Optic neuritis is inflammation of the optic nerve. In optic neuritis, the covering around the optic nerve (myelin) is damaged by inflammation (demyelination), which typically results in blurred or dark vision.
Your immune system normally protects your body from infections. However, it can become confused and attack your own body (autoimmune reaction). Most cases of optic neuritis are caused by an autoimmune reaction to the optic nerve, but optic neuritis can be directly caused by certain infections.
Optic neuritis can be caused by systemic conditions or infections, or may not have any known cause (idiopathic). Many diseases can cause optic neuritis, including multiple sclerosis (MS). Multiple sclerosis is an autoimmune disease that specifically attacks your brain and spinal cord. Optic neuritis is frequently a manifestation of MS, and sometimes the very first sign of the disease. Optic neuritis can also be caused by other neurological inflammatory diseases such as neuromyelitis optica (NMO) or myelin oligodendrocyte glycoprotein (MOG)-associated disease.
In optic neuritis, the eye itself is not affected, but the optic nerve behind the eye is inflamed. This may cause blurred vision, darkened vision, decreased color vision, or decreased peripheral vision. The most common symptom of optic neuritis is decreased vision, which happens suddenly or quickly over the course of 1-3 days. Many people describe the blurring and darkening of their vision as “dimming” or like “the brightness is turned down.” Optic neuritis does not affect your glasses prescription.
Most people with optic neuritis will have eye pain or discomfort when looking in different directions. When the optic nerve is inflamed and the eye moves, there may be pulling on the optic nerve that can cause irritation. This pain typically goes away after several days.
Neuro-ophthalmologists specialize in diseases of the optic nerve. While a neuro-ophthalmologist may do the same tests as your regular eye doctor, a neuro-ophthalmologist is experienced in sorting out the differences between optic neuritis and other optic nerve diseases.
If your symptoms and eye exam are typical for optic neuritis, your doctor may choose to order very few tests at first. If your symptoms are unusual, your doctor may order other tests.
There has been a lot of research that links the most common form of optic neuritis with multiple sclerosis. Most people with multiple sclerosis will have an episode of optic neuritis in their lifetime. While not everyone who gets optic neuritis will develop multiple sclerosis, people who have optic neuritis have a greater risk for having MS in the future, compared to those who have never had an episode. Because early detection and treatment may keep you from having more severe problems, it is important to follow your doctor’s advice.
An MRI of the brain is recommended in optic neuritis because it can help determine the risk for developing MS in the future, and determine if you need additional treatment.
In typical cases of optic neuritis, no treatment is necessary. Research has shown that there is no difference in final vision, or the likelihood of developing MS in the future, between people with optic neuritis who were treated and those who were not treated. Treatment can speed up recovery; however, the treatment for optic neuritis has many side effects and is therefore not recommended for everyone. Treatment may be recommended in:
Typically, treatment consists of intravenous (IV) steroids for 3 days, followed by pills taken by mouth (oral steroids) for an additional 10 to 15 days. There is evidence that only using oral steroids (prednisone) in doses of 60-80 mg per day INCREASES the risk of recurrence of optic neuritis. Alternatively, your doctor may recommend oral steroids at high doses similar to IV steroids for the first 3 to 5 days.
Depending on your overall health, steroid treatment may not be safe for you. Steroids have many side effects including fluid retention, increased blood pressure, increased blood sugar, weight gain, increased appetite, mood and behavior problems, stomach irritation, and glaucoma. Over the long term, steroids can decrease your ability to fight off infection, worsen diabetes, thin your bones, skin, and hair, increase bruising, form cataracts, and increase fat deposits.
Your doctor will check your eyes and vision when you are first having symptoms (acute phase). After determining if you need treatment, other testing, or a referral to a neurologist, your doctor may recheck your eyes and vision after a few weeks to months. Once your vision has stabilized and as long as you do not have any new episodes, you can have routine eye exams.
Copyright © 2021. North American Neuro-Ophthalmology Society. All rights reserved.
This information was developed collaboratively by the Patient Information Committee of the North American Neuro-Ophthalmology Society. This has been written by neuro-ophthalmologists and has been edited, updated, and peer-reviewed by multiple neuro-ophthalmologists. The views expressed in this brochure are of the contributors and not their employers or other organizations. Please note we have made every effort to ensure the content of this is correct at time of publication, but remember that information about the condition and drugs may change. Major revisions are performed on a periodic basis.
This information is produced and made available “as is” without warranty and for informational and educational purposes only and do not constitute, and should not be used as a substitute for, medical advice, diagnosis, or treatment. Patients and other members of the general public should always seek the advice of a physician or other qualified healthcare professional regarding personal health or medical conditions.
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