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Optic Neuritis

What is optic neuritis?


The optic nerve sends messages from your eyes to your brain so that you can interpret visual images. When the optic nerve is irritated and inflamed, it doesn't carry messages to the brain as well, and you can't see clearly.

Optic neuritis can affect your vision and cause pain. When the nerve fibers become inflamed, the optic nerve can also start to swell. This swelling typically affects one eye, but can affect both at the same time.

Optic neuritis can affect both adults and children. The underlying cause isn't completely understood, but experts believe that a viral infection may trigger the immune system to attack the optic nerve as if it were a foreign invader.


What causes optic neuritis?

The cause of optic neuritis isn’t always clear. It may be caused by an infection, however, it is a common condition among those who have multiple sclerosis (MS), a progressive, neurologic disorder. About 50% of people who have MS will develop optic neuritis. It's often the first sign of MS.

Who is at risk for optic neuritis?

You are at increased risk for optic neuritis if you:

  • Have a history of multiple sclerosis
  • Live in higher altitudes
  • Are Caucasian

What are the symptoms of optic neuritis?

The following visual problems are common with optic neuritis:

  • Diminished vision (usually the main symptom)
  • Inability to see out of one eye
  • Abnormal reaction of the pupil when exposed to bright light
  • Pain in the eye, especially when you move it


Just because you have severe symptoms doesn’t necessarily mean that optic neuritis will never go away. Additionally, not everyone who has optic neuritis has problems with his or her vision. It's possible for the optic nerve to be inflamed without affecting vision. A careful, medical evaluation of the eye can generally pinpoint optic neuritis even if you don’t have symptoms.

How is optic neuritis diagnosed?

Your healthcare provider can diagnose optic neuritis with these tests:

  • Thorough medical exam
  • Evaluation of your eyes' response to direct bright light 
  • MRI scan of the brain

MRI Scan

  • Testing of the ability to differentiate color

More testing may help to determine the underlying cause of the optic neuritis. However, identifying a specific cause isn’t always possible.

How is optic neuritis treated?


Sometimes your healthcare provider may recommend a brief course of steroids, usually injected into your vein, to help your vision improve more quickly and minimize inflammation and swelling.


What are the complications of optic neuritis?

Taking corticosteroids on a long-term basis can lead to side effects, such as high blood sugar, weight gain, and bone problems, that affect your whole body. Overall, corticosteroids won’t likely lead to a better outcome than letting the condition run its course. However, in people with certain brain changes seen on MRI intravenous steroids may help prevent future episodes of optic neuritis.

When should I call my healthcare provider?

If you have eye pain or any trouble with your vision, see your doctor for an eye exam. If you've already been diagnosed with optic neuritis, call your doctor if your symptoms change, worsen, or don't get any better.

Key points about optic neuritis


Next steps


  • Before your visit, write down questions you want answered.
  • Ask if your condition can be treated in other ways.
Online Medical Reviewer: Shelat, Amit, MD
Date Last Reviewed: 7/1/2016