Magnitude and pattern of significant refractive errors among primary school children in Ntcheu and Lilongwe Districts in Malawi

Abstract

A cross sectional school based study was conducted on significant refractive errors in primary school children in Lilongwe and Ntcheu districts in Malawi. The objective of the study was to determine the prevalence and pattern of significant refractive errors in primary school children aged 12 - 15 years in the two districts. Method: All children aged 12 - 15 years attending randomly selected public schools and were present during the survey period were included in the study. The random sampling was a two stage process; first three education zones were randomly selected in the two districts. With lower numbers of school children in the rural areas, three full primary schools were again randomly selected from each of the three zones in Ntcheu and two schools from each of the three zones in Lilongwe. In the selected schools all pupils aged 12 - 15 years were examined. A case was defined as a pupil with a significant refractive error if the visual acuity during the study period was 6112 or worse in the better e e with the use of a Snell ens chart and was improving with refraction. Objective and subjective refraction was done only in the cases. Data was analysed using SPSS version 12.0. A p-value of < 0.05 was considered statistically significant. Results: A total number of 1448 pupils in Lilongwe and 1276 pupils In Ntcheu participated in the study. In Lilongwe the prevalence of refractive errors was 2.3%. Myopia accounted for 1.7%, hypermetropia 0.4% and astigmatism 0.3%. In Ntcheu, an overall prevalence of 2.4% was noted with hypermetropia accounting for 1.4%, myopia only 0.8% and astigmatism 0.1%. The prevalence of myopia was significantly higher in Lilongwe as compared to Ntcheu with a p-value = 0.012. The prevalence of hypermetropia was significantly higher in Ntcheu with a p-value = 0.001. No significant difference was found with the prevalence and pattern of astigmatism in the two districts. Conclusion: A low prevalence of significant refractive errors was found in the two districts in Malawi. There is no significant difference in the refractive error magnitude in the two districts. There is a significant difference however in the patterns of refractive errors in the urban and rural districts, with more myopia in the urban than the rural while hypermetropia is more in the rural setting.