Corneal epithelial dendritic cells associated with ocular pain in dry eye disease

To investigate the association between active corneal epithelial dendritic cells (CEDCs) and ocular pain in patients with dry eye disease (DED).

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.

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.

The findings suggest that infiltrating CEDCs in the corneal subbasal layer are a potential risk factor for ocular pain in DED.