Prevalence and risk factors of myopia amongst Grade 8 learners in the Vhembe district, South Africa

Abstract

Background: Myopia is the most common cause of refractive errors in both adults and children in many countries. However, it is not a simple refractive error but sometimes and eyesight-threatening disorder. The disorder has a great impact on public health and the socio-economic well-being of people, particularly children.

Aim: The study aimed to assess the prevalence of myopia amongst secondary school learners.

Setting: The study was conducted in the Vhembe District, South Africa.

Methods: A cross-sectional study was carried out amongst 297 Grade 8 students of 13 to 14 years of age. The students were selected using a multi-stage-stratified cluster sampling technique from three secondary schools. Two public secondary schools and one private secondary school. The learners’ socioeconomic background, type of school and parental myopia were assessed by a questionnaire before visual acuity assessment. Learners with visual acuity of less than or equal to 6/12 in the worse eye, who showed vision improvement with pinhole, underwent non-cycloplegic retinoscopy and subjective refraction were selected. Myopia was defined as a spherical equivalent of less than or equal to −0.50 dioptre (D). Data were analysed using descriptive statistics.

Results: A total of 289 learners completed the study (156 aged 14 years and 133 aged 13 years). A total of 30 learners were identified to have myopic refractive error making the prevalence of 10.4%. Of the 154 females, 14 (47.0%) had myopia, whilst 16 (53.0%) of the 135 males had myopia making males slightly more myopic than females. From the total learners diagnosed to have refractive error (n = 40), myopia constituted 30/40 (75.0%) of the learners indicating that it is the commonest type of refractive error amongst secondary learners. Myopia was more common amongst older age children (14 years; 57.0%). About 18 (60.0%) participants were from the urban area. A total of 17 (57%) of the myopic learners attended private school and about 63% of the participants’ parents were myopic.

Conclusion: Spending more time indoor and continuous reading without resting are risk factors of myopia whilst increased outdoor activities were observed as protective environmental factors against myopia in secondary school learners. Doing more outdoors activities may be beneficial to protect against myopia onset.