Novel findings of corneal neural features in FBN1-related marfan syndrome.

PURPOSE: To evaluate corneal subbasal nerve plexus alterations in genetically confirmed FBN1-related Marfan syndrome (MFS) using in vivo confocal microscopy (IVCM). METHODS: This cross-sectional case-control study included patients with genetically confirmed FBN1-related MFS and healthy controls. Corneal imaging was performed using IVCM, and six representative images of the subbasal nerve plexus were analyzed with ACCMetrics software. Quantitative parameters included corneal nerve fiber length (CNFL), corneal nerve fiber density (CNFD), corneal nerve branch density (CNBD), corneal nerve total branch density (CTBD), corneal nerve fiber area (CNFA), corneal nerve fiber width (CNFW), and corneal nerve fractal dimension (CNFraD). Between-group differences were assessed using the Mann-Whitney U test. Age-stratified analyses and interaction models adjusted for sex were used to examine the consistency of group effects across age categories. RESULTS: 49 participants were included (30 MFS, 19 controls). Compared with controls, patients with MFS showed significantly reduced CNFL, CNFD, CNBD, CTBD, CNFA, and CNFraD (all P < 0.001), while CNFW did not differ between groups (P = 0.33). Similar reductions were observed in both <18 and ≥18 years subgroups, with no significant group-by-age interaction. Qualitative abnormalities included reduced corneal nerve density with simplified branching, microneuroma-like terminal enlargements, and hyper-reflective deposits adjacent to nerve fibers and the epithelial basement membrane. CONCLUSIONS: FBN1-related MFS is associated with significant quantitative and morphological alterations of the corneal subbasal nerve plexus. Corneal nerve assessment using IVCM may provide a noninvasive marker of microstructural involvement in this systemic connective tissue disorder.