BACKGROUND AND OBJECTIVES: Anterior visual pathway involvement is common in multiple sclerosis (MS) and optical coherence tomography (OCT) can be utilized to examine the integrity of the ganglion cell axons (peri-papillary retinal nerve fiber layer
pRNFL) and cell bodies (ganglion cell & inner plexiform layer
GCIPL). OCT angiography (OCTA) can be used to investigate the retinal microvasculature. In this systematic review and meta-analysis, we synthesized OCT and OCTA findings in MS. METHODS: We identified studies that performed OCT and OCTA in people with MS and included data permitting at least one of the following comparisons: 1) MS optic neuritis (MS-ON) vs healthy-control (HC) eyes
2) MS non-ON (MS-NON) vs HC eyes
and 3) MS-ON vs MS-NON eyes. RESULTS: The OCT meta-analysis included 170 studies and 8542 HC, 5529 MS-ON, and 14,822 MS-NON eyes. MS-ON and MS-NON eyes had lower pRNFL and GCIPL thickness compared to HC. There was no difference in inner nuclear layer (INL) thickness between HC and MS
INL was thicker in MS-ON compared to MS-NON eyes. The OCTA meta-analysis included 24 studies and 1344 HC, 505 MS-ON, and 1168 MS-NON eyes. MS-ON and MS-NON eyes had lower peripapillary vessel density and macular superficial vessel density compared to HC. We also summarized 12 studies evaluating the diagnostic yield of inter-eye differences in OCT measurements for detecting unilateral optic nerve involvement. CONCLUSIONS: OCT allows for reliable quantification of retinal neuro-axonal damage in MS. In our review, we highlight studies demonstrating that OCT can establish robust thresholds for detecting unilateral optic nerve involvement.