Optical Coherence Tomography Segmentation Analysis in Relapsing Remitting versus Progressive Multiple Sclerosis (P6.402)

Objective: To compare the OCT segmentation analysis findings among patients with relapsing remitting (RRMS) and progressive MS (PMS) subtypes. Furthermore, we assessed the correlation between thickness of individual retinal layers with neurologic disability expressed by EDSS scores and contrast sensitivity. Background: Optical coherence tomography (OCT) with new segmentation softwares has emerged as a valuable tool in assessing axonal loss and neuro-degeneration in multiple sclerosis (MS) by in-vivo imaging, delineation and quantification of retinal layers. Histopathological studies have shown that retinal involvement in MS extends into the deep retinal layers especially and this has been associated with disease progression. We have compared the OCT segmentation findings and their correlation with neurologic disability expressed by expanded disability status scale (EDSS) scores and visual function in patients with RRMS and PMS. Design/Methods: Cross-sectional study of 113 MS patients (29 PMS, 84 RRMS) and 38 healthy controls. Spectral domain OCT (SDOCT) using the macular cube acquisition protocol and segmentation of the retinal layers for quantifying the thicknesses of the retinal layers. Results: The retinal nerve finer layer (RNFL) ( p = 0.023), the ganglion-cell/inner plexiform layer (GCIPL) ( p = 0.006) and the outer plexiform layer (OPL) ( p = 0.033) were significantly thinner in PMS compared to RRMS. There was significant negative correlation between the ONL and EDSS ( r = −0.554, p = 0.02) in PMS patients. In RRMS patients with prior optic neuritis, the GCIPL correlated negatively ( r = −0.317; p = 0.046), while the photoreceptor layer (PR) correlated positively with EDSS ( β = 0.478; p = 0.003). Conclusions: Patients with PMS exhibit more atrophy of both the inner and outer retinal layers than RRMS. The ONL in PMS and the GCIPL and PR in RRMS can serve as potential surrogate of disease progression. This has implications in the assessment of progression in MS. Disclosure: Dr. Behbehani has nothing to disclose. Dr. AL-Hassan has nothing to disclose. Dr. Al-Salahat has nothing to disclose. Dr. Sriraman has nothing to disclose. Dr. Oakley has received personal compensation for activities with Carl Zeiss Meditec Inc. Dr. Alroughani has received personal compensation from Biogen, Bayer, Novartis, Sanofi Genzyme, Roche, and Merck as an advisor and/or speaker. Dr. Alroughani has received personal compensation in an editorial capacity for Current Treatment Options in Neurology. Dr. Alroughani has received research support from Biogen and Novartis.