IL18 and Keratoconjunctivitis sicca: To study the potential involvement of the NLRP3 inflammasome in dry eye patients, we prospectively recruited patients with SSDE and NSSDE, and collected tear and impression cytology samples to evaluate mRNA and protein expression of NLRP3 inflammasome and its downstream inflammatory factors-caspase-1, IL-1β, and IL-18.