ORIGINAL ARTICLES
Refractive error study in children: results from La Florida, Chile

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Abstract

PURPOSE:

To assess the prevalence of refractive errors and vision impairment in school-age children in a suburban area (La Florida) of Santiago, Chile.

METHODS:

Random selection of geographically defined clusters was used to identify a representative sample of children 5 to 15 years of age. Children in the 26 selected clusters were enumerated through a door-to-door survey and invited to report to a community health clinic for examination. Visual acuity measurements, cycloplegic retinoscopy, cycloplegic autorefraction, ocular motility evaluation, and examination of the external eye, anterior segment, media, and fundus were done from April through August 1998. Independent replicate examinations of all children with reduced vision and a sample of those with normal vision were done for quality assurance monitoring in six clusters.

RESULTS:

A total of 6,998 children from 3,830 households were enumerated, and 5,303 children (75.8%) were examined. The prevalence of uncorrected, presenting, and best visual acuity 0.50 (20/40) or worse in at least one eye was 15.8%, 14.7%, and 7.4%, respectively; 3.3% had best visual acuity 0.50 or worse in both eyes. Refractive error was the cause in 56.3% of the 1,285 eyes with reduced vision, amblyopia in 6.5%, other causes in 4.3%, with unexplained causes in the remaining 32.9%. Myopia −0.50 diopter or less in either eye was present in 3.4% of 5-year-old children, increasing to 19.4% in males and 14.7% in females by age 15. Over this same age range, hyperopia 2.00 diopters or greater decreased from 22.7% to 7.1% in males and from 26.3% to 8.9% in females. Females had a significantly higher risk of hyperopia than males.

CONCLUSIONS:

Refractive error, associated primarily with myopia, is a major cause of reduced vision in school-age children in La Florida. More than 7% of children could benefit from the provision of proper spectacles. Efforts are needed to make existing programs that provide free spectacles for school children more effective. Further studies are needed to determine whether the upward trend in myopia continues far beyond 15 years of age.

Section snippets

Methods

The study population was selected by random cluster sampling. La Florida was segmented into 317 clusters, each with a population of approximately 1000 inhabitants based on the 1992 census, including approximately 200 children ages 5 to 15 years. Clusters were defined by grouping community blocks, using streets as cluster boundaries. Each such cluster was contained entirely within a single neighborhood community. Twenty-six clusters were selected randomly with equal probability from the 317. The

Results

Within the 26 clusters, 3,830 houses with children 5 to 15 years of age were identified: 1,740 (45.4%) had one child; 1,377 (36.0%) had two children; 481 (12.6%) had three children; and 232 (6.1%) had four or more children. Six families had eight children. No children in the 5 to 15 year age range were found in 4,042 of the enumerated households. Information regarding children in the household was refused, at each of up to three visits, for an additional 1,464 houses. Another 214 houses were

Discussion

An uncorrected visual acuity of 0.50 or worse was present in at least one eye in 15.8% of the study population. With best vision, this number decreased to 7.4%. Because few children wore glasses, 7.3% of the cohort could benefit from the provision of correcting lenses. The prevalence of best-corrected visual acuity 0.50 or worse in the better eye, 3.3% (173 of 5,265), was higher than that reported in the China or Nepal surveys.2, 3

Much of the vision loss beyond that attributed to refractive

Acknowledgements

The authors thank Luz Maria Nuñez for her efforts in coordinating the fieldwork and to Luis Bustos for assistance with data management. The authors also acknowledge the clerical assistance of Jeanne King, National Eye Institute, in the preparation of this manuscript.

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This study was supported by the World Health Organization under National Institutes of Health Contract N01-EY-2103, Bethesda, Maryland.

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