FN1 and open-angle glaucoma: As a possible mechanism responsible for the increase in IOPs, resistance to elevated AH outflow by the TM caused by the excess deposition of extracellular matrix (ECM) molecules such as collagens (COLs), fibronectin (FN) and others appears to be primarily involved in the etiology of both primary open angle glaucoma (POAG) as well as steroid-induced glaucoma (SG)6.