PurposeTo evaluate the 3‐year treatment outcomes of XEN 45 gel stent in open‐angle glaucoma patients.MethodsIn this prospective, single‐centre interventional study, consecutive eyes with uncontrolled intraocular pressure (IOP) or signs of disease progression despite medical treatment underwent XEN implantation either alone or combined with phacoemulsification (Phaco + XEN).Main outcome measuresSurgical success was defined as 'complete' when 36‐month unmedicated IOP was ≤15 mmHg with a relative IOP reduction ≥ 20% from medicated baseline, while the definition of qualified success allowed no more medications than at baseline. Other definitions of success with different IOP thresholds were also analysed. Secondary outcomes included mean IOP reduction, changes in ocular hypotensive medications and rates of reoperations.ResultsOut of 149 eyes initially included, 92 eyes (61.7%) of 68 patients had complete 3‐year data (XEN: n = 26; Phaco + XEN: n = 66) after 38.2% were lost to follow‐up. Mean age was 76.3 ± 9.1 years, and 66.2% were female. Mean medicated IOP decreased from 20.8 ± 7.4 mmHg (21.0 ± 7.4 [XEN] vs. 20.0 ± 6.9 mmHg [Phaco + XEN]) at baseline to 13.1 ± 3.4 mmHg (12.9 ± 2.9 [XEN] vs. 12.9 ± 3.4 [Phaco + XEN]) at 3 years (−37.0%; p < 0.001). Medications decreased from 1.9 ± 1.3 (2.4 ± 1.5 [XEN] vs. 1.9 ± 1.2 [Phaco + XEN]) to 0.4 ± 0.9 (0.3 ± 0.8 [XEN] vs. 0.5 ± 0.9 [Phaco + XEN]) (−78.9%; p < 0.001). Complete success and qualified success were achieved in 29.0% and 31.0% of eyes, respectively. Needling revision was performed in 51 eyes (55.4%), and 26.1% underwent reoperations. Risk factors for surgical failure included male gender (odds ratio [OR]:3.6; p = 0.03), diagnosis of POAG (OR: 4.5; p < 0.01) and undergoing needling revision (OR: 4.6; p < 0.01). While the type of procedure had no effect on the outcomes of PEXG, POAG eyes undergoing combined surgery had significantly higher rates of failure (OR: 7.29; p = 0.023). Most patients stable at 12‐month remained so through to 3 years.ConclusionsAt 3 years, XEN gel stent implantation achieved clinically significant IOP and medication reduction despite relatively high rates of needling and reoperations. Identifying patients at risk preoperatively may help optimize surgical outcomes.

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Introduction: Corneal integrity has long been a preoccupation of glaucoma surgeons considering glaucoma drainage device surgery or antimetabolite-enhanced trabeculectomy. Despite having demonstrated a good safety profile and significant intraocular pressure–lowering capacities, the impact of XEN gel stents on endothelial density was never specifically investigated. The purpose of this study is to assess the effect of XEN gel stents on central endothelial cell density (ECD) over 24 months. To achieve this, we compared the effect on ECD of combined XEN surgery with that of a standard phacoemulsification procedure. Methods: This was an investigator-initiated, retrospective study, conducted at a single tertiary glaucoma center. Patients with primary or secondary open-angle glaucoma who underwent XEN implantation combined with phacoemulsification between January 2015 and June 2016 were retrospectively enrolled. Patients who had undergone standalone phacoemulsification over the same period of time were enrolled to form the control group of this comparative study. The primary outcome measure was the ECD. Patients who had undergone standalone XEN implantation and patients for whom both a baseline and 24-month ECD could not be obtained were excluded from the analysis. Percentages of ECD reductions were calculated for each studied eye, and the mean of ECD reductions was calculated for each group as well as for subgroups. Results: Thirty-two eyes of 23 patients (mean age=76.0±7.9 y, 60% female) underwent standalone phacoemulsification (n=15) or combined XEN surgery (n=17) and had an ECD both at baseline and 24-month postoperatively. Mean baseline ECDs were 2568±491 versus 2379±335 cells/mm2, respectively (P=0.21). In the combined XEN surgery group, 58.8% of eyes (n=10) required at least 1 mitomycin C (MMC)-enhanced needling revision to maintain their target intraocular pressure. In the standalone phacoemulsification group, ECD decreased by a mean 14.5%, from 2567.7±491.2 to 2196.1±591.9 cell/mm2 (P=0.072). In the combined XEN surgery group, ECD decreased by a mean 14.3%, from 2378.8±334.7 to 2039.6±451.1 cell/mm2 (P=0.018). The difference in percentage reduction of ECD between the 2 groups was not statistically significant (P=0.226). Within the combined XEN surgery group, the ECD decreased by a mean of 15.4% in patients who did not undergo needling revisions and by 13.1% in patients who underwent the MMC-augmented procedure (P=0.485). In the 3 patients who underwent >1 needling revision, a 21.3% reduction in ECD was observed, but the difference was not statistically significant (P=0.653). Neither the time of the first needling (P=0.452), the patients’ age (P=0.285), or sex (P=0.308) was statistically associated with ECD loss. Discussion: The present study demonstrated that the XEN gel implant combined with phacoemulsification produces 24-month ECD loss of a similar magnitude to that observed following standalone phacoemulsification. MMC-augmented needling revisions do not appear to have an impact on ECD.

Background/Aims: Both eyes of a same person are not completely independent entities. The purpose of this study was to assess the difference in outcome between the first-operated eye and the fellow-operated eye following bilateral XEN surgery, and to identify potential success predictors for the fellow eye. Methods: This single-site, prospective, nonrandomized interventional study investigated bilateral nonsimultaneous XEN gel stent implantation over 24 months. Its main outcome measure was surgical success, defined as unmedicated intraocular pressure (IOP) ≤15 mm Hg associated with a relative reduction ≥20%. Results: Of 149 enrolled eyes, 74 eyes of 37 patients who underwent bilateral (standalone or combined) XEN implantation, within a mean of 50.5±74.3 days of each other, were analyzed. Postoperatively, mean medicated IOP decreased from 19.0±6.6 (first-operated) and 18.2±5.2 mm Hg (fellow) at baseline (P=0.209) to 13.7±4.0 (−27.9%; P<0.001; first-operated) and 14.1±3.6 mm Hg (−22.5%; P<0.001; fellow) after 2 years (P=0.673). Rates of complete success were comparable between first-operated and fellow eyes (P=0.65). At 2 years, among patients whose first-operated eyes were considered a failure, 92.0% of fellow eyes failed (P=0.001). The odd ratio of a fellow eye experiencing complete success were 16.1 (95% confidence interval: 2.5-101.9, P=0.003) if the first operated eye experienced complete success. Conclusions: The present study demonstrated a strong association between first-operated eyes and fellow eyes following XEN gel stent implantation, in terms of surgical outcomes and IOP reduction. In effect, surgical success in the first-operated eye increases the odds of success in the fellow eye by 16-folds.

Aim: The aim of this report is to explore the risk factors of XEN stent obstruction, suggesting the need for a stricter control of these factors and highlighting areas for further research. Background: Despite its proven effectiveness and safety profile, XEN gel stents (Allergan Plc, Dublin, Ireland) can become obstructed. The causes and predicting factors for such obstructions still require further research. While hyphema has long been known to be responsible for secondary glaucoma through trabecular obstruction, it has not been associated, to date, with XEN gel stent obstruction. Case description: We describe the case of a 55-year-old female patient with primary open-angle glaucoma (POAG) who underwent bilateral XEN gel surgery. Her left eye developed a 2 mm postoperative hyphema, which resolved spontaneously within 8 days. Intraocular pressure (IOP) normalized at 12 mm Hg and increased to 50 mm Hg after 1 month in an otherwise normal-looking eye. Intraoperative examination revealed a nonfunctioning XEN gel stent, which was replaced and sent for laboratory analysis. Macroscopic examination of the tube confirmed obstruction with cellular debris. Tube replacement restored good filtration. Conclusion: This case report confirms cellular debris as a potential cause of XEN gel stent occlusion, suggesting that aqueous red blood cells (RBCs) could potentially pose a threat to the microstents' patency even in cases when the bleeding was minimal and self-limited and where the IOP was still controlled at the time of full hyphema resolution. This observation could lead to recommendations for a stricter control of bleeding risk factors prior to microinvasive glaucoma surgery (MIGS), and it raises the question of whether anterior chamber (AC) washout should be advised in postoperative hyphema. Clinical significance: This case highlights some previously unreported risk factors for XEN stent obstruction and suggests that stricter control of bleeding and monitoring of patients following hyphema could improve surgical outcome.

Précis: This study confirms the safety and efficacy of XEN gel stents in the management of pseudoexfoliative glaucoma 2 years after implantation, with success rates similar to primary open-angle glaucoma regardless of the definition of success. Purpose: To compare the long-term safety and efficacy of XEN gel implant surgery (Allergan Inc., Irvine, CA) in patients with pseudoexfoliative glaucoma (PEXG) and primary open-angle glaucoma (POAG). Setting: Prospective, interventional study in a tertiary glaucoma center. Methods: A total of 110 eyes of 85 patients with POAG (57 eyes) or PEXG (53 eyes) and uncontrolled intraocular pressure (IOP) despite medical treatment underwent combined XEN+cataract surgery or standalone XEN surgery. Mean IOP, mean number of medications, needling rates, and incidence of adverse effects were compared between the 2 groups. Complete surgical success was defined as an unmedicated IOP≤12, 15, 16, or 18 mm Hg at 2 years, both with and without a 20% reduction from baseline. Results: Combined XEN+cataract surgery was performed in 72% of POAG and 76% of PEXG eyes (P=0.67), the remainder underwent standalone XEN surgery. Patient characteristics were similar between the 2 groups except for older age for the patients with PEXG (78.5±8.5 vs. 71.3±8.7 y; P<0.005). Mean medicated IOP were 19.8±5.8 mm Hg (POAG) versus 19.8±8.2 mm Hg (PEXG) at baseline (P=0.98), and 14.5±3.6 mm Hg (−26.8%) versus 14.2±3.8 mm Hg (−28.3%), respectively, at 2 years (P=0.75). Mean medications concomitantly dropped from 1.9±1.6 (POAG) versus 2.0±1.3 (PEXG) to 0.6±0.9 versus 0.4±0.7, respectively (P=0.29). Using the 16 mm Hg threshold, 51.4% (POAG) versus 57.1% (PEXG) eyes achieved complete success (P=0.70) at 2 years. The difference in success rates between the 2 groups was not statistically significant under any of the definitions of success. By 24 months, needling was performed in 42.8% (POAG) and 43.2% (PEXG) (P=0.64), with an average time to needling of 162.8 and 134.9 days, respectively (P=0.46). The rates of adverse effects were 30.6% (POAG) and 36.4% (PEXG) (P=0.66), and additional glaucoma surgeries were carried out in 14.3% (POAG) versus 15.9% (PEXG) (P=0.89). Conclusions: The XEN gel implant as a standalone or combined procedure demonstrated similar efficacy and safety results in PEXG and POAG eyes.

Precis: The surgical outcome of iStent inject devices is associated with device protrusion within the anterior chamber. Schlemm canal (SC) dilatation has a prognostic value. iStent inject devices do not move within the first year after implantation. Introduction: The iStent inject is a device designed to be implanted ab-interno through the trabecular meshwork. The present study follows up on our preliminary report, using successive in vivo anterior segment optical coherence tomography (AS-OCT) imaging to analyze the associations between stent positioning, iridocorneal angle structures, and surgical outcomes. Methods: In total, 54 eyes of 42 patients (73.3±7.4 y) with cataract and mild-to-moderate open-angle glaucoma were examined in this prospective study. All patients underwent implantation of 2 iStent inject devices combined with phacoemulsification. Patients were followed up over a 12-month period. AS-OCT was performed after 3 and 12 months. Thirty unoperated fellow eyes served as control eyes. Results: Intraocular pressure (IOP) decreased from 16.5±4.2 mm Hg at baseline to 15.1±3.7 mm Hg at 12 months (−8.7%; P=0.004), while medications decreased from 1.8±1.0 to 0.5±0.9 (−72.2%; P<0.001). Unmedicated IOP≤18 mm Hg was achieved in 58.8% of operated eyes. No sight-threatening complications were reported. On AS-OCT, 44.9% of devices were buried within the trabeculum. Device position was unchanged between scans. Regression analysis elicited significant predictors: SC dilatation effect [risk ratio (RR)=0.230; P=0.003], greatest SC diameter (RR=0.991; P=0.049), extrusion of the most anterior device (RR=0.993; P=0.012), gonioscopically visible devices (RR=0.406; P=0.040), baseline treatments (RR=2.214; P=0.001), and baseline IOP (RR=0.184; P=0.006). Endothelial cell density decreased by 14.6% at 12 months (P<0.001). Conclusions: This study demonstrates the IOP-lowering and medication-lowering potential of iStent inject surgery in primary open-angle and pseudoexfoliative glaucoma. It confirms that surgical outcomes are positively associated with device protrusion within the anterior chamber, and suggests SC dilatation effect as a favorable prognostic indicator. It shows that stents are stable in time, highlighting the importance of the initial implantation location.

Précis: A larger proportion of iStent inject microstents than suggested by gonioscopic examination could be entirely burrowed within the trabeculum (45.7%). The length of device protrusion within the anterior chamber is linked to postoperative intraocular pressure (IOP). Introduction: The iStent inject is a relatively new device designed to be implanted ab-interno through the trabecular meshwork. Although some preliminary studies have shown IOP-lowering potential, the full extent of the mechanisms through which IOP is reduced remains unconfirmed. The aim of this study was to use in vivo optical coherence tomography analysis of the anatomic and physiological effects of iStent inject device positioning on the structures of the iridocorneal angle and IOP. Methods: In total, 25 eyes of 19 subjects (mean age, 75.5±10.5 y) with mild to moderate open-angle glaucoma were enrolled in this prospective study. All patients underwent implantation of 2 iStent inject devices combined with cataract surgery. In the postoperative period, after IOP stabilized, anterior segment optical coherence tomography (AS-OCT) was performed and several measurements were made of the Schlemm canal (SC) and the devices’ positions. Thirteen unoperated fellow eyes served as control eyes. Results: Overall, 92% of devices were visible on AS-OCT versus 88% visible on gonioscopic examination. Of all visible devices, 54.3% had a protruding portion into the anterior chamber with a mean protruding length of 88.5 µm, and 72% of the devices’ heads were not positioned within the SC, with a mean shortest distance of 109.4 µm. In operated eyes, the average major diameter of SC was 308.7±197.4 µm (median, 303.8 µm) versus 126.9±60.3 µm in control eyes. Device protrusion and larger SC diameters were associated with lower postoperative IOP (r s=−0.54; P=0.005 and r s=−0.43; P=0.04, respectively), whereas the distance between the devices’ heads and SC was inversely associated with SC dilatation (r s=−0.41; P=0.04). Conclusions: This study highlights the value of AS-OCT in exploring the positioning of trabecular bypass devices such as the iStent inject. Our study shows that more microstents than suggested by gonioscopy could be completely burrowed within the trabeculum. It also suggests that the surgical outcomes of cataract surgery combined with iStent inject implantation may be connected to the amplitude of device protrusion within the anterior chamber as well as the postoperative dimensions of the SC.