Abstract
Purpose: :
to evaluate the intrasession repeatability and variability of retinal nerve fiber layer (RNFL) measurements in healthy subjects using 3 instruments: Cirrus HD-OCT (Carl Zeiss Meditec), SOCT Copernicus HR (Optopol) and 3D OCT-1000 (Topcon).
Methods: :
The RNFL thickness was measured by Cirrus HD-OCT and SOCT Copernicus HR in 25 healthy volunteers. Each person was examined by both instruments in one session. One experienced operator took 2 measurements with each instrument. In another similar group of 25 healthy subjects the RNFL measurements were performed by 3D OCT-1000. The same operator took 2 measurements in one session. The repeatability was evaluated by J.M.Bland-D.G.Altman analysis (1996). Within-subject coefficients of variation were calculated using J.M.Bland method.
Results: :
All instruments demonstrated similar intrasession repeatability: 3.21 µm for Cirrus HD-OCT, 3.57 µm for SOCT Copernicus HR and 4.20 µm for 3D OCT-1000 (the differences were not statistically significant). Within-subject coefficient of variation was equal for SOCT Copernicus HR and 3D OCT-1000 (1.40±0.20%). Cirrus HD-OCT showed slight but insignificant tendency for lower variability (within-subject coefficient of variation was 1.23±0.17%).
Conclusions: :
All three spectral domain optical coherence tomographs demonstrated good intrasession repeatability and low variability of RNFL measurements.
Keywords: imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) • nerve fiber layer