Prevalence of Myopia and Axial Length Distribution in China: The Wuhu Children and Adolescents Eye Study.

Purpose: To re-assess myopia prevalence, update the database of ocular biometric parameters, and assess the prevalence of fundus abnormalities in schoolchildren and adolescents in Wuhu, Anhui Province, China.

Methods: The Wuhu Children and Adolescents Eye Study (WCAES) is a longitudinal population-based cohort study, and the cross-sectional analysis results of the baseline assessment are reported here. It included 315,569 out of 330,173 eligible children and adolescents (95.6%), ages 2 to 19 years, from 513 schools with measurements of presenting distance visual acuity (PDVA) and uncorrected distance visual acuity (UDVA), non-cycloplegic autorefractometry, ocular biometry, and color fundus photography. Fundus abnormalities were assessed by an artificial intelligence-based system.

Results: Prevalences of likely myopia (-1.00 D < refractive error ≤ -0.50 D), myopia (refractive error ≤-1.00 D), low myopia (-3.00 D < refractive error ≤ -1.00 D), moderate myopia (-6.00 D < refractive error ≤ -3.00 D), and high myopia (refractive error ≤ -6.00 D) were 13.58% (95% confidence interval [CI], 13.46-13.70), 56.92% (95% CI, 56.74-57.10), 32.87% (95% CI, 32.70-33.04), 19.74% (95% CI, 19.60-19.88), and 4.31% (95% CI, 4.24-4.38), respectively. Among high-school students, myopia prevalence was 92.18% (95% CI, 91.68-92.68). High myopia prevalence rates in kindergarten, elementary, middle, and high schools were 0.30% (95% CI, 0.18-0.43), 1.53% (95% CI, 1.48-1.59), 9.05% (95% CI, 8.86-9.24), and 18.57% (95% CI, 17.84-19.29), respectively. Higher prevalence of overall myopia and high myopia was associated (all P < 0.001) with female sex (odds ratio [OR] = 0.81 and OR = 0.91, respectively), older age (OR = 1.45 and OR = 1.48, respectively), longer axial length (OR = 3.71 and OR = 5.89, respectively), and higher prevalence of fundus tessellation (OR = 1.10 and OR = 1.21, respectively.). The percentage of myopic individuals using vision correction and the prevalence of an age-dependent defined suboptimal PDVA in the myopic population were 48.05% (95% CI, 47.81-48.28) and 65.84% (95% CI, 65.51-66.16), respectively.

Conclusions: Compared with previous studies, the present investigation suggests a further rise in the prevalence of myopia, particularly high myopia, in the younger generations in China.