Therapeutic Plasma Exchange in Myelin Oligodendrocyte Glycoprotein–Related Optic Neuritis: Restoring Vision Through Early Intervention – A Case Report

Myelin oligodendrocyte glycoprotein immunoglobulin G-associated optic neuritis (MOG-IgG ON) typically presents as severe, painful, and recurrent vision loss, often accompanied by optic disc oedema, which can result in significant visual morbidity. We report the case of a 27-year-old female of African ethnicity with a history of headache and bilateral gradual, progressive vision loss. Ophthalmic examination revealed no light perception and stage 3 papilloedema in both eyes. Magnetic resonance imaging (MRI) demonstrated bilateral optic neuritis, and anti-MOG-IgG was positive, confirming a diagnosis of MOG-IgG ON. The patient demonstrated notable visual improvement after the initiation of plasma exchange (PLEX) and high-dose corticosteroids within 53 hours of admission, followed by rituximab therapy. A total of seven sessions of PLEX were conducted, resulting in an improvement of ≥ 2 levels in the visual outcome scores by the end of the seventh session. Ultimately, a visual acuity of 6/6 in each eye was achieved after the administration of two doses of intravenous (IV) rituximab. This case study highlights the critical importance of early PLEX initiation to prevent irreversible optic nerve damage in MOG-IgG ON.