Prevalence and Causes of Visual Impairment and Blindness in Adults Aged 45 Years and Older from Parintins: The Brazilian Amazon Region Eye Survey

ABSTRACT

Purpose

To determine the prevalence and causes of visual impairment and blindness in adults aged 45 years and older from Parintins, Brazilian Amazon Region.

Methods

A random cluster sampling method was used to identify subjects 45 years of age and older from urban and rural census sectors of Parintins city, Amazonas State, from March 2014 to May 2015. Participants underwent a detailed ocular examination, including presenting (PVA) and best corrected visual acuity (BCVA). The main cause of PVA<20/32 per eye was determined.

Results

A total of 2384 subjects were enumerated and 2041 (85.6%) examined. The prevalence of presenting mild visual impairment – MiVI (<20/32 – ≥20/63) in the better-seeing eye was 17.0% [95% CI: 15.3–18.7%], and 8.5% [95% CI: 7.3–9.7%] with best correction. The prevalence of presenting moderate visual impairment – MVI (<20/63 – ≥20/200) was 18.4% [95% CI: 16.2–20.6%], and 6.9% [95% CI: 5.8–8.0%] with best correction. The prevalence of presenting bilateral VA <20/200 was 4.3% [95% CI: 3.6–5.0%], and 3.3% [95% CI: 2.5–4.0%] with best correction and increased with older age. Cataract (47.8%) and glaucoma (7.5%) were its main causes. In less severely affected eyes, uncorrected refractive errors (MVI: 42.6%; MiVI: 79.0%), cataract (MVI: 40.6%; MiVI: 13.7%) and pterygium (MVI: 7.6%; MiVI: 2.7%) were the main causes.

Conclusions

Most cases of visual impairment in Parintins are either preventable or treatable, and public health initiatives should target cataract surgical services and refraction with spectacle provision.

KEYWORDS:

• visual impairment
• blindness
• prevalence
• cataract
• refractive error

Conflict of Interest

No conflicting relationship exists for any author.

Additional information

Funding

This paper was funded by Instituto da Visão - IPEPO, São Paulo, SP; Fundação Piedade Cohen, Manaus, AM; Conselho Nacional de Desenvolvimento Científico e Tecnológico – CNPq, Brasília, Brasil, Programa Ciência sem Fronteiras (Grant # 402120/2012-4 to SRS, SM and JMF; Research Scholarships to SRS and RBJ); Fundação de Amparo à Pesquisa do Estado de São Paulo, FAPESP, São Paulo, Brasil (Grant # 2013/16397-7 to SRS); SightFirst Program – Lions Club International Foundation (Grant #1758 to SRS). The sponsor or funding organization had no role in the design or conduct of this research.