In another study in which IL-1β, IL-6, and pro-matrix metalloproteinase (MMP)-9 tear levels were measured in patients with different types of ocular diseases, including a group of 20 hyposecretive moderate dry eye patients, only proMMP9 was significantly increased in DED patients [37]. The gene discussed is MMP9; the disease is Keratoconjunctivitis sicca.