Prevalence of refractive errors in Vietnamese school children: a meta-analysis.

Clinical relevance: The findings provide greater information on the level of refractive errors in Vietnam, which could assist clinicians and relevant stakeholders to identify high-risk groups and prioritise interventions and preventative measures, contributing to more efficient eye care and cost-effective strategies.

Background/aims: Vietnam, a developing country in Southeast Asia, has shown an increase in myopia progression in recent years. However, the prevalence of refractive errors across the country is unclear. The aim of this study was to estimate the pooled prevalence of different refractions in children across Vietnam, and to explore differences between rural and urban areas, and male and female children.

Methods: A systematic literature search was performed to capture all studies up to April 2024, using online databases including Medline, Web of Science, Scopus, and CINAHL. This was carried out independently by two researchers, following the 2020 Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines (PROSPERO ID: CRD42024524780). The quality assessment of included studies was conducted using the Joanna Briggs Institute Prevalence Critical Appraisal Tool checklist. Meta-analysis was performed to estimate pooled refractive error prevalence, with robustness evaluated using 95% confidence intervals and sensitivity analyses.

Results: 15 school-based studies were identified (children n = 32,211), of which 6 qualified for meta-analysis inclusion (n = 15,825). The pooled refractive error, myopia, and hyperopia prevalences were calculated respectively as 37.60% [95%CI: 27.78-47.43], 28.83% [95%CI: 19.24-38.42], and 0.41% [95%CI: 0.24-0.59] with high heterogeneities of 99%, p<0.01. Refractive error prevalence was greater in urban locations, and female children.

Conclusions: This systematic review and meta-analysis of refractive error prevalence in Vietnamese school children indicates a significant presence of refractive error, especially myopia. However, the large interval ranges suggest that further research using a standardised protocol is required to achieve more accurate estimates.