CYP1B1 and open-angle glaucoma: Later, CYP1B1 was found to be a modifier gene for primary open-angle glaucoma (POAG), the major glaucoma type in the adult population (Stoilov et al., 1997; Quigley and Broman, 2006; Vasiliou and Gonzalez, 2008; Aponte et al., 2010).