Advances in magnetic resonance (MR) orbital imaging using fat suppression techniques and contrast enhancement have increased our ability to visualize the area of inflammation in patients with optic neuritis. Our understanding of the natural history of optic neuritis continues to expand. The high risk of developing multiple sclerosis (MS) after an episode of optic neuritis has been confirmed with longitudinal studies. The most important predictive factor for the future development of MS continues to be an abnormal MR image at presentation. Treatment with intravenous steroids temporarily reduces this risk but has no effect on visual outcome. Although subjective visual complaints are common, objective measures of vision show only mild loss in most patients.