title: Effect of artificial scotomas on open-loop disparity vergence eye movements.
abstract: OBJECTIVE
  To investigate the effect of an artificial scotoma on open-loop disparity vergence responses (DVRs) and vergence control mechanisms, we examined open-loop DVRs to disparity stimuli using monocular artificial scotomas in normal subjects.
  
  
  METHODS
  Using a mirror haploscope with two computer monitors, we delivered disparity stimuli on a pair of random dot patterns subtending 40 by 30 degrees at 47 cm from each eye. The scotomas were black circles located in the center of a random dot pattern for the left eye. Eye movements of both eyes were recorded with a magnetic search coil system.
  
  
  RESULTS
  We first found that the amplitudes of DVRs were gradually decreased and the latency of DVRs was moderately increased as the size of the scotomas was increased. Second, monocular responses from each eye were symmetrical although the stimuli to each eye were asymmetrical.
  
  
  CONCLUSIONS
  The results suggest that the monocular eye movements in disparity vergence are controlled by a binocular central mechanism, not driven separately by monocular inputs in the open-loop window.
authors.affiliation: *MD, PhD †MD ‡PhD Department of Ophthalmology, Shanghai Children's Hospital, Jiaotong University, Shanghai, China (DY, ZT); Vision Center, Department of Ophthalmology, The Children's Hospital of Akron, Northeast Ohio Medical University, Akron, Ohio (DY, RWH, MK); Optometry Centre, School of Chemical and Life Sciences, Singapore Polytechnic, Singapore, Singapore (MZ); and Department of Biomedical Engineering, University of Minnesota, Twin Cities, Minneapolis, Minnesota (EH).
authors.forename: Dongsheng
authors.initials: D
authors.lastname: Yang
authors.forename: Richard W
authors.initials: RW
authors.lastname: Hertle
authors.forename: Mingxia
authors.initials: M
authors.lastname: Zhu
authors.forename: Zheng
authors.initials: Z
authors.lastname: Tai
authors.forename: Eric
authors.initials: E
authors.lastname: Hald
authors.forename: Matthew
authors.initials: M
authors.lastname: Kauffman
mesh_terms: D000328:Adult; D003290:Convergence, Ocular / Q000502:physiology*; D053483:Eye Movement Measurements; D005133:Eye Movements / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D008954:Models, Biological; D012607:Scotoma / Q000503:physiopathology*; D015357:Vision Disparity / Q000502:physiology*; D055815:Young Adult