• allergy
• cornea
• corneal collagen cross-linking
• eye rubbing
• in vivo confocal microscopy
• keratoconus
• langerhans cells
• quality of life

The corneal microstructural features and in particular Langerhans cells density and morphology were assessed in consecutive patients undergoing corneal collagen cross-linking for progressive keratoconus. In our previous research we highlighted a reduction in eye rubbing behavior in keratoconus patients after cross-linking. Corneal cross-linking is known to produce typical ultrastructural changes in treated keratoconic corneas, but the effect of the treatment on Langerhans cells and its correlation with clinical outcomes haven't yet been investigated. Langerhans cells are dendritic presenting cells of the cornea and are typically activated in inflammatory and allergic environments, such as those associated with eye rubbing behavior. Quality of life, eye rubbing behavior, clinical features were assessed and in vivo confocal microscopy was performed in patients before and after treatment. Several correlations were noted between clinical and ultrastructural parameters. Among those, significant correlation between eye rubbing behavior and Langerhans cells density and morphology before treatment was demonstrated. These variables also showed significant reduction after treatment.