69 years) deemed free of dementia at baseline were included. Habitual distance visual acuity worse than 0.3 logMAR units in the better-seeing eye was used to define VI. The incident dementia was based on electronically linked hospital inpatient and death records. Results : During a median follow up of 5.96 years, the presence of VI was significantly associated with incident dementia (HR=1.78, 95% CI: 1.18-2.68, P=0.006). There was a clear trend between the severity of VI and the risk of dementia (P for trend=0.002). Conclusions : We found VI was associated with increased risk of dementia, with a progressively greater risk among those with worse visual acuity. Our findings suggested that visual impairment might be a modifiable risk factor for dementia and highlighted the potential value of VI elimination to delay the manifestation of dementia.