Comparison of the results of Ex-PRESS^® surgery for primary open-angle glaucoma between high and low preoperative intraocular pressure

Purpose: To compare surgical outcomes of Ex-PRESS® (EXP) surgery for primary open-angle glaucoma (POAG) between low preoperative intraocular pressure (IOP) and high preoperative IOP. Methods: This was a retrospective non-randomized study. Seventy-nine POAG patients who underwent EXP surgery and were followed for > 3 years were included. Patients with a preoperative IOP of ≦ 16 mmHg and > 16 mmHg with tolerant glaucoma medications were defined as the low IOP group and the high IOP group, respectively. We compared the surgical outcomes, postoperative IOP and number of glaucoma medications. Success was defined as a postoperative IOP of ≦ 15 mmHg and a reduction of > 20% from the preoperative IOP to the postoperative IOP. Results: EXP surgeries significantly decreased IOPs from 13.2 ± 2.0 to 9.1 ± 2.9 mmHg in the low IOP group (p < 0.001), and from 22.5 ± 4.8 to 12.5 ± 4.0 mmHg in the high IOP group (p < 0.001). The mean postoperative IOP was significantly low in the low IOP group at 3 years (p = 0.0008). Success rates compared using the Kaplan–Meier survival curve were not significantly different (p = 0.449). Conclusions: EXP surgery was useful for POAG patients with a low preoperative IOP.