Post-flu-vaccination optic neuritis is an extremely rare condition with anincidence ranging from 0.003 cases to 0.89 per 100 000population. The exact pathophysiology is not clearly defined. Most of the patients with post-flu-vaccination optic neuritis tend to present with progressive worsening of vision in 2-3 weeks postvaccine administration. A prompt fundus examination supplemented with MRI imaging of the orbit is required to establish the diagnosis. On diagnosis, early initiation of high-dose oral or IV steroids is recommended to prevent optic atrophy or worsening of vision. Most patients tend to have complete recovery of vision when started on steroids. However, if the patient continues to have worsening symptoms while being treated with a high dose of steroids, plasmapheresis (PLEX) is an effective intervention.