If you have pain in the eye and temporary loss of vision, wake up as you may be suffering from optic neuritis, an inflammation of the bundle of nerve fibers that transmit visual information to your brain from your eye. The condition is generally associated with an autoimmune disorder caused by an infection. In some people, the symptoms of optic neuritis could indicate multiple sclerosis, a disease that damages the nerves in your brain and spinal cord.If you have suffered just one episode of optic neuritis then chances are that you will recover your vision, especially with the support of steroid medications. Although the exact cause is unknown, it is believed to develop when the immune system mistakenly targets the substance (myelin) covering your optic nerve, resulting in inflammation and damage to the myelin, which helps electrical impulses travel quickly along the optic nerve, from the eye to the brain. In the brain, those electrical impulses are converted into visual information.
At the first level your doctors is likely to check your eye for vision and other possible defects that could be causing the symptoms. Beyond a routine eye exam, the diagnostic procedure may include tests like ophthalmoscopy and pupillary light reaction test. You may also be asked to go through blood tests and more advanced tests like an MRI scan (See Tech and Procedures).
Optic neuritis usually gets better on its own. In some cases, steroid medications are used, because they help reduce inflammation in the optic nerve. You need to be extremely mindful that although steroids are an effective treatment for the condition they carry serious side effects and therefore ought to be taken only under specialist medical supervision.
Ophthalmoscopy: A bright light is shone into your eye to study underlying structures. The doctor tries to check in particular whether your optic disk is swollen, which happens in about one-third of people with optic neuritis. The optic disc is the area where the optic nerve enters the retina in your eye.
Pupillary light reaction test: Your doctor may move a flashlight in front of your eyes to see how your pupils respond when they’re exposed to bright light. Pupils in eyes affected by optic neuritis don’t constrict as much as they normally must.
Visual response test (Visual 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 visual stimuli. This type of test is able to detect the slowing of electrical conduction resulting from damaged areas on the optic nerve.
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 solution to make the optic nerve and other parts of your brain more visible on the pictures. An MRI is also important to pinpoint the areas in your brain where myelin might have been damaged (lesions) and thereby determine your chances of developing multiple sclerosis. An MRI also can help rule out tumors or other conditions, which too produce similar symptoms.
Blood tests: A blood test is available to check 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).