title: Peripapillary nerve fiber layer thickness measurement reproducibility using scanning laser polarimetry.
abstract: OBJECTIVE
  The authors assess the reproducibility of retinal nerve fiber layer (RNFL) thickness measurements using scanning laser polarimetry.
  
  
  METHODS
  The right eyes of five healthy individuals were scanned by two trained operators (S.T.H., H.I.) using the Nerve Fiber Analyzer II (Laser Diagnostic Technologies, Inc., San Diego, CA, U.S.A.). Each participant was scanned six consecutive times per session for five sessions carried out over separate days within a two-week period. Intra- and interoperator measurement reproducibility was assessed.
  
  
  RESULTS
  Intraoperator reproducibility was high. Mean coefficients of variation for total RNFL thickness measurements were 4.48 +/- 1.76% and 4.92 +/- 2.32% for operators 1 and 2, respectively. Interoperator reproducibility was high (p = 0.20-0.93) if a single ellipse was applied to the images of both examiners. However, measurement reproducibility worsened if each operator created his own measurement ellipse (p < or = 0.05 for 3 out of 5 participants).
  
  
  CONCLUSIONS
  Interoperator error in image analysis can be minimized by using a single ellipse for the baseline and all subsequent scans even if subsequent scans are acquired by different operators.
authors.affiliation: Department of Ophthalmology, New York Eye and Ear Infirmary, NY 10003, USA.
authors.forename: S T
authors.initials: ST
authors.lastname: Hoh
authors.forename: H
authors.initials: H
authors.lastname: Ishikawa
authors.forename: D S
authors.initials: DS
authors.lastname: Greenfield
authors.forename: J M
authors.initials: JM
authors.lastname: Liebmann
authors.forename: S J
authors.initials: SJ
authors.lastname: Chew
authors.forename: R
authors.initials: R
authors.lastname: Ritch
mesh_terms: D000328:Adult; D006801:Humans; D007091:Image Processing, Computer-Assisted; D007834:Lasers; D009412:Nerve Fibers; D015588:Observer Variation; D009887:Ophthalmoscopy / Q000379:methods*; D009898:Optic Disk / Q000033:anatomy & histology*; D009900:Optic Nerve / Q000033:anatomy & histology*; D012016:Reference Values; D015203:Reproducibility of Results