People with ocular rosacea have higher amounts of natural antimicrobial proteins like LL‑37, HNP1‑3 and hBD‑2 in their tears and eye cells, showing that their eye’s innate immune system is over‑active, which also links to worse tear stability and more eye irritation.

<i>Purpose</i>: To investigate the role of innate immunity in ocular rosacea. <i>Methods</i>: Thirty-two patients with ocular rosacea patients (group-1) and 28 healthy volunteers (group-2) who served as controls were enrolled in the study. Tear function parameters were assessed, conjunctival impression cytology was performed and tear samples were collected. Human-neutrophil-peptides (HNP) 1-3 and human-beta-defensin-2 (hBD-2) levels were measured in tears by using ELISA tests. Cathelicidin leucin-leucin-37 (LL-37), hBD-2, human-beta-defensin-9 (hBD-9) gene expression levels were measured in the conjunctival impression cytology samples using real-time polymerase chain reaction. <i>Results</i>: Tear HNP1-3 (<i>p</i>&#xa0;=&#xa0;0.024), hBD-2 (<i>p</i>&#xa0;&lt;&#xa0;0.001), conjunctival LL-37 gene expression rate (<i>p</i>&#xa0;=&#xa0;0.014) and ocular surface disease index scores (<i>p</i>&#xa0;=&#xa0;0.001) were higher and the tear break-up time was lower (<i>p</i>&#xa0;=&#xa0;0.003) in group-1. No other differences were found between the groups. <i>Conclusion</i>: The results of this study suggest the role of abnormal innate immunity in the pathophysiology of ocular rosacea by revealing elevated antimicrobial peptide levels.