Global Prevalence and Causes of Visual Impairment and Blindness in Children

Abstract

Purpose: To determine the global prevalence and common causes of visual impairment (VI) and blindness in children. Methods: In this meta-analysis, a structured search strategy was applied to search electronic databases including PubMed, Scopus, and Web of Science, as well as the list of rEFERENCES in the selected articles to identify all population-based cross-sectional studies that concerned the prevalence of VI and blindness in populations under 20 years of age up to January 2018, regardless of the publication date and language, gender, region of residence, or race. VI was reported based on presenting visual acuity (PVA), uncorrected visual acuity (UCVA), and best corrected visual acuity (BCVA) of equal to 20/60 or worse in the better eye. Blindness was reported as visual acuity worse than 20/400 in the better eye. Results: In the present study, 5711 articles were identified, and the final analyses were done on 80 articles including 769,720 people from twenty-eight different countries. The prevalence of VI based on UCVA was 7.26% (95% confidence interval [CI]: 4.34%–10.19%), PVA was 3.82% (95% CI: 2.06%–5.57%), BCVA was 1.67% (95% CI 0.97%–2.37%), and blindness was 0.17% (95% CI: 0.13%–0.21%). Refractive errors were the most common cause of VI in the subjects of selected articles (77.20% [95% CI: 73.40%–81.00%]). The prevalence of amblyopia was 7.60% (95% CI: 05.60%–09.10%) and congenital cataract was 0.60% (95% CI: 0.3%–0.9%). Conclusion: Despite differences in the definition of VI and blindness, based on PVA, 3.82%, and based on BCVA, 1.67% of the examined samples suffer from VI.

Global prevalence of developmental disabilities in children and adolescents: A systematic umbrella review

“…The most common reason for exclusion was the absence of global and regional prevalence estimates for children and adolescents. Of the 10 articles selected for inclusion that reported pooled global prevalence estimates of disabilities ( 10 – 12 , 23 – 29 ), three articles focused on ASD and the remaining seven articles were each focused on one disability. A summary of the selected reviews is presented in Table 1 .…”

“…One systematic review by Yekta et al published in 2022 met our inclusion criteria ( 12 ). The review included 80 studies published between 1971 and 2018 from 28 countries, 19 of which are LMICs.…”

“…Evidence from global health databases suggests that about 240 million children globally have developmental disabilities based on parent-reported functional difficulties compared to 290 million children using statistical modeling techniques (3). Although systematic reviews and meta-analyses are more suited for evaluating the effectiveness of health interventions and accuracy of diagnostic tests from clinical trials (7)(8)(9), it is not uncommon to use pooled prevalence estimates from individual primary studies as proxies for the global and regional prevalence of children with developmental disabilities (10)(11)(12)(13). However, it is unclear how such prevalence estimates compare with those reported in global health databases from the World Health Organization (WHO), United Nations Children's Fund (UNICEF), the World Bank or the Global Burden of Disease (GBD) Study published by the Institute for Health Metrics and Evaluation (IHME), USA.…”

Body mass index and visual impairment in Israeli adolescents: A nationwide study

“…[17][18][19] BCVA <6/9 in one eye defined unilateral VI; BCVA <6/9 in both eyes defined bilateral VI; BCVA ≥6/9 in both eyes defined normal vision. [8][9][10][11]…”

“…6,7 Global data on the prevalence of visual impairment in young populations are limited, 8 with recent estimates suggesting a prevalence near 1% in developed countries. [9][10][11] While the Israeli National Registry of the Blind consistently reports annual incidence rates for childhood blindness and severe VI, 12,13 specific prevalence metrics for VI of all severities within the Israeli paediatric population are not available.…”