title: Comparison of manually corrected retinal thickness measurements from multiple spectral-domain optical coherence tomography instruments.
abstract: OBJECTIVE
  To compare retinal thickness measurements from three different spectral domain optical coherence instruments when manual segmentation is employed to standardise retinal boundary locations.
  
  
  METHODS
  40 eyes of 21 healthy subjects were scanned on the Cirrus HD-OCT, Topcon 3D-OCT-2000 and Heidelberg Spectralis-OCT. Raw data were imported into custom grading software (3D-OCTOR). Manual segmentation was performed on every data set, and retinal thickness values in the foveal central subfield were computed.
  
  
  RESULTS
  37 eyes of 20 subjects were gradable on every machine. The average retinal thicknesses for these eyes were 236.7 μm (SD 20.1), 235.7 μm (SD 20.4) and 236.5 μm (SD 18.0) for the Cirrus, 3D-OCT-2000 and Spectralis, respectively. Comparing manual retinal thickness measurements between any two machines, the maximum difference was 18.2 μm. The mean absolute differences per eye between two machines were: 4.9 μm for Cirrus versus 3D-OCT-2000, 3.7 μm for Cirrus versus Spectralis and 4.4 μm for 3D-OCT-2000 versus Spectralis.
  
  
  CONCLUSIONS
  When a uniform position is used to locate the outer retinal boundary, the retinal thickness measurements derived from three different spectral domain optical coherence instruments devices are virtually identical. Manual correction may allow OCT-derived thickness measurements to be compared between devices in clinical trials and clinical research.
authors: Doheny Eye Institute and Department of Ophthalmology, Keck School of Medicine of University of Southern California, Los Angeles, California 90033, USA.
authors: Florian M
authors: FM
authors: Heussen
authors: Yanling
authors: Y
authors: Ouyang
authors: Emma C
authors: EC
authors: McDonnell
authors: Ramsudha
authors: R
authors: Narala
authors: Humberto
authors: H
authors: Ruiz-Garcia
authors: Alexander C
authors: AC
authors: Walsh
authors: SriniVas R
authors: SR
authors: Sadda
mesh_terms: D000328:Adult; D000368:Aged; D003941:Diagnostic Techniques, Ophthalmological / Q000295:instrumentation*; D005260:Female; D006801:Humans; D008297:Male; D012016:Reference Values; D015203:Reproducibility of Results; D012160:Retina / Q000033:anatomy & histology*; D041623:Tomography, Optical Coherence / Q000295:instrumentation*; D055815:Young Adult