title: Oculomotor function after virtual reality use differentiates symptomatic from asymptomatic individuals.
abstract: Some individuals who use virtual reality (VR) head-mounted displays (HMD) have adverse visual symptoms.
  
  
  OBJECTIVE
  We measured oculomotor functions of symptomatic (n = 10) and asymptomatic (n = 10) individuals to determine if there were fundamental oculomotor performance differences.
  
  
  METHODS
  Before and after 20 min of biocular VR-HMD use, we measured: phorias, fixation disparity, gradient accommodative convergence to accommodation ratio (AC/A), stereopsis, and nearpoint of convergence.
  
  
  RESULTS
  We observed an exophoric shift in the nearpoint phoria of almost all subjects, whereas the farpoint phoria showed no trend. Interestingly, we observed that the phoric shift at far and near was highly correlated for the asymptomatic subjects but not for the symptomatic subjects. In addition, the (stimulus) AC/A ratio of symptomatic subjects was reduced after a period of VR-HMD use, whereas asymptomatic subjects' AC/A ratio was not reduced.
  
  
  CONCLUSIONS
  The oculomotor changes among the symptomatic subjects (increased exophoria at near and reduced AC/A) appears consistent with a reduced accommodative response. In contrast, the asymptomatic subjects show changes (correlated change in phorias) which seem most consistent with adaptation in the tonic component of vergence and/or accommodation.
authors.affiliation: Medical University of South Carolina, Department of Ophthalmology, Charleston 29425, USA.
authors.forename: S E
authors.initials: SE
authors.lastname: Morse
authors.forename: B C
authors.initials: BC
authors.lastname: Jiang
mesh_terms: D000065:Accommodation, Ocular / Q000502:physiology; D000328:Adult; D003290:Convergence, Ocular / Q000502:physiology; D003941:Diagnostic Techniques, Ophthalmological; D005099:Exotropia / Q000175:diagnosis* / Q000209:etiology / Q000503:physiopathology*; D005133:Eye Movements; D005260:Female; D005403:Fixation, Ocular / Q000502:physiology; D006801:Humans; D008297:Male; D009801:Oculomotor Muscles / Q000503:physiopathology*; D014584:User-Computer Interface; D015357:Vision Disparity / Q000502:physiology; D015348:Vision, Binocular / Q000502:physiology