title: Refractive surgery in anisometropic adult patients induce plastic changes in primary visual cortex.
abstract: OBJECTIVE
  To prospectively study the effect of refractive surgery in the primary visual cortex of adult anisometropic and isometropic myopic patients.
  
  
  METHODS
  Two anisometropic and two isometropic myopic patients were examined with multifocal functional magnetic resonance imaging technique (mffMRI) before refractive surgery and at 3, 6, 9 and 12 months postoperatively. Two controls without refractive surgery were also examined with mffMRI in the beginning and in the end of the study. Anisometropic patients had only their more myopic eye operated to correct the anisometropia. The myopic isometropic patients had their both eyes operated.
  
  
  RESULTS
  Operated anisometropic eyes showed 65% reduced amount of active voxels in foveal data at 12 months postoperatively compared with the preoperative situation. In unoperated anisometropic eyes, the corresponding value was 86% and in myopic patients and controls 31% and 1%, respectively. To confirm this finding, the number of activated voxels representing the innermost ring of the stimulus was also calculated, and an exactly similar phenomenon was encountered in the anisometropic patients. Both anisometropic patients improved the best-spectacle-corrected visual acuity in the operated eye after refractive surgery.
  
  
  CONCLUSIONS
  Our results suggest that plastic changes may take place in the primary visual cortex of anisometropic adult patients after refractive surgery.
authors.affiliation: Department of Ophthalmology, University of Helsinki, Helsinki, Finland.
authors.forename: Elisa
authors.initials: E
authors.lastname: Vuori
authors.forename: Simo
authors.initials: S
authors.lastname: Vanni
authors.forename: Linda
authors.initials: L
authors.lastname: Henriksson
authors.forename: Timo M T
authors.initials: TM
authors.lastname: Tervo
authors.forename: Juha M
authors.initials: JM
authors.lastname: Holopainen
mesh_terms: D000328:Adult; D015858:Anisometropia / Q000503:physiopathology / Q000601:surgery*; D015350:Contrast Sensitivity / Q000502:physiology; D063171:Corneal Pachymetry; D019781:Corneal Topography; D005260:Female; D006801:Humans; D020731:Keratomileusis, Laser In Situ; D054018:Lasers, Excimer / Q000627:therapeutic use*; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009216:Myopia / Q000503:physiopathology / Q000601:surgery*; D009473:Neuronal Plasticity / Q000502:physiology*; D018903:Photorefractive Keratectomy; D011446:Prospective Studies; D014792:Visual Acuity / Q000502:physiology; D014793:Visual Cortex / Q000502:physiology*; D055815:Young Adult