Zimbabwe eyecare and learning (ZEAL)

Abstract

Background: Hyperopia is a common refractive error among young children that, if uncorrected, may cause visual discomfort, impaired near visual function and increased risk of amblyopia and strabismus. In high-income settings, uncorrected hyperopia has been associated with poorer academic outcomes. Evidence from low- and middle-income countries (LMICs), where access to eye care is limited, is scarce. This thesis investigated the prevalence of hyperopia, its association with reading performance, and the short-term effects of spectacle correction among primary schoolchildren in Zimbabwe.

Methods: Four components were conducted: (1) a systematic review and meta-analysis of hyperopia and academic outcomes; (2) a school-based cross-sectional study of the prevalence of moderate-to-high hyperopia (>/=+2.00 D); (3) a cross-sectional study assessing the association between uncorrected hyperopia and reading performance compared with matched emmetropic peers; and (4) a pre-post interventional study evaluating changes in reading after 45 minutes of spectacle wear.

Results: The systematic review found that children with uncorrected hyperopia performed worse academically than emmetropes (standardised mean difference [SMD] -0.18, 95% CI -0.27 to -0.09), with stronger effects on reading-specific skills. No studies were identified from Sub-Saharan Africa. In Zimbabwe, the prevalence of moderate-to-high hyperopia (>/=+2.00 D) was 4.66% (95% CI 3.72–5.77). Among Grade 4 children, uncorrected low hyperopia (>/=+1.50 D but <+2.00 D) was associated with reduced reading fluency (word fluency, P = 0.049; story fluency, P = 0.031). Following 45 minutes of spectacle wear, short-term improvements across grades were observed, with the largest gains observed in Grade 4 for story fluency (+8.42 correct words per minute; P = 0.0005).

Conclusion: Even low levels of uncorrected hyperopia were associated with reduced reading fluency in Zimbabwean children. Short-term improvements following spectacle correction highlight the importance of accessible refractive services. Longitudinal trials are needed to confirm sustained benefits and develop effective school-based screening strategies in LMICs.

Date of Award	Dec 2025
Original language	English
Awarding Institution	Queen's University Belfast
Sponsors	Northern Ireland Department for the Economy
Supervisor	Nathan Congdon (Supervisor), Ving Fai Chan (Supervisor) & Julie-Anne Little (Supervisor)