Background/aims 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.
- Optical coherence tomography
- image analysis
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Funding NIH Grant EY03040; NEI Grant R01 EY014375; DFG Grant He 6094/1-1.
Competing interests SRS and ACW share in royalties from intellectual property licensed to Topcon Medical Systems by the Doheny Eye Institute. SRS also serves on the scientific advisory board for Heidelberg Engineering and receives research support from Carl Zeiss Meditec and Optovue Inc.
Ethics approval Ethics approval was provided by the University of Southern California, Los Angeles, California, USA.
Provenance and peer review Not commissioned; externally peer reviewed.