July 17, 2003 -- An acute episode of visual disturbance called optic neuritis could signal onset of multiple sclerosis.
A new study, published in The Archives of Ophthalmology, finds that about 40% of people with acute optic neuritis -- an inflammation of the optic nerve -- will develop the degenerative disease within 10 years.
If a brain lesion also is detected in a person with optic neuritis, the odds are significantly higher that a person will develop the disease -- 56% higher in 10 years, writes researcher Roy W. Beck, MD, PhD, with the Optic Neuritis Study Group at the Jaeb Center for Health Research in Tampa, Fla.
Multiple sclerosis is a condition of the brain and spinal cord where the immune system destroys nerve coverings. These coverings help protect nerves and conduct nerve messages. This process of inflammation can be seen in brain scans as plaque, or lesions.
Optic neuritis results when the disease affects the eye nerves and causes inflammation. Symptoms include blurred vision or graying of vision or even blind spots. It usually recovers fully and occurs more commonly in women than men, Beck says.
His study involves 388 patients seen in 15 clinics across the U.S. All were newly diagnosed with optic neuritis, and were between 18 and 46 years old. Each had a brain scan to determine whether they had lesions or not.
Every year afterward, each patient had follow-up brain scans and other neurological tests to determine whether they had developed MS or not.
- Among the 388 patients, 336 developed MS within 10 years later.
- Patients who had an optic neuritis episode had a 38% risk of developing MS within 10 years, and 40% risk within 12 years.
- The average time to developing signs of the disease was 3 years.
- Of those people who did not develop the disease within the first 5 years the chances of later developing the disease was much smaller --7%.
- Patients with one or more large brain lesions at the beginning of the study had a 56% risk of developing MS - a nearly 50% higher risk than those without measurable brain lesions.
- Those with no or smaller brain lesions had a 22% risk of MS within 10 years.
However, as Beck points out, some 40% of people who have optic neuritis will never develop multiple sclerosis. Also, optic neuritis is often a symptom of other neurological disorders.