"This technique has the potential to provide a powerful and reliable assessment strategy to measure structural changes in the central nervous system, both for diagnostic purposes and in clinical trials to monitor whether potential treatments can prevent deterioration or restore nerve function,” said Dr. Elliot Frohman, professor of neurology and ophthalmology, director of the Multiple Sclerosis Clinical Center at the University of Texas (UT) Southwestern (Dallas, USA) and cosenior author of the study, which appears in the June 2010 issue of the journal Annals of Neurology.
The technique, called optical coherence tomography (OCT), effectively measures thinning of the retina in individuals with multiple sclerosis, the researchers found. "An ophthalmologist might someday be able to use OCT to identify retinal thinning during a routine eye exam and consider MS as a prime diagnosis,” Dr. Frohman said. "However, this prospect is a long way off.”
Retinal thinning can occur as a result of multiple sclerosis, but this study, according to Dr. Frohman, is the first to track such thinning over time in a single group of patients. The study involved 299 patients with MS who were tracked for six months to 4.5 years.
The researchers found that the retinas thinned significantly with time, and patients often concurrently lost visual sharpness. Overall, the study indicated that OCT is effective, easy to use, and sensitive to changes over time. It could also be used with current clinical measures. Because the retina is easily visible through the pupil, it provides a convenient route for evaluating nerve damage, compared with other parts of the body. As a result, retinal measurement might be able to pick up signs of multiple sclerosis before a person develops other symptoms, according to Dr. Frohman.
OCT machines already are available. Patients look into a device similar to those that measure vision for corrective lenses. Near infrared light, which is invisible to the eye, penetrates the retina and provides information on its thickness. The measurement takes a few seconds for each eye.
Future studies are needed to ascertain whether OCT can characterize the effectiveness of treatments, according to Dr. Frohman.
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