ESR1 and open-angle glaucoma: Multiple studies examined the association between PMHs and IOP, with most identifying an association between the use of PMHs and lower mean IOP values,4,25–30,40,41 and this association with lower IOP was more consistent among estrogen-only PMH users than among combined estrogen-plus-progesterone users.8,25,26 Any potential relationship between PMH use and lower risks of POAG might, therefore, be hypothesized to occur through an IOP-mediated pathway, potentially driven through estrogen-receptor signaling.