SIPA1L1 and open-angle glaucoma: To try to corroborate the observations in HTM cells, we used Western blotting and ELISA to assess the concentrations of SIPA1L1 in TM cells and aqueous humor samples obtained from patients with both POAG and cataracts (POAG group) and compared them to samples from patients with angle-closure glaucoma (ACG) and cataract or cataract-only (non-POAG group).