Anti-MOG antibodies have been described in idiopathic inflammatory optic neuritis (ON), such as aquaporin4-IgG seronegative neuromyelitis optica spectrum disorders and chronic relapsing inflammatory optic neuropathy, among others.  Visual symptoms typically include acute onset vision loss and  pain with monophasic or relapsing courses.  Some cases of ON are associated with acute disseminated encephalomyelitis or follow it years later.  We present a patient with progressive optic neuropathy and anti-MOG antibodies.

A 32-year-old man presented with right eye “haziness” and “itching” but no abnormality on ophthalmologic exam was found.  Two years later, symptoms progressed and right optic nerve pallor was identified.  Neurological examination was otherwise normal.  Brain MRI demonstrated few nonspecific white matter changes.  Serum studies were negative for inflammatory or infectious etiologies.  Lumbar puncture was negative for oligoclonal bands.  VEP showed prolonged latency on the right.  One year later, he reported continued worsening.

On neuro-ophthalmologic examination, visual acuity (VA) was 20/30 OD with reduced color vision. There was a 2+ right afferent pupillary defect (APD) and diffuse pallor of the optic disc. Visual fields (VF) showed an inferior nasal and temporal field defect OD.  Optical coherence tomography (OCT) demonstrated thinning of the retinal nerve fiber layer (RNFL) OD.  Over the next year, vision deteriorated to 20/40 with worsened color vision OD and remained normal OS.  His APD worsened to 3+ and the VF deficit enlarged.  OCT demonstrated progressive RNFL thinning OD: initial presentation average thickness 57 microns decreased to 52 microns- most pronounced loss superiorly and inferiorly. Stable exam OS.  MOG testing returned positive 1:100.