title: Predictive factors affecting the short term and long term exodrift in patients with intermittent exotropia after bilateral rectus muscle recession and its effect on surgical outcome.
abstract: OBJECTIVE
  To determine the predictive factors that affect short term and long term postoperative drift in intermittent exotropia after bilateral lateral rectus recession and to evaluate its effect on surgical outcome.
  
  
  METHODS
  Retrospective review of 203 patients with diagnosis of intermittent exotropia, who had surgical corrections with more than 3 years of followup. Different preoperative parameters were obtained and evaluated using Pearson's correlation analysis.
  
  
  RESULTS
  The proportion of exodrift increased from 62% at 6 weeks to 84% at 3 years postoperatively. The postoperative drift was 4.3 ± 8.1 PD at 6 weeks, 5.8 ± 8.4 PD at 6 months, 7.2 ± 8.3 PD at 1 year, 7.4 ± 8.4 PD at 2 years, and 7.7 ± 8.5 PD at 3 years. Preoperative deviation and initial overcorrection were significant factors affecting the postoperative drift at 3 years (r = 0.177, P = 0.011, r = -0.349, and P < 0.001, resp.).
  
  
  CONCLUSIONS
  Postoperative exodrift along three years occurs in a majority of patients after bilateral lateral rectus recession for intermittent exotropia. The long term surgical success is significantly affected by this postoperative exodrift. A larger preoperative deviation and a larger initial overcorrection are associated with a larger early and late postoperative exodrift.
authors.affiliation: Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong.
authors.forename: Jason C S
authors.initials: JC
authors.lastname: Yam
authors.affiliation: Department of Ophthalmology, Tung Wah Eastern Hospital, Hong Kong.
authors.forename: Gabriela S L
authors.initials: GS
authors.lastname: Chong
authors.affiliation: Department of Ophthalmology, Tung Wah Eastern Hospital, Hong Kong.
authors.forename: Patrick K W
authors.initials: PK
authors.lastname: Wu
authors.affiliation: Department of Ophthalmology, Tung Wah Eastern Hospital, Hong Kong.
authors.forename: Ursula S F
authors.initials: US
authors.lastname: Wong
authors.affiliation: Department of Ophthalmology, Tung Wah Eastern Hospital, Hong Kong.
authors.forename: Clement W N
authors.initials: CW
authors.lastname: Chan
authors.affiliation: Department of Ophthalmology, Tung Wah Eastern Hospital, Hong Kong.
authors.forename: Simon T C
authors.initials: ST
authors.lastname: Ko
mesh_terms: D000293:Adolescent; D002675:Child, Preschool; D005099:Exotropia / Q000473:pathology / Q000601:surgery*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D009801:Oculomotor Muscles / Q000601:surgery*; D011184:Postoperative Period; D017568:Rectus Abdominis / Q000601:surgery*; D016896:Treatment Outcome; D014792:Visual Acuity
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