Medical hypothesis, discovery & innovation in optometry

Abstract

Background: Uncorrected refractive error is the most common cause of vision impairment and the second leading cause of blindness worldwide. Its prevalence differs among and within countries. This study was aimed at exploring the pattern and prevalence of refractive error among school children in the Wangsa Maju Township, Kuala Lumpur, Malaysia.
Methods: A stratified, multistage, cluster random sampling in a geographically defined area was employed, and 245 school children, aged 8–12 years, from two primary schools in Wangsa Maju Township, Kuala Lumpur, were recruited. The cross-sectional study employed interviewing, measuring uncorrected distance visual acuity (UCDVA) using the Snellen chart, cycloplegic refraction under a streak retinoscope refined subjectively, and a detailed slit-lamp examination to assess the anterior and posterior segments. Myopia, hyperopia, and astigmatism were defined as spherical equivalent (SE) greater than or equal to - 0.50, SE greater than or equal to + 2.00, and cylindrical greater than or equal to 0.75 D, respectively. Reduced UCDVA was defined as an unaided visual acuity < 6/9.
Results: The mean (standard deviation) age of the participants was 10.42 (1.22) years. The overall prevalence of refractive error was 47.8%. Of 245 screened school children, including 42 (35.9%) boys and 75 (64.1%) girls, 117 had refractive error, with a prevalence of refractive error of 17.1% and 30.6% in boys and girls, respectively. Myopia was the most common type (30.2%), followed by astigmatism (16.3%) and hyperopia (1.2%). The prevalence of reduced UCDVA was 36.3% among the screened school children, attributable to refractive error with a significantly high positive correlation (r = +.721; P < 0.01). Among those with refractive errors, sex differences in the magnitude of refractive errors were not statistically significant in the three types of refractive errors (all P > 0.05).
Conclusions: The prevalence of refractive error among primary school children in Wangsa Maju Township, Kuala Lumpur, Malaysia was 47.8%; girls outnumbered boys, but the magnitude of refractive errors showed no sex differences. The prevalence of reduced UCDVA was 36.3%, attributable to refractive error. Irrespective of sex, myopia had the highest prevalence compared to other refractive errors, and its prevalence increased with age. Future population-based studies are required to address the limitations concerning environmental risk factors for refractive error and the impact of ethnic or familial backgrounds on their prevalence in a similar but larger population using the same protocol.