Prevalence of Refractive Errors in a Brazilian Population: The Botucatu Eye Study

• Published in: Ophthalmic epidemiology 2009-01, Vol.16 (2), p.90-97
• Main Authors: Schellini, Silvana Artioli, Durkin, Shane R., Hoyama, Erika, Hirai, Flavio, Cordeiro, Ricardo, Casson, Robert J., Selva, Dinesh, Padovani, Carlos Roberto
• Format: Article
• Language: English
• Subjects: Adolescent; Adult; Age Distribution; Aged; Aged, 80 and over; anisometropia; Astigmatism; Brazil; Brazil - epidemiology; Child; Child, Preschool; Cluster Analysis; Cross-Sectional Studies; Humans; hypermetropia; Infant; Middle Aged; myopia; Prevalence; Refraction, Ocular; refractive error; Refractive Errors - epidemiology; risk factors; Sex Distribution; Urban Population - statistics & numerical data; Vision Disorders - epidemiology; Visual Acuity; Visually Impaired Persons - statistics & numerical data; Young Adult
• ISSN: 0928-6586; 1744-5086
• DOI: 10.1080/09286580902737524

Purpose: To determine the prevalence and demographic associations of refractive error in Botucatu, Brazil.Methods: A population-based, cross-sectional prevalence study was conducted, which involved random, household cluster sampling of an urban Brazilian population in Botucatu. There were 3000 individuals aged 1 to 91 years (mean 38.3) who were eligible to participate in the study. Refractive error measurements were obtained by objective refraction.Results: Objective refractive error examinations were performed on 2454 residents within this sample (81.8% of eligible participants). The mean age was 38 years (standard deviation (SD) 20.8 years, Range 1 to 91) and females comprised 57.5% of the study population. Myopia (spherical equivalent (SE) < − 0.5 dropters (D)) was most prevalent among those aged 30-39 years (29.7%; 95% confidence interval (CI) 24.8-35.1) and least prevalent among children under 10 years (3.8%; 95% confidence interval (CI) 1.6-7.3). Conversely hypermetropia (SE > 0.5D) was most prevalent among participants under 10 years (86.9%; 95% CI 81.6-91.1) and least prevalent in the fourth decade (32.5%; 95% CI 28.2-37.0). Participants aged 70 years or older bore the largest burden of astigmatism (cylinder at least −0.5D) and anisometropia (difference in SE of > 0.5D) with a prevalence of 71.7% (95% CI 64.8-78.0) 55.0% (95% CI 47.6-62.2) respectively. Myopia and hypermetropia were significantly associated with age in a bimodal manner (P < 0.001), whereas anisometropia and astigmatism increased in line with age (P < 0.001). Multivariate modeling confirmed age-related risk factors for refractive error and revealed several gender, occupation and ethnic-related risk factors. Conclusions: These results represent previously unreported data on refractive error within this Brazilian population. They signal a need to continue to screen for refractive error within this population and to ensure that people have adequate access to optical correction.