Visual Impairment and Risk of Dementia: the UK Biobank Study

ABSTRACT INTRODUCTION 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. 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). DISCUSSION Visually impaired individuals were more likely to develop incident dementia, with a progressively greater risk among those with worse visual acuity. Our findings highlight the value of regular vision screening and elimination of VI. HIGHLIGHTS The association between VI and dementia has been poorly understood; VI is associated with incident dementia in non-demented adults; There is a clear trend between the severity of VI and the risk of dementia; VI may be a marker of increased dementia risk. RESEARCH IN CONTEXT SYSTEMATIC REVIEW We searched and reviewed the literature using traditional sources (e.g., PubMed and GoogleScholar). While the association between VI and cognitive function/decline are increasingly studies, investigation of the association between VI and the risk of dementia has been largely overlooked. INTERPRETATION We found that visually impaired individuals were more likely to develop incident dementia, with a progressively greater risk among those with worse visual acuity. Our findings imply that VI may be an important marker of dementia. FUTURE DIRECTIONS These findings call for more studies to investigate (a) the role of visual acuity changes on the risk of dementia; (b) the relationship between other components of visual function and incident dementia; (c) the relationship between eye diseases and incident dementia; and (d) the potential benefits of vision rehabilitation on dementia prevention.