Assessment of Optic Nerve Head Using Optical Coherence Tomography Angiography After Retrobulbar Neuritis in Multiple Sclerosis Patients

To evaluate long-term structural and microvascular changes in the peripapillary retina in patients with multiple sclerosis (MS), with a specific focus on differences between eyes with a history of retrobulbar neuritis (RBN) and those without, using optical coherence tomography (OCT) and optical coherence tomography angiography (OCTA). Unlike previous OCTA studies, our analysis focused on the chronic post-acute stage and explored the relationship between structural and vascular alterations within the peripapillary region. This retrospective cross-sectional study included 60 eyes from 30 MS patients who underwent standardized OCT and OCTA imaging between December 18, 2024, and January 30, 2025. Participants were divided into two groups based on their history of RBN. Structural OCT parameters (RNFL and GCL thickness) were measured using Cirrus HD-OCT. Peripapillary vessel density was quantified from Spectralis OCTA images using ImageJ, with a standardized square region of interest (444 × 444 px) applied to measure integrated density (IntDen) for total, superficial, deep, and avascular vascular zones. Group differences were assessed, and correlation analyses were performed to examine structure–vascular relationships. Eyes in the RBN group showed a trend toward reduced RNFL and GCL thickness, with a significant reduction limited to the inferior RNFL quadrant (p = 0.008). OCTA-derived IntDen values showed decreased vessel density in the superficial and deep capillary plexuses, as well as an enlarged avascular zone in RBN eyes. A strong correlation between RNFL and GCL (r = 0.74) and moderate correlations between structural and superficial vascular parameters (r ≈ 0.41) were observed in the RBN group. In contrast, these correlations were weak or absent in the non-RBN group. Heatmap visualization confirmed tighter coupling of structural and vascular changes in eyes with prior RBN. RBN in MS is associated with localized structural and microvascular retinal alterations, most prominently affecting the inferior peripapillary region, while global thinning was not significant. Reduced vessel density, particularly within the superficial and deep capillary plexuses, reflects chronic neurovascular remodeling after prior inflammation. OCTA provides complementary information to structural OCT and may serve as a useful tool for detecting and monitoring post-inflammatory and subclinical retinal changes in MS.