MIGS have been developed as a surgical alternative for glaucomatous patients. To analyze the change in intraocular pressure (IOP) and glaucoma medications using different MIGS devices (Trabectome, iStent, Excimer Laser Trabeculotomy (ELT), iStent Supra, CyPass, XEN, Hydrus, Fugo Blade, Ab interno canaloplasty, Goniscopy-assisted transluminal trabeculotomy) as a solo procedure or in association with phacoemulsification. Randomized control trials (RCT) and non-RCT (non randomized comparative studies, NRS, and before-after studies) were included. Studies with at least one year of follow-up in patients affected by primary open angle glaucoma, pseudoexfoliative glaucoma or pigmentary glaucoma were considered. Risk of Bias assessment was performed using the Cochrane Risk of Bias and the ROBINS-I tools. The main outcome was the effect of MIGS devices compared to medical therapy, cataract surgery, other glaucoma surgeries and other MIGS on both IOP and use of glaucoma medications 12 months after surgery. Outcomes measures were the mean difference in the change of IOP and glaucoma medication compared to baseline at one and two years and all ocular adverse events. The current meta-analysis is registered on PROSPERO (reference n° CRD42016037280). Over a total of 3,069 studies, nine RCT and 21 case series with a total of 2.928 eyes were included. Main concerns about risk of bias in RCTs were lack of blinding, allocation concealment and attrition bias while in non-RCTs they were represented by patients’ selection, masking of participants and co-intervention management. Limited evidence was found based on both RCTs and non RCTs that compared MIGS surgery with medical therapy or other MIGS. In before-after series, MIGS surgery seemed effective in lowering both IOP and glaucoma drug use. MIGS showed a good safety profile: IOP spikes were the most frequent complications and no cases of infection or BCVA loss due to glaucoma were reported. Although MIGS seem efficient in the reduction of the IOP and glaucoma medication and show good safety profile, this evidence is mainly derived from non-comparative studies and further, good quality RCTs are warranted.

The XEN Gel Microstent is a subconjunctival microinvasive glaucoma surgical device developed with the aim of improving the predictability and safety profile of bleb-forming glaucoma surgical procedures. The stent is a hydrophilic tube composed of a porcine gel cross-linked with glutaraldehyde with good stability and biocompatibility with minimal tissue reaction. This device has demonstrated promising outcomes with fewer risks compared to traditional surgeries. The aim of the review is to present early studies on different designs of the XEN Gel Stent, to summarize different surgical techniques of implantation and to analyze more comprehensively the results, complications and rates of needling of the commercially available device (Xen 45). The review will address separately special cases (PXG, UVG, ICE, congenital glaucoma) and describe small series and case reports.

Purpose: Evaluate long-term outcomes after one, two, or three trabecular micro-bypass stents implanted in a standalone procedure in eyes with open-angle glaucoma taking ocular hypotensive medication. Patients and methods: Prospective randomized ongoing study of 119 subjects (109 with 42-month follow-up) with open-angle glaucoma, preoperative intraocular pressure (IOP) 18–30 mmHg on one to three glaucoma medications, and unmedicated (post-washout) IOP 22–38 mmHg. Subjects were randomized to receive one (n=38), two (n=41), or three (n=40) iStent trabecular micro-bypass stents in a standalone procedure. Postoperatively, IOP was measured with medication and annually following washout. Data included IOP, medications, gonioscopy, pachymetry, visual field, visual acuity, adverse events, and slit-lamp and fundus examinations. Results: Preoperative mean medicated IOP was 19.8±1.3 mmHg on 1.71 medications in one-stent eyes, 20.1±1.6 mmHg on 1.76 medications in two-stent eyes, and 20.4±1.8 mmHg on 1.53 medications in three-stent eyes. Post-washout IOP prior to stent implantation was 25.0±1.2, 25.0±1.7, and 25.1±1.9 mmHg in the three groups, respectively. Postoperatively, Month 42 medicated IOP was 15.0±2.8, 15.7±1.0 and 14.8±1.3 mmHg in the three groups, and post-washout IOP (Months 36–37) was 17.4±0.9, 15.8±1.1 and 14.2±1.5 mmHg, respectively. IOP reduction ≥20% without medication was achieved in 89%, 90%, and 92% of one-, two-, and three-stent eyes, respectively, at Month 12; and in 61%, 91%, and 91% of eyes, respectively, at Month 42. The need for additional medication remained consistent at Months 12 and 42 in multi-stent eyes (four two-stent eyes and three three-stent eyes at both time points), whereas it increased in single-stent eyes (four eyes at Month 12 versus 18 eyes at Month 42). Safety parameters were favorable in all groups. Conclusion: The standalone implantation of either single or multiple iStent^® device(s) produced safe, clinically meaningful IOP and medication reductions through 42 months postoperatively, with incrementally greater and more sustained reductions in multi-stent eyes.

To evaluate the effectiveness and safety of the Preserflo MicroShunt implant (Santen) in patients with primary open-angle glaucoma (POAG) and pseudoexfoliation glaucoma (PXG). Retrospective, open-label, multicenter study. Patients with insufficiently controlled primary POAG or PXG who underwent a standalone MicroShunt implantation procedure. Consecutive patients with POAG and PXG who underwent surgery with the ab externo minimally invasive glaucoma surgery device Preserflo MicroShunt with mitomycin C. Primary end points were mean change in intraocular pressure (IOP) and number of hypotensive medications from baseline through month 12. Success was defined as an IOP of 18 mmHg or less and an IOP reduction of 20% or more, with (qualified) or without (complete) any hypotensive medication. Among the 130 patients who underwent MicroShunt implantation, 104 fulfilled the inclusion and exclusion criteria and were included in the analysis. Eighty-one eyes (77.9%) were diagnosed with POAG and 23 eyes (22.1%) were diagnosed with PXG. The mean age was 71.4 ± 12.6 years, and 45 patients (43.3%) were women. Mean IOP was lowered significantly from 25.1 ± 6.5 mmHg at baseline to 14.1 ± 3.4 mmHg at month 12 (P < 0.0001). At month 12, 27 eyes (26.0%) were categorized as complete successes and 61 eyes (58.7%) were categorized as qualified successes. The mean number of hypotensive medications was reduced significantly from 3.0 ± 1.0 medications at the preoperative visit to 0.77 ± 0.95 medication at month 12 (P < 0.001). Throughout the study, 19 eyes (18.3%) required needling and 14 eyes (13.5%) underwent surgical revision. Eight eyes (7.7%) showed hyphema and 5 eyes (4.8%) showed choroidal detachment. These were resolved with medical therapy without sequelae. Four patients underwent subsequent surgeries, and 2 patients underwent trabeculectomy (at months 3 and 6): One patient underwent transscleral cyclophotocoagulation at month 3 and 1 patient underwent MicroPulse cyclophotocoagulation at month 4. In this retrospective study, the MicroShunt effectively lowered IOP and the need for IOP-lowering medications.

Purpose: To investigate the efficacy and safety of a cross-linked gel stent (XEN45) with or without cataract surgery in the treatment of glaucoma patients. Setting: Five university hospitals. Design: Prospective multicenter clinical trial. Methods: Patients with glaucoma inadequately controlled by treatment or poor compliance or intolerance to topical therapy were included. Patients were divided into those who had an implant only (Solo Group; phakic and pseudophakic patients) and those who had an implant combined with cataract surgery (Combo Group). Differences in mean intraocular pressure (IOP) and number of medications between the baseline preoperative visit and study end (12 months), and the rate of qualified and complete success, were evaluated. Results: The Solo Group comprised 115 glaucoma patients (43 phakic and 72 pseudophakic) and the Combo Group comprised 56 patients. Compared with baseline, mean IOP (23.9 ± 7.6 to 15.5 ± 3.9) and number of medications (3.0 ± 1.1 to 0.5 ± 1.0) decreased significantly at 12-month follow-up (P < .001 for both). A >20% and >30% reduction in IOP from baseline was achieved by 72.3% and 52.6% of patients, respectively. IOP at 1 week postoperatively was a predictor of success, and the needling rate was inversely correlated with early postoperative IOP. The number of preoperative medications and patient age were not significantly associated with failure. Conclusions: Insertion of a cross-linked gel stent alone or combined with phacoemulsification might be effective and safe in the treatment of open-angle glaucoma, with a substantial reduction in IOP and number of medications.