title: Study of preferred background luminance in watching computer screen in children.
abstract: BACKGROUND
  In recent years, computers have been intensively used at home. In contrast to paper-based books and documents, computer screen is self-illuminated with larger screen-background luminance difference, which greatly induces visual discomfort. To compensate for that, one effective solution is to offer an additional background luminance. In this study, we investigated whether and to what extent additional background lighting is needed in looking at a computer display comfortably.
  
  
  METHODS
  In this study, 60 healthy children aged from 9 to 12 years and 58 adults aged from 21 to 39 years participated in the experiments. They were asked to choose their most preferred background luminance intensities at three screen luminance levels. The data were analyzed by Matlab (R2012b) and SPSS 20.0.
  
  
  RESULTS
  Both children and adult participants selected a non-dark background as their comfortable lighting condition when watching a computer display (children: t (59) = 22.0, P < 0.01, adults: t (57) = 15.5, P < 0.01). Comparatively, children preferred brighter background in general ( F (1,116) = 7.0, P < 0.01). More importantly, participants' preferred background luminance levels were linearly correlated with screen luminance intensities (children: slope = 0.97, R(2) = 0.98; adults: slope = 0.38, R(2) = 1.00).
  
  
  CONCLUSIONS
  These results indicate that varying background luminance to maintain screen-background luminance ratio is beneficial to human visual comfort.
authors.affiliation: Department of Ophthalmology, Eye and Ear, Nose and Throat Hospital, Fudan University, Shanghai 200031, China.
authors.forename: Yang
authors.initials: Y
authors.lastname: Shen
authors.affiliation: Philips Research China, Shanghai 200233, China.
authors.forename: Shuguang
authors.initials: S
authors.lastname: Kuai
authors.affiliation: Philips Research China, Shanghai 200233, China.
authors.forename: Weixi
authors.initials: W
authors.lastname: Zhou
authors.affiliation: Philips Research China, Shanghai 200233, China.
authors.forename: Sheng
authors.initials: S
authors.lastname: Peng
authors.affiliation: Department of Ophthalmology, Eye and Ear, Nose and Throat Hospital, Fudan University, Shanghai 200031, China.
authors.forename: Mi
authors.initials: M
authors.lastname: Tian
authors.affiliation: Philips Research China, Shanghai 200233, China. Email: kevin.kj.liu@philips.com.
authors.forename: Kangjun
authors.initials: K
authors.lastname: Liu
authors.affiliation: Department of Ophthalmology, Eye and Ear, Nose and Throat Hospital, Fudan University, Shanghai 200031, China. Email: xingtaozhou@163.com.
authors.forename: Xingtao
authors.initials: X
authors.lastname: Zhou
mesh_terms: D000328:Adult; D002648:Child; D003201:Computers; D015350:Contrast Sensitivity / Q000502:physiology*; D005260:Female; D006801:Humans; D008029:Lighting; D008297:Male; D009216:Myopia / Q000517:prevention & control; D055815:Young Adult