Abstract
Purpose: :
To compare retinal thickness measurements produced by different time-domain and spectral-domain optical coherence tomography (TD-OCT and SD-OCT) devices when imaging normal and pathologic eyes
Methods: :
110 eyes were imaged by six different OCT devices: Stratus from Carl Zeiss Meditec Inc., Dublin, CA, USA (software version 4.0.2), Cirrus from Carl Zeiss Meditec Inc., Dublin, CA, USA (Software version 2.0.0.54), Spectralis HRA+OCT from Heidelberg Engineering, Heidelberg, Germany (Software version 3.1.4), RTVue-100 from Optovue Inc., Fremont, CA, USA (Software Version 2.5), SDOCT Copernicus HR from Optopol Technology S.A., Zawiercie, Poland (Software version 2.01) and 3D OCT-1000 from Topcon Corporation, Tokyo, Japan (Software version 2.12). Eyes were normal of affected by different retina pathologies, including exudative and non-exudative age related macular degeneration, epiretinal membrane, cystoid macular edema, macular hole, branch retinal vein occlusion, Stargardt’s disease and central serous chorioretinopathy. For each instrument we used standard analysis protocols for macular thickness evaluation. Mean retinal thickness values between the instruments in central and mid peripheral areas were compared
Results: :
The 6 different devices produced measurements that differ in variance (Bartlett test p=0.006), and mean values (Friedman test p<0.001). Altman-Bland analysis revealed that the limits of agreement (LOA) for all the comparisons were not acceptable. Regression was calculated comparing all the instruments and it was elaborated into a conversion table, despite a high standard error for both intercepts and slopes conversion values
Conclusions: :
This study suggests that retinal thickness measurements obtained with various OCT devices are different beyond clinical practice tolerance, according to Altman-Bland analysis. Furthermore, regression analysis reveals very high standard error values. These differences in retinal thickness measurements among the instruments appear to be primarily due to the analysis algorithms used to set retinal inner and outer boundaries
Keywords: imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) • imaging/image analysis: clinical • macula/fovea