Optic neuritis is inflammation of the optic nerve that disrupts the transmission of visual information from the eye to the brain. It can cause eye pain and partial or, in some cases, total vision loss, affecting one or both eyes.
Also called retrobulbar neuritis, this condition is most common in adults between 20 and 45 years old. It is usually linked to multiple sclerosis but can also be caused by a brain infection, tumor, or heavy metal poisoning.
Treatment for optic neuritis is managed by an ophthalmologist, who may prescribe corticosteroids in the form of injections or tablets, and in some cases, recommend surgery.
Optic neuritis symptoms
The main symptoms of optic neuritis include:
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Sudden eye pain;
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Pain that worsens when moving the eye;
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Decreased ability to distinguish colors, especially red;
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A dark, bright, blurry, or flickering spot in the center of vision;
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Seeing flashes of light, even with eyes closed;
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Partial or total vision loss in one or both eyes.
Vision loss is usually temporary, but some people may experience lasting effects, such as blurred vision or difficulty distinguishing colors. It’s important to see an ophthalmologist whenever symptoms of optic neuritis appear to ensure an accurate diagnosis and appropriate treatment.
Confirming a diagnosis
An ophthalmologist can diagnose optic neuritis by assessing symptoms, reviewing medical history, and performing vision tests.
Tests that may be recommended include:
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Visual acuity and visual field tests;
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Color vision testing;
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Visual evoked potential (VEP) test;
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Pupillary reflex evaluation;
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Fundus examination (eye exam).
A brain MRI may also be ordered to identify possible brain changes related to multiple sclerosis or a brain tumor.
Possible causes
The main causes of optic neuritis include:
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Multiple sclerosis;
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Brain infections, such as meningitis or viral encephalitis;
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Brain tumor;
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Autoimmune diseases;
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Use of certain medications, including some antibiotics;
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Exposure to toxic substances such as methanol, lead, or arsenic.
Graves’ disease can also cause optic neuritis due to eye involvement known as Graves’ orbitopathy. In many cases, however, the cause of optic neuritis is unknown, and the condition is referred to as idiopathic optic neuritis.
These conditions can damage the myelin sheath, the protective layer that surrounds nerves and allows electrical impulses to travel efficiently, leading to inflammation of the optic nerve and resulting symptoms.
Treatment options
In many cases, optic neuritis improves on its own, with symptoms resolving over several weeks or months without specific treatment.
However, an ophthalmologist may prescribe corticosteroids, such as intravenous methylprednisolone for 3 days followed by oral prednisone for another 11 days, to reduce inflammation of the optic nerve and speed up recovery.
Surgery to decompress the optic nerve may be recommended when a tumor is the underlying cause.
If optic neuritis is associated with multiple sclerosis, treatment for the underlying condition should also be started under the guidance of a neurologist or rheumatologist.