Optic Neuritis and Multiple Sclerosis (MS)

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Multiple sclerosis (MS) commonly causes vision-related symptoms, including optic neuritis—an impairment of the optic nerve, which detects visual input in the eye and sends corresponding messages to the brain. Multiple sclerosis is the most common cause of optic neuritis, though not the only one, and the eye condition can be the first symptom that you have this autoimmune disease.

Usually, optic neuritis resolves on its own, but you can have some persistent vision loss even after an episode improves. Treatment can hasten recovery and may minimize residual vision loss.

Optic Neuritis Symptoms
Verywell / Cindy Chung

Symptoms

Optic neuritis usually comes on fairly quickly and can cause eye pain and vision loss within a few days or weeks. It often affects one eye, but it may affect both.

You can experience optic neuritis on its own or as part of an MS exacerbation (relapse).

Common symptoms of optic neuritis include:

  • Eye pain, which is worse when you move your eye (or eyes). The pain usually subsides after a couple of days.
  • Vision impairment: This can manifest with blurred or hazy vision and difficulty reading. It typically lasts longer than eye pain.
  • Photophobia (sensitivity to light)
  • Vision loss: During a bout of optic neuritis, vision loss in the affected eye(s) can be quite substantial, but complete blindness is not common.
  • Blind spots: You may have a scotoma, which is a blind spot in the middle of your visual field. You might not notice a scotoma, especially if you can see all around it, but your doctor can often identify this on your vision examination.

Keep in mind that the first time you experience any eye pain or vision changes, you should seek medical attention right away.

After Resolution of Your Optic Neuritis

While you may have a total improvement of your symptoms, it's also possible that what you experienced during an exacerbation may not completely go away. Your vision can be better on some days than others, and this is very common with MS.

Unfortunately, it is impossible to predict how much you will improve or whether you will improve at all.

Causes

Neuromyelitis optica, also known as Devic's disease, is a type of demyelinating disorder that affects predominantly the optic nerves and the spinal cord. As compared with MS related optic neuritis, patients with Devic's disease tend to have a more severe presentation and more frequent bilateral involvement.

Inflammation and Demyelination

Optic neuritis occurs due to inflammation and consequent demyelination of the optic nerve (also known as the second cranial nerve or cranial nerve two). Demyelination is the loss of myelin, a protective fatty coating that insulates nerves, allowing them to function more efficiently. Without it, electrical messages (including those related to sight) travel slowly.

Triggers

After a bout of optic neuritis, it is common to experience vision loss that comes on when your body temperature goes up, such as with a fever or in a hot climate. This is part of Uhthoff’s phenomenon, which is the worsening of MS symptoms that can occur with warmer body temperatures.

Infection or stress can also cause transient worsening of vision in patients with optic neuritis.

Diagnosis

There are many vision changes that can occur with MS, and they are not all related to optic neuritis. Your doctor can often identify optic neuritis based on your symptoms and your physical examination.

Your eye examination can measure your visual acuity (how well you see) using an eye chart that contains letters or shapes. And your doctor will also assess your visual fields to identify a scotoma or another visual field cut.

An examination of your eye using an ophthalmoscope—a tool that allows your doctor to see structures behind your pupil—can help identify the inflammation and swelling that are often seen in optic neuritis. This is a non-invasive test and it doesn't hurt.

Sometimes, you may need to have your pupils dilated (widened) with medicated eye drops to make the optic nerve and the nearby blood vessels more visible.

If your doctor is concerned that you could have other lesions in your brain, you may need brain magnetic resonance imaging (MRI), especially if the cause of your optic neuritis has not been established. In some instances, a gadolinium-enhanced MRI of the brain and optic nerve may identify optic neuritis.

A visual evoked potential (VEP) exam can assess the function and communication between the optic nerve and the brain. And a lumbar puncture (spinal tap) can identify inflammatory changes to help distinguish MS from other causes of optic neuritis.

Differential Diagnoses

Though MS is the most common cause of optic neuritis, other inflammatory conditions such as lupus may be suspected. While less common, an infection such as hepatitis can cause optic neuritis in one or both eyes.

Your doctor will use the above tests (and possibly others) to come to a firm diagnosis.

Treatment

It is hard to predict the disease course of optic neuritis and whether it will improve without treatment or not. For this reason, treatment for an MS relapse is usually initiated as soon as someone is diagnosed with optic neuritis. These treatments can help speed up recovery and reduce the degree of disability.

Full or almost full recovery generally takes a few months. However, as with many symptoms of an MS exacerbation, there can be residual effects.

MS relapses are generally treated with several days of intravenous (IV) Solu-Medrol, a steroid and in some cases, this is followed by an oral steroid taper. In severe cases, plasmapheresis can be used to treat an MS exacerbation. Disease-modifying treatments (DMTs) are used for the prevention of MS exacerbations and progression.

A Word From Verywell

Keep in mind that optic neuritis can be the main factor that prevents you from driving—and this can be a huge change in your life. As you adjust to your MS, be sure to seek out support services in your region or through national organizations so that you can get the help you need when it comes to your daily life.

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