Source: DGNews  |  Posted 2 years ago

By Ed Susman

FORT LAUDERDALE, Fla -- May 5, 2009 -- Researchers suggest that clinicians make a point of checking patients with multiple sclerosis (MS) for diminished vision even when the patients have not experienced any vision-related symptoms such as optic neuritis.

The study was presented here on May 3 at the Association for Research in Vision and Ophthalmology (ARVO) 2009 Annual Meeting.

"Our findings suggest a subclinical axonal loss in the anterior vision pathways of patients with multiple sclerosis that occurs without symptoms," said presenter Esther Bisker, MD, University of Pennsylvania, Philadelphia, Pennsylvania on behalf of lead author Laura Balcer,MD, University of Pennsylvania.

More precise studies that can reveal vision loss, such as low-contrast acuity tests, will help identify patients who may have deteriorating sight.

"Our study indicates that these tests should be performed among all patients diagnosed with multiple sclerosis, not just those with a history of vision complications," said Dr. Bisker.

She stated that visual dysfunction and axonal loss commonly occur with MS and that optical coherence tomography has enabled researchers to see the unique correlations between structure and function of the anterior visual pathway in this disease.

The researchers followed 1,011 patients in the MS treatment programs at the University of Pennsylvania; Johns Hopkins University, Baltimore, Maryland; and University of Texas Southwestern Medical School, Dallas, Texas.

High-contrast and low-contrast visual acuity were checked at 6- and 12-month intervals, and optical coherence tomography was used to determine differences in thickness of the retinal nerve fibre layer. The final analysis involved 336 patients.

The patients were separated into 2 study groups -- 1 involving 428 eyes of patients who did not experience optic neuritis and the other involving 220 eyes of patients who did experience optic neuritis. Patients had a mean age of 44 years, and 85% were diagnosed with relapsing-remitting MS.

The eyes of patients with MS were separated into 2 groups, those that lost vision and those that did not. Of the eyes that lost vision, 29% had a past history of optic neuritis, while 35% of the eyes who did not lose vision had a past history of optic neuritis.

In this collaborative study, it was noted that thinning of the retinal nerve fiber layer, as measured by optical coherence tomography, occurs over time in eyes of patients with MS, even in the absence of acute optic neuritis.

Statistically significant differences in the degree of thinning were noted by 2 years of follow-up in all eyes with multiple sclerosis and even among those without an optic neuritis history.

Funding for this study was provided by the National MS Society and the National Eye Institute.

[Presentation title: Clinical and Ocular Imaging Characteristics of Eyes With Visual Loss Over Time in Multiple Sclerosis. Abstract 927-D709]