Optic neuritis 3 of 4

Risk factors

Risk factors for optic neuritis arising from autoimmune disorders include:

·       Age. Optic neuritis most often affects young adults ages 20 to 45 years; the average age of onset is about 30 years. Older people or children also can develop optic neuritis, but it occurs less frequently in these groups.

·       Sex. Women are twice as likely as men are to develop optic neuritis.

·       Race. Optic neuritis occurs more in whites than in other races.

·       Genetic mutations. Certain genetic mutations may increase your risk of developing optic neuritis or multiple sclerosis.

When to seek medical advice

Eye conditions can be serious, because some problems can cause you to lose your vision. Contact your doctor under the following conditions:

·       New symptoms. Anytime you have eye pain or notice a change in your vision

·       Worsening symptoms. If you have optic neuritis and experience new eye pain, worsening vision or symptoms that don't improve with treatment

·       Unusual symptoms. If you have unusual symptoms, including numbness or weakness in one or more limbs, which may be an indication of a neurological disorder

Screening and diagnosis

If your doctor suspects that you may have optic neuritis, he or she will refer you to a doctor who specializes in diagnosing and treating eye diseases (ophthalmologist).To help make a diagnosis of optic neuritis, the eye specialist will likely check your vision and your perception of different colors. He or she may also perform the following eye tests:

·       Ophthalmoscopy. During this examination, your doctor shines a bright light into your eye and examines the structures at the back of your eye. This eye test evaluates the optic disk, which is the area where the optic nerve enters the retina in your eye. The optic disk becomes swollen in about one-third of people with optic neuritis.

·       Pupillary light reaction test. Your doctor may swing a flashlight in front of your eyes to see how your pupils respond when they're exposed to bright light. Eyes affected by optic neuritis don't constrict as much as healthy eyes do when stimulated by light.

Other tests to diagnose optic neuritis may include:

·       Visually evoked potentials test. To perform this test, you sit before a screen on which an alternating checkerboard pattern is displayed. Attached to your head are wires with small patches to record your brain's responses to the visuals. This type of test is able to detect the slowing of electrical conduction resulting from damaged areas on nerves.

·       Magnetic resonance imaging (MRI) scan. An MRI scan is a test that uses a magnetic field and pulses of radio wave energy to make pictures of your body. During an MRI to check for optic neuritis, you may be injected with a contrast agent to make the optic nerve and other parts of your brain more visible on the pictures. An MRI is also important to determine whether there are areas in your brain where the myelin has been damaged (lesions), which indicate a high risk of developing multiple sclerosis. (3) An MRI also can help rule out tumors or other conditions that can mimic optic neuritis.

·       Blood tests. A new blood test called a NMO-IgG blood test checks for antibodies for neuromyelitis optica. People with severe optic neuritis may undergo this test to determine whether they're likely to develop neuromyelitis optica. An erythrocyte sedimentation rate (ESR) blood test is used to detect inflammation occurring in your body. This test may help determine whether optic neuritis is caused by inflamed cranial arteries (cranial arteritis).