title: Effects of Bilateral Superior Oblique "Hang-Back" Recession in Treatment of A-pattern Strabismus with Superior Oblique Overaction.
abstract: OBJECTIVE
  To investigate the efficacy and safety of bilateral hang-back recession of superior oblique (SO) muscles in the treatment of A-pattern strabismus with superior oblique overaction (SOOA).
  
  
  METHODS
  Thirty-one (31) patients (62 eyes) with A-pattern horizontal deviation and SOOA underwent hang-back recession of SO and retrospective analysis of the surgical amount of hang-back recession of SO, preoperative and postoperative A-pattern, ocular motility, and corrected objective torsion. Patients were evaluated before and 6 to 9 months after surgery.
  
  
  RESULTS
  The average A-pattern horizontal deviation was 27.58 ± 11.47 prism diopters (PD) before surgery and 3.48 ± 3.70 PD after surgery (n=31, P<0.05). The mean corrected A-pattern was horizontal deviation 24.10 ± 10.32 PD. The average scale of SOOA on a scale of +1 to +4 was +3.05 ± 0.80 before surgery and +0.42 ± 0.50 after surgery in 62 eyes (P<0.05). The mean corrected objective torsion was 4.91° ± 4.53°. The surgical amount of SO hang-back recession ranged from 4 to 10 mm (mean: 7.62 ± 1.18 mm), which was related to the preoperative A-pattern and corrected A-pattern. There were no surgical complications.
  
  
  CONCLUSIONS
  SO hang-back recession is a safe and efficient option for A-pattern caused by SOOA.
authors.affiliation: a Tianjin Eye Hospital, Clinical College of Ophthalmology of Tianjin Medical University , Tianjin Key Laboratory of Ophthalmology and Vision Science , Tianjin , China.
authors.forename: Yueping
authors.initials: Y
authors.lastname: Li
authors.affiliation: a Tianjin Eye Hospital, Clinical College of Ophthalmology of Tianjin Medical University , Tianjin Key Laboratory of Ophthalmology and Vision Science , Tianjin , China.
authors.forename: Huizhi
authors.initials: H
authors.lastname: Ma
authors.affiliation: a Tianjin Eye Hospital, Clinical College of Ophthalmology of Tianjin Medical University , Tianjin Key Laboratory of Ophthalmology and Vision Science , Tianjin , China.
authors.forename: Kanxing
authors.initials: K
authors.lastname: Zhao
mesh_terms: D000293:Adolescent; D000328:Adult; D002648:Child; D002675:Child, Preschool; D005133:Eye Movements / Q000502:physiology; D005260:Female; D006801:Humans; D008297:Male; D009801:Oculomotor Muscles / Q000503:physiopathology / Q000601:surgery*; D013508:Ophthalmologic Surgical Procedures; D012189:Retrospective Studies; D013285:Strabismus / Q000503:physiopathology / Q000601:surgery*; D014785:Vision, Ocular / Q000502:physiology; D014792:Visual Acuity / Q000502:physiology
keywords: A-pattern; superior oblique hang-back recession; superior oblique overaction (SOOA); surgery