Objective  To examine the time spent on outdoor activities and its association with myopia among urban Beijing schoolchildren at vulnerable age of myopia onset.

  Methods  Using cluster sampling, we conducted a questionnaire survey and visual examination among 2 196 schoolchildren aged 10 – 11 years in 11 primary schools in an urban district of Beijing during November – December 2018.

  Results  For the 2 031 valid participants, the average outdoor activity time was 2.24 ± 0.67 hours per day (h/d) and the outdoor time for leisure and physical activities were 1.12 ± 0.46 h/d and 1.12 ± 0.40 h/d, respectively. The detection rate of myopia among the participants was 62.3%. The overall outdoor activity time was not significantly different between the 1 266 myopic participants and the 765 participants with normal vision (P > 0.05). The subgroup analysis demonstrated that the myopic participants had significantly less outdoor leisure time than the normal vision participants did (1.11 ± 0.44 h/d vs. 1.15 ± 0.49 h/d, P < 0.05); while, the disparity was significantly different only for the outdoor leisure time on weekends (1.21 ± 0.87 h/d vs. 1.33 ± 1.01 h/d, P < 0.05) but not for that on weekdays (1.06 ± 0.45 h/d vs. 1.09 ± 0.49 h/d, P > 0.05).

  Conclusion  Among the schoolchildren aged 10 – 11 years in urban Beijing, the outdoor activity time is insufficient and the detection rate of myopia is high; the schoolchildren with myopia spend less outdoor leisure time on weekends than those with normal vision.