Optic Disc Cupping in Neuromyelitis Optica Spectrum Disorder, Myelin Oligodendrocyte Glycoprotein Antibody-Associated Disease, and Multiple Sclerosis and Its Relationship With Optical Coherence Tomography Parameters: A Multicenter Study

Background: Although cupping of the optic nerve is classically a sign of glaucomatous optic neuropathy, it has been shown that cupping can sometimes occur after an episode of optic neuritis (ON). The purpose of this study was to compare cupping in patients after ON from multiple sclerosis (MS), neuromyelitis optica spectrum disorder (NMOSD), or myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD) and to investigate the relationship between cupping and retinal nerve fiber layer (RNFL) and ganglion cell complex (GCC) thinning. Methods: This was a retrospective cohort involving patients (≥18 years) with ON from 3 institutions. Patients were eligible if they had optical coherence tomography (Cirrus, OCT) performed ≥6 months after a single unilateral ON. The amount of thinning and cupping was estimated from the difference in the OCT parameters between affected and unaffected eyes. Univariable and multivariable regressions were used to investigate the relationship between cupping and ON etiology. Pearson correlation was used to investigate the relationship between cupping and RNFL and GCC. Results: Eighty-six subjects (MS: 35, NMOSD: 26, and MOGAD: 25) were included. There was no significant difference in gender and race between the groups, and most patients (86.1%) were female. Patients with NMOSD were significantly older than patients with MS or MOGAD ( P = 0.002). In the univariate model, cupping was significantly higher in the NMOSD group ( P = 0.017); however, after adjusting for age, GCC, and RNFL of the affected eye, the difference was no longer statistically significant ( P = 0.949). The correlation between cupping asymmetry and RNFL and GCC of the affected eye was inversely strong in patients with MS (R = −0.60 and R = −0.64, respectively), inversely moderate in patients with MOGAD (R = −0.34 and R = −0.40, respectively), and weak in patients with NMOSD (R = −0.03 and R = −0.17, respectively). Conclusions: Our results demonstrated that cupping after ON is correlated with RNFL and GCC thinning; although cupping was overall greater in the NMOSD group, once adjusted for age, RNFL, and GCC, it did not differ among patients with MS, NMOSD, and MOGAD.