The diagnosis of optic neuritis is based on an analysis of the patient’s condition, along with ancillary tests to distinguish it from other diseases. Patients with optic neuritis can be categorized into two groups, “typical” and “atypical”. Typical optic neuritis is often associated with multiple sclerosis and consists of subacute unilateral visual deficits (vision loss is rare); significant recovery of vision at 6 to 10 weeks; papillary edema of the optic nerve, if present, is usually mild; and enhancement of short segments (segments smaller than approximately 50% of the optic nerve) is seen on MRI. Atypical optic neuritis, on the other hand, may result in more severe vision loss and may be associated with neurologic or systemic diseases other than multiple sclerosis. It has an onset of bilateral vision loss; very severe visual impairment or complete visual loss (unilateral or bilateral); no recovery of vision or worsening of the impairment at 6 to 10 weeks, and severe optic papillary edema may also be present. Longitudinal broad (≥80% of the optic nerve) enhancement or visual cross-enhancement, recurrent optic neuritis, or hormone-dependent optic neuritis may also be typical features on MRI. It is recommended that patients with optic neuritis seek prompt medical attention to evaluate their condition and follow medical advice.