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

Abstract

Purpose: To provide contemporary and future estimates of childhood myopia prevalence in Africa.

Methods: A systematic online literature search was conducted for articles on childhood (≤18 years) myopia (spherical equivalent [SE] ≤ -0.50D; high myopia: SE ≤ -6.00D) in Africa. Population- or school-based cross-sectional studies published from 1 Jan 2000 to 30 May 2021 were included. Meta-analysis using Freeman-Tukey double arcsine transformation was performed to estimate the prevalence of childhood myopia and high myopia. Myopia prevalence from subgroup analyses for age groups and settings were used as baseline for generating a prediction model using linear regression.

Results: Forty-two studies from 19 (of 54) African countries were included in the meta-analysis (N = 737,859). Overall prevalence of childhood myopia and high myopia were 4.7% (95% CI: 3.3%-6.5%) and 0.6% (95% CI: 0.2%-1.1%), respectively. Estimated prevalence across the African regions was highest in the North (6.8% [95% CI: 4.0%-10.2%]), followed by Southern (6.3% [95% CI: 3.9%-9.1%]), East (4.7% [95% CI: 3.1%-6.7%]) and West (3.5% [95% CI: 1.9%-6.3%]) Africa. Prevalence from 2011 to 2021 was approximately double that from 2000 to 2010 for all studies combined, and between 1.5 and 2.5 times higher for ages 5-11 and 12-18 years, for boys and girls and for urban and rural settings, separately. Childhood myopia prevalence is projected to increase in urban settings and older children to 11.1% and 10.8% by 2030, 14.4% and 14.1% by 2040 and 17.7% and 17.4% by 2050, respectively; marginally higher than projected in the overall population (16.4% by 2050).

Conclusions: Childhood myopia prevalence has approximately doubled since 2010, with a further threefold increase predicted by 2050. Given this trajectory and the specific public health challenges in Africa, it is imperative to implement basic myopia prevention programmes, enhance spectacle coverage and ophthalmic services and generate more data to understand the changing myopia epidemiology to mitigate the expanding risk of the African population.

Keywords: Africa; childhood; myopia; prevalence; systematic review and meta-analysis; time trends.

FIGURE 1

Preferred reporting items for systematic reviews and meta‐analyses (PRISMA) flowchart of steps in identifying studies.

FIGURE 2

Map of Africa showing prevalence of childhood myopia in each country included in the meta‐analysis. Number in parenthesis represents number of studies in each country.

FIGURE 3

Forest plot of overall prevalence of childhood myopia in Africa. The prevalence of (a) childhood myopia in Africa was estimated to be 4.7% (95% CI: 3.3%–6.5%) and (b) high myopia was estimated to be 0.6% (95% CI: 0.2%–1.1%). The diamond represents the pooled estimate.

FIGURE 4

Leave‐one‐out sensitivity plot of all studies reporting the prevalence of childhood myopia in Africa. A leave‐one‐out sensitivity analysis provides an untransformed prevalence estimate and was performed to evaluate the contribution of each study to the overall estimate of childhood myopia in Africa. This revealed that the overall estimate of childhood myopia in Africa was most affected by the study by Rushood et al., followed by the Saa et al. study.

FIGURE 5

Funnel plot of studies reporting the prevalence of myopia in Africa.

FIGURE 6

Forest plot showing prevalence of childhood myopia in (a) East Africa (b) West Africa (c) North Africa (d) Southern Africa. The diamond represents the pooled estimates.

FIGURE 7

Prevalence of childhood myopia (%) in African children from the year 2000 to 2050. (a) Urban (b) rural (c) overall. The filled circles indicate the pooled prevalence estimate from the meta‐analysis and the open circles indicate the predicted prevalence of myopia using a linear regression model. The dashed black lines running on either side of the linear fit/regression line represents the 95% prediction interval.

FIGURE 8

Prevalence of childhood myopia (%) in African children from the year 2000 to 2050. (a) 5–11 years (b) 12–18 years. The filled circles indicate the pooled prevalence estimate from the meta‐analysis and the open circles indicate the predicted prevalence of myopia using a linear regression model. The dashed black lines running on either side of the linear fit/regression line represent the 95% prediction interval.