Prevalence and Causes of Vision Impairment and Blindness in Older Adults in Brazil: The São Paulo Eye Study

Purpose: Investigate prevalence and causes of vision impairment/blindness in older adults in a low-middle income area of Sao Paulo, Brazil. Methods: Cluster sampling, based on geographically defined census sectors, was used in randomly selecting cross-sectionally persons 50 years of age or older. Subjects were enumerated through a door-to-door survey and invited for measurement of presenting and best-corrected visual acuity and an ocular examination. The principal cause was identified for eyes with presenting visual acuity less than 20/32. Results: A total of 4,224 eligible persons in 2,870 households were enumerated, and 3,678 (87.1%) examined. The prevalence of presenting visual acuity ≥ 20/32 in both eyes was 61.6% (95% confidence interval [CI]: 59.4%–63.9%), and 80.4% (95% CI: 78.8%–82.1%) with best correction. The prevalence of visual impairment (< 20/63 to ≥20/200) in the better eye was 4.74% (95% CI: 3.97%–5.53%), and 2.00% (95% CI: 1.52%–2.49%) with best correction. The prevalence of presenting bi...