Multiple sclerosis is the most common cause.
Loss of vision may develop, and there may be pain with eye movement.
Magnetic resonance imaging is done.
If multiple sclerosis seems possible, corticosteroids may be given.
(See also Overview of Optic Nerve Disorders Overview of Optic Nerve Disorders The small photoreceptor cells of the retina (the inner surface at the back of the eye) sense light and transmit impulses to the optic nerve. The optic nerve from each eye carries impulses to... read more .)
Causes of Optic Neuritis
Optic neuritis is most common among adults aged 20 to 40 years. Optic neuritis is most often caused by multiple sclerosis Multiple Sclerosis (MS) In multiple sclerosis, patches of myelin (the substance that covers most nerve fibers) and underlying nerve fibers in the brain, optic nerves, and spinal cord are damaged or destroyed. The cause... read more . However, some people who have optic neuritis are found only later to have multiple sclerosis. Optic neuritis may also be caused by the following:
Infections such as viral encephalitis Encephalitis Encephalitis is inflammation of the brain that occurs when a virus directly infects the brain or when a virus, vaccine, or something else triggers inflammation. The spinal cord may also be involved... read more (especially in children), meningitis Introduction to Meningitis Meningitis is inflammation of the layers of tissue that cover the brain and spinal cord (meninges) and of the fluid-filled space between the meninges (subarachnoid space). Meningitis can be... read more , syphilis Syphilis Syphilis is a sexually transmitted infection caused by the bacteria Treponema pallidum. Syphilis can occur in three stages of symptoms, separated by periods of apparent good health. It... read more
, sinusitis Sinusitis Sinusitis is inflammation of the sinuses, most commonly caused by a viral or bacterial infection or by an allergy. Some of the most common symptoms of sinusitis are pain, tenderness, nasal congestion... read more , tuberculosis Tuberculosis (TB) Tuberculosis is a chronic contagious infection caused by the airborne bacteria Mycobacterium tuberculosis. It usually affects the lungs. Tuberculosis is spread mainly when people breathe... read more 
, and human immunodeficiency virus Human Immunodeficiency Virus (HIV) Infection Human immunodeficiency virus (HIV) infection is a viral infection that progressively destroys certain white blood cells and can cause acquired immunodeficiency syndrome (AIDS). HIV is transmitted... read more 
(HIV)Spread of a cancerous tumor to the optic nerve
Chemicals or drugs such as lead, methyl alcohol, quinine, arsenic, and certain antibiotics
Myelin oligodendrocyte glycoprotein autoantibody (MOG-IgG) disease
Rare causes include diabetes Diabetes Mellitus (DM) Diabetes mellitus is a disorder in which the body does not produce enough or respond normally to insulin, causing blood sugar (glucose) levels to be abnormally high. Urination and thirst are... read more , pernicious anemia, certain autoimmune diseases, Graves disease that affects the orbit (the socket that holds the eyeball), bee stings, and injuries. However, the cause of optic neuritis is often unknown.
Symptoms of Optic Neuritis
Optic neuritis causes vision loss, which may be mild or severe and may occur in one or both eyes. Loss of vision may increase over 1 or 2 days. Vision in the involved eye or eyes can range from almost normal to complete blindness. Color vision may be particularly affected, but the person may not realize it. Most people have mild eye pain, which often feels worse with eye movement. Depending on the cause, vision usually returns within 2 to 3 months but not always completely. Some people have repeat episodes of optic neuritis.
Diagnosis of Optic Neuritis
A doctor's evaluation
Usually magnetic resonance imaging
Diagnosis involves examination of the reactions of the pupils and observing the back of the eyes with a light with magnifying lenses (ophthalmoscope). The head of the optic nerve at the back of the eye (optic disk) may appear swollen. Testing the field of vision may reveal loss of a portion of the visual field. Magnetic resonance imaging (MRI) of the brain may show evidence of multiple sclerosis Multiple Sclerosis (MS) In multiple sclerosis, patches of myelin (the substance that covers most nerve fibers) and underlying nerve fibers in the brain, optic nerves, and spinal cord are damaged or destroyed. The cause... read more , myelin oligodendrocyte glycoprotein autoantibody (MOG-IgG) disease, or, rarely, a tumor pressing on the optic nerve. Spinal cord imaging may be done in people with neurologic symptoms.
Treatment of Optic Neuritis
Sometimes corticosteroids
For tumors, relief of pressure
In some instances, such as when multiple sclerosis Multiple Sclerosis (MS) In multiple sclerosis, patches of myelin (the substance that covers most nerve fibers) and underlying nerve fibers in the brain, optic nerves, and spinal cord are damaged or destroyed. The cause... read more seems possible, corticosteroids may be given by vein to treat optic neuritis. After a few days, corticosteroids are given by mouth. These drugs may hasten recovery and reduce the chance of a recurrence. If the optic neuritis is related to multiple sclerosis or an infection, the underlying disease should also be treated.
If a tumor is pressing on the optic nerve, vision usually improves once the pressure caused by the tumor is relieved.
Magnifiers, large-print devices, and talking watches (low-vision aids) may help people with loss of vision.
