Extraordinarily Low Prevalence of Refractive Error and Visual Impairment in Primary and Secondary School Learners in Kabwe District, Zambia

Abstract

Objective: Kabwe District is largely an urban town in the Central Province of Zambia. We aimed to determine the prevalence of refractive errors and visual impairment in primary and secondary school learners in this District. Method: A cross-sectional survey of 41 primary and secondary schools in Kabwe District. The examination included visual acuity (VA) testing, cycloplegic retinoscopy with subjective refinement if indicated, ocular motility testing and anterior segment and fundus examinations in visually impaired children. Results: There was an estimated total of 32,971 learners who were eligible to participate of which 23,915 (72.5%) were enrolled into the survey. Of the 2,424 learners examined by the mobile ophthalmic team, 418 were refracted representing 17.2 %. Of the 418 learners refracted, 359 were diagnosed with refractive errors and prescribed spectacles. The mean spherical equivalent in the right eyes was 0.57 diopter (D) (95% confidence interval [CI], 0.49 - 0.75), and the mean spherical equivalent in the left eyes was 0.59 (95% CI, 0.50 - 0.71). The prevalence of hyperopia was 0.9% (95% CI, 0.4 - 1.3; 207 subjects), and the prevalence of myopia was 0.5% (95% CI, 0.1-1.0; 119 subjects). The majority of learners (98.3%; 95% CI, 97.0 -99.0) had normal unaided binocular VA (at least 6/9 in their better eye). The overall prevalence of any visual impairment (presenting VA 6/9 in the better eye) was 1.7% (95% CI, 1.0 -2.5; 418 subjects) and the overall refractive error prevalence was 1.5% (95% CI, 1.0 -2.3; 359 subjects). In multivariate logistic regression analysis, age (P 0.001) was a significant predictor and female gender (P 0.06) was a borderline significant predictor of the presence of any visual impairment. Conclusions: Visual impairment is not a public health concern in this school-aged population in Kabwe District. The prevalence of uncorrected significant refractive errors among learners is not too high to justify a regular school eye screening programme in schools in Kabwe District.