Validation of inter-eye difference thresholds in optical coherence tomography for identification of optic neuritis in multiple sclerosis

Highlights

• Inter-eye differences in retinal thickness may identify unilateral optic neuritis in MS.

• pRNFL inter-eye difference ≥5 µm displayed 69% sensitivity and specificity 68%.

• GCIPL inter-eye difference ≥4 µm displayed 67% sensitivity and specificity 78%.

• Inter-eye differences in retinal thickness accurately demonstrate previous optic neuritis.

• Inter-eye differences might be included into a new version of the MS diagnostic criteria.

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.