Prevalence and determinants of myopia among primary school children in Berbera city, Somaliland

Abstract

Background: Myopia (short sightedness) is a refractive error where the visual acuity is good at near and poor at distance. According to WHO estimates, 12 million children are visually impaired due to refractive errors. Children with myopia face difficulties in schooling, stigmatization and discrimination leading to school drop outs and long-term health challenges at community level. Objective: The overall of objective of this study was to establish the prevalence and determinants of myopia among primary school children in Berbera, Somaliland. Methods: A cross-sectional study design was used to assess the presence and degree of myopia and its determinants. Simple random sampling was used to select schools to be sampled from list of private and public schools and stratified and systematic sampling methods were applied to identify proportions of sample size per school, gender, grades and individuals to be screened. A Snellen’s E chart at 20ft were used for visual acuity. Only children with visual acuity less than the recommended normal vision (20/20) in at least one eye had to undergone further evaluation. Parents or guardians of the children were interviewed to assess the determinants with myopia. The data was entered and analysed in SPSS version 20.0. The univariate and bivariate analysis was performed on all variables and chi-square test or logistic regression were done to determine statistical associations between dependent variables and the key independent variables. The significance level was set at p<0.05 and 95% Confidence limits. Results: A total of 382 children, from 4 primary schools, gave consent to participate in this study. The mean age of the children was 11 + of 2.7 years. Out of these 382 children, 32 (8.4%) children were observed to have visual acuity less than 20/20 feet. Refractive error was the main reason (6.3%) that caused the reduction of the visual acuity of the children. This study established the prevalence rate of myopia as 3.4% (95% CI: 2 - 5%), which was the leading cause of refractive errors followed by Astigmatism of 1.6%. The degree of myopia varied from 20/30 – 20/200 which is equivalent to -0.5 to -2.0 diopters. Statistical associations were observed between children with myopia and type of school children study (2 = 5.101, df = 1, P=0.024) (OR: 4.908; 95% CI: 1.07, 22.449, P=0.04). The majority (84.6%) of the myopic children in this study had either parent or sibling with history of myopia. Myopia was also associated with the duration that children played with computer/mobile phones games per day (2=6.135; df=1; P=0.013) (AOR=4.374, 95% CI: 1.143, 16.740, P-value=0.031) after adjusting for household income and level of education of parents/guardians, watching TV and children’s involvement in outdoor games. In the multiple logistic analysis, no association was found between length of hours that children watched TV per day and myopia (AOR=3.440, 95% CI 0.877;13.490, P-value=0.076). Conclusion: Myopia was the most common condition causing reduction in visual acuity among primary school children in Berbera, which went unnoticed until it was revealed by this study followed by Astigmatism. Recommendation: The Somaliland Ministries of Health and Education should come up with a policy that will establish visual screening programme at primary schools for early detection of visual impairment in children, including myopia and other refractive errors that affect school children’s vision and learning.