In Vivo confocal microscopy evaluation of corneal layer alterations in patients with trigeminal neuralgia

PurposeTo investigate corneal microstructural alterations in patients with trigeminal neuralgia using in vivo confocal microscopy and to compare these findings with healthy controls.MethodsIn this prospective, cross-sectional study, sixty patients with unilateral trigeminal neuralgia and sixty matched healthy controls underwent central corneal imaging using in vivo confocal microscopy. Images were obtained from all corneal layers. Quantitative analysis of the subbasal nerve plexus assessed corneal nerve fiber density (CNFD), corneal nerve fiber length (CNFL), and corneal nerve branch density (CNBD). Qualitative evaluation of epithelial morphology, dendritic cell density, stromal keratocyte activation, and endothelial features was performed. Associations between corneal findings and disease duration were analyzed.ResultsCompared with controls, trigeminal neuralgia patients demonstrated significant reductions in CNFD, CNFL, and CNBD (all p < 0.001), accompanied by increased nerve tortuosity, fragmentation, and focal nerve dropout. Dendritic cell density and anterior stromal keratocyte activation were increased, particularly in patients with longer disease duration, while posterior stromal layers and endothelial morphology remained preserved. Disease duration was independently associated with greater subbasal nerve loss and inflammatory changes.ConclusionsTrigeminal neuralgia is associated with significant neurodegenerative and inflammatory alterations of the cornea, primarily involving the subbasal nerve plexus. In vivo confocal microscopy provides a sensitive, non-invasive tool for detecting these changes and may aid in assessing disease severity and progression. To our knowledge, this is the first study to demonstrate disease duration-dependent multilayer corneal microstructural alterations in trigeminal neuralgia using in vivo confocal microscopy.