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

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 ( increment M) were - 1.51 +/- 2.02 D and - 0.56 +/- 0.45 D respectively. DV was not significantly correlated with increment M (Spearman's rho = -0.25, p = 0.08), while SDD was negatively correlated to increment M (Spearman's rho = -0.42, p = 0.003). Although SDD was not a significant predictor in multivariate analysis, the regional DV at 15 degrees-20 degrees eccentricity was significant (p = 0.001). Home size (F-2,F-50 = 7.01, p = 0.002) and time spent outdoors (Independent t = -2.13, p = 0.04) were also associated with increment 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.