Epidemiology of visual impairment and blindness in Africa: a systematic review and Bayesian meta-analysis

Background
Estimates of visual impairment (VI) and blindness in Africa are limited by outdated surveys, regional data gaps, and methodological heterogeneity. This study aimed to determine the pooled prevalence and leading causes of VI and blindness, disaggregated by key demographics, to inform public health action.

Methods
A systematic review and Bayesian hierarchical meta-analysis of population-based studies in Africa was conducted. PubMed, Scopus, and Web of Science databases were searched. Studies reporting prevalence of VI or blindness were included. Data were extracted, age-standardized to 50 years, and analyzed to generate pooled estimates by subregion, sex, setting, and cause.

Findings
A total of 91 studies (340,182 individuals) were included. The age-standardized prevalence was 9.47% (95% CrI: 3.88%–20.14%) for VI and 1.89% (95% CrI: 1.24%–2.91%) for blindness. Prevalence estimates were higher in rural than urban settings and in females compared to males, though credible intervals overlapped for sex. Cataract was the leading cause of blindness (1.22%, 95% CrI: 0.77%–1.90%) and a major cause of VI (5.40%, 95% CrI: 1.70%–15.21%), followed by uncorrected refractive error. A significant increase in the odds of VI was observed over time (OR 1.72 per decade, 95% CrI: 1.05–2.89), while blindness prevalence remained stable.

Interpretation
Treatable conditions, notably cataract and refractive error, account for most vision loss in Africa. The rising burden of VI, coupled with persistent geographic and gender inequities, underscores the need to expand surgical and refractive services, strengthen targeted delivery, and improve surveillance in underserved regions.

Funding
None.