Paul Harasymowycz

Purpose: To evaluate the safety and effectiveness of a new Schlemm’s canal microstent to lower diurnal IOP and medication use in patients with primary open angle glaucoma (POAG) and cataract Methods: HORIZON is a prospective, multi-centre, randomized, controlled clinical trail comparing con- current phacoemulsification with a Schlemm’s canal microstent. Eligible subjects had mild to moderate POAG treated with 1-4 topical hypotensive medica- tions, IOP (DIOP) of 22-34 mmHg. Following suc- cessful phacoemulsification and lens replacement, study eyes were randomized 2:1 into Hydrus Microstent (HM) or no stent (NS) groups. Follow-up was conducted at 1 and 7 days, and at 1, 3, 6, 12,
18 and 24 months postoperatively.
Results: 556 eyes from 556 study subjects were ran- domized to HM (N = 369) or NS (N = 187. Screen- ing IOP was 18.0 3.1 mmHg on 1.7 1.0
glaucoma medications. Pre operative unmedicated DIOP was 25.5 3.0 mmHg in the HM group and
25.4 2.9 mmHg in the NS group. At 24 months, the mean reduction in DIOP was -7.5 4.1 mmHg in the HM group and -5.2 3.9 mmHg in the NS group (difference = −2.3 mmHg, 95% CI −3.0 to
−1.6, P < 0.001) and mean medication count was reduced 82.4% in the HM group vs 58.8% in the NS group (difference = 23.6%, P < 0.001). Follow up BCVA and VF changes were equivalent in both groups. Conclusion: This study demonstrated that concur- rent Schlemm’s canal stenting in patients undergo- ing cataract surgery is safe and effective in lowering IOP and medication use compared to cataract sur- gery alone at 24 months.