Systematic review and meta-analysis of myopia prevalence in African school children

Abstract

Purpose Increased prevalence of myopia is a major public health challenge worldwide, including in Africa. While previous studies have shown an increasing prevalence in Africa, there is no collective review of evidence on the magnitude of myopia in African school children. Hence, this study reviews the evidence and provides a meta-analysis of the prevalence of myopia in African school children. Methods This review was conducted using the 2020 Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guidelines. Five computerized bibliographic databases, PUBMED, Scopus, Web of Science, ProQuest, and Africa Index Medicus were searched for published studies on the prevalence of myopia in Africa from 1 January 2000 to 18 August 2021. Studies were assessed for methodological quality. Data were gathered by gender, age and refraction technique and standardized to the definition of myopia as refractive error ≥ 0.50 diopter. A meta-analysis was conducted to estimate the prevalence. Significant heterogeneity was detected among the various studies (I2 >50%), hence a random effect model was used, and sensitivity analysis was performed to examine the effects of outliers. Results We included data from 24 quality assessed studies, covering 36,395 African children. The overall crude prevalence of myopia over the last two decades is 4.7% (95% CI, 3.9–5.7) in African children. Although the prevalence of myopia was slightly higher in females (5.3%, 95%CI: 4.1, 6.5) than in males (3.7%, 95% CI, 2.6–4.7; p = 0.297) and higher in older [12–18 years 5.1% (95% CI, 3.8–6.3) than younger children (aged 5–11 years, 3.4%, 95% CI, 2.5–4.4; p = 0.091), the differences were not significant. There was a significantly lower prevalence of myopia with cycloplegic compared with non-cycloplegic refraction [4.2%, 95%CI: 3.3, 5.1 versus 6.4%, 95%CI: 4.4, 8.4; p = 0.046]. Conclusions Our results showed that myopia affects about one in twenty African schoolchildren, and it is overestimated in non-cycloplegic refraction. Clinical interventions to reduce the prevalence of myopia in the region should target females, and school children who are aged 12–18 years.

Regional variations and temporal trends of childhood myopia prevalence in Africa: A systematic review and meta‐analysis

“…The current estimate of childhood myopia is similar to a recent meta‐analysis estimate in Africa, 23 despite differences in the number of studies included, which provides some reassurance as to the validity of the various estimates based on current data. This study addresses some of the key limitations of all previous reviews, 23–25 particularly the recent review by Ovenseri‐Ogbomo et al, 23 such as lack of time trend analysis and future projections of childhood myopia prevalence in Africa. Analysis of the temporal trends and projections of the trends could be useful in developing targeted policy measures in addressing the condition in future.…”

“…Also, there has not been any previously pooled estimates across the different regions to highlight geographic variations of childhood myopia across the continent (given the development disparities, 88 myopia prevalence may vary across the different regions). Furthermore, the study by Ovenseri‐Ogbomo et al 23 did not provide an estimate for childhood high myopia prevalence in Africa. Our study therefore provides for the first‐time pooled regional estimates of childhood myopia, childhood high myopia prevalence and changing trends in childhood myopia prevalence as well as projecting the prevalence in Africa by the year 2050.…”

“…Previous systematic reviews, meta‐analyses and future projections on myopia prevalence have been conducted for Asian and Western countries, 21,22 with very limited pooled estimates on myopia in Africa. Existing meta‐analyses suggest that the prevalence of childhood myopia in Africa is relatively low, ranging from 4.7% to 6.2% 23–25 . However, these meta‐analyses are based on a limited number of studies, with as few as six to eight included studies in some reviews (compared with China for example, where a recent meta‐analysis included more than 40 studies) 21 .…”

Childhood vision impairment and refractive error in Zimbabwe: A hospital-based retrospective study

“…Also, the prominent prevalence of keratoconus might have contributed to astigmatism as a leading cause of vision impairment. In the case of noncycloplegic refraction among the children, the prevalence of myopia were likely to be overstated as suggested by Ovenseri-Ogbomo et al ( 23 ). Also, myopia was more prevalent in females than males which is consistent with a review study in Africa by Ovenseri-Ogbomo et al ( 23 ).…”

“…In the case of noncycloplegic refraction among the children, the prevalence of myopia were likely to be overstated as suggested by Ovenseri-Ogbomo et al ( 23 ). Also, myopia was more prevalent in females than males which is consistent with a review study in Africa by Ovenseri-Ogbomo et al ( 23 ). Girls have a higher risk of myopia than boys due to early developmental differences and less time spent outdoors than boys ( 24 ).…”