Symptom Management

When Optic Neuritis Comes Back

By Robert K. Shin, M.D.
Optic neuritis is a vision problem caused by inflammation or demyelination of the optic nerve – the nerve that connects the eye to the brain. Optic neuritis can occur by itself (idiopathic optic neuritis) or may be associated with demyelinating diseases such as multiple sclerosis or neuromyelitis optica (NMO, or Devic’s disease).
More than half of all people with MS will experience optic neuritis at some point in their lives. In fact, for 15 percent to 20 percent of people with MS, optic neuritis will be the first sign of the disease. Not all people who get optic neuritis, however, will go on to develop MS. Many studies have examined this relationship between optic neuritis and MS over time. Depending on the study, the risk of developing MS after an episode of optic neuritis varies from 42 percent to 63 percent – roughly 50/50 odds.
Brain MRI can help to predict which people with optic neuritis will go on to develop MS. People with optic neuritis who have a normal brain MRI scan have a relatively low risk of going on to develop MS, ranging from 8 percent to 25 percent, depending on the study. People with optic neuritis who have demyelination (spots, plaques or lesions) on their brain MRI, have a much higher risk of developing MS, possibly as high as 80 percent. Though this risk is significant, and much greater than the risk of MS in people who start out with a normal brain MRI, it should be noted that 20 percent to 40 percent of the “high-risk” people in these studies who had an episode of optic neuritis did not go on to develop MS even after many years of follow-up.
People with optic neuritis usually notice blurry vision or hazy vision affecting one eye. Less commonly, both eyes can be affected at the same time. Often the center of vision is involved, but any part of the visual field may be affected.
People with optic neuritis may describe the blur as a “film” over their eye or a “smudge.” Colors may seem faded or less intense in the eye affected by optic neuritis.
Optic neuritis is almost always associated with some eye pain or discomfort, especially with eye movements, which may be described as an ache or “sticking” sensation behind the eye. In optic neuritis, the blurring of vision may gradually worsen over the course of a week or so. Afterward, there is usually a gradual recovery of vision, occurring over four to six weeks, though additional recovery may occur over six to twelve months or longer.
Intravenous steroids (commonly methylprednisolone, also known as Solu-Medrol®) are often given to treat optic neuritis. Typically 1,000 mg of IV methylprednisolone are infused daily for three to five days. IV steroids do not appear to improve the ultimate visual outcome, but they do seem to speed up the recovery of vision. High doses of oral steroids (for example: 1,000 mg of prednisone per day, given every other day, for a total of three to five doses) may also be used. Low doses of oral steroids (in the range of 60 mg to 100 mg per day) seem to be associated with an increased risk of a recurrent episode of optic neuritis and should be avoided.
With or without steroid treatment, optic neuritis almost always gets better, though the vision in the affected eye may not return 100 percent. Vision in that eye might not be as clear as before, and colors may remain faded or “washed out.” Depth perception or 3D-vision is often not as good after an episode of optic neuritis, making it more difficult to judge distances, as when climbing stairs or reaching for objects.
Optic neuritis may be a one-time- only event; however approximately 15 percent to 20 percent of the time, it can come back in the same eye or may develop in the other eye. When optic neuritis returns, it is called “recurrent optic neuritis.”
Recurrent optic neuritis is generally treated with IV steroids just as a single episode of optic neuritis might be. The visual outcome after recurrent optic neuritis probably has less to do with how many episodes of optic neuritis have occurred, and more to do with what is the underlying cause of the optic neuritis.
Most of the time, when optic neuritis is recurrent, the patient either has or is ultimately diagnosed with MS. In these cases, visual recovery is generally good, though not guaranteed. It is possible, however, for recurrent optic neuritis to occur in the setting of NMO as well, and when it does, visual recovery may not be quite as good. A blood test (NMO- IgG) that identifies antibodies specific to NMO may be helpful in distinguishing MS from NMO.
Sometimes recurrent optic neuritis occurs without any evidence of either MS or NMO. This disorder, known as chronic relapsing inflammatory optic neuropathy, is somewhat poorly understood. Eye pain can be more severe and long- lasting with CRION than the mild aching seen with optic neuritis associated with MS. Vision loss may be more severe with CRION as well. Fortunately, both the pain and the vision loss associated with episodes of CRION generally respond very well to IV steroids, but if steroid treatment is stopped, CRION may come back. Therefore, sometimes prolonged steroid treatment or additional immunosuppressant medications are necessary.
Most of the time, recurrent optic neuritis has the same significance as any other series of relapses or exacerbations seen with MS and should be treated as such. For patients who were originally diagnosed with idiopathic optic neuritis, recurrence of optic neuritis might prompt a visit to a neurologist in order to find out if MS is likely or not. For people who already have a diagnosis of MS, it may still be important to see a neurologist if optic neuritis recurs to review MS treatment options.
Sometimes, however, recurrent optic neuritis may be a clue that there is a different process occurring, such as NMO or CRION. In those cases, recurrent optic neuritis might prompt additional testing or a change in which medications are used for treatment and for how long.
Dr. Robert K. Shin is a Professor in the Department of Neurology at MedStar Georgetown University Hospital. He specializes in multiple sclerosis and neuro-ophthalmology.