Visual Impairment in Ethiopia: Systematic Review and Meta-Analysis

Author: Awoke, N., Tekalign, T., Teshome Guta, M., Lenjebo, T. L., Dendir, G., Obsa, M. S., Asinake, G., Lambebo, A. A., & Bekele, M. L.

Geographical coverage: Ethiopia

Sector: Burden of Disease

Sub-sector: Prevalence

Equity focus: Not reported

Study population: Paediatric patients with cataract

Review type: Effectiveness review

Quantitative synthesis method: Narrative synthesis

Qualitative synthesis method: Not applicable

Background: Visual impairment (VI) poses a significant global public health burden, affecting over 2.2 billion people worldwide, with a disproportionate impact on low-income countries. In Ethiopia, VI leads to severe personal, social, and economic consequences, particularly in regions with limited access to eye care services. Globally, most cases of VI are preventable or treatable; however, many remain undiagnosed due to barriers in early detection and intervention. The rising prevalence of VI is associated with factors such as ageing, systemic diseases, and socio-demographic conditions. These challenges are exacerbated in resource-limited settings, where eye health infrastructure is often inadequate. Despite national efforts to strengthen eye care services, Ethiopia continues to face high rates of avoidable blindness and visual disability. Therefore, understanding the burden and distribution of VI in specific regions is critical for implementing targeted public health strategies.

Objective: To present the national prevalence of visual impairment at the end of “VISION 2020”. To evaluate the effectiveness of the “VISION 2020” programme in Ethiopia.

Main findings: The review included 18 studies, comprising 14,953 participants, published between 1997 and 2020. All included studies were cross-sectional and conducted in Ethiopia, with sample sizes ranging from 312 to 2,693 and reported prevalence rates between 1.8% and 36.5%. Regarding the methodological quality, 6 studies were considered to be at low risk of bias, while the remaining were rated as having moderate risk of bias.

The meta-analysis revealed that the pooled prevalence of visual impairment in Ethiopia, after correction for publication bias by Duval and Tweedie’s trim and fill analysis, was estimated to be 6.24% (95% confidence interval [CI]: 2.66 to 9.82). The pooled prevalence of visual impairment among school children and adults in Ethiopia was 6.13% (95% CI: 4.27 to 7.98) and 19.89% (95% CI: 10.85 to 28.93), respectively. The findings indicated that refractive error was the most common cause of VI in Ethiopia (pooled prevalence: 40.84%, 95% CI: 27.10 to 54.59). The other causes in decreasing order of prevalence were cataract, trachoma, glaucoma, and corneal opacity. Among school-age children, amblyopia was the most common cause with a pooled prevalence of 4.68% (95% CI: 1.38 to 7.98).

Methodology:

The searches were conducted in PubMed, Embase, Web of Science, Scopus, and Google Scholar to identify all observational studies conducted in Ethiopia and published in English between 2002 and 2020. The studies were included if they reported the prevalence of visual impairment in Ethiopia. In addition, relevant unpublished studies were found by hand-searching using Google.

Two reviewers independently extracted the relevant data and critically appraised the quality of the included studies using the JBI Critical Appraisal Checklist for prevalence studies. Disagreements between the reviewers were resolved by contacting a third reviewer. The findings were synthesised using a random-effects model meta-analysis. Heterogeneity was assessed using I² statistics, and publication bias using a funnel plot and Egger asymmetry test. Subgroup analysis was performed based on the sample size to minimise the potential random variations between the primary studies. Sensitivity analysis was conducted to explore the effect of a single study on the pooled estimates.

Applicability/external validity: The review only included studies conducted in Ethiopia reporting the prevalence of visual impairment, limiting its applicability to other countries and regions. However, it highlighted the lack of data from some Ethiopian regions, as well as differences in the source of data, the professionals involved in diagnosis, and the methods used to measure visual impairment. The review emphasised caution in interpreting the results of this meta-analysis.

Geographic focus:

Included studies were conducted in Ethiopia.

Summary of quality assessment:

Overall, there is medium confidence in the review’s conclusion. The searches were comprehensive. Inclusion and exclusion criteria were clearly defined, and two reviewers independently extracted data and assessed study quality using established tools, with disagreements resolved through consultation with a third reviewer. Characteristics of included studies were well-documented, meta-analyses were appropriately performed, and heterogeneity was addressed. However, the search was limited to identifying articles published in the English language only, and the review did not provide a list of excluded studies. In addition, the review did not specify the number of reviewers independently involved in the screening, and did not analyse/report the findings by the risk of bias status.