Ethnic differences in refraction and ocular biometry in a population-based sample of 11-15-year-old Australian children

Abstract

Purpose: To examine the prevalence of refractive error and distribution of ocular biometric parameters among major ethnic groups in a population-based sample of 11-15-year-old Australian children.

Methods: The Sydney Myopia Study examined 2353 students (75.3% response) from a random cluster-sample of 21 secondary schools across Sydney. Examinations included cycloplegic autorefraction, and measures of corneal radius of curvature, anterior chamber depth, and axial length.

Results: Participants mean age was 12.7 years (range 11.1-14.4); 49.4% were female. Overall, 60.0% of children had European Caucasian ethnicity, 15.0% East Asian, 7.1% Middle Eastern, and 5.5% South Asian. The most frequent refractive error was mild hyperopia (59.4%, 95% confidence interval (CI), 53.2-65.6), defined as spherical equivalent (SE) +0.50 to +1.99 D. Myopia (SE-0.50 D or less) was found in 11.9%, 95% (CI 6.6-17.2), and moderate hyperopia (SE> or =+2.00 D) in 3.5%, 95% (CI 2.8-4.1). Myopia prevalence was lower among European Caucasian children (4.6%, 95% CI 3.1-6.1) and Middle Eastern children (6.1%, 95% CI 1.3-11.0) than among East Asian (39.5%, 95%, CI 25.6-53.5) and South Asian (31.5%, 95%, CI 21.6-41.4) children. European Caucasian children had the most hyperopic mean SE (+0.82 D) and shortest mean axial length (23.23 mm). East Asian children had the most myopic mean SE (-0.69 D) and greatest mean axial length (23.86 mm).

Conclusion: The overall myopia prevalence in this sample was lower than in recent similar-aged European Caucasian population samples. East Asian children in our sample had both a higher prevalence of myopia and longer mean axial length.