Visual Acuity Thresholds Associated with Activity Limitations in the Elderly
Purpose: Activity Limitations, which induce loss of autonomy in the elderly, are a major public health problem. We investigated the associations between objectively determined visual impairments and activity limitations and assessed the visual acuity thresholds associated with these restrictions.
Methods: The study sample consisted of 1887 people aged 63 years and over from a population-based cohort. Moderate to severe visual impairment was defined as presenting visual acuity lower than 20/70, according to the World Health Organization (WHO) definition. In addition, we studied mild visual impairment, defined as visual acuity (20/70-20/40). Multivariate logistic regressions were used to estimate the associations between vision and instrumental activities of daily living (IADL) limitations. Using receiver-operating characteristic (ROC) curves, we identified visual acuity thresholds that maximized the Youden index ([sensitivity + specificity]-1) for predicting IADL limitations.