Literacy is an independent risk factor for vision impairment and poor visual functioning

Abstract

Purpose. People with limited literacy are at increased risks of chronic systemic conditions. The authors therefore investigated the independent contribution of limited literacy on visual impairment and visual function in a large eye survey in Singapore. Methods. The authors undertook a population-based, cross-sectional study of Asian Malays (≥40 years old). Visual impairment was defined as logMAR (logarithm of minimal angle of resolution) visual acuity > 0.30 in the better-seeing eye. Information regarding reading and writing literacy levels and other independent variables, including sociodemographic measures (e.g., education, income), were obtained from a standardized interview. Visual functioning was assessed using a modified and validated version of the Vision-Specific Functioning Scale using Rasch analysis. Results. Of the 3280 participants, 553 (16.9%) had inadequate reading literacy and 688 (21.0%) had inadequate writing literacy. In multivariate analysis, persons with inadequate reading literacy were more likely to have presenting visual impairment (odds ratio [OR] = 2.66; 95% confidence interval [CI] = 1.91 to 3.72; P < 0.001), best-corrected visual impairment (OR = 2.59; 95% CI = 1.70 to 3.96; P < 0.001), and poorer visual functioning (β coefficient = 0.58; 95% CI = 1.57 to 3.02; P < 0.001), even controlling for education, income, and other patients' characteristics. Similar associations were found for inadequate writing literacy. Conclusions. Inadequate literacy is independently associated with visual impairment and poorer visual functioning. Interventions that address literacy may help to reduce socioeconomic disparities in visual impairment. © 2011 The Association for Research in Vision and Ophthalmology, Inc.