Validation of inter-eye difference thresholds in optical coherence tomography for identification of optic neuritis in multiple sclerosis
Gabriel Bsteh, Harald Hegen, Patrick Altmann, Michael Auer, Klaus Berek, Anne Zinganell, Franziska Di Pauli, Paulus Rommer, Florian Deisenhammer, Fritz Leutmezer, Thomas Berger
Abstract
OBJECTIVE: To examine and validate thresholds for inter-eye differences in peripapillary retinal nerve fibre (pRNFL) and ganglion cell + inner plexiform layer (GCIPL) thicknesses for identifying unilateral optic neuritis in MS. METHODS: In this two-centre, cross-sectional study, optical coherence tomography was performed in 340 patients with clinically isolated syndrome (CIS) and MS. Cut-off values of inter-eye difference for identification of eyes with a history of unilateral ON were evaluated by receiver-operating characteristics analysis. RESULTS: For pRNFL ≥5 µm, sensitivity was 69% and specificity 68%, while for GCIPL ≥4 µm sensitivity was 67% and specificity 78%. The areas under the curve (AUC) were 0.72 (95% confidence interval: 0.64 - 0.79) for pRNFL and 0.78 (95%CI: 0.72 - 0.85) for GCIPL, indicating GCIPL as the superior model (p<0.001). When analysing only CIS patients, GCIPL inter-eye difference ≥4 µm also remained significant, while pRNFL inter-eye difference did not. INTERPRETATIONS: Inter-eye differences of ≥4 μm for GCIPL and to a lesser degree ≥5 μm for RNFL are robust thresholds for identifying unilateral optic nerve lesions. These thresholds could be used to demonstrate previous symptomatic and possibly asymptomatic ON and might be included into a new version of the diagnostic criteria.