Purpose To evaluate the effectiveness of an ab interno subconjunctival gelatin implant as primary surgical intervention in reducing intraocular pressure (IOP) and IOP-lowering medication count in medically uncontrolled moderate primary openangle glaucoma (POAG). Methods In this prospective, non-randomized, open-label, multicenter, 2-year study, eyes with medicated baseline IOP 18-33 mmHg on 1-4 topical medications were implanted with (phaco + implant) or without (implant alone) phacoemulsification. Changes in mean IOP and medication count at months 12 (primary outcomes) and 24, clinical success rate (eyes [%] achieving ≥ 20% IOP reduction from baseline on the same or fewer medications without glaucoma-related secondary surgical intervention), intraoperative complications, and postoperative adverse events were assessed. Results The modified intent-to-treat population included 202 eyes (of 218 implanted). Changes (standard deviation) in mean IOP and medication count from baseline were − 6.5 (5.3) mmHg and − 1.7 (1.3) at month 12 and − 6.2 (4.9) mmHg and − 1.5 (1.4) at month 24, respectively (all P < 0.001). Mean medicated baseline IOP was reduced from 21.4 (3.6) to 14.9 (4.5) mmHg at 12 months and 15.2 (4.2) mmHg at 24 months, with similar results in both treatment groups. The clinical success rate was 67.6% at 12 months and 65.8% at 24 months. Overall, 51.1 (12 months) and 44.7% (24 months) of eyes were medication-free. The implant safety profile compared favorably with that published for trabeculectomy and tube shunts. Conclusions The gelatin implant effectively reduced IOP and medication needs over 2 years in POAG uncontrolled medically, with an acceptable safety profile. ClinicalTrials.gov registration number: NCT02006693 (registered in the USA).

Purpose: To assess the 3-year effectiveness and safety of the XEN gel stent implanted ab interno in open-angle glaucoma (OAG). Methods: This study was a multicentre, retrospective chart review of consecutive patients with OAG who underwent ab-interno gel stent placement alone or combined with phacoemulsification between 1 January 2014 and 1 October 2015. Outcome measures included mean changes in intraocular pressure (IOP) and IOP-lowering medication count from medicated baseline at 1, 2, 3 (primary outcome) and 4 years (if available) postimplantation. Intraoperative complications, adverse events of special interest (AESIs) and secondary surgical interventions (SSIs) were recorded. Results: The safety and effectiveness populations included 212 eyes (primary and secondary) and 174 eyes (primary), respectively. Mean IOP and medication decreased from 20.7 mmHg and 2.5 at baseline (n = 163 primary/first implanted eyes) to 13.9 mmHg and 1.1 medications (n = 76) at 3 years postimplantation, respectively. Mean changes from baseline in IOP (À5.6, À6.2 and À6.6 mmHg) and IOP-lowering medication count (À1.8, À1.6 and À1.4) were statistically significant at 1, 2 and 3 years postimplantation, respectively. Results appeared comparable when implantation was performed with (n = 76) or without (n = 98) phacoemulsification. In primary eyes with 4-year IOP and medication count data (n = 27), mean IOP was 14.0 mmHg on 1.3 medications at 4 years postimplantation. Fifteen (7.1%) eyes had intraoperative complications, 31 (14.6%) experienced 46 postoperative AESIs, and 26 (12.3%) required SSI. Conclusion:The gel stent effectively lowered IOP and IOP-lowering medication count over 3 years, with a predictable and acceptable safety profile, when implanted via the traditional ab-interno technique.

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The XEN Gel Stent (Allergan Inc., an Abbvie company) is an implant that lowers intraocular pressure by creating a filtration pathway from the anterior chamber to the subconjunctival space, using the same pathway as trabeculectomy. While the primary method for implantation is via ab interno approach, it is also possible to implant the device ab externo. This technique paper details the surgical steps for closed conjunctival implantation of the Gel Stent and provides surgical pearls for enhancing outcomes.

The surgical management of glaucoma offers the potential to lower intraocular pressure (IOP) independent of patients’ compliance with their medication regimen. Procedures such as trabeculectomy and tube shunt placement often yield large magnitudes of IOP reduction, but may be associated with short- and long-term complications. Microinvasive glaucoma surgery (MIGS) offers an alternative surgical approach that is inherently less invasive; however, most devices that fit in this category are associated with a lesser degree of IOP-lowering efficacy compared with traditional glaucoma surgeries. A newer MIGS device, a gel stent that facilitates drainage to the subconjunctival space, appears to offer similar IOP reduction to trabeculectomy, but with much less tissue manipulation; better predictability; and less sight-threatening complications, thus making it a potentially safer and more predictable surgical option in appropriate patients. The following proposed protocol, based on evidence-based practices and augmented where necessary by the opinions of experienced surgeons, provides guidance for the pre-, intra-, and postoperative management of patients receiving a gel stent implant. The goal of this protocol is to provide a framework for better patient selection and preparation, surgical pearls, and how best to assess and manage patients in the postoperative period.