Optic neuritis affects the optic nerve, which carries images from the eye to the brain. It's an inflammation of the optic nerve, which affects vision.
Many cases occur without any known underlying cause. However, there is an association with multiple sclerosis (MS). Optic neuritis is the first symptom for around one in four people with MS (Source: NICE).
Fortunately, most people recover without needing treatment, and many don't experience long-lasting damage to their sight.
Optic neuritis symptoms
Optic neuritis can develop in adults and rarely in children. In adults, it's more likely to affect one eye; in children under ten, it's more likely to occur in both eyes. The condition can develop quickly, in a matter of hours or days, and can worsen over a couple of weeks. There are typically three common symptoms of optic neuritis. These include:
- Pain behind the affected eye, often made worse with eye movement.
- Difficulty seeing, particularly with the central vision becoming blurred and hazy. Your peripheral (side) vision can also be affected. This can develop over hours or days.
- Difficulty distinguishing and seeing colours clearly; things look faded.
Less common signs and symptoms of optic neuritis include:
- Sensitivity to bright light.
- Seeing flashing lights at the side of your vision.
- Worse vision when your body is warm (for example, after a hot bath or strenuous exercise).
Optic neuritis causes
Optic neuritis is often associated with multiple sclerosis, as it can be an early sign of the condition. However, there are many other possible causes for optic neuritis, such as inflammation, infection, and rare diseases.
In a lot of cases, the reasons for optic neuritis aren't known. This is known as ' idiopathic' when the underlying cause of an eye condition cannot be identified.
Optic neuritis and MS
Diseases of the nervous system can cause optic neuritis. One cause of optic neuritis is multiple sclerosis, which affects the central nervous system. With MS, the protective coating on nerves, called myelin, is eroded, and this happens to the myelin on the optic nerve.
Optic neuritis can be an early sign of multiple sclerosis, so you may see a neurologist if you're diagnosed with it. They will do further tests which can include blood tests, an OCT scan to look closely at the nerves in the eye, a brain MRI scan, and a CT scan.
Around a quarter of people with MS will experience optic neuritis as their first symptom (Source: NICE). For people who experience one episode of optic neuritis, the chance of developing MS is around 50% after 15 years, strongly associated with whether an MRI scan shows lesions on the brain (Source: JAMA Neurology).
How is optic neuritis diagnosed?
If you think you're experiencing possible symptoms of optic neuritis, such as blurred vision and eye pain, you should see an optician.
Can an optician see optic neuritis?
An optician will ask about your symptoms, check your vision, and examine your eyes, for example, looking at your pupils and sometimes using an OCT scan (optical coherence tomography). If they suspect you have optic neuritis, they'll refer you to a hospital eye specialist (ophthalmologist) for more tests.
An ophthalmologist can confirm a diagnosis of optic neuritis by:
- Asking about your symptoms.
- Asking about your medical records or family history.
- Testing your vision, including how you see colours and your peripheral vision.
- Doing a range of tests such as examining your eye to look at the optic nerve, optic disc, and retina.
- Referring you for further tests to discover if an underlying condition might have caused your optic neuritis.
Always get medical help if you notice sudden changes to your sight. You can call 111, who can advise whether you should see an optician or need more urgent help from A&E.
Optic neuritis treatment
If you have optic neuritis, or it's suspected, you'll be referred to an ophthalmologist (eye specialist). They'll give you more information about the condition and its treatment.
Optic neuritis typically heals without treatment. A major clinical study (the Optic Neuritis Treatment Trial, or ONTT) found that most people begin to recover after two weeks. The vast majority of improvement happens within one month but can continue for up to a year, and 82% of patients made a good visual recovery (Source: Ophthalmology).
If an underlying illness or infection has caused your optic neuritis, this should be treated. In the early stages of optic neuritis, over-the-counter painkillers can relieve your discomfort if you have eye pain.
Steroid medication (corticosteroids) can accelerate recovery of the optic nerve but doesn't make a difference to the long-term outcome of the condition. Steroids can have undesirable side effects, so they are only rarely considered as part of a treatment plan.
Optic neuritis can cause lasting damage to the optic nerve (called 'optic atrophy'), but three in four people recover without significant vision loss.
When to get medical advice
The NHS recommend adults should have an eye test every two years. Your optician can detect a range of eye conditions as part of a routine eye exam, allowing prompt treatment.
Living with optic neuritis
Symptoms of optic neuritis, such as temporary vision problems and eye pain, can be quite unsettling, and you might benefit from support to manage these while you recover. You'll also have follow-up appointments with your ophthalmologist to monitor your condition and recovery.
Frequently asked questions
Reviewed in March 2022