Morphological changes in vernal keratoconjunctivitis over time: A confocal imaging perspective

PURPOSE: To compare and analyze corneal confocal changes in patients with vernal keratoconjunctivitis (VKC) based on the disease duration. METHOD: A prospective cross-sectional hospital-based analysis of patients with VKC who underwent laser scanning confocal microscopy of the central cornea. Based on disease duration, patients were categorized as Group A (<5 years) and Group B (>5 years) irrespective of their disease activity. ACC Metrics was used for nerve fiber layer analysis, while Image J was used to evaluate the superficial epithelium and anterior stromal keratocytes. RESULTS: Confocal microscopy was performed on 38 eyes of 21 patients, with 22 eyes in Group A and 16 in Group B. Both groups had a comparable distribution of active versus inactive cases and mild versus severe grades. Group B demonstrated a significant increase in superficial epithelial cell length and inflammatory cell density. Additionally, Group B exhibited significantly thinner sub-basal nerves, along with increased stromal nerve thickness, branching, and deflection compared to Group A. No significant differences were observed in sub-basal nerve density or length, or in keratocyte density and area. Although an increase in activated keratocytes was noted in Group B, it did not reach statistical significance. CONCLUSION: Corneal confocal microscopy reveals distinct morphological changes in VKC based on disease duration, suggesting that chronicity may contribute to progressive neuroinflammatory alteration in the cornea.