Background: Neuromyelitis optica spectrum disorder (NMOSD) is an autoimmune inflammatory disorder of the central nervous system with prominent involvement of the optic nerves and spinal cord. Optic neuritis in NMOSD can result in severe visual impairment, and recurrent attacks may lead to optic atrophy and permanent visual loss. This study evaluated optic nerve involvement and visual outcomes following corticosteroid therapy in patients with NMOSD.

Methods: A prospective evaluatory study was conducted among 17 patients (34 eyes) diagnosed with NMOSD who attended the neurology department. Demographic and clinical history were recorded. Visual acuity, colour vision, pupillary reactions, anterior and posterior segment examinations were performed. OCT, visual field testing and VEP were performed wherever feasible. MRI findings and AQP4/MOG antibody status were documented. Patients with active disease received intravenous methylprednisolone 1 g/day for 3 days followed by oral prednisolone with gradual tapering and were followed up at 1, 3 and 6 months.

Results: Of 17 patients, 15 (88.2%) were female and 2 (11.8%) were male. Eye involvement was present in 14 patients. Nine patients (52.9%) had bilateral involvement, five (29.4%) had unilateral involvement and three (17.6%) had no eye involvement. Among affected eyes, 12 (52.1%) showed optic neuritis, 6 (26.1%) had disc edema and 5 (21.7%) had optic atrophy. Three eyes (13.0%) had complete visual loss, while 20 (86.9%) had partial visual loss. Significant visual improvement after treatment was reported in 14 affected eyes (60.8%), while 9 (39.1%) showed minimal improvement. Among the significantly improved eyes, 8 were associated with anti-MOG positivity.

Conclusion: Optic nerve involvement is a major ocular manifestation of NMOSD and may progress from unilateral to bilateral disease with recurrent attacks. High-dose intravenous methylprednisolone followed by oral corticosteroid therapy was associated with visual improvement in a substantial proportion of affected eyes. The observed better recovery among anti-MOG-positive eyes is an exploratory finding that requires confirmation in larger studies.

KEYWORDS: Neuromyelitis Optica Spectrum Disorder, Optic Neuritis, Optic Atrophy, anti-AQP4, Anti-MOG, Corticosteroids, Visual Outcome.