What is MS?
Multiple sclerosis (MS) is a neurological condition in which the body’s immune system mistakenly attacks the protein (myelin) that surrounds and protects the nerves. It affects the brain and spinal cord, causing a range of symptoms that can affect vision, balance and mobility. It is estimated that there are 130,000 people living with MS in the UK, with nearly 7,000 people newly diagnosed every year.1
What are MS eye symptoms?
Depending on which nerve is affected, MS can cause various eye symptoms, including:
- Double vision
- Pain when you move your eyes
- Involuntary eye movements
(flicking rapidly from side to side or up and down)
- A blind or blurred spot in your central vision
- Colours can look darker or ‘washed out’
- Flashes of light when you move your eyes
- Vision loss in affected eye
- Feeling that things are spinning (vertigo)
Symptoms may vary depending on the severity of the condition and how recently you have been diagnosed.
How does MS affect the eyes?
Some eye conditions are commonly associated with multiple sclerosis. The most common vision problems are to do with eye movement. Fortunately, the prognosis is good for recovery from many of the vision problems that are associated with MS, as listed below.
Optic neuritis is an inflammation of the optic nerve — the part of the eye that carries signals to the brain. For around 1 in 5 people with multiple sclerosis, optic neuritis is their first symptom.2
In MS, optic neuritis occurs when the immune cells mistakenly attack the myelin sheath that surrounds and protects the optic nerve, causing it to swell. This can cause damage to the optic nerve and disrupt the signal between the eye and the brain so that visual information is not interpreted correctly. Sometimes, this can include blind spots, where both eyes leave out a section of the visual field.
Double vision (diplopia)
When the nerves that control your eye movement become inflamed or damaged due to MS, it can also mean that the eyes don’t work together properly to form clear images. This can lead to double vision, a condition that causes you to see two images of a single object. Double vision in both eyes is known as binocular diplopia and is most common, whereas double vision in one eye is known as monocular and is the least common of the two.
Optic nerve damage can also lead to nystagmus — the involuntary movement of the eyes that causes them to flick rapidly from side to side, up and down, or around.
Often, this can be very subtle, without affecting your vision, but in some cases, it can cause the sensation that the environment around you is moving or wiggling – this is called oscillopsia – and might also make you feel quite sick or affect your balance.
Nystagmus in MS patients may also be caused by nerve damage to the parts of the brain that coordinate balance, muscle movements and vision.
Can an optician detect MS?
Only a neurologist (a specialist in nerves and the nervous system) can make a diagnosis of multiple sclerosis. But many people will start their journey with an optician, as eye problems are a common first symptom. MS can present itself in many different ways, but eye problems are often the first symptom in many people or, if not, it’s likely that people with MS will experience eye problems at some point, which is why regular eye tests are so important.
There are certain things that can signal the early signs of MS during an eye test, and if an optician spots something unusual, they’ll refer you on to an ophthalmologist (eye specialist) for further tests and to rule out other causes. Then, if there is further cause for concern, the ophthalmologist would hand you over to a neurologist.3 So it’s important to have regular eye tests to keep an eye on any changes over time, but also to see your optician whenever you have any changes in your vision.
Can an OCT scan help to detect MS?
OCT (optical coherence tomography) is a very useful tool in detecting signs of optic neuritis, a common early symptom in MS patients. This is because it allows the optometrist to get a really good look at the health of the optic nerve, as well as the thickness of the retinal layers.
The retinal nerve fibre layer (RNFL) thickness is a good indicator of optic neuritis, and your optometrist will be looking for a thinning of this layer which shows a loss of nerve fibres. RNFL thickness can also be useful to measure for a range of neurological conditions, including MS, with studies showing that MS patients tend to have a thinner RNFL compared with healthy subjects.4 Just ask your optician about adding an OCT scan to your normal eye test.
It's important to note that diagnosing multiple sclerosis involves a wide range of tests, and eye tests and OCT scans are just a small part of this process. There’s also a lot of ongoing research that suggests OCT can be helpful for established cases of multiple sclerosis, with research suggesting that the loss of nerve fibres in the eye could reflect the effects multiple sclerosis has on the brain, in effect mirroring the changes. OCT could therefore be an important part in the ongoing monitoring of MS as well as measuring the success of treatment and trials.4,5
Treatment for MS eye symptoms
Most eye conditions that are caused by MS improve on their own over time, yet some people can find the symptoms hard to manage. For the conditions previously mentioned, various treatments are available:
Optic Neuritis treatment
One way to detect optic neuritis is by performing an OCT scan, this enhanced eye examination can be added to your routine eye test. If your optometrist suspects you have optic neuritis, they’ll refer you to a hospital eye department where your diagnosis will be confirmed, and a treatment plan developed.
For binocular double vision, glasses with lenses incorporating prisms can be used to help the eyes align the two images into a single image. Sometimes, temporarily, an eye patch can help, as can minor surgery.
Because monocular diplopia is quite rare, treatment will depend very much on the cause. Your optician will help to determine the right solution and suggest the best treatment for you. In some cases, they may recommend you visit your GP or hospital eye department for treatment. For more information head to our double vision page.
There’s no cure for nystagmus at the moment, but some of its underlying conditions can often be treated. It’s mostly about learning to cope with its effects. The following may be recommended to you:
● Glasses and contact lenses
Consistently taking medication to relieve symptoms of MS can help - some medications can reduce the side effects of vision problems and the flare-ups they can cause. You can find more information, advice and support around nystagmus at Nystagmus Network.
Other options are also available and will be recommended to you depending on the severity of your condition. If you ever have any concerns about your vision or eye health, get in touch with your local store to book an eye test.