Corneal confocal microscopy reveals nerve fiber alterations in migraine irrespective of subtype or visual hypersensitivity

AimCorneal confocal microscopy (CCM) is a non-invasive ophthalmic imaging technique for evaluating the corneal microstructure, particularly the subepithelial nerve plexus. This dense, dynamic plexus contains small nerve fibers from the ophthalmic branch of the trigeminal nerve. This study aimed to evaluate corneal nerve alterations in individuals with migraine, including its subtypes and visual hypersensitivity (measured with the Leiden visual sensitivity scale (L-VISS), a validated nine-item questionnaire).MethodsIn total, 55 migraine participants were included, including 26 with episodic migraine and 29 with chronic migraine, as well as 55 age- and sex-matched controls. All subjects underwent CCM, and automated corneal nerve fiber density (ACNFD), length (ACNFL) and branch density (ACNBD) were assessed using the Rostock Cornea Module (Heidelberg Retina Tomograph III). Data were compared with age- and sex-matched healthy volunteers.ResultsReduced ACNFD, ACNFL and ACNBD were found in migraine participants compared to controls (all p < 0.001). No difference was found between episodic migraine and chronic migraine, and regression analysis showed no significant effect for (inter)ictal visual hypersensitivity.ConclusionsThese findings support the utility of CCM as a sensitive tool for detecting nerve fiber pathology in migraine and highlight its potential in further understanding migraine pathophysiology. The observed nerve changes, present irrespective of migraine frequency status or visual hypersensitivity, suggest a broader role for peripheral nerve dysfunction in migraine beyond sensory hypersensitivity symptoms.