Eyes on Multiple Sclerosis

Pace of retinal layer thinning may indicate MS disease progression

(RxWiki News) Vision problems are common in those living with multiple sclerosis (MS) and are often an early symptom of relapse. A simple and specific eye exam may be a good way to track the disease.

A recent study looked at the relationship between multiple sclerosis and the rate of thinning of a layer of the retina, a light-sensitive layer of tissue that lines the inner surface of the eye.

The study suggests that the progression of MS can be estimated based on the amount of thinning that has occurred. For those with more active MS, the layer thins more quickly.

"Talk to a doctor about any MS symptoms."

John N. Ratchford, MD of the Johns Hopkins University of Medicine in Baltimore, Maryland and colleagues examined 164 patients with MS and 59 healthy controls.

The study participants were given eye scans to measure the ganglion cell/inner plexiform (GCIP) and retinal nerve fiber layers every six months for about 21 months. The measurements were taken using optical coherence tomography (OCT), a simple noninvasive imaging technique that can help estimate the quality and thickness.

The study participants also received magnetic resonance imagining (MRI) of the brain at the beginning of the study and every year that they were in the study thereafter. The MRI detected lesions on the brain that indicate disease activity.

In MS, the body’s immune system attacks the myelin around the nerve fibers of the brain, spinal cord and optic nerve. Myelin is a fatty substance that insulates and protects the nerves.

Damage to the nerves can result in poor transmission of electrical signals that control functions like movement and speech.

To correct an attack on the myelin, the body attempts to increase blood supply. The area then becomes inflamed and swollen. If it is big enough, it is visible on an MRI and is referred to as a lesion.

The retina is considered to be a part of the central nervous system (CNS). Its nerve cells are not covered by myelin and nerve damage can more easily be observed through it.

This study revealed that patients with MS relapses had 42 percent faster rates of annual GCIP thinning than those without relapses.

MS patients with new gadolinium-enhancing lesions had 42 percent faster thinning than those without the lesions. The presence of new T2 lesions indicated a 36 percent faster thinning than in MS patients with an absence of the lesions.

Worsening disability was associated with 37 percent more thinning than those with no change in disability. Those who had the disease for less than 5 years had 43 percent faster thinning than those with MS diagnosis for more than 5 years.

The highest rates of thinning were seen in those with a combination of new gadolinium-enhancing lesions, new T2 lesions and disease duration of less than 5 years. These patients experienced 70 percent faster thinning than those without all three characteristics.

The changes that occur to the retina are believed to be a reflection of other CNS processes within the body. By measuring the GCIP thickness, the researchers can get an overall idea of what is occurring throughout the CNS.

While it is unlikely that OCT will replace MRI for monitoring patients with MS, the test could be an inexpensive complement.

The study was published online in Neurology, the medical journal of the American Academy of Neurology.

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

Study authors report associations with over a dozen pharmaceutical companies, including Medical Logix for the development of continuing medical education programs in neurology, as well as one employee who is a cofounder and employee of Voxeleron, a vision software company. An association with Carl Zeiss Meditec, a medical technology company that manufactures tools for eye examinations and medical lasers was also reported.

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Review Date: 
December 26, 2012