Multiple Sclerosis and Vision — multiple sclerosis (MS) is a chronic disease in which the body’s own immune system damages the covering of nerve fibres in the brain and spinal cord. Very often the illness first shows itself through the eyes, because the optic nerve is one of the first areas to be affected. This is why paying attention to sudden changes in vision can help detect MS at an early stage.
How multiple sclerosis affects vision
In multiple sclerosis the immune system destroys myelin — the protective sheath that covers nerve fibres. The optic nerve and the parts of the brain that control eye movements are very sensitive to this kind of damage. When the signal from the eye to the brain slows down or is interrupted, a person notices blurred vision, pain when moving the eye, double vision or a “jumping” picture. For many patients it is exactly a vision problem that becomes the first warning sign, bringing them to a doctor before other signs of the disease appear.
Causes and mechanism
- The immune system mistakenly attacks myelin — the sheath around nerve fibres.
- Inflammation develops in the optic nerve (optic neuritis), and signal transmission is disrupted.
- Damage to the nerve pathways that control eye movements causes double vision and nystagmus.
- Areas of damage can appear in different parts of the brain, so the symptoms vary.
- The exact cause of MS is unknown; heredity, past infections and environmental factors all play a role.
Visual symptoms
- Sudden loss or blurring of vision in one eye.
- Pain in the eye that gets worse when moving the eyeball.
- Double vision (diplopia).
- Involuntary swinging movements of the eyes (nystagmus).
- Impaired colour perception — colours appear dull or “washed out”.
- A feeling of a “curtain” or dark spot in front of the eye.
- Poor coordination of eye movements, when both eyes move out of sync (internuclear ophthalmoplegia).
Why this is a neuro-ophthalmological condition
The visual signs of multiple sclerosis lie on the border between neurology and ophthalmology. The eye itself is healthy, while the cause of the problem is in the nerves and brain responsible for vision. This is why such patients are cared for by a neuro-ophthalmologist — a doctor who understands both the structure of the eye and the workings of the nervous system. This specialist can distinguish optic neuritis from other causes of vision loss, assess the condition of the optic nerve and refer the patient to a neurologist for a full examination in time.
Diagnosis
- Testing of visual acuity, visual fields and colour perception.
- Examination of the fundus to assess the state of the optic disc.
- Optical coherence tomography (OCT) — measures the thickness of the retinal nerve fibres and helps track changes over time.
- Assessment of eye movements to detect nystagmus, double vision and ophthalmoplegia.
- If needed — referral for a brain MRI and a consultation with a neurologist.
Treatment and follow-up
Multiple sclerosis is treated by a neurologist, but the neuro-ophthalmologist plays a very important role in early detection and monitoring. Acute episodes of optic neuritis often resolve on their own, and vision largely recovers; doctors may use anti-inflammatory therapy to speed up recovery. The key is not to delay: seeing a doctor early makes it possible to diagnose the condition in time, start treatment of the underlying disease and regularly monitor the optic nerve using OCT. Scheduled check-ups help to notice new changes in time and keep the course of the disease under control.
When to seek urgent care
Seek help immediately if vision in one eye has sharply worsened over a few hours or days, pain appears when moving the eye, sudden persistent double vision develops, or you feel a dark curtain in front of the eye. Such symptoms require prompt examination — delay can affect the recovery of vision.
German Eye Clinic, phone 0 800 507 670, the “Neuro-ophthalmologist consultation” service page.
