Optic Neuritis, Symptoms and Causes
Optic Neuritis Definition
Optic neuritis is inflammation of the optic nerve which connects the eye and the brain. Sudden inflammation can cause injury to the insulation, or myelin sheath, that surrounds each nerve fiber and cause the nerve to swell. Sudden inflammation may cause sudden, reduced vision in the affected eye. Vision often returns to normal within 2-3 weeks without treatment.
Optic Neuritis Symptoms
Common optic neuritis symptoms are:
- Loss of vision in one eye, over the course of one or more hours
- Changes in the way the pupil reacts to bright light
- Loss of color vision
- Discomfort in and around the eye
- Eye movement causes more pain
Optic Neuritis Causes
The precise cause of optic neuritis is unknown, but there are several possible causes:
- Autoimmune disorder. One possible explanation is that the immune system mistakenly targets the myelin sheath covering the optic nerve which results in inflammation and damage to the myelin. It's not certain why the immune system does this.
- Autoimmune diseases such as muscular sclerosis and neuromyelitis optica are associated with optic neuritis.
- Infections. Optic neuritis can be caused by bacterial infections such as Lyme disease and cat scratch fever or by viruses such as measles, mumps and herpes.
- Cranial arteritis. Inflamed arteries in the head can block blood flow to the eyes and brain, causing permanent vision loss or a stroke.
- Drugs. Some drugs have been connected to the development of optic neuritis.
- Radiation therapy in the head area is an uncommon cause of optic neuritis.