Abstract
AIM: To investigate the association between active corneal epithelial dendritic cells (CEDCs) and ocular pain in patients with dry eye disease (DED). METHODS: This cross-sectional study enrolled 67 DED patients, who were divided into two groups based on numerical rating scale (NRS) scores: the mild pain group (n=44) and the moderate-to-severe pain group (n=23). In vivo confocal microscopy (IVCM) was used to image the subbasal layer of the central cornea. Corneal nerve characteristics were analyzed using ACCMetrics software, while CEDCs were quantified manually with Image J software. Regression and correlation analyses were performed to assess the impact of active CEDCs on ocular pain. Additionally, the Luminex method was employed to compare the concentrations of inflammation-related cytokines in tears between patients with ≥2 CEDCs and those with <2 CEDCs. Differences in cytokine levels between the two groups were analyzed using Student's t-test. RESULTS: The study included 44 eyes of 44 patients with mild ocular pain (12 males and 32 females) and 23 eyes of 23 patients with moderate-to-severe ocular pain (3 males and 20 females). The mean age was 36.2±13.5y in the mild pain group and 39.7±12.4y in the moderate to severe pain group. There were no significant differences in age or sex between the two groups (P=0.30; P=0.19). Multivariable regression analysis showed that older age [odds ratio (OR) =1.05, 95% confidence interval (CI) 1.00-1.11] and a higher number of CEDCs (OR=1.80, 95%CI 1.17-2.76) were associated with ocular pain. Patients with ≥2 CEDCs had significantly higher tear concentrations of interleukin (IL)-6 (P<0.05), IL-8 (P<0.05), and tumor necrosis factor (TNF)-α (P<0.05) compared to those with <2 active CEDCs. CONCLUSION: The findings suggest that infiltrating CEDCs in the corneal subbasal layer are a potential risk factor for ocular pain in DED.