Prevalence and influence factors for myopia and high myopia in schoolchildren in Shandong, China

The aim of the study was to identify the prevalence and risk factors of myopia and high myopia in students from primary school and junior high school in Shandong.A total of 35,614 subjects completed the visual acuity test, refraction error measurement, and questionnaire in 2019. The visual acuity test was performed using the standard logarithmic visual acuity chart and the refractive error was measured by an automatic refractometer without cycloplegia.The average age was 12.38 ± 1.78 years, with 18,501 boys and 17,113 girls. The overall prevalence of myopia and high myopia was 68.02% and 5.90%, respectively, and reached up to 85.54% and 13.13% for the grade 9 students. The risk factors included girls, parental myopic history, time spent doing homework, and less sleep time. Performing eye exercise was significantly associated with a lower risk of myopia. Use of mobile devices and reading while lying down were only related to myopia, not high myopia.The prevalence of myopia and high myopia is at a high level. In addition to genetic factors, continuous close work and a lack of sleep was an important factor associated with children myopia and high myopia.