Minimally invasive bleb-forming procedures, such as the XEN® Gel Stent and the PRESERFLO™ MicroShunt, are surgical options used to lower intraocular pressure (IOP) in patients with primary open-angle glaucoma (POAG). This review compares the safety and efficacy of the two devices. A literature search was conducted using Ovid Medline and Embase. Studies were included if they were published in journals with an impact factor above 1.5 and reported outcomes at least 6 months after implantation of XEN or PRESERFLO. Only adult patients with POAG were included. The main outcomes assessed were mean IOP reduction, change in the number of glaucoma medications, and the occurrence of key complications or further interventions. Both devices demonstrated consistent and clinically meaningful IOP reduction in published studies. In a two-year, single-centre retrospective study, 41 eyes treated with XEN showed IOP reduction from 19.2 ± 4.4 mmHg to 13.8 ± 3.8 mmHg (a 28% reduction). In the same study, PRESERFLO in 41 eyes lowered IOP from 20.1 ± 5.0 mmHg to 12.1 ± 3.5 mmHg (a 39% reduction). The average number of medications decreased by approximately 62% with XEN and 69% with PRESERFLO. After 24 months, about 62% of XEN eyes and 64% of PRESERFLO eyes no longer required medications. Early hypotony, defined as IOP ≤ 5 mmHg, occurred in 24% of XEN and 39% of PRESERFLO cases. Persistent hypotony was reported in about 8% of XEN cases. Needling was more common after XEN (20%) than after PRESERFLO (5%). At two years, XEN studies showed around 28% IOP reduction, whereas PRESERFLO studies reported IOP lowering of about 35-39% over the same period. In conclusion, both PRESERFLO and XEN are effective options for managing POAG. However, PRESERFLO may offer more consistent IOP reduction, greater medication-use reduction, and fewer post-operative interventions, making it a potentially more reliable long-term option.

Background/Objectives: This paper will compare the outcomes—safety and efficacy—of three minimally invasive glaucoma surgeries (MIGSs),the Hydrus Microstent, iStent, and Gonioscopy-Assisted Transluminal Trabeculotomy (GATT), for intraocular pressure (IOP) reduction in patients with primary open-angle glaucoma (POAG). Methods: A literature search of Ovid Medline and Embase identified studies evaluating the Hydrus, iStent, and GATT. Data on IOP reduction, medication use, and complications were analyzed. Results: Studies show the Hydrus, iStent, and GATT reduce IOP and medication burden in POAG patients, with some complications. For the Hydrus, studies showed 37.09% (27.5 ± 4.4 to 17.3 ± 3.7 mmHg) and 25% (16.8 to 12.6 mmHg) IOP reduction. Meanwhile, medication burden decreased from 2.5 ± 0.7 to 1.0 and from 2.1 to 1.15. For the iStent, studies showed a 36.39% (21.1 to 13.4 mmHg) and 8.19% (17.1 to 15.7 mmHg) IOP drop. Medication burden decreased from 2.87 to 1.24 and from 1.7 to 0.26. For GATT, studies showed a 49.33% (27.70 ± 10.30 to 14.04 ± 3.75) and 39.09% (26.40 ± 6.37 to 16.08 ± 2.38) IOP drop. Medication burden reduced from 3.73 ± 0.98 to 1.82 ± 1.47 and from 3.12 ± 0.80 to 0.45 ± 0.96. Conclusions: The Hydrus, iStent, and GATT are effective alternatives to trabeculectomy for mild to moderate POAG. They reduce and control IOP and dependence on medications with manageable safety profiles. In all three options, there were some clinically significant complications based on the p-value. For the Hydrus, it was PAS. For the iStent, they were PAS, FB sensation, IOP spikes, and microhyphema. For GATT, it was IOP spikes. However, further long-term studies, especially randomized controlled trials, are needed to support these results.