School-based vision screening for early detection of refractive errors among children aged 5-14 years in Mathare and Kibera, Nairobi, Kenya

Background: Uncorrected refractive errors are a major cause of avoidable visual impairment among school-aged children, yet many children in underserved urban settings remain undiagnosed. This study evaluated school-based vision screening for early detection of refractive errors among children aged 5-14 years in Mathare and Kibera, Nairobi, Kenya. Methods: A descriptive analytical cross-sectional study using a mixed-methods approach was conducted from 17th April to 30th May 2026 in seven selected primary schools. A total of 1,050 children underwent visual acuity screening and confirmatory refraction where indicated. Quantitative data were analyzed using descriptive statistics, chi-square tests and logistic regression in STATA 17. Qualitative data from focus group discussions and key informant interviews were analyzed thematically. Results: Overall, 201 children had refractive errors, representing 19.1% of those screened (95% CI: 16.9-21.6). Myopia was the predominant refractive error (86.1%), followed by hyperopia (12.9%) and astigmatism (1.0%). Refractive error proportions differed significantly across schools (p=0.001). Public school attendance was associated with lower odds of refractive error compared with private school attendance (OR=0.64, 95% CI: 0.42-0.98; p=0.040), while increasing age was associated with higher odds (OR=1.07, 95% CI: 1.01-1.14; p=0.032). Key barriers to referral uptake included cost, limited awareness, stigma, weak follow-up systems and transport constraints. Conclusions: School-based vision screening was feasible and identified a substantial burden of previously undiagnosed refractive errors. Integration of routine eye screening into school health services, strengthened referral systems and affordable spectacles are needed in informal settlements.