TGFB1 and open-angle glaucoma: TGFβ is a key player contributing to structural changes in the ECM of the trabecular meshwork (TM) and the optic nerve head (ONH), as characteristically seen in POAG, and TGFβ has a role in the production of protease inhibitors that hinder ECM degradation and cause an abnormal deposition of connective tissue that marks the onset of fibrotic disease (1–6).