Optic neuritis (ON) is a rare inflammatory disorder of the optic nerve that results in vision loss. It is characterized by rapid and variable vision loss, pain in, around and behind the eye, and changes in color vision. Subjects in this study will be followed for 12 months total and randomized in a 2:1 ratio to receive either an IV infusion medication or a placebo infusion. Low Contrast Visual Acuity will be tracked at 3 months. After 3 months, participants will continue the study
through Month 12 in the safety follow-up part of the study intended to provide longer
term safety information.