Study of neurodegeneration in multiple sclerosis using optical coherence tomography of the retina and magnetic resonance morphometry of the brain

To search and study the relationship between the change in the thickness of the retinal ganglionic complex layers and the volumetric indicators of the brain in patients with multiple sclerosis (MS). Fifty-seven MS patients aged 19 to 68 years (mean age 39.6±11.2 years) were examined with a diagnosis confirmed by the 2017 McDonald criteria and no previous history of optic neuritis. All patients underwent MRI brain morphometry, optical coherence tomography (OCT) of the retina, and an Expand Disability Status Scale (EDSS) assessment. A direct correlation was found between the thickness of most layers of the "internal" retina and the total volume of white and gray matter of the telencephalon, nuclei accumbens, pallidum, ventral diencephalon, superior parietal gyrus, thalamus, and inversely with the size of the ventricular system of the brain, subcallosal zone, total volume of cerebrospinal fluid (CSF), and foci of brain lesion. The transverse size of the ganglion cell layer (GCL) correlated most with the volumetric parameters of the brain: with the volumes of gray (r=0.426; p=0.001) and white (r=0.564; p<0.000) matter, the nucleus accumbens (r=0.841; p<0.000), thalamus (r=0.542; p=0.000), CSF (r=-0.601; p<0.000), and cingulate gyrus (r=0.304; p=0.002). A less distinct correlation was found between the brain parameters and the thickness of the ganglion cell layer and the inner plexiform layer (GCIPL) with volumes of gray (r=0.389; p=0.002) and white (r=0.439; p=0.000) matter, nucleus accumbens (r=0.463; p=0.000), thalamus (r=0.447; p=0.000), CSF (r=-0.518; p<0.000), cerebellum (r=0.331; p=0.012), and peripapillary retinal nerve fiber layer (pRNFL) with volumes of white matter (r=0.419; p=0.001), nucleus accumbens (r=0.421; p=0.001), thalamus (r=0.396; p=0.002), CSF (r=-0.368; p=0.004), and hippocampus (r=0.399; p=0.002). A significant positive correlation was found between the thickness of the macular retinal nerve fiber layer (mRNFL) and cerebellar volumetric parameters (r=0.351; p=0.007). The anatomical and pathological structure of the eye's retina reflects the neurodegeneration of the central nervous system as a whole. The most sensitive markers of regional gray matter atrophy of the brain are macular thickness in GCL and GCIPL, as well as pRNFL.