The diversified defocus profile of the near-work environment and myopia development

Kai Yip Choi, Angela Yuen Ting Mok, Chi Wai Do, Paul Hong Lee, Henry Ho lung Chan

Research output: Journal article publicationJournal articleAcademic researchpeer-review

15 Citations (Scopus)


Purpose: To quantify the defocus characteristics in the near-work environment at home and investigate the relationship with subsequent myopia progression. Methods: Fifty subjects (aged 7–12 years) were recruited and followed for 1 year. The home near-work environment (writing desk) was measured at a baseline home-visit using the Kinect-for-Windows to capture a 3-dimensional image. The depth values of the image were then converted into scene defocus with respect to the subject’s viewpoint. The defocus characteristics were quantified as the dioptric volume (the total amount of net defocus, or DV) and standard deviation of the defocus values (SDD). Information on home size, time spent outdoors, and in front of a desk were also obtained. Univariate correlation, and multivariate regression were used to assess the association between myopia progression, defocus characteristics, and other co-variates. Results: The baseline spherical equivalent refraction (M) and refraction change over 1 year (∆M) were − 1.51 ± 2.02 D and − 0.56 ± 0.45 D respectively. DV was not significantly correlated with ∆M (Spearman’s ρ = −0.25, p = 0.08), while SDD was negatively correlated to ∆M (Spearman’s ρ = −0.42, p = 0.003). Although SDD was not a significant predictor in multivariate analysis, the regional DV at 15°–20° eccentricity was significant (p = 0.001). Home size (F2,50 = 7.01, p = 0.002) and time spent outdoors (Independent t = −2.13, p = 0.04) were also associated with ∆M, but not time spent in front of desk (Independent t = 0.78, p = 0.44). Conclusion: The defocus profile in the home environment within the para-central field of view is associated with childhood refractive error development.

Original languageEnglish
Pages (from-to)463-471
Number of pages9
JournalOphthalmic and Physiological Optics
Issue number4
Publication statusPublished - 9 Jun 2020


  • home size
  • living environment
  • myopia
  • near work

ASJC Scopus subject areas

  • Ophthalmology
  • Optometry
  • Sensory Systems


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