ConditionEyes & vision
Optic Neuritis
Optic neuritis is inflammation of the optic nerve, which carries visual signals from the eye to the brain. It typically causes blurred or dim vision in one eye over hours to days, pain when moving the eye, and faded colors. It most often affects adults aged 20 to 45, especially women, and is commonly linked to multiple sclerosis. Most people recover much of their vision within weeks to months. Steroids speed recovery, and an MRI helps predict the risk of MS.
Also called: Retrobulbar neuritis, demyelinating optic neuritis, optic nerve inflammation
At a glance
- What it is
- Inflammation of the optic nerve, often from demyelination.
- Who gets it
- Mostly adults 20 to 45, women about three times more often than men.
- Symptoms
- Vision loss in one eye over hours to days, pain with eye movement, faded colors.
- Linked conditions
- Multiple sclerosis, neuromyelitis optica, MOG antibody disease, infections.
- Treatment
- IV steroids speed recovery. Treat the underlying condition. Most vision recovers.
When to get help
Call 911 or go to the ER
- Sudden loss of vision in one or both eyes, even if painless
- Vision loss with weakness, numbness, slurred speech or facial droop
- Vision loss in both eyes at once, or severe vision loss with vomiting or hiccups (possible neuromyelitis optica)
See a doctor within a day or two
- Blurred or dim vision in one eye developing over hours to days, with pain when moving the eye (see an eye doctor or ER the same day)
- Age over 50 with new vision loss and headache, scalp tenderness or jaw pain when chewing (possible giant cell arteritis)
- Vision getting worse beyond 2 weeks or not improving after 4 weeks
Book a routine appointment
- Colors appearing washed out in one eye, or vision dimming with heat or exercise after previous optic neuritis
- Follow-up to discuss MS risk and MRI results
What happens in optic neuritis
The optic nerve is a bundle of over a million nerve fibers wrapped in myelin, a fatty insulating layer. In most optic neuritis, the immune system attacks the myelin (demyelination), slowing or blocking signals. Swelling of the nerve causes pain when the eye moves, because the eye muscles tug on the inflamed nerve sheath. In about two-thirds of adults, the inflammation is behind the eye (retrobulbar), so the nerve looks normal on examination.
Symptoms
- vision loss in one eye, developing over hours to days and usually worst within 1 to 2 weeks. It ranges from mild blurring to severe loss
- pain around or behind the eye, worse with eye movement, in about 9 in 10 people
- faded or washed-out colors, especially red
- a dark or blurry spot in the center of vision
- flashing or flickering lights in some people
- Uhthoff's phenomenon: temporary worsening of vision with heat, exercise or hot showers, often after recovery
Causes and associations
| Cause | Features |
|---|---|
| Multiple sclerosis | Most common association. Optic neuritis is the first symptom of MS in about 1 in 5 people |
| Isolated (idiopathic) optic neuritis | No other condition found, but MS risk remains |
| Neuromyelitis optica spectrum disorder (NMOSD) | Severe, sometimes both eyes, poor recovery without treatment. AQP4 antibodies |
| MOG antibody-associated disease (MOGAD) | Often both eyes, marked optic disc swelling, responds well to steroids but may recur |
| Infections | Syphilis, Lyme disease, cat scratch disease, tuberculosis, viruses |
| Inflammatory diseases | Sarcoidosis, lupus |
| Medicines | Some TNF inhibitors and immune checkpoint inhibitors |
Atypical features suggest a cause other than MS and need further testing: no pain, both eyes affected, severe loss or no light perception, a very swollen optic disc, or no improvement after 3 weeks. In people over 50, giant cell arteritis must be ruled out.
Diagnosis
An eye doctor or neuro-ophthalmologist will:
- test visual acuity, color vision and visual fields
- check the pupils for a relative afferent pupillary defect, a key sign that the optic nerve is affected
- examine the optic nerve head (it may look normal or swollen)
- use OCT to measure nerve fiber thickness
Tests:
- MRI of the brain and orbits with contrast: confirms optic nerve inflammation and looks for MS lesions in the brain, which predict future MS
- blood tests: AQP4 and MOG antibodies, and tests for syphilis, Lyme disease, sarcoidosis or lupus as indicated
- lumbar puncture in some cases
Treatment
- High-dose IV methylprednisolone for 3 to 5 days, sometimes followed by a short oral taper, speeds visual recovery. It does not change the final level of vision in typical optic neuritis. Low-dose oral prednisone alone is not recommended, because the large Optic Neuritis Treatment Trial found it was linked to more recurrences.
- Plasma exchange for severe vision loss that does not respond to steroids, especially in NMOSD.
- Long-term treatment for the underlying condition: disease-modifying therapy for MS, and specific immune treatments for NMOSD or recurrent MOGAD.
- Treatment of infections where identified.
Recovery and outlook
- Vision usually starts improving within 2 to 4 weeks, with most recovery by 3 months and continuing for up to a year.
- Most people with typical optic neuritis recover vision of 20/40 or better.
- Subtle problems may persist: reduced color or contrast vision, and dimming with heat or exercise.
- Recurrences can occur in the same or the other eye.
Risk of multiple sclerosis
In the Optic Neuritis Treatment Trial, about half of people developed MS within 15 years. The risk was about 1 in 4 if the initial brain MRI showed no lesions, and much higher if it showed one or more lesions. Starting MS disease-modifying therapy early in high-risk people reduces the chance of further attacks.
Frequently asked questions
What are the symptoms of optic neuritis?
The main symptoms are blurred or dim vision in one eye that develops over hours to days, pain when moving the eye, faded colors (especially red), and a dark spot in the center of vision. It usually affects one eye.
Is optic neuritis a sign of MS?
It can be. Optic neuritis is often the first symptom of multiple sclerosis, and about half of people with typical optic neuritis develop MS within 15 years. An MRI of the brain helps estimate the risk.
How long does optic neuritis take to heal?
Vision often starts improving within 2 to 4 weeks, with most recovery within 3 months. Improvement can continue for up to a year. Most people regain good vision, though colors or contrast may remain slightly reduced.
What is the treatment for optic neuritis?
High-dose IV steroids speed up recovery of vision, although final vision is similar without them in typical cases. Treatment also targets the underlying cause, such as MS, neuromyelitis optica or an infection.
Can optic neuritis cause blindness?
Permanent blindness is uncommon in typical optic neuritis, and most people recover well. Severe or permanent vision loss is more likely with neuromyelitis optica or other atypical causes, which need urgent, specific treatment.
Sources
This guide was written from current patient and clinical guidance, including:
- American Academy of Ophthalmology: Optic neuritis
- National Eye Institute (NEI): Optic neuritis
- Optic Neuritis Treatment Trial (ONTT) findings, Archives of Ophthalmology and Neurology
- National Multiple Sclerosis Society: Vision problems and optic neuritis
- MedlinePlus (US National Library of Medicine): Optic neuritis