MMP9 and keratoconus: IL-10, IL-6, MMP-9, MMP-1, HGF, VEGFA, MMP-3, MMP-2, TGFB1, IL-4, IL-2, and IFNG are key inflammatory factors in KC, and the IL-17 signalling pathway may play an important role in the pathogenesis and development of KC (15).