RNFL And Macular Volume Loss By High-definition Oct In MS Without History Of Optic Neuritis

Abstract

Multiple Sclerosis (MS) is a chronic immune-mediated disease of the central nervous system (CNS), with both inflammatory and degenerative components. The visual system is frequently involved, often in the form of visual loss from optic neuritis. Retinal Nerve Fiber Layer (RNFL) loss has been demonstrated in individuals with MS, not only in those with previous optic neuritis but also in absence of historical evidence of previous acute inflammation/demyelination of the optic nerve. PURPOSE: To examine the peripapillary RNFL, central macular thickness and average macular thickness, in Relapsing Remitting MS (RRMS) patients without history of optic neuritis and compare them to that of healthy controls. METHODS: Peripapillary RNFL measurements of all quadrants, central macular thickness and average macular thickness were performed in 32 eyes of healthy volunteers and 60 eyes of individuals with a diagnosis of RRMS using high definition spectral domain optical coherence tomography (HD-OCT). All eyes had both Macular Cube 512 × 128 scan and RNFL measurement by the Optic Disc Cube 200 × 200 protocol. RESULTS: Eyes of individuals with MS with no previous optic neuritis had significantly decreased overall RNFL thickness (89.1 μm) compared to controls (98.0 μm) (p<0.05). It mainly affected the temporal quadrant (56.6 μm) versus (67.8 μm) (p<0.05), and inferior quadrant (117.9 μm) versus (132.1 μm) (p<0.05) respectively. Also, the MS group demonstrated significantly decreased average macular thickness (280 μm) compared to the control group (287 μm) (p<0.05). A significant correlation between RNFL and average macular volume was also found in MS eyes (r =.69, p<0.01). CONCLUSIONS: RNFL and average macular volume are significantly decreased in MS patients without history of optic neuritis compared to healthy controls. HD-OCT is a quick, inexpensive and promising tool to detect subclinical changes in RNFL and macular volumes in individuals with MS. Longitudinal studies should be encouraged to examine disease progression over time in MS.