Refractive error among urban preschool children in Xuzhou, China.

The prevalence of refractive errors in urban preschool children in Xuzhou, China remains unknown. Children attending twelve randomly selected kindergartens participated in this study. Visual acuity, ocular alignment, cover-uncover test, cycloplegic refraction, slit-lamp and funduscopy were performed under a standardized testing environment. Cycloplegic streak retinoscopy was performed for all subjects. The mean spherical equivalent (SE) refractive error was the main outcome measure. Emmetropia was defined as refractive status between +1.75 diopters (D) and -0.75D. Myopia, hyperopia, astigmatism and anisometropia were defined as SE < -0.50D, SE > +2.0 D, cylindrical error > 1.0 D and SE difference ≥ 1 D between fellow eyes, respectively. Out of 2349 eligible children, 2255 (96%) children completed a refractive examination. Of the 2255 children, the mean SE of right eyes was +1.14 ± 0.95 diopters (D). Mean SE of the right eyes did not decline with age (r = -0.01; P = 0.56). The majority (86.6%) of children were emmetropia. The prevalence of myopia and hyperopia was 0.9% and 14.3%, respectively. The mean astigmatism for the right eyes was 0.87 ± 0.62 D. The prevalence of With-the-rule, against the rule and oblique astigmatism was 93.8%, 4.7% and 1.5%, respectively. The mean anisometropia between two eyes was 0.14 ± 0.38 D. The most common type of refractive error was hyperopia (14.3%), followed by astigmatism (8.8%), anisometropia (3.2%), and myopia (0.9%). The refractive status in this population of urban Xuzhou preschool children was stable and there was no evidence of a myopic refractive shift over this age range in our cross-sectional study.