Optic neuritis is an inflammatory condition involving the optic nerve, which presents with various abnormalities of vision. The patient may notice blurred or distorted vision, reduced color vision, or a blind spot. There is also frequently a history of pain with eye movement, and this may precede the visual loss. The condition usually occurs in adults under 45 years of age, and women are affected much more frequently than men.

The visual deficit may worsen over a period of approximately 7 days, then typically remains stable (at that level) for 3 to 8 weeks, followed by gradual visual improvement. The great majority of patients with optic neuritis will recover much of their vision within 6 months of the onset of optic neuritis.

When a patient with reduced vision presents to the ophthalmologist, vision, eye pressure, and pupillary function is evaluated and the eyes are dilated such that the optic nerves and retina can be examined. There is always an abnormal pupil in optic neuritis, known as an afferent pupillary defect (paradoxically dilates when light is shone in the eye). The optic nerve in this disorder may appear normal or swollen. A visual field (peripheral vision) test may then be completed, and the patient is usually scheduled to have a MRI of the brain. The MRI (in this case) is a brain-imaging study, which will assist in the determination as to whether any central nervous system lesions are present.

There is a risk of developing multiple sclerosis (MS) in patients with optic neuritis. Fifteen years after the onset of optic neuritis, approximately 75% of women will have developed MS, and about 34% of men will have developed MS. For those patients with an abnormal MRI of the brain (white matter lesions), the risk of developing another sign or symptom of MS is 36% in 2 years. However, only 3% of patients with a normal MRI of the brain had another sign or symptom of MS within 2 years. MS is characterized by exacerbations and remissions of motor and sensory function, and may produce mild or severe disabilities over a period of years.

The treatment of optic neuritis has changed in recent years due to a landmark series of studies known as the Optic Neuritis Treatment Trials. In these studies, patients with optic neuritis were randomized to treatment with intravenous (IV) steroids, oral steroids, or placebo, and were subsequently followed and intensively evaluated for several years. From these studies, ophthalmologists learned that treatment with s

This MRI shows bright spots on the right optic nerve: