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. 

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. That’s why regular eye tests are so important. Here, we’ll talk about how they can help to detect MS eye symptoms, and how OCT (optical coherence tomography) scans are proving to be helpful with MS diagnosis and ongoing treatment.

How does multiple sclerosis affect the eyes?

Optic neuritis

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.1

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.

Nystagmus

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.

What are the symptoms of MS in the eye?

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)

Can you tell if you have MS from an eye exam?

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.

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 your over to a neurologist.2 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 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.3

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.3,4

Talk to an expert about your symptoms

If you’re experiencing any of the symptoms we’ve mentioned above, it’s worth booking an appointment so one of our optometrists can take a closer look at your eyes. 

References

1. MS Trust. (2018) Visual Problems. Available at: https://www.mstrust.org.uk/a-z/visual-problems. [Accessed 1 April 2020]

2. NICE. (November 2019) Multiple sclerosis in adults: management. [Online]. Available at:https://www.nice.org.uk/guidance/CG186/chapter/1-Recommendations#diagnosing-ms-2 [Accessed 11 March 2020].

3. Cédric Lamirel, Nancy J. Newman, and Valérie Biousse. (2010) Optical Coherence Tomography (OCT) in Optic Neuritis and Multiple Sclerosis. [Online]. Available at:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3005938/ [Accessed 15 March 2020]

4. National MS Society (2015). Leading Edge Collaboration in Eye-Related Research Earns Investigators at NYU Langone Medical Center, Johns Hopkins, and the UT Southwestern Medical Center the 2015 Barancik Prize for Innovation in MS Research. [Online]. Available at: https://www.nationalmssociety.org/About-the-Society/News/Leading-Edge-Collaboration-in-Eye-Related-Research [Accessed 15 March 2020]