Optic Neuritis
Robert Shin, MD and Kimberly Winges, MD
Vision is very important in almost everything we do, including watching television, reading a book, driving, and many other daily and recreational activities. When MS disturbs vision, it can have a significant impact on quality of life. People with MS can have many kinds of vision problems, one of the most common being optic neuritis. Other inflammatory diseases of the central nervous system, such as neuromyelitis optica (NMO) and myelin-oligodendrocyte glycoprotein associated disease (MOGAD) can also cause optic neuritis.
Optic neuritis is caused by inflammation or demyelination of the optic nerve, the nerve that connects the eye to the brain. People with optic neuritis generally complain of blurry vision or hazy vision affecting one eye. Often the center of vision is most affected, making it difficult to see people’s faces or creating a “line” in the center of their vision. Some people with optic neuritis describe the blur as a “film” over their eye. Color perception is usually affected as well, with colors seeming faded or less intense in the eye affected by optic neuritis. Optic neuritis is often associated with some eye pain or discomfort, especially with eye movements, which may be described as an ache or “sticking” sensation behind the eye. Heat will worsen the vision temporarily, and sometimes patients will describe blurry vision during exercise or a hot shower.
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 a 4 to 6-week period. Intravenous (IV) methylprednisolone (a type of steroid known as Solu-Medrol), sometimes followed by oral steroids (most commonly prednisone), is often given to treat optic neuritis. Steroid treatment does not appear to improve the ultimate visual outcome, but it does speed up the recovery of vision. With or without steroid treatment, the first episode of optic neuritis almost always gets better, though the vision in the affected eye may not return 100% and recurrent episodes almost always have some permanent damage. Vision in the affected eye might not be as clear as before, low contrast vision may decline, and colors may remain faded or “washed out.” Depth perception or 3-D 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.
More than half of all people with MS will experience optic neuritis at some point in their lives. In fact, for 15% to 20% 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% to 63% -- roughly 50/50 odds.
Brain magnetic resonance imaging (MRI) can be very useful in predicting whether a person with optic neuritis will go on to develop MS. People with optic neuritis who have a normal brain MRI scan have a low risk of going on to develop MS, ranging from 8% to 25%, depending on the study. People with optic neuritis who have demyelination (also called spots, plaques, or lesions) on their brain MRI, have a much higher risk of developing MS, possibly as high as 80%.
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% to 40% 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.
Though optic neuritis generally goes away on its own, with or without treatment, it is still important for people with optic neuritis to be seen by a neurologist 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 after an episode of optic neuritis to review MS treatment options.
