Association between Time Spent on Smart Devices and Change in Refractive Error: A 1-Year Prospective Observational Study Among Hong Kong Children and Adolescents

Chi Wai Do, Lily Yee Lai Chan, Andy C.Y. Tse, Cheuk Chi Teris Cheung, Chun Lung So, Wing Chun Tang, Chin Hung Geoffrey Chu, Grace P Y Szeto, Regina L.T. Lee, Hong Lee (Corresponding Author)

Research output: Journal article publicationJournal articleAcademic researchpeer-review


This study examined the association between smart device usage and the 1-year change in refractive error among a representative sample of Hong Kong children and adolescents aged 8–14 years. A total of 1597 participants (49.9% male, mean age 10.9, SD 2.0) who completed both baseline (2017–2018) and 1-year follow-up (2018–2019) eye examinations were included in the present study. The non-cycloplegic auto-refractive error was measured and the average spherical equivalent refraction (SER) was analyzed. The participants also self-reported their smart device usage at baseline. Multivariate regression adjusted for age, sex, baseline SER, parents’ short-sightedness, BMI, time spent on moderate-to-vigorous physical activity (MVPA), and caregiver-reported socio-economic status showed that, compared with the reference group (<2 h per day on both smartphone and tablet usages), those who spent ≥2 h per day using a smartphone and <2 h per day using a tablet had a significantly negative shift in refractive error (1-year change in SER −0.25 vs. −0.09 D, p = 0.01) for the right eye, while the level of significance was marginal (1-year change −0.28 vs. −0.15 D, p = 0.055) for the left eye. To conclude, our data suggested spending at most 2 h per day on both smartphones and tablets.

Original languageEnglish
Article number8923
Pages (from-to)1-11
Number of pages11
JournalInternational Journal of Environmental Research and Public Health
Issue number23
Publication statusPublished - 1 Dec 2020


  • Handheld device
  • Myopia
  • Prospective
  • Smartphone
  • Tablet
  • Teenage

ASJC Scopus subject areas

  • Public Health, Environmental and Occupational Health
  • Health, Toxicology and Mutagenesis

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