Project Summary The accumulation of mutant myocillin leads to decreased aqueous humor outflow and results in ER dysfunction. Grp94 is a major chaperone localized to the ER that is responsible for modulating ER stress and the folding of select client proteins to maintain proteostasis. Through a number of key studies, it has been shown that Grp94 attempts to fold mutant myocillin, but instead co-aggregates and creates a toxic gain of function for Grp94 that results in POAG. Recently, we discovered Grp94 selective inhibitors and demonstrated both in vitro and in vivo that they reduced aggregation and restore intraocular pressure, providing a new mechanism for the treatment of POAG. Therefore, we propose in this application to optimize our lead compounds, determine their mechanism of action, and provide additional data to support their development as topically administered therapeutics not only for POAG, but also steroid-induced glaucoma.