title: Reproducibility of tear meniscus measurement by Fourier-domain optical coherence tomography: a pilot study.
abstract: OBJECTIVE
  To study the reproducibility of tear meniscus measurement with high-speed high-resolution Fourier-domain optical coherence tomography (FD-OCT).
  
  
  METHODS
  Twenty normal participants were enrolled in this prospective study. The lower tear meniscus in the right eye of each subject was imaged by vertical scans centered on the inferior cornea and the lower eyelid using an FD-OCT system (RTVue; Optovue, Inc., Fremont, CA) with a corneal adaptor. The system performs 26,000 axial scans per second and has a 5-micron axial resolution. Each subject was examined at two visits 30 to 60 days apart. Each eye was scanned twice on each visit. The scans were taken 2 seconds after a blink. The lower meniscus height, depth, and cornea-meniscus angle were measured with a computer caliper. The cross-sectional area was calculated using a two-triangle approximation.
  
  
  RESULTS
  The between-visits coefficient of variation was 17.5%, 18.0%, 35.5%, and 12.2% for meniscus height, depth, area, and angle, respectively. The intraclass correlations for these parameters were 0.605, 0.558, 0.567, and 0.367, respectively.
  
  
  CONCLUSIONS
  FD-OCT measures lower tear meniscus dimensions and area with higher between-visits reproducibility than previous OCT instruments. FD-OCT may be a useful way to measure dry eye severity and treatment effectiveness.
authors.affiliation: Doheny Eye Institute and Department of Ophthalmology, University of Southern California, Los Angeles, California, USA.
authors.forename: Sheng
authors.initials: S
authors.lastname: Zhou
authors.forename: Yan
authors.initials: Y
authors.lastname: Li
authors.forename: Ake Tzu-Hui
authors.initials: AT
authors.lastname: Lu
authors.forename: Pengfei
authors.initials: P
authors.lastname: Liu
authors.forename: Maolong
authors.initials: M
authors.lastname: Tang
authors.forename: Samuel C
authors.initials: SC
authors.lastname: Yiu
authors.forename: David
authors.initials: D
authors.lastname: Huang
mesh_terms: D000328:Adult; D005260:Female; D005500:Follow-Up Studies; D005583:Fourier Analysis; D006801:Humans; D008297:Male; D008875:Middle Aged; D010865:Pilot Projects; D011446:Prospective Studies; D012016:Reference Values; D015203:Reproducibility of Results; D013666:Tears / Q000737:chemistry*; D041623:Tomography, Optical Coherence / Q000379:methods*; D055815:Young Adult