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Optic Neuritis

What is optic neuritis?

Optic neuritis is a condition that affects the eye and your vision, and occurs when the optic nerve is inflamed.

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.

Loss of vision in optic neuritis commonly reaches its maximum effect within a few days and starts improving within 4 to 12 weeks. 

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. Over 60% of people who have MS will develop optic neuritis, and often, it's 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 difficulties are common with optic neuritis:

  • Diminished vision (usually the main symptom)
  • Trouble distinguishing colors, or noticing that colors aren't as vibrant as usual
  • Vision that appears blurry — particularly if it occurs after your body temperature has risen — after you've just taken a hot shower or finished a workout, for instance
  • 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

The symptoms of optic neuritis can vary widely in severity. More extensive optic nerve inflammation leads to more noticeable symptoms.

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?

A health care provider can diagnose optic neuritis with these tests:

  • Thorough medical exam
  • Evaluation of your eyes' response to direct bright light 
  • Testing of visual acuity using the letter chart to see how well you can see
  • MRI scan of the brain

MRI Scan

  • Testing of the ability to differentiate color
  • Exam of the back of the eye, known as the fundus

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?

In some cases, you may not need any treatment for optic neuritis. After a few weeks, it may go away on its own and your vision will return to normal. This is more likely if you don’t have another health condition that has triggered the optic neuritis.

Sometimes a health care 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.

You may also need treatment for another health condition if it’s considered the source of your optic neuritis.

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. There are also side effects from steroids. However, in people with certain brain changes seen on MRI intravenous steroids may help prevent future episodes of optic neuritis.

Can optic neuritis be prevented?

Since health care providers can't always identify the cause of optic neuritis, it can not be prevented.

When should I call my health care provider?

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

Key points

  • Just because optic neuritis often clears up without treatment doesn't mean that you shouldn’t seek medical advice.
  • If you have optic neuritis, you may actually have another health condition that's causing it.
  • A complete medical exam may help your health care provider find other health conditions that can be treated.

Next steps

Tips to help you get the most from a visit to your health care provider:

  • Before your visit, write down questions you want answered.
  • Bring someone with you to help you ask questions and remember what your provider tells you.
  • At the visit, write down the names of new medicines, treatments, or tests, and any new instructions your provider gives you.
  • If you have a follow-up appointment, write down the date, time, and purpose for that visit.
  • Know how you can contact your provider if you have questions.
Online Medical Reviewer: Jones, Niva MD
Online Medical Reviewer: Petersen, Sheralee, MPAS, PA-C
Date Last Reviewed: 1/2/2014
© 2000-2015 The StayWell Company, LLC. 780 Township Line Road, Yardley, PA 19067. All rights reserved. This information is not intended as a substitute for professional medical care. Always follow your healthcare professional's instructions.
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