title: Agreement between intraoperative measurements and optical coherence tomography of the limbus-insertion distance of the extraocular muscles.
abstract: OBJECTIVE
  To assess the agreement between intraoperative measurements of the limbus-insertion distance of the extraocular muscles with those measured by spectral domain optical coherence tomography.
  
  
  METHODS
  An analysis was made of a total of 67 muscles of 21 patients with strabismus. The limbus-insertion distance of the horizontal rectus muscles were measured using pre-operative SD-OCT and intra-operatively in 2 ways: 1) direct, after a conjunctival dissection in patients who underwent surgery, or 2) transconjunctival in patients who were treated with botulinum toxin, or in those who were not going to be operated. The intraclass correlation coefficient and Bland-Altman plots were calculated to determine the concordance between the 2 methods.
  
  
  RESULTS
  The mean age was 45.9 ±20.9 years (range 16 to 85), with 52% being women. The percentage of identification by direct intraoperative measurement was 95.6% (22/23), by transconjunctival intraoperative measurement 90.9% (40/44), and by OCT 85% (57/67), with 22 muscles finally being analysed for the agreement study between direct intraoperative measurement and OCT measurements, and 35 muscles for the agreement between transconjuctival intraoperative measurement and OCT. The intraclass correlation coefficient showed good agreement with OCT and direct intraoperative measurements (0.931; 95% confidence interval (95% CI): 0.839-0.972; P<.001), and with transconjunctival intraoperative measurements (0.889; 95% CI: 0.790-0.942; P<.001).
  
  
  CONCLUSIONS
  The SD-OCT is an effective technique to measure the distance from the insertion of the horizontal rectus muscles to the limbus, with a high agreement with intraoperative measurements being demonstrated.
authors.affiliation: Departamento de Oftalmología, Complejo Asistencial de Ávila, Ávila, España. Electronic address: depablo.lucia@gmail.com.
authors.forename: L
authors.initials: L
authors.lastname: de-Pablo-Gómez-de-Liaño
authors.affiliation: Departamento de Oftalmología, Hospital Universitario Clínico San Carlos, Instituto de Investigación sanitaria (IdISSC), Madrid, España.
authors.forename: J I
authors.initials: JI
authors.lastname: Fernández-Vigo
authors.affiliation: Departamento de Oftalmología, Hospital Universitario Clínico San Carlos, Instituto de Investigación sanitaria (IdISSC), Madrid, España.
authors.forename: N
authors.initials: N
authors.lastname: Ventura-Abreu
authors.affiliation: Departamento de Oftalmología, Hospital Universitario Clínico San Carlos, Instituto de Investigación sanitaria (IdISSC), Madrid, España.
authors.forename: L
authors.initials: L
authors.lastname: Morales-Fernández
authors.affiliation: Departamento de Oftalmología, Hospital Universitario Clínico San Carlos, Instituto de Investigación sanitaria (IdISSC), Madrid, España.
authors.forename: J
authors.initials: J
authors.lastname: García-Feijóo
authors.affiliation: Departamento de Oftalmología, Hospital Universitario Clínico San Carlos, Instituto de Investigación sanitaria (IdISSC), Madrid, España.
authors.forename: R
authors.initials: R
authors.lastname: Gómez-de-Liaño
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003430:Cross-Sectional Studies; D061827:Dimensional Measurement Accuracy; D005260:Female; D006801:Humans; D007432:Intraoperative Period; D008297:Male; D008875:Middle Aged; D009801:Oculomotor Muscles / Q000033:anatomy & histology* / Q000000981:diagnostic imaging*; D013285:Strabismus / Q000601:surgery*; D041623:Tomography, Optical Coherence; D055815:Young Adult
keywords: Distancia inserción-limbo; Estrabismo; Extraocular muscles; Horizontal rectus muscles insertion; Inserción de rectos horizontales; Limbus-insertion distance; Músculos extraoculares; Optical coherence tomography; Strabismus; Tomografía de coherencia óptica