title: Spectral domain optical coherence tomography to assess the insertion of extraocular rectus muscles.
abstract: To determine the distance of the horizontal rectus muscle insertion to the limbus using spectral domain optical coherence tomography (SD-OCT) and to evaluate whether results are correlated with sex, age, or axial length.
  
  
  
  The right eyes of healthy, white subjects were imaged with SD-OCT. Subjects' sex and age were recorded, and axial length was measured using an optical biometer. The distance from the horizontal rectus insertion to the limbus was measured. The intraclass correlation coefficient (ICC) was used to assess the reproducibility of the measurements with a subset of images. A multivariate model was adjusted to analyze whether sex, age, and axial length was correlated with insertion distance.
  
  
  
  A total of 187 right eyes were included. Mean participant age was 43.7 ± 22.1 years (range, 6-85). Of the 187 patients, 129 were female; 25 were children. Mean axial length was 23.9 ± 1.6 mm (range, 20.4-29.3). Mean rectus insertion distance to the limbus was 6.47 ± 0.52 mm (range, 5.2-7.6 mm) for the lateral rectus muscle and 5.22 ± 0.51 mm (range, 4.1-6.1 mm) for the medial rectus muscle. ICC was >0.87 for intra- and interobserver reproducibility. The insertion-limbus distance was correlated with sex, being greater in males (P = 0.040 for the lateral rectus muscle; P = 0.036 for medial rectus muscle). There was no correlation between this distance and axial length or age (P > 0.156).
  
  
  
  In this study cohort, the insertion distance of the horizontal rectus muscles to the limbus on SD-OCT was greater in males than females; however, age and axial length were not correlated with insertion distance.
authors.affiliation: Department of Ophthalmology, Complejo Asistencial de Ávila, Ávila, Spain. Electronic address: depablo.lucia@gmail.com.
authors.forename: Lucía
authors.initials: L
authors.lastname: De-Pablo-Gómez-de-Liaño
authors.affiliation: Department of Ophthalmology, Hospital Universitario Clínico San Carlos, Instituto de Investigación sanitaria (IdISSC), Madrid, Spain.
authors.forename: José Ignacio
authors.initials: JI
authors.lastname: Fernández-Vigo
authors.affiliation: Department of Ophthalmology, Hospital Universitario Clínico San Carlos, Instituto de Investigación sanitaria (IdISSC), Madrid, Spain.
authors.forename: Néstor
authors.initials: N
authors.lastname: Ventura-Abreu
authors.affiliation: Department of Ophthalmology, Hospital Universitario Clínico San Carlos, Instituto de Investigación sanitaria (IdISSC), Madrid, Spain.
authors.forename: Laura
authors.initials: L
authors.lastname: Morales-Fernández
authors.affiliation: Department of Preventive Medicine, Hospital Universitario Clínico San Carlos, Instituto de Investigación sanitaria (IdISSC), Madrid, Spain.
authors.forename: Cristina
authors.initials: C
authors.lastname: Fernández-Pérez
authors.affiliation: Department of Ophthalmology, Hospital Universitario Clínico San Carlos, Instituto de Investigación sanitaria (IdISSC), Madrid, Spain.
authors.forename: Julián
authors.initials: J
authors.lastname: García-Feijóo
authors.affiliation: Department of Ophthalmology, Hospital Universitario Clínico San Carlos, Instituto de Investigación sanitaria (IdISSC), Madrid, Spain.
authors.forename: Rosario
authors.initials: R
authors.lastname: Gómez-de-Liaño
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D058452:Axial Length, Eye / Q000033:anatomy & histology; D002648:Child; D003430:Cross-Sectional Studies; D005260:Female; D064368:Healthy Volunteers; D006801:Humans; D016850:Limbus Corneae / Q000000981:diagnostic imaging* / Q000502:physiology; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D009801:Oculomotor Muscles / Q000000981:diagnostic imaging* / Q000502:physiology; D011446:Prospective Studies; D012737:Sex Factors; D041623:Tomography, Optical Coherence