SERPINF1 and eye disorder: Serine protease activity is not only dependent on the abundance of the protease, but also on the absence or presence of endogenous serine protease inhibitors, or serpins, which have been associated with a variety of angiogenesis-related eye diseases (e.g., pigment epithelium derived factor, PEDF) [70], detected in ocular-derived cell lines (e.g., serine protease inhibitor E1, SERPINE1 [a.k.a. heat-shock protein 47, HSP47]) [71], as well as in human tear fluid (e.g., secretory leukocyte protease inhibitor) [72].