Fig. 3

Representation of the optic nerve inflammation during acute phase optic neuritis in patients with MS, MOGAD and NMOSD. A) Schematic illustration of ON manifestations (dark blue areas) in MS involves unilateral short segment ON. Bilateral anterior ON in MOGAD is common and associated with accompanying optic disc edema extending more than 50% of optic nerve length bilaterally with optic nerve sheaths and perioptic fat involvement. AQP4 + NMOSD often represents bilateral ON involving the chiasm(Adapted from: Jeyakumar et al. Eye 2024, Cacciaguerra & Flanagan. Neurology Clinics 2024). Panel B) represents classic MRI findings in ON (arrows) due to MS which involves a short segment, often with patchy contrast enhancement in the optic nerve. In MOGAD, long-segment of contrast enhancement with involvement of the posterior globe is observed, and in NMOSD, a typical clinical manifestation is evident by bilateral involvement of the posterior optic nerves with involvement of the chiasm