Structural Eye Neurodegeneration Common Among MS Patients with Optic Neuritis, Danish Study Finds

Structural changes of the eye retina are a common feature among multiple sclerosis (MS) patients with a clinical history of optic neuritis, a Danish study finds.

The study, “Long-term structural retinal changes in patients with optic neuritis related to multiple sclerosis,” appeared in the journal Clinical Ophthalmology.

Loss of the myelin protective layer of optic nerve cells due to inflammation causes optic neuritis. About 20 percent of MS have it, and optic neuritis is a symptom of disease progression in about 40 percent of patients. In most cases, symptoms persist, leading to visual impairment or blindness, along with pain.

Non-invasive optical coherence tomography (OCT) can help evaluate neurodegeneration of optic nerve cells. This imaging technique allows a three-dimensional evaluation of internal eye structures, including the thickness of the retina nerve fiber layer (RNFL). Previous studies have shown that MS patients may present progressive RNFL loss, but this can also be caused by optic neuritis.

The use of OCT has been proposed to distinguish MS subtypes and evaluate disease activity. However, little clinical data is available to validate OCT’s accuracy and potential as a diagnostic tool.

To find out more, a Danish research team conducted a long-term evaluation of structural and functional visual outcomes in MS patients with and without a history of optic neuritis.

The team studied 82 patients from Odense University Hospital — one of the largest hospitals in southern Denmark — who had been diagnosed with MS between 2000 and 2006. Participants provided optic neuritis history, while researchers tested visual acuity and color vision, and conducted a structural evaluation via OCT.

Researchers observed that patients with a history of optic neuritis had significantly more RNFL thickness loss than those without optic neuritis. They linked reduced RNFL thickness with a 1.56 times higher risk of optic neuritis development.

Nevertheless, the team did not find any association between optic neuritis and functional impairment of visual acuity or color vision.

“We demonstrated structural, but not functional, visual changes in patients with ON [optic neuritis] during the course of MS,” the authors wrote.

Use of high-resolution OCT devices coupled with up-do-date analysis software can improve the diagnostic efficacy of this imaging technique in MS patients, said researchers, who urged more studies to address the relevance of structural changes in MS.