Evaluating Fundoscopy as a Screening Tool for Optic Nerve Atrophy in Multiple Sclerosis: An Optical Coherence Tomography (OCT) Comparative Study

<b>Background:</b> Multiple sclerosis (MS) is a chronic, immune-mediated disorder of the central nervous system (CNS), characterized by inflammation, demyelination, and neurodegeneration, resulting in the disruption of axonal signal conduction. Optic neuritis (ON) occurs in over 70% of MS cases, highlighting the involvement of the optic nerve in the progression of the disease. Optic nerve atrophy secondary to the inflammatory episode can be observed during fundoscopy as pallor in the temporal quadrant or of the entire optic disc. Our study aims to evaluate the diagnostic capacity of fundus ophthalmoscopy when compared with the temporal thickness of the pRNFL (peripapillary retinal nerve fiber layer) measured using optical coherence tomography (OCT). <b>Methods</b>: We analyzed 88 eyes from 44 relapsing remitting MS patients using fundus photography (FP) and OCT optic disc measurements, correlating the temporal pallor of the optic disc seen in fundus photographs (FPs) with structural parameters obtained using OCT. <b>Results</b>: Our analysis revealed the significant capacity of optic disc pallor grading using FPs in MS patients in order to discriminate between normal and quadrants with pallor (<i>p</i> = 0.006) or strong pallor (<i>p</i> = 0.003) and between ones with light pallor and moderate pallor (<i>p</i> = 0.002) or strong pallor (<i>p</i> = 0.001), while being unable to clearly differentiate between normal quadrants and ones with light pallor (<i>p</i> = 0.608) or between pallor and strong pallor (<i>p</i> = 0.33). <b>Conclusions</b>: Fundoscopy and FP are useful screening tools in evaluating optic nerve atrophy in MS patients that could be used to assess neurodegeneration because of their universal availability. With the proposed inclusion of the optic disc as the fifth part of the CNS, the optic nerve will benefit from multiple exploratory techniques in order to increase the understanding of disease progression and patient quality of life.