Background: Previous studies have reported that reduced visual acuity is associated with functional dependence in older persons. The purpose of this study was to determine whether components of vision impairment besides reduced acuity contribute to reduced functional independence.
Methods: Community dwelling adults aged 65 years and older were administered a battery of vision tests including distance acuity, letter contrast sensitivity, disability glare, and stereoacuity. A physical function questionnaire assessed self-reported difficulty with activities of daily living (ADL's), Instrumental activities of daily living (IADL's), and mobility activities. A visual function questionnaire assessed self-reported difficulty with a wide variety of everyday visual activities.
Results: Multiple logistic regression analysis showed that reduced acuity and reduced contrast sensitivity were independently associated with an overall vision disability score. Acuity was associated with difficulty in tasks requiring good resolution and adaption to changing light conditions, whereas contrast sensitivity was associated with difficulty in tasks requiring distance judgments, night driving, and mobility. Glare and stereoacuity were not associated with self-reported disability.
Conclusions: Reduced acuity and contrast sensitivity are significant risk factors for self-reported disability.