title: Astigmatic changes after horizontal rectus muscle surgery in intermittent exotropia.
abstract: OBJECTIVE
  To evaluate the changes of refractive astigmatism after horizontal rectus muscle surgery in intermittent exotropic children.
  
  
  METHODS
  Sixty-nine exotropic patients were retrospectively reviewed. Of those, 35 patients received unilateral lateral rectus recession (BLR group, 35 eyes) and 34 patients received unilateral lateral rectus recession and medial rectus resection (R&R group, 34 eyes). Non-cycloplegic refractions were measured until 6 months postoperatively. Spherical equivalent (SE), J0 and J45 using power vectors were calculated to determine and compare the changes of refractive astigmatism and axis in both groups.
  
  
  RESULTS
  SE significantly decreased after surgery for the first week and did not changed thereafter in both groups (p = 0.000 and p = 0.018, respectively). In BLR group, J0 showed significant changes at the first week and 1 month after surgery (p = 0.005 and p = 0.016, respectively), but in R&R group, J0 changed significantly between 1 week and 3 months postoperatively (p = 0.023 and p = 0.016, respectively). J45 did not change significantly as time passed in both groups (all p > 0.05). There was no statistically significant difference in the magnitude of changes in SE, J0 and J45 between the two groups after the 6-month follow-up (p = 0.500, p = 0.244 and p = 0.202, respectively).
  
  
  CONCLUSIONS
  Horizontal rectus muscle surgery in intermittent exotropic children tends to induce a statistically significant change in astigmatism in the with-the-rule direction and myopic shift in SE. This astigmatism change seems to occur within the first 3 months after surgery. Thus, astigmatism induced by surgery should be checked and corrected at least 3 months after horizontal strabismus surgery.
authors.affiliation: Department of Ophthalmology & Visual Science, Bucheon St. Mary's Hospital, The Catholic University of Korea College of Medicine, Bucheon, Korea.
authors.forename: Seung Woo
authors.initials: SW
authors.lastname: Hong
authors.forename: Nam Yeo
authors.initials: NY
authors.lastname: Kang
mesh_terms: D000293:Adolescent; D001251:Astigmatism / Q000209:etiology* / Q000503:physiopathology; D002648:Child; D002675:Child, Preschool; D005099:Exotropia / Q000150:complications / Q000503:physiopathology / Q000601:surgery*; D005133:Eye Movements; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D009801:Oculomotor Muscles / Q000601:surgery; D013508:Ophthalmologic Surgical Procedures / Q000379:methods*; D012189:Retrospective Studies; D016896:Treatment Outcome; D015348:Vision, Binocular / Q000502:physiology*