title: Repeatability and reproducibility of optic nerve head topography using the retinal thickness analyzer.
abstract: OBJECTIVE
  The objective was to determine the reproducibility and repeatability of topographic disk parameters with the retinal thickness analyzer (RTA).
  
  
  METHODS
  Thirty-nine eyes of 39 healthy subjects were included. Three observers performed three consecutive measurements of optic disk topography independently. Combined repeatability (intra-observer component of variability) and reproducibility (inter-observer component of variability, R and R) was assessed by variance component analysis.
  
  
  RESULTS
  Six topographic parameters (disk area, cup area, cup volume, mean cup depth, maximum depth, and cup shape measure) revealed an acceptable repeatability and reproducibility expressed as the percentage of the total measurement variability (range 17.6-28.4%). The average reproducibility and repeatability of all optic disk parameters measured using the RTA was not acceptable (combined R and R = 33.4%).
  
  
  CONCLUSIONS
  Repeatability and reproducibility of the optic disk topography analysis using the RTA reveals a high variation, and should, therefore, be interpreted carefully for glaucoma diagnosis and for monitoring the disease.
authors.affiliation: Department of Ophthalmology, University of Mainz, Mainz, Germany. ehoffmann@glaucoma.ucsd.edu
authors.forename: Esther M
authors.initials: EM
authors.lastname: Hoffmann
authors.forename: Felipe A
authors.initials: FA
authors.lastname: Medeiros
authors.forename: Christina
authors.initials: C
authors.lastname: Kramann
authors.forename: Norbert
authors.initials: N
authors.lastname: Pfeiffer
authors.forename: Franz H
authors.initials: FH
authors.lastname: Grus
mesh_terms: D000328:Adult; D003941:Diagnostic Techniques, Ophthalmological / Q000295:instrumentation; D005260:Female; D006801:Humans; D007429:Intraocular Pressure; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D009898:Optic Disk / Q000033:anatomy & histology*; D015203:Reproducibility of Results; D012160:Retina / Q000033:anatomy & histology*; D014792:Visual Acuity