What is optic neuritis?
Optic neuritis is inammation of the optic nerve and/or its covering (myelin sheath).
What causes optic neuritis?
The inammation occurs when the immune system of one’s body mistakenly attacks the optic nerve and/or its myelin sheath. Optic neuritis is a broad term describing a condition which may be caused by a wide range of underlying diseases.
Possible causes:
- Idiopathic or unknown, although a viral infection may be responsible
- Multiple sclerosis (MS)
- Neuromyelitis optica (NMO)
- Myelin oligodendrocyte glycoprotein (MOG)-associated optic neuritis
- Autoimmune conditions
- Systemic lupus erythematosus (SLE), Sjogren’s syndrome, sarcoidosis, granulomatosus with polyangiitis, etc.
- Infections
- Bacterial infections such as Lyme disease, syphilis, etc., viral infections such as measles, mumps and herpes.
Examination by your ophthalmologist, together with investigations such as blood tests and MRI are important to help differentiate the different types of optic neuritis.
What are the symptoms of optic neuritis?
Symptoms may affect one or both eyes, and include:
Blurring of vision
You may notice sudden vision loss developing over days.
Loss of colour vision
You may notice that colours appear less vibrant than usual.
Eye pain
This may feel like a dull ache behind the eye. Your eye pain may be worsened by eye movement.
How is optic neuritis diagnosed?
You will need to see an ophthalmologist to make the diagnosis. Your ophthalmologist will take a medical history and perform a full eye examination.
Your optic disc (part of the optic nerve that is visible in the eye) may or may not appear swollen. The following tests may be required in order to diagnose and help distinguish the different causes of optic neuritis:
Visual field test
Measures the degree and pattern of visual loss in your eld of vision.
Optical coherence tomography
Measures the thickness of your eye’s retinal nerve bre layer, which may be thicker in the acute stage of optic neuritis in the presence of optic disc swelling, or thinner in the late stage due to optic nerve damage.
Blood tests
To check for infections or specific antibodies that may cause different types of optic neuritis.
Magnetic resonance imaging (MRI)
Scan to look for changes in your optic nerve or brain. You may also receive an injection of a contrast (dye) during the scan.
Lumbar puncture
May be performed to analyse the fluid surrounding your brain and spine (cerebrospinal uid) for abnormalities.
How is optic neuritis treated?
Some patients with optic neuritis, especially the idiopathic type, may get better without any treatment. However, many patients need treatment to improve their vision. The aim of treatment is to reduce inammation and limit the amount of optic nerve damage.
Intravenous Methylprednisolone
A three- to ve-day course of high dose intravenous corticosteroids may be offered to reduce inammation in the optic nerve. This is usually followed by a longer course of oral corticosteroids. Possible side effects from steroid treatment include:
- Hypertension, irregular heart beat
- High blood sugar
- Electrolyte (salt) imbalance in the blood
- Gastric bleeding (usually in patients with pre-existing gastric ulcers)
- Infections
- Weight gain
- Osteoporosis
- Mood changes, insomnia
Let your doctor know if you have a history of:
- Gastric ulcers
- Tuberculosis
- Hepatitis B or C carrier
Plasma Exchange Therapy
When steroid therapy fails and severe vision loss persists, this treatment may be offered to
help you recover some vision.
Plasma is the liquid portion of your blood that contains disease-causing antibodies. This treatment removes plasma from your blood and replaces it with a substitute.
Will my vision improve completely after treatment?
Most patients recover their vision completely. It may take up to one year. This tends to be the case when optic neuritis is not related to an underlying health condition (see “What causes optic neuritis?”). In some cases, however, vision recovery may be incomplete.
Will my vision improve completely after treatment?
If you have an underlying health condition (see “What causes optic neuritis?”) that triggered the optic neuritis, this has to be treated. Otherwise, optic neuritis may recur.
