Background: The iStent inject is a Micro-Invasive Glaucoma Surgical (MIGS) device that has shown to reduce IOP and to be safe for glaucoma patients with fewer complications than regular surgery. Objective: To investigate, up to 15 - 20 months, the efficacy and safety of implantation of two second-generation trabecular microbypass stents in patients with or without prior glaucoma surgery. Methods: Fifty-seven eyes were implanted with the iStent inject. The population was comprised of eyes with primary open-angle glaucoma (n = 51), pseudoexfoliation glaucoma (n = 5) and ocular hypertension (n = 1). Major outcome parameters included IOP, medication needs and corrected distance visual acuity (CDVA). Follow-up time points were one day, 2 - 4 months, 9 - 14 months and 15 - 20 months. Results: The main reason to perform MIGS was IOP reduction in 68.4%, reduced number of medications due to drug intolerance in 24.6% and reduced medication due to compliance issues in 7.0% of the eyes. IOP decreased by 22.47%, from 19.40 ± 3.83 mmHg preoperatively (preop) to 15.04 ± 1.67 mmHg at 15-20 months postoperatively. IOP reduction was achieved at all follow-up time points (p Conclusions: Insertion of the iStent inject in patients with or without prior glaucoma surgery shows effective and sustained improvements in IOP with no safety concerns.