Measuring the Optic Nerve Improves Diagnosis of Multiple Sclerosis

The thickness of the retinal layer can be used as a biomarker to assist in early diagnosis of multiple sclerosis, according to research done by Medical University of Vienna and recently published in Neurology.

Multiple sclerosis impacts the brain and spinal cord. In patient with MS, the immune system attacks myelin, the protective layer of nerve fibers. It causes problems with vision, arm and leg movement and balance. About 20% of patients with MS experience optic neuritis or inflammation of the optic nerve. It can sometimes take years to get a diagnosis of multiple sclerosis. There is no single test for MS. Doctors often assess symptoms, but the disease can affect people differently.

Researchers in this study have demonstrated that using optical coherence tomography (OCT) imaging of the retina can aid in earlier diagnosis of multiple sclerosis. This means patients can access treatment soon and potentially have better outcomes. Optical coherence tomography is a non-invasive test that uses light waves to take cross-section images of the retinal. It is used to diagnosis glaucoma, age-related macular degeneration and diabetic retinopathy.

Gabriel Bsteh, M.D., Ph.D.

“We have identified a new biomarker for MS diagnosis, namely the retinal layer thickness, which can be likened to a window to the brain,” Gabriel Bsteh, M.D., Ph.D., a neurologist and clinical neuroscientist in the department of Neurology at the Medical University of Vienna, said in a press release. “If we use optical coherence tomography alongside the current criteria to diagnose MS, we obtain significantly more accurate results at a much earlier stage. This means we can initiate treatment measures sooner, which considerably improves the long-term prognosis for patients.”

The research team — led by Bsteh and Thomas Berger, M.D., of the department of Neurology at MedUni Vienna and the University Hospital Vienna — collaborated with colleagues from department of Ophthalmology and optometrics to examine 267 patients with multiple sclerosis over a period of five years.

Their research built on previous study results that showed that MS-related damage to the retina can indicate the risk for permanent disability and reflects changes in the brain. Researchers in the current study wanted to determine whether adding optical coherence tomography could improve diagnosis.

Bsteh and his colleagues conducted a prospective observational study that included patients who had a first “demyelinating event,” which is what clinicians call an occurrence of neurologic symptoms that last for about 48 hours. During a baseline visit six months after the event, patients received cerebral and spinal cord MRI, diagnostic lumbar puncture and optical coherence tomography. Follow up visits were done biannually.

Researchers found that adding optical coherence tomography improves diagnostic accuracy and that optic nerve changes indicated an increased risk for second demyelinating event.

“OCT shows very good concordance with MRI detection of optic nerve involvement, but has some considerable advantages over MRI as it is non-invasive, inexpensive, easy to perform and accessible, fast, and produces standardized, reliable quantitative measures,” researchers wrote. “Thus, OCT represents an attractive option for determining involvement of the optic nerve.”

A limitation of the study is that the outcomes and inclusion criteria were defined retrospectively, which the researchers said could potentially introduce a selection bias. OCT scans were conducted at two different centers creating the potential of confounding inter-rater variability. Additionally, patients in the study were almost exclusively White, and researchers indicated this could limit the applicability of the results to other ethnicities.