Optic Neuritis

Optic neuritis is a condition that affects the eye and your vision. It occurs when your 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. 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 it can affect both at the same time.

Optic neuritis can affect both adults and children. The underlying cause isn't always 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.

The cause of optic neuritis isn’t always clear. It may be caused by an infection. But it is a common condition among those who have multiple sclerosis (MS), which is a progressive nervous system disorder. About half of people who have MS will develop optic neuritis. It's often the first sign of MS. Another inflammatory condition called neuromyelitis optica can also attack the optic nerve and the spinal cord. It is similar to MS but is a different disorder.

You are at increased risk for optic neuritis if you:

• Have a history of MS or neuromyelitis optica.

• Live in higher altitudes.

• Are Caucasian.

The following visual problems 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. Plus, 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.

Your healthcare 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.

• Testing of the ability to differentiate color.

• Exam of the back of the eye, known as the fundus.

• Visual field testing.

• Spinal tap (lumbar puncture), less commonly needed.

• Blood tests to look for proteins that attack the optic nerve.

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

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 your healthcare provider may recommend a brief course of steroids, usually injected into your vein. These may 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.

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. But in people with certain brain changes seen on MRI, IV (intravenous) steroids may help prevent future episodes of optic neuritis.

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