Vision Restoration of Steroid-Refractory Prelaminar Optic Nerve Inflammation with Plasmapheresis: Report of Two Cases and Literature Review.

Introduction: Inflammation of the prelaminar compartment of the optic nerve involves the most anterior segment of the nerve. It can occur in isolation, in the setting of immunological or demyelinating disorders. Case Presentation: We present two 32- and 41-year-old female patients with sequential bilateral isolated prelaminar optic neuritis with atypical features. In both instances, plasma exchange (PLEX) was initiated for the second affected eye after corticosteroids proved ineffective, resulting in excellent visual recovery. Both patients lost vision in the fellow eye due to a similar attack that was also refractory to steroids. Our cases did not show any associated demyelinating lesions on imaging and did not show biomarkers such as aquaporin-4 or myelin oligodendrocyte glycoprotein (MOG) antibody in serum workup. They were followed for more than 5 years with stable vision in the only eye. Conclusion: In cases of isolated severe progressive prelaminar optic nerve inflammation refractory to steroid treatment, PLEX can be helpful, even if workup is unremarkable for neuromyelitis optica or other systemic and neurologic conditions.