title: Eye movement and pupil size constriction under discomfort glare.
abstract: OBJECTIVE
  Involuntary physiological responses offer an alternative means to psychophysical procedures for objectively evaluating discomfort glare. This study examined eye movement and pupil size responses to glare discomfort using new approaches to analysis: relative pupil size and speed of eye movement.
  
  
  METHODS
  Participants evaluated glare discomfort using the standard de Boer rating scale under various conditions manipulated to influence glare discomfort. Eye movement was recorded using an electro-oculogram (EOG), and pupil size was recorded using Tobii glasses. Ten young (mean age: 24.5 years old) and 10 senior (mean age: 61 years old) participants were recruited for this experiment.
  
  
  RESULTS
  Subjective evaluation of glare discomfort was highly correlated with eye movement (multiple correlation coefficient [R(2)] of >0.94, P < 0.001) and pupil constriction (R(2) = 0.38, P < 0.001). Severe glare discomfort increased the speed of eye movement and caused larger pupil constriction. Larger variations of eye movement were found among seniors.
  
  
  CONCLUSIONS
  The two physiological responses studied here to characterize discomfort glare under various lighting conditions had significant correlation with the subjective evaluation. The correlation between discomfort glare and physiological responses suggests an objective way to characterize and evaluate discomfort glare that may overcome the problems of conventional subjective evaluation. It also offers an explanation as to why long-term exposure to discomfort glare leads to visual fatigue and eyestrain.
authors: Institute for Electric Light Sources, Fudan University, Engineering Research Center of Advanced Lighting Technology, Ministry of Education, Shanghai, China.
authors: Yandan
authors: Y
authors: Lin
authors: School of Architecture, University of Sheffield, Sheffield, United Kingdom.
authors: Steve
authors: S
authors: Fotios
authors: Department of Architectural Engineering, The Pennsylvania State University, University Park, Pennsylvania, United States.
authors: Minchen
authors: M
authors: Wei
authors: Shenzhen Institute of Building Research Co. Ltd., Shenzhen, Guangdong, China.
authors: Yihong
authors: Y
authors: Liu
authors: Shanghai Institute of Technical Physics, Chinese Academy of Sciences, Shanghai, China.
authors: Weihong
authors: W
authors: Guo
authors: Institute for Electric Light Sources, Fudan University, Engineering Research Center of Advanced Lighting Technology, Ministry of Education, Shanghai, China.
authors: Yaojie
authors: Y
authors: Sun
mesh_terms: D000328:Adult; D000368:Aged; D004585:Electrooculography; D005260:Female; D019466:Glare / Q000009:adverse effects*; D006801:Humans; D008297:Male; D008875:Middle Aged; D015877:Miosis / Q000503:physiopathology*; D011601:Psychophysics; D012016:Reference Values; D012025:Reflex, Pupillary / Q000502:physiology*; D055815:Young Adult
keywords: discomfort glare; eye movements; pupil constriction