Refractive Errors Survey In Older Adults In An Argentinean City

Abstract

Purpose: : To assess the prevalence of refractive errors in an older population of individuals from the city of Villa Maria, Argentina.

Methods: : Subjects aged 40+ received a demographic, medical and ophthalmologic exam. Visual acuity was obtained with an ETDRS chart for each eye. After pupil dilation with 1% tropicamide, autorefraction was performed. The mean of five measurements was registered. The spherical equivalent (SE) was calculated. As right and left eyes had similar SE (r = 0.812) only the data for the right eyes (OD) were used for the refractive error prevalence analysis. Myopia and hyperopia were defined with a ± 0.50 diopters criterion. Anisometropia was defined as a difference of more than 1 diopter in SE between both eyes.

Results: : This study included 562 subjects, aged 40 to 90 (mean age: 59.9 ± 10.1 years old). Four hundred and seven patients (72.4%) were women. The mean SE of the OD was +0.714 diopters (range -22 to +8.25 diopters) and the power of the cylinder was, on average, 0.858 diopters (greatest 6.50 diopters). In this sample, 13.2 % (95% confidence interval [CI], 10.4-16.0) of subjects were affected by myopia and 62.6% (95% CI, 58.6-66.6) exhibited hyperopia. Myopia prevalence was lower in men (8.4% versus 15.0%) but this difference among genders was not statistically significant (chi² = 4.29, p = 0.117). There were 72 subjects (12.8%, CI 95% 10.0-15.6) with anisometropia greater than 1 diopter, and 142 subjects (25, 2%, CI 95% 21.6-28.8) with astigmatism greater than 1 diopter. Seven subjects were contact lens users.

Conclusions: : The present study shows the prevalence of refractive error in an adult population of Hispanic residents in Argentina. The prevalence of myopia was low in comparison with the hyperopic refractive defect that was commonly found in the population studied.

Keywords: clinical (human) or epidemiologic studies: prevalence/incidence • refraction • visual acuity