Fourier-domain OCT in multiple sclerosis patients: reproducibility and ability to detect retinal nerve fiber layer atrophy.

PURPOSE: To evaluate the ability of Fourier-domain (FD) optical coherence tomography (OCT) to detect retinal nerve fiber layer (RNFL) atrophy in multiple sclerosis (MS) patients. To test the intrasession reproducibility of RNFL thickness measurements in MS and healthy subjects using Cirrus (Carl Zeiss Meditec, Dublin, CA) and Spectralis (Heidelberg Engineering, Heidelberg, Germany) OCT.
METHODS: Two hundred twenty-two eyes of 111 subjects (50 MS patients and 61 healthy subjects) underwent three 360° circular scans centered on the optic disc by the same experienced examiner using the Cirrus and Spectralis OCT instruments. Differences between healthy and MS eyes were compared. The relationship between average thicknesses with each OCT was evaluated. Repeatability was studied by intraclass correlation coefficients and coefficients of variation (COV).
RESULTS: RNFL atrophy was detected in the MS eyes for all OCT parameters (P < 0.05). Cirrus and Spectralis showed an RNFL average thickness of 99.4 and 102.5 μm, respectively, in healthy subjects, and 86.0 and 90.4 μm in the MS eyes. RNFL average thickness in the MS eyes determined by both OCTs correlated (r = 0.812; P < 0.001), but were significantly different (P < 0.001). Reproducibility was good. In the MS eyes, Cirrus measurements showed a mean COV of 5.85%, Spectralis 6.80%, and Spectralis with a progression feature 4.16%. Intraclass correlation coefficients were higher than 0.840. RNFL average thickness correlated with disease duration and an optic neuritis antecedent.
CONCLUSIONS: There are significant differences in RNFL thickness measurements between Cirrus and Spectralis despite a high correlation of measurement between the two instruments. Fourier-domain OCT can be considered a valid device for detecting RNFL atrophy in MS patients.