The aim of the study was to describe the clinical features and characteristics of optic neuritis patients compared with those of patients enrolled in the Optic Neuritis Treatment Trial (ONTT).

We retrospectively included consecutive patients diagnosed with optic neuritis between 2006 and 2015. The inclusion criteria were the same as those of the ONTT; an acute or subacute unilateral visual symptom ≤8 days in duration, a relative afferent pupillary defect, and a visual field defect in the affected eye.

The 41 patients (14 females, 27 males) were of mean age 32.7 years. The incidence of papilledema was 58.5%, thus higher than that of ONTT patients ( p = 0.004), and the incidence of ocular pain was 75.6%, lower than that of ONTT patients ( p = 0.002). Six months after intravenous methylprednisolone therapy, 29 of 32 eyes (90.6%) recovered visual acuity of ≥1.0 or better, and only one eye exhibited poor visual acuity (≤0.5). Orbital magnetic resonance imaging (MRI) was performed on 34 patients, and most (91.2%) exhibited optic nerve enhancement. The three patients who did not exhibit enhancement reported no pain.

The clinical features of Korean optic neuritis patients differed from those of patients of the ONTT. Most patients exhibited optic nerve MRI enhancement associated with ocular pain. If enhancement of the optic nerve is lacking, diseases other than optic neuritis should be suspected because most optic nerves with neuritis exhibit enhancement on MRI.