Optical Coherence Tomography Reveals Distinct Patterns of Retinal Damage in Neuromyelitis Optica and Multiple Sclerosis

Abstract

BackgroundNeuromyelitis optica (NMO) and relapsing-remitting multiple sclerosis (RRMS) are difficult to differentiate solely on clinical grounds. Optical coherence tomography (OCT) studies investigating retinal changes in both diseases focused primarily on the retinal nerve fiber layer (RNFL) while rare data are available on deeper intra-retinal layers.ObjectiveTo detect different patterns of intra-retinal layer alterations in patients with NMO spectrum disorders (NMOSD) and RRMS with focus on the influence of a previous optic neuritis (ON).MethodsWe applied spectral-domain OCT in eyes of NMOSD patients and compared them to matched RRMS patients and healthy controls (HC). Semi-automatic intra-retinal layer segmentation was used to quantify intra-retinal layer thicknesses. In a subgroup low contrast visual acuity (LCVA) was assessed.ResultsNMOSD-, MS- and HC-groups, each comprising 17 subjects, were included in analysis. RNFL thickness was more severely reduced in NMOSD compared to MS following ON. In MS-ON eyes, RNFL thinning showed a clear temporal preponderance, whereas in NMOSD-ON eyes RNFL was more evenly reduced, resulting in a significantly lower ratio of the nasal versus temporal RNFL thickness. In comparison to HC, ganglion cell layer thickness was stronger reduced in NMOSD-ON than in MS-ON, accompanied by a more severe impairment of LCVA. The inner nuclear layer and the outer retinal layers were thicker in NMOSD-ON patients compared to NMOSD without ON and HC eyes while these differences were primarily driven by microcystic macular edema.ConclusionOur study supports previous findings that ON in NMOSD leads to more pronounced retinal thinning and visual function impairment than in RRMS. The different retinal damage patterns in NMOSD versus RRMS support the current notion of distinct pathomechanisms of both conditions. However, OCT is still insufficient to help with the clinically relevant differentiation of both conditions in an individual patient.

Retinal segmented layers with strong aquaporin-4 expression suffered more injuries in neuromyelitis optica spectrum disorders compared with optic neuritis with aquaporin-4 antibody seronegativity detected by optical coherence tomography

“…Previous studies have shown that inner macular segmented layers suffered more severe damage in NMO or NMOSD than MS-ON in general, but for each macular segmented layer, there are controversial studies 4 10 16 17 33. Schneider's10 study showed that the average thickness in the mRNFL, RGCL and IPL was lower in NMOSD than MS-ON but was not significantly different in the INL when controlling for MME influences.…”

Overlapping CNS inflammatory diseases: differentiating features of NMO and MS

“…OCT studies showed that ON in NMO causes more severe neuronal damage and greater thinning of the retinal nerve fibre layer (RNFL) than ON in MS 34–36. Interestingly RNFL thinning in MS showed clear temporal preponderance, while in NMO it was more widespread 34 37…”

Current and Future Potential of Retinal Optical Coherence Tomography in Multiple Sclerosis with and Without Optic Neuritis

“…Although the presence of MMO is related to disability in MS, it is important to note that it is not specific for MS, as MMO is also observed in other diseases [79][80][81][82]. Notably, there have been three recent reports demonstrating MMO in up to 25% of patients with neuromyelitis optica (NMO) [83][84][85]. Therefore, from a clinical practice point of view it may be advised to test for serum anti-AQP4 autoantibodies in those cases with severe ON and MMO, because if positive this will have significant patient management implications.…”