Optic Neuritis

Optic neuritis is inflammation of the optic nerve anywhere along its course.

Optic neuritis may be caused by a viral infection (especially in children), vaccination, meningitis, syphilis, certain autoimmune diseases such as multiple sclerosis, and intraocular inflammation (uveitis (see Section 20, Chapter 232)). However, the cause of optic neuritis is often unknown.

Optic neuritis causes vision loss, which may be mild or severe and may occur in one or both eyes. Loss of vision may occur over days. Vision in the involved eye or eyes can range from almost normal to complete blindness. There may be pain with eye movement. Depending on the cause, vision may recover only to deteriorate later in repeat episodes of worsening vision.

Diagnosis involves examination of the reactions of the pupils and observing the back of the eyes with an ophthalmoscope; the optic disk (the head of the optic nerve at the back of the eye) may appear swollen. Testing peripheral vision may reveal loss of vision at the periphery (side) of the visual field. Magnetic resonance imaging (MRI) may show evidence of multiple sclerosis or, rarely, a tumor pressing on the optic nerve.

Most cases of optic neuritis will improve over a few months without treatment. However, in some instances, treatment with intravenous corticosteroids and other drugs may hasten recovery and reduce the chance of a recurrence. If a tumor is pressing on the optic nerve, vision usually improves once the pressure caused by the tumor is relieved.