title: Clinical features and surgical treatment of A-pattern exotropia.
abstract: OBJECTIVE
  To investigate the clinical characteristics and determine the effective surgical managements of A-pattern exotropia.
  
  
  METHODS
  Thirty-two patients with A-pattern exotropia underwent superior oblique muscle weakening procedures, medial rectus resection or (and) lateral rectus recession. Pre- and post-operative eye position, deviation angle, superior oblique function and binocular vision were examined and analyzed in the cases.
  
  
  RESULTS
  Overaction of the superior oblique muscles (31/32) and underaction of the medial rectus muscle (20/32) were presented in the cases. Postoperatively, a satisfactory ocular alignment was obtained in 28 cases (87.5%), and the A-pattern was corrected in 31 cases (96.9%). Four cases got binocular vision after surgery.
  
  
  CONCLUSIONS
  As one of the most common forms of A and V patterns, A-pattern exotropia showed clinical characteristics of superior oblique muscle overaction and medial rectus muscle underacion, which should be the primary factors in the etiology of A-pattern exotropia, and superior oblique weakening procedures combined with horizontal surgery should be an effective approach to A-pattern exotropia treatment.
authors.affiliation: Zhongshan Ophthalmic Center, Sun Yan-san University, Guangzhou 510060, China.
authors.forename: Jingchang
authors.initials: J
authors.lastname: Chen
authors.forename: Guanghuan
authors.initials: G
authors.lastname: Mai
authors.forename: Daming
authors.initials: D
authors.lastname: Deng
authors.forename: Xiaoming
authors.initials: X
authors.lastname: Lin
authors.forename: Yan
authors.initials: Y
authors.lastname: Guo
authors.forename: Xiao
authors.initials: X
authors.lastname: Yang
authors.forename: Chunxiu
authors.initials: C
authors.lastname: Yuan
mesh_terms: D000293:Adolescent; D000328:Adult; D002648:Child; D002675:Child, Preschool; D003867:Depth Perception / Q000502:physiology; D005099:Exotropia / Q000145:classification / Q000503:physiopathology / Q000601:surgery*; D005133:Eye Movements / Q000502:physiology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009801:Oculomotor Muscles / Q000503:physiopathology / Q000601:surgery*; D013508:Ophthalmologic Surgical Procedures / Q000379:methods; D012189:Retrospective Studies; D015348:Vision, Binocular