Prevalence of Refractive Error and Visual Acuity Among School Children in the Plateau Region of Qinghai, China

Abstract

Purpose: This study aimed to investigate the prevalence of refractive error and visual acuity among school children in the plateau region of Qinghai, China.

Methods: The school-based, cross-sectional study was performed in Menyuan, Qinghai, China. Three kindergartens and three primary schools were randomly enrolled from both rural areas and county towns. The participants had undergone ophthalmic examinations of the intraocular pressure (IOP), uncorrected visual acuity (UCVA), presenting visual acuity (PVA) and best corrected visual acuity (BCVA), cycloplegic refraction, and axial length (AL). Regression analysis was applied to investigate the potential risk factors affecting the prevalence of various refractive errors.

Results: A total of 3770 children were invited to participate, and 3524 (93.5%) had undergone examination. Among the 3524 children (51.8% boys) with a mean age of 8.3±2.3 years, 1049 (29.8%) had myopia, 30 (0.9%) had high myopia, 1692 (48.0%) had mild hyperopia, 152 (4.3%) had medium to marked hyperopia and 925 (26.2%) had astigmatism. The mean SER was -0.16±1.86 D and decreased with age. The AL increased with age from 21.80±0.59 mm at 4-years to 23.53±1.05 mm at 12-years. The myopia prevalence increased with age from 2.0% at 4 years to 62.8% at 12-years. Myopia was associated with increasing age, county town habitation and girls. Among the 723 participants with PVA 20/40 or worse in one eye, 564 (78.0%) were due to uncorrected refractive error, and 83 (22.0%) were due to undercorrected refractive error. Among the 1049 children with myopia, only 254 wore glasses, and 151 children with PVA had a worse BCVA and did not have accurate spectacles.

Conclusion: The prevalence of myopia is very high among school children in Menyuan. Only 24.2% of myopic children wore glasses, and 59.4% of children did not have accurate spectacles. Strategies to improve access to eye care and affordable glasses are needed.

Keywords: glass wear; myopia; plateau region; refractive error; school children.

Figure 1

Spherical equivalent (SE, D) distribution of right eyes, (A) stratified by age and region of habitation, (B) stratified by age and genders in the Qinghai children. The Y axis shows the mean and 95% confidence interval.

Figure 2

Axial length (AL, mm) distribution of right eyes, (A) stratified by age and region of habitation, (B) stratified by age and genders in the Qinghai children. The Y axis shows the mean and 95% confidence interval.

Figure 3

Prevalence of high myopia, myopia, emmetropia, mild hyperopia and medium to marked hyperopia, stratified by age in the Qinghai children. Participants were classified according to SER into high myopia (SER≤−6.0D), myopia (SER≤−0.5 D), emmetropia (SER>−0.50 D and ≤+0.5 D), mild hyperopia (SER>+0.50 D and ≤+2.0 D), and medium to marked hyperopia (>+2.0 D).