"This study suggests that retinal thinning, measured by in-office eye scans, called OCT, may occur at higher rates in people with earlier and more active MS," said Robert Bermel, MD, with the Cleveland Clinic Mellen Center for MS and a member of the American Academy of Neurology, who wrote an accompanying editorial.

For the study, 164 people with MS from the Johns Hopkins MS Center, including 59 who had no disease activity, underwent eye scans that measured thinning of a portion of their retinas every six months for an average of 21 months. Participants were also given MRI brain scans at the start of the study and yearly.

The study found that people with MS relapses had 42 percent faster thinning than people with MS who had no relapses. People with MS who had inflammatory lesions called gadolinium-enhancing lesions experienced 54 percent faster thinning and those with new T2 lesions had 36 percent faster thinning than MS patients without these features of MRI activity.

People whose level of disability worsened during the study experienced 37 percent more thinning than those who had no changes in their level of disability, and those who had the disease less than five years showed 43 percent faster thinning than those who had the disease more than five years.

"As more therapies are developed to slow the progression of MS, testing retinal thinning in the eyes may be helpful in evaluating how effective those therapies are," said study author Peter Calabresi, MD, with Johns Hopkins University School of Medicine in Baltimore and a Fellow of the American Academy of Neurology.

The study was supported by the National Multiple Sclerosis Society, the National Eye Institute and Braxton Debbie Angela Dillon and Skip Donor Advisor Fund.