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Optic neuritis (ON) is the inflammation of the optic nerve, a bundle of nerve fibers responsible for central vision. The optic nerve transmits signals from the eye's retina to the brain for interpretation. This enables you to see and recognize whatever is in your field of view.
Inflammation or irritation of the optic nerve affects how these signals are transferred to the brain. This causes vision problems such as color blindness and blurry vision. It may also result in the swelling of one or both eyes. However, it mostly affects one eye.
Anyone can get optic neuritis, but it's common among those living with multiple sclerosis (MS). The annual incidence of optic neuritis in the United States is about 5 cases per 100,000 people.1
Although some symptoms of ON may seem scary, most people recover without treatment.
Some people may not show any visual signs. Those that do may show symptoms such as:
Optic neuritis symptoms may vary in severity from one person to another—severe inflammation results in more noticeable symptoms.
The exact cause of optic neuritis is unknown. However, experts believe it results when the immune system mistakenly targets the myelin sheath, the substance covering the optic nerve. The myelin sheath insulates the optic nerve like the plastic covers on electric cables.
If damaged by inflammation or swelling, the transmission of electrical signals from the eye to the brain is disrupted. This may result in short or long-term vision loss.
A common condition associated with ON is multiple sclerosis (MS). This is a disease where the immune system targets the nerves in your central nervous system, including the optic nerve. It causes damage to the myelin sheath. Studies indicate that 15 to 20 percent of people with MS have neuritis (nerve inflammation) as one of the symptoms.3
Other conditions linked with inflammation of the optic nerve include:4, 5
Other causes of severe optic neuritis include:
You're more likely to get optic neuritis if you are:
Eye pain due to optic neuritis goes away after a few days, and most people with disturbed vision will realize an improvement.
However, some may be left with blurry, dark, dim, or distorted vision. In severe cases, complete vision loss may occur. Vision usually improves over a few weeks to a month.
Seek medical attention if you experience the following:
Your doctor will perform a complete medical exam to observe the presence of optic nerve inflammation and its causes. Expected tests include:
Other tests may include:
Someone with optic neuritis will recover their vision within 2 to 3 weeks without treatment.
Intravenous (through the vein) corticosteroids such as methylprednisolone or oral corticosteroids such as prednisone can ease inflammation and speed up recovery.7 However, they will not affect the final visual quality.
If the cause of optic neuritis is an underlying condition such as multiple sclerosis, lupus, or microbial infections, your doctor will recommend the appropriate treatment.
If the diagnosis shows Vitamin B12 deficiency in the body, your doctor may prescribe Vitamin B12 shots to supplement your nutrition.
It's important to closely monitor the symptoms of optic neuritis and seek early treatment to avoid disease progression.
If left untreated, symptoms of optic neuritis may be severe, including optic nerve damage.
Other complications may include:
Optic neuritis symptoms generally improve in about 80 percent of people over a few weeks.8 However, some symptoms, such as reduced vision, may persist after recovery.
Sometimes, optic neuritis may occur without either multiple sclerosis (MS) or neuromyelitis optica (NMO), causing a disorder known as chronic relapsing inflammatory optic neuropathy (CRION). CRION is associated with more intense pain and discomfort than optic neuritis occurring alongside MS. There is also a significant risk of blindness with CRION.9
Fortunately, CRION responds well to intravenous (IV) steroids, and oral steroids or other medications may be taken for extended periods to avoid recurrence.
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