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.
Keywords: GATT; Hydrus; iStent; minimally invasive glaucoma surgery; primary open-angle glaucoma.