Reproducibility and differences between cirrus and spectralis fourier-domain OCT in epiretinal membranes

Purpose To evaluate the ability of Fourier-domain (FD) OCT to detect retinal alterations in epiretinal membrane (ERM) eyes. To test the intra-session reproducibility of macular thickness measurements in ERM and healthy subjects using Cirrus and Spectralis OCT. Methods Two hundred and nine of 209 subjects (87 ERM patients and 122 healthy subjects) underwent three macular scans by the same experienced examiner using Cirrus and Spectralis OCT . Differences between healthy and ERM eyes were studied. The relationship between average thicknesses with both instruments was evaluated. Repeatability was studied by intra-class correlation coefficients and coefficients of variation (COV) for the nine areas corresponding to the ETDRS. Results Macular thickness increase was detected in ERM eyes for all OCT parameters (p<0.05). Macular average thickness was 338.45 and 431.99 µm in ERM eyes using Cirrus and Spectralis, respectively. Changes in the morphology of the retinal layers were detected using both OCTs. Macular average thickness in ERM eyes as determined by both OCTs was correlated (r= 0.678; p<0.001), but differences were statistically significant (p=0.044). In ERM eyes, measurements showed a mean COV of 2.96% using Cirrus, 2.21% using Spectralis and 0.99% using Spectralis progression feature. Intra-class correlation coefficients were higher than 0.919. Conclusion Significant differences exist in macular thickness measurements between Cirrus and Spectralis despite the high correlation of measurements between the two instruments. Fourier-domain OCT can be considered a valid device to detect alterations in ERM patients.