title: The effects of visual display distance on eye accommodation, head posture, and vision and neck symptoms.
abstract: OBJECTIVE
  Determine the effects of display viewing distance on both the visual and musculoskeletal systems while the text height is held constant across viewing distances.
  
  
  BACKGROUND
  The distance from the eyes to a computer display may affect visual and neck comfort. If the angular size of the characters remains the same, it is recommended that the display be placed at a farther viewing distance (e.g., 70-100 cm). However, in common usage, the character sizes are not adjusted based on viewing distance.
  
  
  METHODS
  Participants under the age of 35 years (N = 24) performed visually demanding tasks using a computer display for 2 hr each at three viewing distances (mean: 52.4, 73.0, and 85.3 cm) while torso and head posture were tracked. At the end of each task, eye accommodation was measured and symptoms were recorded.
  
  
  RESULTS
  The near distance was associated with significantly less blurred vision, less dry or irritated eyes, less headache, and improved convergence recovery when compared with the middle and far distances. Participants moved their torsos and heads closer to the monitor at the far distance.
  
  
  CONCLUSIONS
  If the computer screen character sizes are close to the limits of visual acuity, it is recommended that the computer monitor be positioned between the near (52 cm) and middle (73 cm) distance from the eyes.
  
  
  CONCLUSIONS
  The location of a computer display should take into account the size of the characters on the screen and the visual acuity of the user.
authors.affiliation: Ergonomics Program, University of California Berkeley, 1301 South 46th St., Bldg. 163, Richmond, CA 94804, USA. david.rempel@ucsf.edu
authors.forename: David
authors.initials: D
authors.lastname: Rempel
authors.forename: Kirsten
authors.initials: K
authors.lastname: Willms
authors.forename: Jeffrey
authors.initials: J
authors.lastname: Anshel
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Jaschinski
authors.forename: James
authors.initials: J
authors.lastname: Sheedy
mesh_terms: D000065:Accommodation, Ocular / Q000502:physiology*; D000328:Adult; D000704:Analysis of Variance; D003626:Data Display / Q000009:adverse effects / Q000592:standards*; D004576:Electromyography; D005260:Female; D019416:Head Movements / Q000502:physiology; D006261:Headache / Q000209:etiology*; D006801:Humans; D020407:Internet; D016014:Linear Models; D008297:Male; D019547:Neck Pain / Q000209:etiology*; D011187:Posture / Q000502:physiology*; D014796:Visual Perception / Q000502:physiology*