Prevalence of Myopia Among School-age Children in Tunisia

Abstract

Purpose: : To assess the prevalence of myopia among school-age children in Tunisia.

Methods: : A cross-sectional, descriptive survey was conducted among 5-15 aged Tunisian children attending primary urban and rural schools in seven representative departments in the country. A total of 6820 children were selected using stratified random cluster sampling. Cycloplegic refractive error was measured among all children with uncorrected visual acuity less than 9/10. Myopia was defined as spherical equivalent (SE) ≤-0.5 diopters (D) and high myopia as SE≤-6.0 D. All myopic children underwent a complete ophthalmic examination with central corneal thickness and axial length measurement and a questionnaire was used to ascertain outdoor activity, near activity, night light exposure, parental education, and history of myopia in the family.

Results: : The overall prevalence of myopia and high myopia in at least one eye was 3.16% and 0.06% respectively. The prevalence of myopia was 4.1% in urban population and 2.96% in rural population. Twenty seven percent of children with refractive error were myopic. In myopic eyes, the mean uncorrected visual acuity was 0.44± .06 (0.05- 0.9), the mean spherical equivalent was -2.74±2.78D (-0.5 to -20.0), the mean axial length was 24.08±1.28mm (19.5-29.8) and the mean central corneal thickness was 551.26±39.92µm. Seventy nine percent of myopic children were 9 to 12 years old. History of parental myopia was noted in 4.2% of myopic children. Myopic children spent a mean of a 13.58±6.3 hours weekly on near work and a mean of 2.64±2.14 hours weekly on outdoor activities. Time spent on near activities was significantly correlated to the myopic SE (p= 0.02).

Conclusions: : Prevalence of myopia in Tunisian school-age children seems to be similar to that in most non Asian countries. This prevalence is higher in urban population. Severity of myopia increases with time spent on near activities. Additional efforts to identify other environmental factors associated with myopia risk are warranted.

Keywords: myopia • clinical (human) or epidemiologic studies: biostatistics/epidemiology methodology • infant vision