Prevalence of Pediatric Cataract in Asia: A Systematic Review and Meta Analysis

Author: Tariq MA, Uddin QS, Ahmed B, Sheikh S, Ali U, Mohiuddin A. 

Geographical coverage: Asia

Sector: Burden of Disease

Sub-sector: Prevalence

Equity focus: Not reported

Study population: Paediatric patients with cataract

Review type: Effectiveness review

Quantitative synthesis method: Meta-analysis

Qualitative synthesis method: Not applicable

Background:

Paediatric cataract is a significant yet treatable cause of childhood blindness. Global initiatives like “Vision 2020” have prioritised addressing childhood blindness. Studies across Asia have reported varied rates of paediatric cataract, reflecting differences in study design, population, and healthcare infrastructure. Though relatively rare, untreated paediatric cataracts lead to lifelong visual impairment and a substantial socio-economic burden. Early diagnosis and prompt treatment are crucial to prevent long-term disability. Thus, reliable prevalence data are essential for planning effective prevention and intervention strategies. However, large-scale epidemiological data from many Asian countries remain limited, complicating policy development.

Objective:

To conduct a systematic review and meta-analysis to estimate the prevalence of paediatric cataract across Asia.

Main findings:

The review included 35 studies (1997–2020) with a total of 1,160,033 participants. All included studies were cross-sectional in design, with sample sizes ranging from 1,084 to 480,574. Of the included studies, 12 were from India; 9 from China; 3 from Nepal; 2 each from Malaysia and Vietnam; and 1 each from Bhutan, Tibet, Thailand, Cambodia, Laos, Bangladesh, Iran, and Indonesia. The methodological quality was rated high for 26 studies and moderate for 9 studies; none were rated low quality.

Between 1997 and 2020, a total of 217 cases of childhood cataract were identified in the populations studied. The estimated pooled prevalence was 3.78 per 10,000 individuals (95% confidence interval: 2.54–5.26), with substantial heterogeneity (I2 = 89.5%). The country-specific pooled prevalence per 10,000 individuals (from lowest to highest) was as follows:

• Indonesia: 0.60 (95% CI: 0.42–0.87)
• Bangladesh: 0.92 (95% CI: 0.30–2.84)
• Iran: 1.47 (95% CI: 0.37–5.88)
• Bhutan: 2.01 (95% CI: 0.28–14.23)
• Laos: 3.45 (95% CI: 0.49–24.44)
• China: 3.68 (95% CI: 1.13–12.02)
• Thailand: 4.27 (95% CI: 0.60–30.27)
• India: 4.47 (95% CI: 2.43–8.22)
• Malaysia: 5.33 (95% CI: 1.74–10.47)
• Nepal: 5.42 (95% CI: 1.48–19.81)
• Vietnam: 9.34 (95% CI: 5.36–12.24)
• Cambodia: 10.86 (95% CI: 4.88–24.14)

Subgroup analysis by study quality showed no significant difference in prevalence between higher-quality studies (4.55 per 10,000; 95% CI: 3.15–6.58) and moderate-quality studies (2.39 per 10,000; 95% CI: 0.77–7.40), as their confidence intervals overlapped. Sensitivity analyses confirmed the robustness of the results.

Methodology:

Searches were conducted in Medline, Embase, Web of Science, Cochrane Library, Google Scholar, and Index Copernicus to identify population-based cross-sectional or cohort studies on paediatric cataract in Asian countries. Studies published in English between 1990 and 15 July 2021 that reported the prevalence of cataract diagnosed by qualified paediatricians or ophthalmologists were included. Reference lists of included studies and related articles were also scanned for additional publications.

Two reviewers independently screened the articles, extracted relevant data, and critically appraised the quality of the included studies using the JBI Critical Appraisal Checklist for prevalence studies. Disagreements were resolved through discussion or by consulting a third reviewer. The findings were synthesised using a random-effects model meta-analysis. Heterogeneity was assessed using the Cochrane Q test and the I2 statistic, and publication bias was evaluated with a funnel plot and Egger’s asymmetry test. Subgroup analyses were conducted to examine prevalence by country, sample size, publication year, study setting, and study quality. Sensitivity analyses were performed to explore sources of heterogeneity and factors associated with prevalence estimates. A meta-regression was also carried out using covariates such as year of publication, year of data collection, percentage of male participants, response rate, study quality score, and sampling method.

Applicability/external validity: The review noted that its results were drawn from studies in only 12 out of 50 countries in Asia. Data were lacking for many parts of Central Asia and the Middle East, as well as other populous countries like Pakistan and Japan. Therefore, the findings may not be representative of the entire Asian population. In addition, by including only English-language publications, the review introduced a risk of language bias, since English is not the first language in many Asian countries. The authors emphasised that the results should be interpreted with caution.

Geographic focus: The review focused on Asia, with included studies representing data from 12 different Asian countries.

Summary of quality assessment:

Overall, there is medium confidence in the review’s conclusions. On the positive side, the literature search was comprehensive, and inclusion/exclusion criteria were clearly defined. Two reviewers independently extracted data and assessed study quality using standardised tools, with disagreements resolved through discussion or a third reviewer. The characteristics of the included studies were well documented, and the meta-analyses were appropriately performed with attention to heterogeneity. However, the search was limited to English-language studies, and the review did not provide a list of excluded studies. These limitations must be considered when interpreting the review’s findings.