title: Binocular summation in visual evoked cortical potential in patients who have significantly different P100 peak latencies in their two eyes.
abstract: OBJECTIVE
  To determine whether binocular summation in visual evoked cortical potential (VEP) is present in patients who have significantly different P100 peak latencies in their two eyes.
  
  
  METHODS
  Twelve patients with unilateral optic neuritis (ON) and 11 normal controls were studied. All of them had visual acuity of > or = 20/20 in both two eyes and good stereoacuity. Transient and steady-state VEPs were recorded with monocular and binocular pattern-reversal stimulation.
  
  
  RESULTS
  In normal controls, the binocular summation ratio was 1.05 with transient stimulation and 1.21 with steady-state stimulation, and in ON patients it was 1.19 and 1.30, respectively. In ON patients, the peak latency of P100 components was delayed significantly when the affected eye was stimulated, but with binocular stimulation the waveform was very similar to that when the fellow eye was stimulated.
  
  
  CONCLUSIONS
  Binocular summation of VECP is not present in ON cases with large differences in the peak latency between the two eyes even if they have good stereoacuity. Binocular summation may not be correlated with stereopsis in adults whose binocular function has already matured.
authors.affiliation: Department of Ocular Oncology, Graduate School of Medicine, Chiba University, 1-8-1 Inohana, Chuo-ku, 260-8670 Chiba, Japan. mizota-a@umin.ac.jp
authors.forename: Atsushi
authors.initials: A
authors.lastname: Mizota
authors.forename: Akiko
authors.initials: A
authors.lastname: Hoshino
authors.forename: Emiko
authors.initials: E
authors.lastname: Adachi-Usami
authors.forename: Naoya
authors.initials: N
authors.lastname: Fujimoto
mesh_terms: D000293:Adolescent; D000328:Adult; D017668:Age of Onset; D005074:Evoked Potentials, Visual / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009902:Optic Neuritis / Q000503:physiopathology*; D010364:Pattern Recognition, Visual / Q000502:physiology; D011930:Reaction Time; D015348:Vision, Binocular / Q000502:physiology*; D014792:Visual Acuity / Q000502:physiology; D014793:Visual Cortex / Q000502:physiology*