Abstract: Objective： To analyze the prevalence of reduced visual acuity (VA) and to examine the association between reduced visual acuity and influencing factors among Chinese Han students, so as to provide bases for the prevention and treatment of reduced visual acuity. Methods: Subjects were from 2014 Chinese National Surveys on Students’ Constitution and Health (CNSSCH). In this survey, 261 832 Han students aged 7-22 years participated. Unaided distance VA was measured using a retro-illuminated lgMAR chart with tumbling-E optotypes. Ametropia was determined by using serial bronchoscopy. Logistic regression was used to assess the association between reduced visual acuity and influencing factors. ArcMap 10 was used to map the regional distribution of reduced visual acuity. Results: Nationwide, the overall prevalence of reduced visual acuity was 66.6%, and was highest among the urban girls (73.5%). The prevalence of myopia was 60.8% and accounted for more than 90% among the students with reduced visual acuity. Compared with 2010 CNSSCH, the increments of reduced visual acuity were highest in the students aged 13-15 years (6.8 percentage points). The prevalence of reduced visual acuity ranged from 50.6% to 76.2% in each province (autonomous region, municipality) in 2014 CNSSCH. The top three of the prevalence of reduced visual acuity were Jiangsu (76.2%), Zhejiang (76.0%) and Shandong (75.9%), and the lowest three were Hainan (50.6%), Guizhou (53.9%) and Xinjiang (57.6%). Logistic regression showed that the girls, urban students, and students who spent ≥2 h per day in their after school homework were more likely to develop reduced visual acuity, but the students with physical activity time ≥2 h per day were less likely to develop reduced visual acuity. Conclusion: Although the situation was different in each province (autonomous region, municipality), reduced visual acuity has become a public concern affecting the health of students in China. Based on the intervention on the key populations, such as urban girls and pre adolescent students, we should also continue to strengthen the prevention and control for reduced visual acuity among all students.

Key words: Visual acuity, Students, Adolescent, Child, Regional distribution