title: Surgical experiences with two-muscle surgery for the treatment of intermittent exotropia.
abstract: BACKGROUND
  The surgical management of intermittent exotropia, or X(T), remains a challenge. Not only are some quoted success rates relatively low (40-83%), but the outcome is notoriously unpredictable with a tendency to exotropic drift over time.
  
  
  METHODS
  In this retrospective study, 118 patients who underwent either bilateral lateral rectus muscle recession (BLR) or unilateral medial rectus muscle resection and lateral rectus muscle recession (R&R) surgery during a 4-year period were reviewed. Surgical outcome between the 2 groups in addition to factors that influence outcome within groups were analyzed. Success was defined as an X(T) < or = 10PD.
  
  
  RESULTS
  Sixty-four subjects underwent BLR, and 54 subjects underwent R&R surgery. Mean preoperative distant X(T) size was 38.7 +/- 6.7 PD. Subjects who underwent R&R did significantly better at 1-year follow-up (success 74.2% vs. 42.2%) but showed significantly more exotropic drift over time (P = 0.01). Within both BLR and R&R groups, subjects with basic-type X(T) did worse than those with divergence-excess X(T) at 1-year follow-up. Consecutive esotropias, however, were more likely with R&R surgery and in those with divergence excess X(T). Preoperative strabismus control, distant X(T) size, and patient age at surgery did not significantly influence outcome.
  
  
  CONCLUSIONS
  In many cases, selection of surgery type continues to depend on the surgeon's preference, which is in turn influenced by his/her past experiences. The debate about which surgical type is best for different X(T) types continues.
authors.affiliation: Singapore National Eye Centre, Singapore, Singapore.
authors.forename: Audrey
authors.initials: A
authors.lastname: Chia
authors.forename: Linley
authors.initials: L
authors.lastname: Seenyen
authors.forename: Quah Boon
authors.initials: QB
authors.lastname: Long
mesh_terms: D002648:Child; D005099:Exotropia / Q000503:physiopathology / Q000601:surgery*; D005133:Eye Movements; D005500:Follow-Up Studies; D006801:Humans; D009801:Oculomotor Muscles / Q000503:physiopathology / Q000601:surgery*; D013508:Ophthalmologic Surgical Procedures / Q000379:methods*; D012189:Retrospective Studies; D012720:Severity of Illness Index; D013997:Time Factors; D016896:Treatment Outcome