Poor Visual Outcome After First Attack in a Cohort of Patients With Myelin Oligodendrocyte Glycoprotein-Related Optic Neuritis

Background: Myelin oligodendrocyte glycoprotein-associated optic neuritis (MOG-ON) is typically a highly treatable condition that responds quickly to treatment with high doses of corticosteroids. We reviewed the cohort of patients with MOG-ON to identify patients who had poor visual outcome after the first attack despite rapid initiation of treatment. Methods: Records of all patients diagnosed with MOG-ON seen in a tertiary neuro-ophthalmology practice were reviewed to identify and describe those with poor visual recovery (final visual acuity of 20/200 or worse in at least one eye) after the first attack despite initiation of treatment within 1 week of symptoms onset. Results: Two patients of 36 fulfilled inclusion criteria: both had bilateral severe optic neuritis at presentation, and both were seen within 7 days of symptoms onset and treated immediately with pulse doses of intravenous corticosteroids followed by very-slow oral taper. Plasma exchange (PLEX) was performed 2 weeks after symptoms onset in both patients because of poor response to steroids, followed by monthly intravenous immunoglobulin infusions. Despite the use of all available treatment modalities, final visual outcome was poor in both patients. In both patients, there was enhancement of intracanalicular portion of optic nerve in the worse-seeing eye. Conclusions: In this cohort of patients with MOG-ON, 2 (5.6%) had very poor visual outcome after the first attack despite immediate initiation of treatment with pulse doses of corticosteroids and subsequent treatment with PLEX. These cases highlight that despite immediate initiation and escalation of treatment, some patients with MOG-ON can have very poor visual outcomes after the initial attack that may be because of the involvement of the intracanalicular portion of the optic nerves.