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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
  1. Pin-Chen Huang1,2,
  2. Ya-Chuan Hsiao3,4,
  3. Ching-Yao Tsai3,4,5,
  4. Der-Chong Tsai4,5,6,
  5. Chi-Wen Chen7,
  6. Chih-Chien Hsu4,8,
  7. Shier-Chieg Huang1,
  8. Meng-Hui Lin9,
  9. Yiing-Mei Liou1,10
  1. 1 Institute of Community Health Care, School of Nursing, National Yang-Ming University, Taipei, Taiwan
  2. 2 Department of Nursing, National Cheng Kung University Hospital, Tainan, Taiwan
  3. 3 Department of Ophthalmology, Taipei City Hospital, Taipei, Taiwan
  4. 4 Faculty of Medicine, National Yang-Ming University, School of Medicine, Taipei, Taiwan
  5. 5 Institution of Public Health, National Yang-Ming University, Taipei, Taiwan
  6. 6 Department of Ophthalmology, National Yang-Ming University Hospital, Yilan, Taiwan
  7. 7 School of Nursing, National Yang-Ming University, Taipei, Taiwan
  8. 8 Department of Ophthalmology, Taipei Veterans General Hospital, Taipei, Taiwan
  9. 9 Department of Health, Taipei City Government, Taipei, Taiwan
  10. 10 School Health Research Center, National Yang-Ming University, Taipei, Taiwan
  1. Correspondence to Professor Yiing-Mei Liou, Institute of Community Health Care, School of Nursing, National Yang-Ming University, Taipei 11221, Taiwan; ymliou{at}


Aim 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.

Methods Myopia Investigation study in Taipei is a longitudinal population-based study that enrolled elementary school students in Taipei. We provided vision and refraction examination 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.

Results 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.

Conclusion 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.

  • epidemiology
  • optics and refraction
  • child health (paediatrics)
  • public health
  • vision

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  • P-CH and Y-CH contributed equally.

  • Correction notice This article has been amended since it was published online. The affiliations have been updated for the second and third authors.

  • Contributors Study supervision: Y-ML, C-YT, S-CH, M-HL. Conception and design: Y-ML, P-CH, C-YT. Conduct of the study: P-CH, Y-ML, C-YT, Y-CH, C-CH. Analysis and interpretation data: P-CH, Y-ML, Y-CH. Writing of manuscript: Y-CH, P-CH, Y-ML, C-YT, D-CT, C-CH, C-WC. Approval and revision of manuscript: Y-CH, Y-ML, P-CH, C-YT, D-CT, C-CH, C-WC, S-CH, M-HL.

  • Funding This study was funded by the Department of Health, Taipei City Government (TCHIRB-1020501/10603111). This project, an investigation of myopia in Taipei, was supported by grants H10237, P10303, 104HM01L and W105004 from the Taipei City Government.

  • Competing interests None declared.

  • Patient consent for publication Not required.

  • Ethics approval The Institutional Review Board of Taipei City Hospital approved the protocols of this study.

  • Provenance and peer review Not commissioned; externally peer reviewed.

  • Data availability statement All data relevant to the study are included in the article or uploaded as supplementary information.

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