Optic neuritis may be viral, may have no known cause, or may be a manifestation of multiple sclerosis
. Most people who have one episode will recover their vision. While eye exam may be entirely normal, another test, called the visual evoked potential, which gives information as to how long electricity takes to move along the nerve, will be abnormal and will point to the diagnosis. Other causes of optic neuropathy, or problems with the optic nerve, that are not demyelinating, can also occur.