Benign Multiple Sclerosis is Associated with Reduced Thinning of the Retinal Nerve Fiber and Ganglion Cell Layers in Non-Optic-Neuritis Eyes

Abstract

Background and PurposeIt is exceedingly difficult to differentiate benign multiple sclerosis (BMS) from relapsing-remitting multiple sclerosis (RRMS) based on clinical characteristics, neuroimaging, and cerebrospinal fluid tests. Optical coherence tomography (OCT) allows quantification of retinal structures, such as the retinal nerve fiber layer (RNFL) thickness, at the optic disc and the ganglion cell layer (GCL) at the macula, on a micrometer scale. It can also be used to trace minor alterations and the progression of neurodegeneration, help predict BMS, and influence the choice of therapy. To utilize OCT to detect the extent of changes of the optic disk and macular microstructure in patients with BMS and RRMS compared to healthy controls (HCs), with special focus on changes related to the presence/absence of optic neuritis (ON).MethodsSpectral-domain OCT was applied to examine eyes from 36 patients with multiple sclerosis (MS), comprising 11 with BMS and 25 with RRMS, and 34 HCs.ResultsThe RNFL and GCL were significantly thinner in eyes previously affected by ON, irrespective of the type of MS (i.e., BMS or RRMS), than in HCs. Significant thinning of the GCL was also observed in non-ON RRMS (and not non-ON BMS) compared to HCs. Correspondingly, a significant association between disease duration and thinning rates of the RNFL and GCL was observed only in non-ON RRMS (-0.54±0.24 and -0.43±0.21 µm/year, mean±SE; p<0.05 for both), and not in non-ON BMS (-0.11±0.27 and -0.24±0.24 µm/year).ConclusionsThe RNFL and GCL were thinner in both ON- and non-ON MS, but the change was more pronounced in ON MS, irrespective of the MS subtype studied herein. GCL thinning and the thinning rate of both the GCL and RNFL were less pronounced in non-ON BMS than in non-ON RRMS. These findings may help to predict the course of BMS.

Optical Coherence Tomography for the Detection of Remote Optic Neuritis in Multiple Sclerosis

“…Results from a study seem to suggest that GCIP thinning occurs earlier than RNFL thinning . We replicated previous studies that found thinning in the GCIP after optic neuritis . As well, we demonstrated, like other reports, thinning of the RNFL and GCIP on OCT even in MS eyes without a history of optic neuritis .…”

“…Previous studies using OCT have shown that optic neuritis eyes of MS patients, and even nonoptic neuritis eyes of MS patients, exhibit thinning of retinal layers compared to healthy controls. This phenomenon has been consistently found in the peripapillary retinal nerve fiber layer (RNFL), as well as in the ganglion cell layer + inner plexiform layer (GCIP) from which retinal nerve fiber axons originate . Within the temporal quadrant of peripapillary RNFL lies the papillomacular bundle (PMB), which serves central vision.…”

Thickness of macular inner retinal layers and peripapillary retinal nerve fibre layer in neuromyelitis optica spectrum optic neuritis and isolated optic neuritis with one episode

“…Our data and the data from the four previously reported studies were meta‐analysed, further confirming significant differences in pRNFL and nonsignificant differences in GC‐IPL and mRNFL, indicating the robustness and reliability of our findings (Huang‐Link et al. ; Lange et al. ; Monteiro et al.…”

Optical Coherence Tomography as a Biomarker for Diagnosis, Progression, and Prognosis of Neurodegenerative Diseases

“…Since then, an increased interest in the application of OCT technology led to a large number of studies on the retinal changes in MS patients with and without previous ON episodes (non-ON). So far, studies using spectral-domain OCT have revealed that the retina in non-ON eyes shows thinner peripapillary RNFL (pRNFL) than healthy controls [16–19]. …”