title: Repeatability and reproducibility of retinal thickness measurements in diabetic patients with spectral domain optical coherence tomography.
abstract: BACKGROUND
  To determine the repeatability and reproducibility of optical coherence tomography (OCT) Spectralis retinal thickness measurements in diabetic patients with clinically significant macular edema (CSME).
  
  
  METHODS
  Twelve eyes of 12 volunteers (without macular pathology - control group) and 21 eyes of 21 diabetic patients with CSME were included in the study. Reproducibility, repeatability, intraclass correlation coefficients (ICCs) and intrasession correlation coefficients were tested with 20 × 15 degree raster scans consisting of 19 high-resolution line scans that were repeated three times by two experienced examiners.
  
  
  RESULTS
  In the control group, examining all regions, coefficient of repeatability was less than 1.1%, while coefficient of reproducibility was less than 2.2%. In diabetic patients, examining all regions, coefficient of repeatability was less than 2.6%, while coefficient of reproducibility was less than 2.4%. ICCs were, respectively, greater than or equal to 0.98 in the control group and 0.99 in diabetic patients. Intrasession coefficients of variation were less than 0.4% in the control group and less than 0.5% in diabetic patients.
  
  
  CONCLUSIONS
  Retinal thickness measurements are repeatable and reproducible with OCT Spectralis in both the control group and diabetic patients. The results indicate that a change in central subfield thickness exceeding 12 µm and 3% in the diabetic patients is likely to be real.
authors.affiliation: Department of Ophthalmology, Eye Clinic, University of Perugia, Perugia, Italy.
authors.forename: Tito
authors.initials: T
authors.lastname: Fiore
authors.forename: Sofia
authors.initials: S
authors.lastname: Androudi
authors.forename: Barbara
authors.initials: B
authors.lastname: Iaccheri
authors.forename: Marco
authors.initials: M
authors.lastname: Lupidi
authors.forename: Fabrizio
authors.initials: F
authors.lastname: Giansanti
authors.forename: Giansanti
authors.initials: G
authors.lastname: Fabrizio
authors.forename: Daniela
authors.initials: D
authors.lastname: Fruttini
authors.forename: Laura
authors.initials: L
authors.lastname: Biondi
authors.forename: Carlo
authors.initials: C
authors.lastname: Cagini
mesh_terms: D000328:Adult; D003930:Diabetic Retinopathy / Q000473:pathology*; D005260:Female; D006801:Humans; D008269:Macular Edema / Q000473:pathology*; D008297:Male; D011446:Prospective Studies; D015203:Reproducibility of Results; D012160:Retina / Q000473:pathology*; D012984:Software; D041623:Tomography, Optical Coherence / Q000379:methods* / Q000592:standards*; D014792:Visual Acuity