Optic Neuritis and Multiple Sclerosis
Vision plays a role in almost everything we do - watching television, reading, driving, and countless other daily activities. When multiple sclerosis (MS) affects vision, it can have a real impact on quality of life. One of the most common vision problems in MS is optic neuritis.
What Is Optic Neuritis?
Optic neuritis is caused by inflammation or damage to the myelin covering of the optic nerve, the nerve that connects the eye to the brain. 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.
People with optic neuritis usually notice blurry or hazy vision in one eye. The center of vision is often most affected, making it hard to see faces clearly or creating a blurred line in the middle of your sight. Some people describe it as a film over the eye. Colors may look faded or less vivid in the affected eye. Many people also have some eye pain or discomfort, especially with eye movements - often described as an ache or a sensation of something pulling behind the eye. Heat can temporarily worsen the blurriness, so you may notice changes during exercise or a hot shower.
What Happens Over Time?
The blurring of vision usually gets worse gradually over about a week, followed by a slow recovery over four to six weeks. Intravenous methylprednisolone (a steroid), sometimes followed by oral steroids like prednisone, is often used to treat optic neuritis. Steroid treatment does not change the final outcome for vision, but it does speed up recovery.
With or without treatment, vision almost always improves after a first episode. However, the affected eye may not return to exactly how it was before. Vision may be slightly less clear, low-contrast vision may be reduced, and colors may remain somewhat faded. Depth perception can also be affected, making it harder to judge distances when climbing stairs or reaching for objects. Repeated episodes are more likely to leave lasting changes.
Optic Neuritis and MS Diagnosis
More than half of all people with MS will experience optic neuritis at some point. For 15 to 20 percent of people with MS, optic neuritis is the very first sign of the disease. However, not everyone who gets optic neuritis will go on to develop MS. Studies suggest roughly a 50/50 chance overall.
Brain MRI can help predict the likelihood of developing MS after an episode of optic neuritis. People with a normal brain MRI have a lower risk, ranging from about 8 to 25 percent. People whose MRI shows demyelinating lesions (sometimes called spots or plaques) have a much higher risk, possibly as high as 80 percent - though even in this group, 20 to 40 percent did not develop MS after many years of follow-up.
When to See a Neurologist
Even though optic neuritis generally improves on its own, it is still important to be seen by a neurologist. For people who have not been diagnosed with MS, a neurologist can help determine whether MS is likely. For people who already have MS, an episode of optic neuritis may be a sign to review treatment options with your MS care team.
Based on an articles by Robert Shin, MD and Kimberly Winges, MD.
