Over half of all people with first-time optic neuritis, a vision-impairing inflammation of the optic nerve, will eventuallydevelop multiple sclerosis (MS).

But researchers report today in the New England Journal of Medicine that treating first-time optic neuritis patients with a combination of intravenous and oral corticosteroids lowers their risk of developing MS within the next two years.

MS is a debilitating disease of the central nervous system that affects as many as 500,000 Americans. This finding, based on two-year patient followup from a large National Eye Institute-supported clinical trial, offers the first scientific evidence ever that intravenous corticosteroids help to delay the progression of MS. It also suggests that this treatment may provide similar benefits for people with not only optic neuritis, but other early symptoms of MS.

“Based on this finding, doctors should strongly consider treating their optic neuritis patients with intravenous corticosteroids, even though this regimen has only a marginal impact on a patient’s recovery of vision,” said Roy Beck, M.D., Ph.D., chairman of the Optic Neuritis Treatment Trial (ONTT) and a professor of ophthalmology and epidemiology at the University of South Florida.

“Optic neuritis is often an early sign of MS, and subsequent inflammations of the central nervous system may lead to increased disability,” said Dr. Beck. “If future attacks of MS can be delayed or prevented with intravenous corticosteroids, patients may be able to maintain a higher quality of life.”

In the ONTT, researchers evaluated 389 patients with optic neuritis who had no other clinical signs of MS when they entered the study. Each patient was randomly assigned to one of three treatment groups: (1) high-dose intravenous methylprednisolone for three days followed by a lower dosage oral prednisone for 11 days, (2) oral prednisone for 14 days, and (3) oral placebo for 14 days.

The investigators found that within the first two years, MS developed in 7.5 percent of the intravenous group, 14.7 percent of the oral corticosteroid group, and 16.7 of the placebo group. The researchers also determined that the protective effect of intravenous therapy lessened after two years, suggesting the need for future studies on possible retreatment strategies.

Dr. Beck stated that he and the other researchers were uncertain how the intravenous therapy slowed the onset of MS, in part because the exact cause of the disease is still unknown.

In addition, the ONTT confirmed previous reports from smaller studies that magnetic resonance imaging (MRI) brain scans can frequently help doctors detect asymptomatic brain lesions in optic neuritis patients that are related to early MS.

In the study, nearly 25 percent of patients with abnormal brain scans developed MS within two years compared to only 5 percent of those with normal brain scans. The more abnormal the initial brain scan, the more likely a person was to develop MS.

Moreover, participants with abnormal brain scans benefitted most from the intravenous corticosteroids. Thirty-six percent of patients in the placebo group who had two or more brain lesions developed MS within two years compared to 16 percent of those in the intravenous group.

Because of this finding, the researchers stated that intravenous corticosteroid treatment may also benefit those with other early symptoms of MS.

“The ONTT is a good example of how the results from vision research can have an impact on a related medical discipline,” said Carl Kupfer, M.D., director of the National Eye Institute. “Since the eye provides nearly 40 percent of our sensory input to the brain,it provides an excellent opportunity to study many of the disorders that affect the brain.”

Optic neuritis affects more than 25,000 Americans each year, primarily women between the ages of 18 and 45. Because studies show that at least half of the people who have an initial attack of optic neuritis will develop MS within 15 years, many physicians consider the disease to be a precursor or early manifestation of MS.

Optic neuritis causes pain and a rapid, often extreme, loss of vision. ONTT scientists reported previously that even without treatment, patients generally recover their vision after the first episode of the disease.

Patients treated with intravenous corticosteroids recovered their vision about two weeks sooner than those receiving a placebo, but this treatment provided them with no long-term visual benefit.

The researchers also found that oral corticosteroids alone are ineffective in treating optic neuritis, and that treatment with these drugs can actually increase a person’s risk for future attacks of optic neuritis.

The National Eye Institute, a part of National Institutes of Health, is the Federal government’s lead agency for the conduct and support of research on the human visual system in health and disease.

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Citations

• Beck RW, Cleary PA, Trobe JD, Kaufman DI, Kupersmith MJ, Paty DW, Brown CH. The Effect of Corticosteroid for Acute Optic Neuritis on The Subsequent Development of Multiple Sclerosis. The Optic Neuritis Study Group. N Engl J Med. 1993 Dec 9. PubMed

December 1993