title: Unilateral strabismus surgery in patients with exotropia results in postoperative lateral incomitance.
abstract: OBJECTIVE
  To determine whether unilateral strabismus surgery creates lateral incomitance in patients with exotropia.
  
  
  METHODS
  Patients >7 years of age with intermittent or constant exotropia who underwent unilateral horizontal rectus muscle surgery between December 2009 and January 2012 were prospectively evaluated. Prism and alternate cover testing was performed with distance fixation in primary position, right gaze, and left gaze after 1 hour of monocular occlusion. Measurements were obtained within 1 month prior to surgery, within 1 week after surgery, and >3 months after surgery. The surgical procedure varied according to the surgeon's discretion. The change in deviation induced by strabismus surgery in lateral gaze was expressed as a percentage of the change in deviation induced in primary position.
  
  
  RESULTS
  A total of 12 patients met inclusion criteria. Of the 11 patients with postoperative examinations within 1 week after surgery, 10 (91%) had greater surgical effect with gaze toward the operated eye (P = 0.007). All 9 patients with >3 months' follow-up had greater surgical effect with gaze toward the operated eye (P = 0.003). On average, the surgical effect in gaze toward the operated eye was 120% of that achieved in primary position; in gaze away from the operated eye, 75% (P < 0.001). Three patients had diplopia in lateral gaze toward the operated eye that remained >6 months after surgery.
  
  
  CONCLUSIONS
  Unilateral strabismus surgery induces lateral incomitance that may cause diplopia >6 months after surgery in patients with exotropia. This should be considered when planning strabismus surgery and counseling patients.
authors.affiliation: University of Arkansas Medical Center, Little Rock; Arkansas Children's Hospital, Little Rock.
authors.forename: Brita S
authors.initials: BS
authors.lastname: Deacon
authors.affiliation: Arkansas Children's Hospital, Little Rock.
authors.forename: Katherine J
authors.initials: KJ
authors.lastname: Fray
authors.affiliation: University of Arkansas Medical Center, Little Rock; Arkansas Children's Hospital, Little Rock.
authors.forename: A Paula
authors.initials: AP
authors.lastname: Grigorian
authors.affiliation: Arkansas Children's Hospital, Little Rock.
authors.forename: Hanya M
authors.initials: HM
authors.lastname: Qureshi
authors.affiliation: University of Arkansas Medical Center, Little Rock.
authors.forename: Horace J
authors.initials: HJ
authors.lastname: Spencer
authors.affiliation: University of Arkansas Medical Center, Little Rock; Arkansas Children's Hospital, Little Rock.
authors.forename: R Scott
authors.initials: RS
authors.lastname: Lowery
authors.affiliation: University of Arkansas Medical Center, Little Rock; Arkansas Children's Hospital, Little Rock. Electronic address: PhillipsPaulH@uams.edu.
authors.forename: Paul H
authors.initials: PH
authors.lastname: Phillips
mesh_terms: D000328:Adult; D000368:Aged; D004172:Diplopia / Q000209:etiology*; D005099:Exotropia / Q000601:surgery*; D005260:Female; D005500:Follow-Up Studies; D007839:Functional Laterality; D006801:Humans; D008297:Male; D008875:Middle Aged; D009801:Oculomotor Muscles / Q000601:surgery*; D013508:Ophthalmologic Surgical Procedures; D011183:Postoperative Complications; D015348:Vision, Binocular