The optic nerve is a fiber-like structure connecting the eyes and visual centers in the brain. When light hits the retina the electrical signals travel through the optic nerve to the brain. This signal transmission gets interrupted by any damage that happens to the optic nerve. As the name indicates, optic neuritis is inflammation of the optic nerve; as a result, visual information cannot be transmitted from the eyes to the brain. It often occurs in the setting of multiple sclerosis. Your vision becomes affected when visual information cannot be passed on due to inflammation.
Optic neuritis occurs in 1 to 5 per 100,000 people. It usually affects one eye but in some circumstances can involve both. It can affect any age group. Studies have shown that the northern USA and western Europe have relatively high numbers of cases.
Causes and Risk factors 2
The exact mechanism of optic neuritis has not been completely understood but it is believed that autoimmunity is the reason behind this. There is an outer covering around the optic nerve called the myelin sheath. It is thought that one’s immune system can damage this protective covering. People with autoimmune diseases are prone to optic neuritis.
These are the risk factors that can lead to optic neuritis:
- Female gender ages between 20 to 40 years.
- Caucasian race
- Multiple sclerosis
- Optic neuritis can also occur with any demyelinating conditions.
Signs and Symptoms of Optic Neuritis 1,3
Generally, patients with optic neuritis are young females who present with visual disturbances and pain in the affected eye. When the patient is examined thoroughly the following signs and symptoms can be noted:
- Sudden visual disturbances (decreased vision or blurring) in one eye, or less commonly in both.
- Changes in color perception
- Pain in the affected eye can be exacerbated by the movement of the affected eye.
- Visual symptoms and pain can be exacerbated by heat or exercise.
- Decreased movement of pupils when light is shined into the eye.
Your ophthalmologist will rule out other diagnoses if a visual impairment is severe and pain is absent.
Optic neuritis is diagnosed after thorough examination and investigations. Examination of suspected optic neuritis patients includes:
- Visual acuity
- Visual field testing
- Color vision testing
- Examination of pupillary light reflexes
- Dilated examination including optic nerve examination
MRI of the brain is usually advised when optic neuritis is suspected. Your ophthalmologist can advise other blood tests e.g. ESR and specific antibody tests to rule out autoimmune conditions.
If an MRI is inconclusive then Visual Evoked Potential testing may be advised.
The main goal of optic neuritis treatment is to reduce damage to vision and prevent recurrent attacks. In the initial few weeks to months, the vision may return to normal on its own but early diagnosis and treatment can speed up the recovery process.
The ONTT (optic neuritis treatment trial) recommends the following:
- IV steroids for three days
- Oral steroids after intravenous
- Monoclonal antibodies in the aggressive condition called neuromyelitis optica
- Patients with multiple sclerosis need immunomodulatory drugs as well
To review, optic neuritis is an inflammatory condition of the eye that results in decreased vision and pain. It is more common in females and has high associations with other autoimmune diseases. Optic neuritis is a reversible condition but recovery is faster with IV and oral steroids. You should consult your ophthalmologist for early diagnosis and treatment to reduce visual impairment and pain.
- Dahl, A. A., MD. (2022, August 12). Adult Optic Neuritis: Practice Essentials, Background, Etiology. Retrieved September 10, 2022, from https://emedicine.medscape.com/article/1217083-overview
- What Is Optic Neuritis? (2022, May 6). American Academy of Ophthalmology. Retrieved September 10, 2022, from https://www.aao.org/eye-health/diseases/what-is-optic-neuritis
- NCBI - WWW Error Blocked Diagnostic. (n.d.). Retrieved September 10, 2022, from https://www.ncbi.nlm.nih.gov/books/NBK557853/