Marked Discordance Between Visual Field Loss and Optic Disc Cupping Revealing MOG Antibody-Associated Optic Neuritis in a Patient With Angle-Closure Glaucoma.

This study reports a case of MOG antibody-associated optic neuritis masquerading as acute angle-closure glaucoma in which marked discordance between optic disc cupping and visual field loss prompted magnetic resonance imaging (MRI) and led to the correct diagnosis. A 69-year-old woman presented with acute ocular pain, decreased vision, and intraocular pressure exceeding 40 mmHg in the right eye. Humphrey visual field testing demonstrated nearly complete central visual field loss, whereas fundus examination revealed only mild optic disc cupping. Because the severity of visual field loss was disproportionate to the optic disc findings, concurrent optic neuritis was suspected. MRI demonstrated a hyperintense lesion in the right optic nerve on short tau inversion recovery (STIR) imaging. Intravenous methylprednisolone pulse therapy was initiated, followed by bilateral cataract surgery combined with ab interno microhook trabeculotomy because of persistent angle closure and anticipated prolonged corticosteroid therapy. Subsequent serological testing confirmed myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD). Five months later, visual acuity recovered to 20/20 with substantial improvement in the visual field, and intraocular pressure remained well controlled. Even in patients with markedly elevated intraocular pressure suggestive of acute angle-closure glaucoma, pronounced discordance between optic disc findings and visual field loss should raise suspicion for concomitant optic neuritis or other nonglaucomatous optic neuropathies. MRI can facilitate the diagnosis of underlying MOG antibody-associated disease and guide appropriate neurological and ophthalmic management.