title: Repeatability and reproducibility of retinal thickness measurements by optical coherence tomography in age-related macular degeneration.
abstract: OBJECTIVE
  To evaluate the repeatability and reproducibility of retinal thickness measurements in exudative age-related macular degeneration (AMD) using Stratus optical coherence tomography (OCT) (Carl Zeiss Meditec, Inc., Dublin, CA).
  
  
  METHODS
  Prospective, observational case series.
  
  
  METHODS
  A total of 200 eyes of 200 subjects with exudative AMD.
  
  
  METHODS
  Macular thickness and fast macular thickness programs of Stratus OCT were performed twice by the same examiners or 2 different examiners. The sequence of examiners was randomized 1:1:1:1. The variability of 1-mm subfield central retinal thickness (CRT), center point thickness (CPT), and retinal volume (RV) was calculated.
  
  
  METHODS
  Interobserver and intraobserver variability of retinal thickness measurements.
  
  
  RESULTS
  Ninety-nine patients/eyes were enrolled in study arm 1 (repeated by the same examiner), and 101 patients/eyes were enrolled in study arm 2 (repeated by different examiners). Values of CPT, CRT, and RV were well correlated (interclass correlation coefficient, 0.71-0.93) in both study arms, revealing better results for the macular thickness program than for the fast macular thickness program. Threshold algorithm line failures were significantly correlated to the absolute differences of 2 repeated measurements for CPT, CRT, and RV but not with manually corrected maximum retinal thickness (MRT). Maximum retinal thickness was significantly influenced by the examiner performing the measurement. Age, lesion composition, examiner performing OCT examination, and sequence of examination had no significant influence.
  
  
  CONCLUSIONS
  The repeatability and reproducibility of retinal thickness measurements were high, presenting better results for CRT and RV versus CPT, and for the macular thickness program versus the fast macular thickness program. The reliability of retinal thickness measurement was most frequently affected by algorithm line failures and fixation problems. A possible solution may be manually corrected measurement, such as MRT.
authors.affiliation: The Ludwig Boltzmann Institute for Retinology and Biomicroscopic Laser Surgery, Vienna, Austria. Ilse.Krebs@wienkav.at
authors.forename: Ilse
authors.initials: I
authors.lastname: Krebs
authors.forename: Stefan
authors.initials: S
authors.lastname: Hagen
authors.forename: Werner
authors.initials: W
authors.lastname: Brannath
authors.forename: Paulina
authors.initials: P
authors.lastname: Haas
authors.forename: Irene
authors.initials: I
authors.lastname: Womastek
authors.forename: Gabriella
authors.initials: G
authors.lastname: de Salvo
authors.forename: Siamak
authors.initials: S
authors.lastname: Ansari-Shahrezaei
authors.forename: Susanne
authors.initials: S
authors.lastname: Binder
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000465:Algorithms; D005451:Fluorescein Angiography; D006801:Humans; D008268:Macular Degeneration / Q000175:diagnosis*; D008875:Middle Aged; D015588:Observer Variation; D011446:Prospective Studies; D015203:Reproducibility of Results; D012160:Retina / Q000473:pathology*; D041623:Tomography, Optical Coherence