Prevalence of visual impairment, blindness, ocular disorders and cataract surgery outcomes in low-income elderly from a metropolitan region of São Paulo - Brazil

Abstract

Purpose: To determine prevalence and causes of visual impairment, blindness, ocular disorders and cataract surgery outcomes in a low-income elderly population from a metropolitan area in the city of São Paulo, Brazil. Methods: Observational study where 801 individuals of 60 years and older underwent presented and best corrected visual acuity measurements as well as ophthalmologic examination. Definition of blindness and visual impairment followed studies conducted in Nepal, China and India. Results: The prevalence of presented and best-corrected visual acuity worse than 20/400 in both eyes was 1.38% (95% CI: 0.69% - 2.45%) and 1.25% (95% CI: 0.60% - 2.29%). Prevalence of visual impairment considering presented and best-corrected visual acuity was, respectively, 24.16% (95% CI: 21.22% - 27.28%) and 12.77% (95% CI: 10.53% - 15.28%). Cataract was the main cause of blindness (30.00%) and visual impairment (54.90%). A total of 54 participants (6.74%) had previous cataract surgery and, with best-corrected visual acuity, 35.12% showed visual acuity better than 20/60 in both eyes. Rates of visual impairment and blindness in this low-income elderly population were high. There was a considerable decrease in prevalence after optical correction emphasizing the importance of uncorrected refractive errors. Conclusion: Cataract was the main cause of blindness; poor visual outcomes in eyes previously operated for cataract reinforce the need to seek good quality cataract services and to provide careful postoperative follow-up.