Purpose To determine prevalence of refractive (RA), corneal (CA) and internal astigmatism (IA), including variation with gender and spherical equivalent refraction (SE), in a population of 12-year-old Chinese children.
Methods A total of 1783 students with a mean age of 12.7 years (range 10.0–15.6 years) completed comprehensive eye examinations in the Anyang Childhood Eye Study. Data of cycloplegic refraction and corneal curvature were analysed.
Results Prevalences of RA, CA and IA ≥1.0 D were 17.4% (95%CI 15.6% to 19.2%), 52.8% (50.5% to 55.1%)%) and 20.9% (19.0% to 22.8%), respectively. With different limits of astigmatism axes classification, including ±15°, ±20° and ±30°, RA and CA axes were mainly ‘with-the-rule’ (WTR) (ie, correcting axis of negative cylinders at or near 180°), while those for IA axes were mainly ‘against-the-rule’ (ATR) (ie, correcting axis of negative cylinders at or near 90°). RA was not different between the genders, but girls had higher prevalence and greater means of CA and IA. RA and CA increased in students with higher ametropia (more myopia and more hyperopia) and were the highest in a high myopic group (SE≤−6 D), while IA was stable across refraction groups. Children with RA higher than 0.50 D were more likely to have lens corrections (51%, 57%, 61% and 69% for magnitudes of ≥0.50 D, ≥0.75 D, ≥1.0 D and ≥1.5 D, respectively).
Conclusions Prevalence of RA in the Chinese 12-year-old children was relatively high compared with other studies. RA and CA had mainly ‘WTR’ astigmatism, while IA was mainly ATR and partially compensated for CA. Girls had greater means and prevalences of CA and IA than did boys. Both RA and CA, but not IA, increased with refractive errors away from emmetropia.
- Chinese children
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HL and S-ML contributed equally.
Contributors NW had full access to all of the data in the study and takes responsibility for the integrity of the data and the accuracy of the data analysis. Study concept and design: S-ML, NW, L-RL, PM, S-YZ. Acquisition, analysis or interpretation of data: HL, SML, DAA, M-TK, J-HG, RY, Y-WB. Drafting of the manuscript: HL, S-ML, DAA. Critical revision of the manuscript for important intellectual content: All authors. Administrative, technical or material support: NW, L-RL. Study supervision: NW.
Funding The ACES was supported by the capital health research and development of special (2016-4-2056), the Ministry of Science and Technology, the Major State Basic Research Development Program of China (‘973’ Program, 2011CB504601) of the Ministry of Science and Technology, the Major International (Regional) Joint Research Project of the National Natural Science Foundation of China (81120108007), the National Natural Science Foundation of China (81300797) and Beijing Nova Program (Z121107002512055).
Competing interests None declared.
Patient consent Obtained.
Ethics approval The Ethics Committee of Beijing Tongren Hospital, Capital Medical University.
Provenance and peer review Not commissioned; externally peer reviewed.