The development of MME was most frequent among patients with anti-aquaporin-4 antibody positive optic neuritis (29% of eyes), with n = 7 out of 643 OA eyes diagnosed with this etiology, followed by patients with infectious optic neuropathy (20% of eyes), with n = 5 out of 643 OA eyes diagnosed with this etiology. Here, AQP4 is linked to optic neuritis.