ORIGINAL ARTICLES
Refractive error study in children: sampling and measurement methods for a multi-country survey

https://doi.org/10.1016/S0002-9394(99)00455-9Get rights and content

Abstract

PURPOSE:

The Refractive Error Study in Children was designed to assess the prevalence of refractive error and vision impairment in children of different ethnic origins and cultural settings.

METHODS:

Population-based cross-sectional samples of children 5 to 15 years of age were obtained through cluster sampling. Presenting, uncorrected, and best-corrected visual acuity, along with refractive error under cycloplegia, were the main outcome measures. Amblyopia and other causes of uncorrectable vision impairment were determined.

RESULTS:

Study design and sample size calculations, survey enumeration and ophthalmic examination methods, quality assurance monitoring, and data analyses and statistical methods are described.

CONCLUSIONS:

The study design, sample size, and measurement methods ensure that the prevalence of age-specific and sex-specific refractive error can be estimated with reasonable accuracy in the target populations. With commonality of methods, a comparison of findings between studies in different ethic origins and cultural settings is possible.

Section snippets

Methods

General economic status and ethnic composition in common with a major segment of the population, familiarity with health and other authorities in the community, and geographic proximity to the study institution were considered in identifying the specific target population within each country. Population-based, cross-sectional samples of the target population were selected through random sampling of children ages 5 through 15 years. For logistical practicality, cluster sampling with

Discussion

Sampling was carried out in such a way that each child living within the target population had an equal chance of being selected for inclusion in the survey. The size of the cluster within which the child resided did not influence the chance of being selected. Drawing the sample from children in schools, instead of from geographically defined populations, would not have produced population-based estimates of refractive error—not just because some children may not be attending school, but the

References (17)

There are more references available in the full text version of this article.

Cited by (270)

  • Reply

    2022, Ophthalmology
  • Outdoor exposure in children from Buenos Aires Province, Argentina

    2022, Archivos de la Sociedad Espanola de Oftalmologia
View all citing articles on Scopus

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

View full text