title: Repeatability and Reproducibility of Spectral-Domain Optical Coherence Tomography Measurements of Retinal Thickness in Rats.
abstract: To evaluate the in vivo repeatability and reproducibility of spectral-domain optical coherence tomography (SD-OCT) measurements of total retinal thickness (TRT) and retinal nerve fiber layer (RNFL) thickness in rats.
  
  
  
  Retinal thickness was measured using an RNFL circular scan with AutoRescan and TruTracking modes in 20 eyes of Long-Evans Tokushima Otsuka rats. Three RNFL circular scan images were acquired with a brief rest between measurements to evaluate intra-session repeatability. Three additional RNFL circular scans were acquired 1 day later to evaluate intersession repeatability. Two experienced examiners independently measured TRT using automatic alignment and RNFL thickness using manual alignment according to the same procedure to evaluate inter-examiner reproducibility 1 week later. The correlation of measurements by OCT and histology was determined.
  
  
  
  For TRT, the intra-session and inter-session intraclass correlation coefficient (ICC) with SD-OCT was between 0.85 and 0.93. The coefficient of variance (CV) ranged from 3.9% to 4.8%. For RNFL thickness, intra-session, and inter-session ICC with SD-OCT were between 0.61 and 0.91. The inter-examiner ICC was 0.74 for TRT and 0.70 for RNFL. The CV was 4.4% for TRT and 6.0% for RNFL. OCT and histologically determined TRT and RNFL thicknesses were significantly positively related based on Pearson's correlation coefficient (TRT, r = 0.781, p < 0.001; RNFL, r = 0.517, p = 0.019).
  
  
  
  TRT and RNFL thickness measurements using SD-OCT in rats had high intra-session and inter-session repeatability and inter-examiner reproducibility in vivo. This method will facilitate longitudinal studies to follow disease processes over time and to evaluate therapeutic effects after experimental intervention.
authors: a Department of Ophthalmology, Kyung Hee University Hospital , Kyung Hee University , Seoul , Korea.
authors: Ji Ho
authors: JH
authors: Yang
authors: a Department of Ophthalmology, Kyung Hee University Hospital , Kyung Hee University , Seoul , Korea.
authors: Seung-Young
authors: SY
authors: Yu
authors: b Department of Medicine, Graduate School , Kyung Hee University , Seoul , Korea.
authors: Tae Gi
authors: TG
authors: Kim
authors: a Department of Ophthalmology, Kyung Hee University Hospital , Kyung Hee University , Seoul , Korea.
authors: Kyung Hoon
authors: KH
authors: Seo
authors: a Department of Ophthalmology, Kyung Hee University Hospital , Kyung Hee University , Seoul , Korea.
authors: Hyung Woo
authors: HW
authors: Kwak
mesh_terms: D000818:Animals; D008297:Male; D023421:Models, Animal; D009412:Nerve Fibers; D051381:Rats; D020318:Rats, Long-Evans; D012016:Reference Values; D015203:Reproducibility of Results; D012165:Retinal Ganglion Cells / Q000166:cytology; D041623:Tomography, Optical Coherence / Q000379:methods*
keywords: RNFL; Rats; SD-OCT; TRT; repeatability; reproducibility