In Vivo Confocal Microscopy Revealed Alteration of Limbal Stem Cells and Sub-Basal Nerve Plexus in Allergic and Dry Eye-Related Ocular Surface Diseases

Purpose: To evaluate alterations of the palisades of Vogt (POV), basal epithelial cell density (BECD), and the corneal sub-basal nerve plexus (SBNP) in patients with vernal keratoconjunctivitis (VKC), blepharokeratoconjunctivitis (BKC), and allergic conjunctivitis (AC) using in vivo confocal microscopy (IVCM). Methods: IVCM imaging of the limbus, central basal epithelial layer, and SBNP was performed in 122 participants (39 VKC, 26 BKC, 42 AC, and 14 normal controls). POV was graded semiquantitatively. To account for intereye correlation, generalized estimating equations were applied, and ordinal logistic regression was used to identify factors associated with POV visibility. Spearman correlation analysis was performed to evaluate relationships between SBNP parameters, BECD, and POV scores. Results: POV visibility was significantly associated with age, disease group, disease duration, and limbal quadrant. Compared with controls, patients with VKC, BKC, and AC showed significantly lower POV scores, accompanied by decreased BECD and SBNP parameters. Older age and longer disease duration were associated with lower POV scores; a more pronounced POV morphology was observed in the superior and inferior quadrants. Significant correlations were observed among BECD, SBNP parameters, and POV scores. Conclusions: Chronic ocular surface inflammation may be associated with disruption of the limbal stem cell niche, reflected by alterations in POV, cellular, and neural parameters, supporting the potential role of IVCM-derived metrics in the early detection of limbal stem cell dysfunction. Translational Relevance: Vivo confocal microscopy may provide noninvasive in vivo biomarkers of limbal niche and corneal nerve alterations in inflammatory ocular surface diseases, with potential value for earlier identification of limbal stem cell deficiency-related changes.