Development of Refractive Parameters in 3-to 6-Year-Old Children and Its Application in Myopia Prediction and Intervention Guidance

Objective. To investigate refractive development and prevalence of myopia in children aged 3-6 years in Hebei Province, China, and to explore the developmental law of refraction, so as to clinically guide the prediction and intervention of myopia. Methods. In May 2019, a total of 6120 people were inspected in 68 kindergartens in 11 cities in Hebei Province. Child refractive refraction was checked under noncycloplegia using a handheld binocular vision screener (SW-800, SUOER, Tianjin, China). Axial length (AL) and corneal radius of curvature (CR) were measured using an ocular biometry (IOLMaster 500, Carl Zeiss, Germany). Myopia was defined as spherical equivalent SE & LE;-0.75 D. Results. A total of 5506 children aged 3-6 years met the criteria and were included in the statistical analysis. The prevalence of myopia was 3.49% (1.93% at age 3, 2.90% at age 4, 3.78% at age 5, and 3.88% at age 6). Overall, the mean SE was +0.67 & PLUSMN;1.05 D (+0.81 & PLUSMN;1.00 D at age 3, +0.79 & PLUSMN;1.05 D at age 4, +0.67 & PLUSMN;1.08 D at age 5, and +0.13 & PLUSMN;1.01 D at age 6); the mean CR was 7.76 & PLUSMN;0.26 mm (7.78 & PLUSMN;0.26 mm at age3, 7.75 & PLUSMN;0.25 mm at age 4, 7.77 & PLUSMN;0.26 mm at age 5, and 7.76 & PLUSMN;0.25 mm at age 6); the mean AL was 22.31 & PLUSMN;0.73 mm (21.98 & PLUSMN;0.63 mm at age 3, 22.12 & PLUSMN;0.69 mm at age 4, 22.34 & PLUSMN;0.73 mm at age 5, and 22.49 & PLUSMN;0.73 mm at age 6). Conclusions. Prevalence of myopia increases with age in children aged 3-6 years in Hebei, China. With the increase of age, CR is basically stable, and AL increases gradually. AL/CR, which is closely related to SE, can be used as an indicator to predict myopia and guide clinical work.