Deep sclerectomy (DS) with the Esnoper Clip drainage implant in patients with uncontrolled primary open angle glaucoma (POAG) achieved a complete success rate of 87.2% at the 1-year follow-up. To investigate the efficacy and safety of DS followed by Esnoper Clip implantation in patients with uncontrolled POAG. In a prospective, consecutive, interventional study, we investigated 39 eyes of 35 patients with uncontrolled POAG who underwent DS with Esnoper Clip implantation. Complete ophthalmologic examinations including corrected visual acuity and intraocular pressure (IOP), were performed preoperatively, and at 1 day, at 1 week as well as at 1, 3, 6, 9, and 12 months postoperatively. Moreover, any goniopunctures and glaucoma medications required postoperatively were noted. The mean preoperative IOP was 20.8±5.2mmHg and it decreased to 13.9±3.1mmHg at 1 year postoperatively ( P <0.001). The number of glaucoma medications decreased from 2.9±0.7 preoperatively to 0.3±0.8 after 1 year ( P <0.001). The complete success rate (IOP≤21mmHg without glaucoma medication) and the qualified success rate (IOP ≤21mmHg with or without glaucoma medication) were 87.2% and 94.9%, respectively. Goniopuncture was performed in 33.3% of cases. No significant corrected visual acuity changes were registered at the final follow-up. Perioperative complications consisted of 3 micro-perforations of the trabeculo-descemet membrane. Postoperative complications included: hyphema (6 eyes), hypotony (6 eyes), shallow anterior chamber (3 eyes), choroidal detachment (4 eyes)-all of which were resolved without surgical intervention during the first postoperative month-and conjunctival dehiscence, which required resuture (2 eyes). Deep sclerectomy with the Esnoper Clip implant was safe and effectively lowered IOP in patients with uncontrolled POAG.