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Protective Behaviours of Near Work and Time Outdoors in Myopia Prevalence and Progression in Myopic Children: a 2-Year Prospective Population Study


Huang P, Hsiao Y, Tsai C, et al


Department of Health, Taipei City Government




British Journal of Ophthalmology


  • This study aims to investigate the protective behaviours of longer near work distance, discontinuing near work and more time outdoors in recess from parent self-report in the myopia prevalence and progression among myopic children aged 9–11 years.

  • Myopia Investigation study in Taipei is a longitudinal population-based study that enrolled elementary school students in Taipei. 

  • Vision and refraction examination was conducted every 6 months. Spherical equivalent (SE) of cycloplegic refraction ≤−0.50 Diopter (D) is defined as myopia. Total 10 743 (70.4%) students completed 2-year refraction data and questionnaire. 

  • The myopia prevalence and progression (difference of SE) in baseline, 6, 12, 18 and 24 months were compared by generalised estimating equations.

  • Children with persistent protective behaviour had significant lower prevalence of myopia. 

  • The protective impact was statistically significant from 6 to 24 months. 

  • In 2 years follow-up, risk ratio after adjusting the background variables and the other two behaviours in near work distance, near work time and outdoor time were 0.71, 0.89 and 0.77. 

  • In SE analysis, after adjusting the other two behaviours, near work distance >30 cm (−0.7 vs −1.04 D; p<0.001), discontinuing near work every 30 min (−0.77 vs −0.96 D, p=0.005) and more time outdoors in recess from parent self-report (−0.75 vs −0.98 D; p=0.012) revealed protective impacts on diminishing myopia progression from 6 to 24 months.

  • In myopic children aged around 10 years in Taipei, longer distance in near work, discontinuing near work every 30 min and more outdoor time from parent self-report are protective behaviours in myopia prevalence and progression in 6–24 months.