Retinal imaging and axonal degeneration in later onset multiple sclerosis

BACKGROUND: Multiple Sclerosis (MS) is a chronic inflammatory disease of the CNS typically affecting younger adults and resulting in neuro-axonal degeneration already at early stages of the disease. Less is known about the effects of a later disease onset (LOMS, onset >50years of age). Analysis of retinal layers by optical coherence tomography (OCT) is a non-invasive method to investigate retinal and neuro-axonal degeneration. We applied OCT to detect differences in retinal damage depending on a later disease manifestation. METHODS: 14 LOMS patients, 14 age- and 14 disease duration-matched normal onset (NOMS) patients with a relapsing remitting disease course and 15 healthy controls (HC) were included. OCT measurement of peripapillary retinal nerve fiber layer (RNFL), total macular volume (TMV), combined ganglion cell/inner plexiform layer (GCIPL), inner nuclear layer (INL) and outer retinal layers (ORL) was conducted. Furthermore, analysis of clinical features and of effects of previous optic neuritis (ON) was performed RESULTS: In a GEE based analysis of age- and disease duration matched NOMS, LOMS patients show no significant differences in retinal layer thickness whereas ON significantly reduced thickness of retinal layers. All MS groups display lower retinal layer thickness as compared to HC independently of type of onset. DISCUSSION: Our LOMS findings are well in line with published OCT data of normal onset MS. As the degree of retinal layer thinning was similar in MS subgroups, retinal neurodegeneration in MS may occur independently of time of disease onset