Purpose Amblyopia is a leading cause of vision impairment among children and young adults. Individual studies showed significant variations in the prevalence of amblyopia in different regions and age groups. This study is to estimate the global prevalence of amblyopia by pooling its prevalence from the previous studies and to project the number of people affected through 2040.
Methods We performed a systematic review and meta-analysis on the prevalence of amblyopia using data published before 20 October 2018. We estimated the prevalence rate of amblyopia and its 95% CI globally and by subgroups (eg, region and age). The prevalence data were applied to United Nations World Population Prospects to derive the projected number with amblyopia through 2040.
Results A meta-analysis of 60 studies (1 859 327 subjects) showed that the pooled prevalence rate of amblyopia was 1.44% (95% CI 1.17% to 1.78%). Prevalences in Europe (2.90%) and North America (2.41%) were higher than in Asia (1.09%) and Africa (0.72%). The highest prevalence was found in subjects over 20 years old (3.29%). There was no difference in the prevalence between genders. We estimated 99.2 (95% CI 71.7 to 146.1) million people with amblyopia in 2019 worldwide, increasing to 175.2 (95% CI 81.3 to 307.8) million by 2030 and 221.9 (95% CI 83.7 to 429.2) million by 2040.
Conclusions The amblyopia is becoming a significant vision problem worldwide. It is of great importance to design and implement amblyopia screening, treatment and related public health strategies.
- Child health (paediatrics)
- Public health
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Contributors HL and C-WP contributed substantially to the conception and design of this paper. ZF, HH and ZS conducted the literature searches and extracted the data from published papers. ZF and BL drafted the paper and carried out statistical analysis.
Funding This investigation was supported by the National Natural Science Foundation of China (grant no. 81673198, 81773449 and 81973061), the Natural Science Foundation of Jiangsu Province (grant no. BK20161595) and the Science and Technology Development Foundation of Nanjing Medical University (grant No. 2017NJMU053).
Competing interests None declared.
Patient consent for publication Not required.
Provenance and peer review Not commissioned; externally peer reviewed.
Data availability statement All data relevant to the study are included in the article or uploaded as online supplementary information.
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