The correlation of cytokines and sensory hypersensitivity in mild dry eye patients characterized by symptoms outweighing signs.

Purpose: To explore the correlation of tear and conjunctival cytokines and sensory hypersensitivity in mild dry eye (MDE) patients characterized by symptoms outweighing signs (DESOS). Methods: The subjects comprised 39 patients with MDE characterized by DESOS, 18 patients with common MDE (CMDE), and 15 healthy controls. The patients with DESOS were randomly subdivided into two groups; the C-DESOS group received artificial tears only, and the G-DESOS group received artificial tears and 0.1% fluorometholone eye drops three times a day. Symptoms were assessed using the Ocular Surface Disease Index (OSDI) and the Neuropathic Pain Symptoms Inventory modified for Eye (NPSI-E) questionnaire. Ocular examinations and in vivo confocal microscopy (IVCM) were also employed. Tear and conjunctival cytokines were measured using Multiplex or RT-PCR on Days 0, 7, and 30. The correlation between the expression of cytokines and hypersensitivity status was analyzed. Results: Compared with the CMDE and control groups, the DESOS groups showed a significant increase in symptom scores and in the ratio of symptoms versus signs. IL-1 β, IL-2, IL-6, and TNF-α in tears and conjunctiva increased in the DESOS groups compared to the CMDE and control groups, indicating a high correlation with hypersensitivity status in the DESOS groups. Glucocorticoid treatment significantly decreased the level of cytokines in tears and conjunctiva in the G-DESOS group and subsequently ameliorated the symptoms. Conclusions: Tear and conjunctival cytokines, including IL-1 β, IL-2, IL-6, and TNF-α, were correlated with sensory hypersensitivity status in the DESOS groups, suggesting they play an important role in the discordance of symptoms outweighing signs.