Vision and refraction and their associates among primary school students in Zhoushan city, 2019: a cross-sectional survey

  Objective  To investigate the status quo and influencing factors of vision and refractive to explore risk factors of myopia among primary school students.

  Methods  Using stratified multistage random sampling, we recruited 2 802 students of grade 1 – 6 in three primary schools in Zhoushan city of Zhejiang province in 2019. Uncorrected and corrected visual acuity were tested and binocular diopter was measured among the students. The students’ information related to myopia prevalence were collected with a self-designed questionnaire. Logistic regression model was used to analyze risk factors of myopia in the students.

  Results  Of the 2 766 students completing the survey, 1633 (59.04%) had poor vision, including 1 037 (37.49%), 192 (6.94%), and 6 (0.22%) with mild, moderate, and high myopia and 398 (14.39%) hyperopia. Among the students, the prevalence of normal vision, mild and moderate myopia, and hyperopia differed significantly by grade (P < 0.05 for all); the prevalence of normal vision and hyperopia decreased with grade but the prevalence of mild and moderate myopia increased with grade. The results of logistic regression analysis revealed following independent risk factors of poor vision: female gender (odds ratio OR = 2.986, 95% confidence interval 95% CI: 1.174 – 7.595), aged 10 years and above (OR = 3.182, 95% CI: 1.416 – 7.149), paternal high myopia (OR = 3.462, 95% CI: 1.505 – 7.963), maternal high myopia (OR = 2.657, 95% CI: 1.302 – 5.422), having more than two hours for close reading and writing after school per day (OR = 2.782, 95% CI: 1.326 – 5.836), and having more than two hours for using electronic products per day (OR = 3.116, 95% CI: 1.260 – 7.707); the results also showed that having more than two hours for outdoor activity per day was a protective factor against poor vision (OR = 0.477, 95% CI: 0.259 – 0.879).

  Conclusion  Among the primary school students in Zhoushan city, the prevalence of myopic ametropia increases with grade; female gender, age, parental high myopia, long time of close reading/writing after school and using electronic devices are risk factors of poor vision and having more time for outdoor activities may prevent myopia to a certain extent.