title: Measurement of the limbus-insertion distance in adult strabismus patients with anterior segment optical coherence tomography.
abstract: OBJECTIVE
  To determine the ability of the anterior segment optical coherence tomography (AS-OCT) in measuring the distance from the corneoscleral limbus to the insertion site of the horizontal extraocular muscles in adult patients with strabismus.
  
  
  METHODS
  A total of 16 strabismus patients were recruited for this study. The limbus-insertion distances of the horizontal rectus muscles were measured with AS-OCT preoperatively and calipers intraoperatively. The intraclass correlation coefficient (ICC), Pearson's correlation coefficients, and Bland-Altman plots were used to evaluate the degree of agreement between the two methods of measurements.
  
  
  RESULTS
  Measurements of the limbus-insertion distances were taken on 37 muscles of the 16 patients: 18 medial rectus (MR) and 19 lateral rectus (LR). The mean limbus-insertion distance of MR and LR measured intraoperatively were 5.32 ± 0.44 mm (range, 4.5-6.1 mm) and 6.58 ± 0.53 mm (range, 5.5-7.5 mm). Comparable results measured with the AS-OCT were 5.72 ± 0.60 mm (range, 4.62-6.82 mm) and 6.80 ± 0.61 mm (range, 5.8-7.86 mm). For MR group and LR group, the values of limbus-insertion distance showed high Pearson's correlation coefficients (0.729 and 0.786, respectively). With the ICC analysis excellent agreement was observed for the measurements of LR group (ICC = 0.75). Fair to good agreement was observed for the MR group (ICC = 0.61). Bland-Altman plots also showed good agreement between the two methods of measurements.
  
  
  CONCLUSIONS
  AS-OCT can image the structure of horizontal rectus muscles well and provide good reliability and accuracy in measurement of the limbus-insertion distance.
authors.affiliation: Department of Ophthalmology, Shanghai tenth People's Hospital, Tongji University School of Medicine, Shanghai, China.
authors.forename: Xiaoqiang
authors.initials: X
authors.lastname: Liu
authors.forename: Fang
authors.initials: F
authors.lastname: Wang
authors.forename: Ying
authors.initials: Y
authors.lastname: Xiao
authors.forename: Xinhai
authors.initials: X
authors.lastname: Ye
authors.forename: Lijie
authors.initials: L
authors.lastname: Hou
mesh_terms: D000328:Adult; D005260:Female; D006801:Humans; D007432:Intraoperative Period; D016850:Limbus Corneae / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D009801:Oculomotor Muscles / Q000473:pathology*; D010865:Pilot Projects; D057234:Preoperative Period; D015203:Reproducibility of Results; D012590:Sclera / Q000473:pathology*; D013285:Strabismus / Q000175:diagnosis* / Q000601:surgery; D041623:Tomography, Optical Coherence / Q000379:methods*; D055815:Young Adult