Key takeaways:
Optic neuritis is inflammation and swelling of the optic nerve that causes vision loss and eye pain.
It’s commonly (but not always) associated with multiple sclerosis .
Optic neuritis may not need treatment, and most people recover nearly all vision within one year.
Having vision changes can be scary, especially if you’ve never experienced them before. Many things can cause changes in your vision. But if you also have eye pain, it could be optic neuritis.
Optic neuritis is inflammation and swelling of the optic nerve — the nerve that connects the eye to the brain and allows us to see. It’s a rare condition that only affects 1 to 2 in 100,000 people per year. It can affect both children and adults, and it’s more common in women than men. It’s commonly associated with multiple sclerosis (MS) — an autoimmune disease that affects the brain and spinal cord. But there are other causes, too.
In this article, we discuss the causes, symptoms, diagnosis, and treatment of optic neuritis.
Experts aren’t exactly sure what causes optic neuritis, but they know the immune system is involved. The immune system is the body’s army. It typically protects us against things that don’t belong (like infections). But it sometimes reacts when it shouldn’t.
When the immune system attacks the optic nerve, it causes optic neuritis. The optic nerve gets inflamed and swells, making it harder to send signals from the eye to the brain. Just like a short in TV wiring, the picture (what you see) gets blurry.
Optic neuritis has several causes, but it’s commonly associated with MS. Optic neuritis is the first sign of MS in about 15% to 20% of people.
Not always. About half of people will develop MS within 15 years of an optic neuritis episode. The risk of developing MS is higher if a brain MRI shows changes at the time of optic neuritis (more below).
But optic neuritis can happen by itself. Or, it can be caused by other conditions that rev up the immune system. For example:
Neuromyelitis optica (also known as Devic’s disease)
Infections (like syphilis or Lyme disease)
Cancer (due to paraneoplastic syndromes — symptoms triggered by an abnormal immune response to a cancer)
The most common symptoms of optic neuritis are vision changes and eye pain. Symptoms build over hours to days, and peak within 2 weeks. Optic neuritis tends to affect one eye at a time, but in rare cases it can affect both eyes.
Specifically, symptoms may include:
Blurry or dim vision, usually in the center of the eye
Complete vision loss (in severe cases)
Eye pain, especially when moving the eyeball
Flashes or flickers of light
Trouble seeing colors correctly, which may appear dull or faded
To diagnose optic neuritis, healthcare providers use clues from:
Your story
Physical exam — with special attention paid to the eyes, muscles, and nerves
Visual acuity testing (how well you can read letters from a distance)
MRI of the brain and orbits (eye sockets) — a type of imaging test that can directly examine the optic nerves and brain for signs of inflammation
An ophthalmologist — a medical doctor who specializes in eye conditions — is commonly involved in the process.
Once optic neuritis is diagnosed, more blood tests might be ordered to find the cause. A lumbar puncture (spinal tap) might be performed, too. But it isn’t always necessary.
Optic neuritis causes some pretty scary symptoms. But interestingly, it might not need treatment. Optic neuritis starts to improve without treatment within 2 to 4 weeks. It can take up to 1 year to completely recover, and most people recover nearly all vision.
When it comes to treatment options, steroids (strong anti-inflammatory medications) may speed up recovery, but don't really affect the final outcome. And, steroids can cause a lot of side effects, like trouble sleeping, mood swings, and high blood sugar. Studies suggest that steroids infused into the vein followed by steroid pills are better than pills alone, which can raise the risk of getting optic neuritis again.
Treatment might be considered if:
You have severe vision loss.
Your provider suspects MS based on an abnormal brain MRI. Steroids or other treatments may be suggested.
So, should you receive steroids or not? That’s a tough question. But together with your doctor, you can discuss the risks and benefits and decide what’s best for you.
Good news. Most people with optic neuritis recover nearly all vision within 1 year. But, people with very severe optic neuritis may experience more severe long-term vision changes. Rarely, optic neuritis can cause blindness.
Yes. Optic neuritis can recur in either eye, but the chances of recurrence depend on the underlying cause. For example, about 1 in 3 people with MS will get optic neuritis again. Chances are lower when optic neuritis is due to other conditions.
Optic neuritis is inflammation of the optic nerve that causes vision loss and eye pain. It’s commonly associated with MS, but doesn’t always mean MS is the problem. Though symptoms are frightening, optic neuritis gets better within months to a year. And most people will recover their vision. If you are concerned about optic neuritis, talk to your provider. Together, you’ll figure out the next best steps to keep your eyes as healthy as possible.
American Academy of Ophthalmology. (2016). Optic nerve.
Beck, R. W., et al. (1992). A randomized, controlled trial of corticosteroids in the treatment of acute optic neuritis. New England Journal of Medicine.
Beck, R. W., et al. (2004). Visual function more than 10 years after optic neuritis: Experience of the optic neuritis treatment trial. American Journal of Ophthalmology.
Boyd, K. (2022). What is optic neuritis? American Academy of Ophthalmology.
Churchill, J., et al. (2022). What’s an ophthalmologist? American Academy of Ophthalmology.
Johns Hopkins Medicine. (n.d). Neurological exam.
Johns Hopkins Medicine. (n.d). Neuromyelitis optica.
MedlinePlus. (2020). Immune system and disorders.
National Institute of Neurological Disorders and Stroke. (2022). Paraneoplastic syndromes.
Optic Neuritis Study Group. (1991). The clinical profile of optic neuritis. Experience of the optic neuritis treatment trial. Archives of Ophthalmology.
Optic Neuritis Study Group. (2008). Multiple sclerosis risk after optic neuritis: Final optic neuritis treatment trial follow-up. Archives of Neurology.
Sørenson, T. L., et al. (1999). Optic neuritis as onset manifestation of multiple sclerosis: A nationwide, long-term survey. Neurology.
Toosy, A. T., et al. (2014). Optic neuritis. Lancet Neurology.
University of California San Francisco. (2019). Ophthalmoscopy.
Vedula, S. S., et al. (2007). Corticosteroids for treating optic neuritis. Cochrane Database Systematic Reviews.