MOG and optic papillitis: Moreover, anti-MOG antibody-positive ON was reported as unilateral or bilateral papillitis or papilloedema in 15 of 50 patients (30%), and optic disc atrophy was observed in 13 patients (59.1%).[21] Furthermore, most patients with MOG antibody-positive ON were aware of posterior bulbar pain,[21] which indicates a symptom of retrobulbar ON.