Trabecular Micro-bypass Stent Research Articles

Prospective, Non-randomized, 36-Month Study of Second-Generation Trabecular Micro-Bypass Stents with Phacoemulsification in Eyes with Various Types of Glaucoma.

IntroductionThe aim of this study was to assess 36-month outcomes after cataract surgery and implantation of two second-generation trabecular micro-bypass stents (iStent inject, Glaukos Corporation, San Clemente, CA, USA) into eyes with predominantly primary open-angle glaucoma (POAG) or pseudoexfoliative glaucoma (PEX).MethodsThis prospective, non-randomized, consecutive cohort study included eyes with POAG (n = 60), PEX (n = 15), appositional narrow-angle (n = 4), pigmentary (n = 1), or neovascular (secondary) (n = 1) glaucoma and cataract requiring surgery. All eyes (n = 81) underwent ab interno iStent inject implantation following cataract surgery. Effectiveness endpoints through 36 months included intraocular pressure (IOP), number of medications, and proportion of eyes with ≥ 20% IOP reduction, IOP ≤ 18 mmHg, and IOP ≤ 15 mmHg. Safety measures included corrected distance visual acuity (CDVA), adverse events, and secondary surgeries. Outcomes were evaluated for the overall cohort, and for the POAG and PEX subgroups.ResultsPreoperatively, 32.1% of eyes had undergone prior glaucoma surgery, 56% were on 3–4 medications, and 1 eye (1%) was medication-free. At 36 months postoperatively, mean IOP reduced by 37% (14.3 ± 1.7 mmHg versus 22.6 ± 6.2 mmHg preoperatively), and mean medication burden decreased by 68% (0.8 ± 0.9 versus 2.5 ± 1.1 medications preoperatively). IOP reduced by ≥ 20% in 78% of eyes; 100% of eyes reached IOP ≤ 18 mmHg and 71% reached ≤ 15 mmHg. Medication burden reduced considerably: 22 eyes (54%) were medication-free compared to 1 eye (1%) preoperatively; 1 eye (2%) required ≥ 3 medications compared to 45 eyes (56%) preoperatively; and 92.7% of eyes required reduced medications postoperatively. From 3 through 36 months, mean IOP remained ≤ 15.0 mmHg, and mean number of medications remained ≤ 0.9. Outcomes in the POAG and PEX subgroups included 33% and 32% lower IOP, and 68% and 64% fewer medications, respectively. iStent inject showed a favorable safety profile, including no intraoperative complications, minimal adverse events, and a stable CDVA.ConclusionThis real-world cohort of eyes with various types of glaucoma and considerable disease burden exhibited durable and safe IOP and medication reductions through 36 months following iStent inject implantation with cataract surgery. Outcomes were similarly beneficial in eyes with POAG and PEX.FundingArticle processing charges were funded by Glaukos Corporation (San Clemente, CA, USA).

PMD73 - ECONOMIC IMPACT OF THE TREATMENT OF PRIMARY OPEN-ANGLE GLAUCOMA ON HIP FRACTURE: A COST-EFFECTIVENESS ANALYSIS

World prevalence of glaucoma in people between 40-80 years is projected at 76 million people in 2020. A metanalysis found that risk of a fall in people whose visual impairment was caused by glaucoma, was greater versus population with general disability. This study estimates the cost-effectiveness of trabecular micro-bypass stent versus medications only for intraocular pressure control for patients with open-angle glaucoma. A Markov model, with stages from 0 (ocular hypertension without glaucoma) to 5 and bilateral blindness was developed inclusive of Colombian people older than 40 years in 2018 from a societal perspective, comparing trabecular micro-bypass stent versus timolol+dorzolamide+latanoprost or timolol+dorzolamide+brimatoprost or timolol+brimonidine, in terms of clinical and economic outcomes over a lifetime horizon. Both costs and health outcomes had an annual rate discount of 5%. Health outcomes were evaluated in terms of hip fractures avoided and life years gained (LYG) by deaths avoided, related with hip fractures complications. Trabecular micro-bypass costs include use of latanoprost in 80% of patients. Trabecular micro-bypass stent were estimated to have 10,569 discounted LYG more than timolol+dorzolamide+latanoprost or timolol+dorzolamide+brimatoprost, and 11,413 discounted LYG more than timolol+brimonidine. Trabecular micro-bypass stent avoided 27 hip fractures versus timolol+dorzolamide+latanoprost or timolol+dorzolamide+brimatoprost, and 29 versus timolol+brimonidine. Cumulative costs at 40 years with trabecular micro-bypass stent were € $3.756.198 lower than timolol+dorzolamide+latanoprost; € $10.539.157 lower than timolol+dorzolamide+brimatoprost; and € $6.830.957 lower than timolol+brimonidine. With a willingness-to-pay of USD $6,380 GDP per capita, trabecular micro-bypass stent has a probability of 81% to be chosen. In one-way sensitive analysis, with the lowest efficacy of trabecular micro-bypass and the highest efficacy of medications only, trabecular micro-bypass stent always was dominant. Trabecular micro-bypass stent were estimated to be a highly cost-saving strategy, because have more LYG by deaths avoided related with hip fractures complications and avoid more hip fractures.

Cost-effectiveness analysis of iStent trabecular micro-bypass stent for patients with open-angle glaucoma in Colombia

Objective: To estimate the cost-effectiveness of trabecular micro bypass stent vs laser trabeculoplasty or medications only, for patients with open-angle glaucoma in a setting of the Colombian System Health.Methods: This is a cost-effectiveness analysis that based its assumptions in external data sources, used to extrapolate the quality-of-life related to health, survival, and costs. A Markov model, with stages from 0 (ocular hypertension without glaucoma) to 5 and bilateral blindness, was developed inclusive of Colombians older than 40 years in 2018, from a societal perspective, comparing trabecular micro-bypass stents vs laser trabeculoplasty, timolol + dorzolamide + brimonidine, timolol + dorzolamide + latanoprost, or timolol + dorzolamide + brimatoprost, in terms of clinical and economic outcomes over a lifetime horizon. Both costs and health outcomes had an annual rate discount of 5%. Health outcomes were evaluated in terms of QALYs related with loss of visual acuity. Trabecular micro-bypass costs include the joint use of timolol, and the costs of laser trabeculoplasty include the combined use of timolol + dorzolamide.Results: Trabecular micro-bypass stents were estimated to have 127,971 more discounted QALYs vs laser trabeculoplasty; 405,982 vs timolol + dorzolamide + brimonidine; and 378,287 vs timolol + dorzolamide + latanoprost or timolol + dorzolamide + brimatoprost. Cumulative costs with trabecular micro-bypass stents at 40 years was $13,252,318 lower than laser trabeculoplasty; $6,403,534, lower than timolol + dorzolamide + brimonidine; $22,311,064, lower than timolol + dorzolamide + latanoprost; and $29,156,113 lower than timolol + dorzolamide + brimatoprost.Conclusions: The trabecular micro-bypass stent is a highly cost-saving strategy due to more QALYs related to a lower rate of the population with loss of visual acuity in the long-term, and because the costs associated with additional medications and complications are lower with trabecular micro-bypass stents.

Efficacy of Cataract Surgery With Trabecular Microbypass Stent Implantation in Combined-Mechanism Angle Closure Glaucoma Patients

To evaluate the effectiveness of trabecular microbypass stent (iStent) implantation in combined mechanism glaucoma (CMG). Retrospective cohort study. We reviewed the medical charts of patients with the following scenarios: (1) primary open-angle glaucoma (POAG) undergoing phacoemulsification (PE), (2) POAG undergoing PE with iStent (POAG-PE/iStent), (3) CMG undergoing PE (CMG-PE), and (4) CMG undergoing PE with iStent (CMG-PE/iStent). CMG was defined as narrow-angle glaucoma patients whose angle had opened after iridotomy. Linear mixed-effects models were performed to determine the effect of iStent on postoperative 1-year success rate (intraocular pressure [IOP] ≤ 18 without medication), IOP, and number of medications. Data from 301 eyes were available. The number of eyes (subjects) was 61 (45) in the POAG-PE, 60 (50) in POAG-PE/iStent, 93 (76) in CMG-PE, and 87 (70) in CMG-PE/iStent group. Success criteria were achieved in 13.1% for POAG-PE, 33.3% for POAG-PE/iStent (POAG-PE vs POAG-PE/iStent B 3.01; P < .001), 37.6% for CMG-PE, and 43.7% for CMG-PE/iStent (CMG-PE vs CMG-PE/iStent B 2.25; P < .001). There was no difference in the IOP between POAG-PE and POAG-PE/iStent, and between CMG-PE and CMG-PE/iStent. The iStent significantly reduced number of medications in the POAG (B-0.70; P<.001) and CMG group (B-0.52; P < .001). Comparing the effect of iStent on POAG and CMG, the analysis showed similar iStent efficacy in terms of the success rate, IOP, and number of medications (P > .05). Combined PE/iStent significantly increased success rate and reduced number of medications in CMG patients compared to PE alone. The effects of iStent were comparable between POAG and CMG groups.

Histopathologic Examination of Trabecular Meshwork Changes After Trabecular Bypass Stent Implantation.

The purpose of this article was to evaluate how human trabecular meshwork (TM) is influenced by the chronic presence of trabecular bypass implants. Human TM samples were obtained intraoperatively from 3 patients who had previously undergone implantation of a trabecular micro-bypass stent. Trabecular strips were obtained with a goniotomy blade from areas directly adjacent to the stent after stent removal. Tissue samples were preserved, processed, cut, and stained according to standardized laboratory protocol. Harvested samples were compared with human cadaveric TM from an eye without ocular disease as well as TM obtained from a glaucomatous eye without prior stent placement. In all samples, a significant increase in the amount of fibrous material compared with cellular material was noted when compared with controls. In a single strip, a basement membrane-like structure was noted, which correlated with a semiopaque membrane noted intraoperatively overlying the stent and adjacent TM. Further, TM cells were absent from areas adjacent to the stent implantation site with related collapse of collagen beams. These findings indicate that inflammatory and fibrotic changes are present surrounding the device with clear differences noted when compared with both healthy and glaucomatous controls. These changes suggest a possible etiology for device failure over time. Further studies are necessary to tease out differences in TM tissue reaction to various implant materials as well as to make comparisons to procedures that excise TM.

PMD13 - A Canadian Cost-Utility Analysis of two Trabecular Micro-Bypass Stents in Patients with Mild-to-Moderate Open-Angle Glaucoma

To estimate the cost-utility of two micro-bypass trabecular stents (MBTS) implantation versus standard of care (SOC) in the Canadian healthcare setting. A Markov model was designed to track progression of glaucoma through health states defined using Hodapp-Parrish-Anderson stages and death: mild, moderate, advanced, severe/blind glaucoma over a 15 year time horizon. Reduction in intraocular pressure (IOP) and medication use due to MBTS and SOC were identified from MBTS randomized clinical trials and meta-analyzed. Transition probabilities were estimated using IOP-adjusted rate of decline in visual field (VF) loss. A 10% decline in relative treatment effect per year was conservatively assumed for extrapolation of efficacy beyond trial follow-up. Unit costs and utilization of healthcare resources, and progression-related utility scores for the general Canadian population were obtained by literature review and reflect 2017 Canadian costs. IMS Brogan PharmaStat was used to estimate medication costs with wastage. Probabilistic and 1-way sensitivity analyses were conducted to estimate the impact of parameter and methodological uncertainty on costs and quality-adjusted life years (QALYs). The meta-analysis showed a relative reduction of 1.13 medications/patient and an IOP change of -1.10 mmHg at 36 months favoring MBTS. The model estimated MBTS therapy was the dominant strategy as it was associated with an incremental improvement in quality of life (0.071 QALYs), and a decrease in healthcare costs of $2,995 per patient over a lifetime. Sensitivity analyses showed that results were robust to variations in model assumptions. The costs of the MBTS procedure are expected to be recouped over a few years due to decreased medication use and downstream procedures avoided. Together with the quality of life gains expected with MBTS, it becomes increasingly cost-effective with longer time horizons as it dominates SOC after 2.9 years.

Prospective Evaluation of Two iStent® Trabecular Stents, One iStent Supra® Suprachoroidal Stent, and Postoperative Prostaglandin in Refractory Glaucoma: 4-year Outcomes.

IntroductionThis study evaluates long-term outcomes of two trabecular micro-bypass stents, one suprachoroidal stent, and postoperative prostaglandin in eyes with refractory open angle glaucoma (OAG).MethodsProspective ongoing 5-year study of 80 eligible subjects (70 with 4-year follow-up) with OAG and IOP ≥ 18 mmHg after prior trabeculectomy and while taking 1–3 glaucoma medications. Subjects received two iStent® trabecular micro-bypass stents, one iStent Supra® suprachoroidal stent, and postoperative travoprost. Postoperative IOP was measured with medication and annually following medication washouts. Performance was measured by the proportion of eyes with ≥ 20% IOP reduction on one medication (the protocol-specified prostaglandin) versus preoperative medicated IOP (primary outcome); and the proportion of eyes with postoperative IOP ≤ 15 and ≤ 18 mmHg on one medication (secondary outcome). Additional clinical and safety data included medications, visual field, pachymetry, gonioscopy, adverse events, visual acuity, and slit-lamp and fundus examinations.ResultsPreoperatively, mean medicated IOP was 22.0 ± 3.1 mmHg on 1.2 ± 0.4 medications, and mean unmedicated IOP was 26.4 ± 2.4 mmHg. Postoperatively, among eyes without later cataract surgery, mean medicated IOP at all visits through 48 months was ≤ 13.7 mmHg (≥ 37% reduction), and annual unmedicated IOP was ≤ 18.4 mmHg (reductions of ≥ 30% vs. preoperative unmedicated IOP and ≥ 16% vs. preoperative medicated IOP). At all postoperative visits among eyes without additional surgery or medication, ≥ 91% of eyes had ≥ 20% IOP reduction on one medication versus preoperative medicated IOP. At month 48, 97 and 98% of eyes achieved IOP ≤ 15 and ≤ 18 mmHg, respectively, on one medication. Six eyes required additional medication, no eyes required additional glaucoma surgery, and safety measurements were favorable throughout follow-up.ConclusionIOP control was achieved safely with two trabecular micro-bypass stents, one suprachoroidal stent, and postoperative prostaglandin. This microinvasive, ab interno approach introduces a possible new treatment option for refractory disease.Trial RegistrationNCT01456390.FundingGlaukos Corporation.Electronic supplementary materialThe online version of this article (10.1007/s12325-018-0666-4) contains supplementary material, which is available to authorized users.

Implantation of a CyPass Supraciliary Stent Combined With Targeted iStent Trabecular Microbypass Stents in a Phakic Patient With Primary Open-angle Glaucoma

To report the first successful implantation of a CyPass supraciliary stent combined with 2 targeted iStent trabecular microbypass stents in a phakic primary open-angle glaucoma patient with markedly elevated intraocular pressures (IOP) on maximum tolerable medical therapy. Case report. A 52-year-old phakic male patient with primary open-angle glaucoma with uncontrolled IOP in the right eye (OD) of 36 mm Hg on maximal topical pharmacotherapy. The patient underwent implantation of a single CyPass supraciliary stent combined with the targeted implantation of 2 iStent trabecular microbypass stents, 1 right facing stent and 1 left facing stent. Postoperatively, off of all glaucoma medications, the IOP decreased to 10 mm Hg on day 1 and continued to be controlled between 10 to 13 mm Hg until postoperative month 6, with only 1 glaucoma medication added after postoperative month 5. In addition, there were no postoperative complications to date. The combined implantation of a CyPass supraciliary stent and iStent trabecular microbypass stents can successfully lower IOP and decrease medication burden with minimal risk for complications.

Safety and efficacy of intravitreal injection of steroid and antibiotics in the setting of cataract surgery and trabecular microbypass stent

To evaluate the safety and efficacy of intravitreal administration of a steroid and antibiotics during cataract surgery compared with the typical postoperative topical regimen in preventing postoperative inflammation, pain, cystoid macular edema (CME), and endophthalmitis. Private practice, Sioux Falls, South Dakota, USA. Retrospective case series. The study group included eyes that had an intravitreal injection of triamcinolone-moxifloxacin-vancomycin at the time of cataract surgery with concomitant trabecular microbypass stent insertion. The control eyes had the same procedure but were prescribed topical antibiotics, steroids, and nonsteroidal antiinflammatory drugs postoperatively. Data were recorded preoperatively and 1day, 1week, 1month, and 3months postoperatively. Primary outcomes included the number of glaucoma medications, intraocular pressure (IOP), and IOP spikes of at least 15mm Hg from baseline. There were 234 eyes in the study group and 249 eyes in the control group. The mean reduction in glaucoma medications was 0.24 drops in the study group and 0.80 drops in the control group 3months postoperatively, whereas the mean IOP reduction was 2.59mm Hg in the study group and 3.63mm Hg in the control group. Pressure spikes were detected at 54 (5.7%) of 936 postoperative visits in the study group and at 37 (3.7%) of 996 visits in the control group. There were no cases of severe inflammation, CME, infection, or retinal detachments. Both groups had similar postoperative pressure reductions and incidence of IOP spikes. The results indicate that intravitreal injections of a steroid and antibiotics might be a safe option for glaucomatous eyes having cataract surgery with trabecular microbypass stent insertion.

Changes in Flow Density Measured Using Optical Coherence Tomography Angiography after iStent Insertion in Combination with Phacoemulsification in Patients with Open-Angle Glaucoma.

Purpose To evaluate changes in flow density after the implantation of a trabecular microbypass stent (iStent) in combination with cataract surgery. Methods A total of 48 eyes of 48 patients, who underwent either cataract surgery alone (cataract group) or cataract surgery with implantation of two iStent inject devices (iStent group), were prospectively included in this study. Intraocular pressure (IOP) and flow density data before and after surgery were extracted and analyzed. Results In the iStent group, the mean IOP was 18.2 ± 3.3 mmHg prior to surgery and 13.2 ± 2.3 at follow-up, and this difference was statistically significant (p < 0.001). The mean IOP in the cataract group also improved significantly after surgery (before: 17.1 ± 2.4; after: 15.1 ± 2.7 p = 0.003). The flow density (whole en face) in the superficial and deep retinal OCT angiogram of the macula (superficial: p = 0.002; deep: p = 0.034) and in the ONH (p = 0.011) improved significantly after surgery in the iStent group. The differences in the cataract group were not significant. Conclusions Flow density of the macula and ONH, as measured by OCTA, improved significantly after cataract surgery with iStent. Noninvasive quantitative analyses of flow density provide a new parameter, which can help for the monitoring of therapy success after glaucoma surgery.

Institution of a Surgical Curriculum for Trabecular Microbypass Stent Placement

Purpose This article evaluates whether a targeted, stepwise curriculum for microbypass stent placement leads to successful insertion of the iStent (Glaukos, Laguna Hills, CA) by resident surgeons. Participants Senior (postgraduate year 4) ophthalmology residents (9 residents) from three classes during the 2015 to 2016, 2016 to 2017, and 2017 to 2018 academic years. Design Residents participated in a three-stage surgical curriculum. First, a wet laboratory was held for residents to gain familiarity with the device and develop bimanual surgical proficiency. The wet laboratory involved several stations, with each station requiring increased dexterity for successful completion. Next, residents practiced bimanual intraoperative gonioscopy after routine phacoemulsification procedures. Finally, residents performed combined phacoemulsification and iStent insertion under the supervision of an experienced attending surgeon. Primary success was determined by correct anatomical placement of the device confirmed via subsequent intraoperative gonioscopy by the supervising surgeon. Secondary success was measured by change in intraocular pressure (IOP) and number of topical hypotensive medications used after surgery. Residents provided feedback about the effectiveness of the curriculum via an online survey. Results There were a total of 43 cases. There were no significant intraoperative complications, including hyphema. The iStent location was confirmed during both intraoperative and postoperative gonioscopy and was noted to be in appropriate position for the duration of the follow-up period (6–12 months) for all patients. Average preoperative IOP in our subjects was 17.5 ± 4.0 mm Hg and mean number of preoperative medications was 1.4 ± 1.0. At 6 months' postoperative, average IOP was 14.5 ± 2.2 mm Hg (13% reduction from baseline [±15%]). At 12 months' postoperative, average IOP was 14.4 ± 3.5 mm Hg, with a reduction of 14% (±18%). The mean number of medications at follow-up was 1.2 ± 1.1. Mean postoperative IOP at 6 and 12 months was significantly lower compared with baseline (p = 0.0002, p = 0.0001). Residents agreed that the curriculum prepared them to perform iStent insertion during residency and most residents felt prepared after residency. Conclusion This stepwise surgical curriculum for trabecular microbypass stent placement leads to successful performance of the procedure by residents and is a useful model for other residency programs.

Efficacy of 2 Trabecular Micro-Bypass Stents During Phacoemulsification for Mild to Advanced Primary Open-angle Glaucoma Controlled With Topical Hypotensive Medications.

The purpose of the current study was to evaluate the efficacy and adverse event profile of 2 trabecular micro-bypass stents implanted during standard phacoemulsification cataract surgery in patients with mild to advanced open-angle glaucoma whose intraocular pressure (IOP) was well controlled by topical medications. This study was a retrospective analysis of patients with mild to advanced chronic open-angle glaucoma who underwent phacoemulsification and implantation of 2 stents. For all patients, preoperative and postoperative characteristics were evaluated, including number of medications and IOP. Postoperative visits were scheduled at 7 days and at months 1, 6, 12, and 24 after surgery. At each visit, IOP and the number of medications were noted. In total, 63 eyes of 41 patients were included in the study. The vast majority of eyes (85.7%) were diagnosed with primary open-angle glaucoma. Preoperative mean IOP at baseline was 16.8±3.0 mm Hg (range, 10 to 24 mm Hg) with a mean of 2.3±0.9 medications. The mean IOP reduction represented a 13% decrease at 1 month (P<0.001), 13% at 6 months (P<0.001), 12% at 1 year (P<0.001), and 10% at 2 years (P<0.001), concomitant with a 23% reduction in the mean number of medications (P<0.001), 35% (P<0.001), 40% (P<0.001), and 40% (P<0.001), respectively, at each scheduled follow-up visit. At 24 months postoperatively, 19 of 23 (83%) patients experienced an IOP decrease compared with the preoperative visit. No severe device-related adverse events were observed. Patients with mild to advanced glaucoma can benefit from micro-bypass implantation even if their IOP is well controlled with topical hypotensive medications. Expectations for these reductions should be moderate.

Cost-comparison of two trabecular micro-bypass stents versus selective laser trabeculoplasty or medications only for intraocular pressure control for patients with open-angle glaucoma

Aim: Patients with open-angle glaucoma (OAG) whose intraocular pressure is not adequately controlled by one medication have several treatment options in the US. This analysis evaluated direct costs of unilateral eye treatment with two trabecular micro-bypass stents (two iStents) compared to selective laser trabeculoplasty (SLT) or medications only.Materials and methods: A population-based, annual state-transition, probabilistic, cost-of-care model was used to assess OAG-related costs over 5 years. Patients were modeled to initiate treatment in year zero with two iStents, SLT, or medications only. In years 1–5, patients could remain on initial treatment or move to another treatment option(s), or filtration surgery. Treatment strategy change probabilities were identified by a clinician panel. Direct costs were included for drugs, procedures, and complications.Results: The projected average cumulative cost at 5 years was lower in the two-stent treatment arm ($4,420) compared to the SLT arm ($4,730) or medications-only arm ($6,217). Initial year-zero costs were higher with two iStents ($2,810) than with SLT ($842) or medications only ($996). Average marginal annual costs in years 1–5 were $322 for two iStents, $777 for SLT, and $1,044 for medications only. The cumulative cost differences between two iStents vs SLT or medications only decreased over time, with breakeven by 5 or 3 years post-initiation, respectively. By year 5, cumulative savings with two iStents over SLT or medications only was $309 or $1,797, respectively.Limitations: This analysis relies on clinical expert panel opinion and would benefit from real-world evidence on use of multiple procedures and treatment switching after two-stent treatment, SLT, or polypharmaceutical initial approaches.Conclusions: Despite higher costs in year zero, annual costs thereafter were lowest in the two-stent treatment arm. Two-stent treatment may reduce OAG-related health resource use, leading to direct savings, especially over medications only or at longer time horizons.

Implantation of trabecular micro-bypass stent using a novel "landing strip" technique.

To describe a novel technique of creating a landing strip within the trabecular meshwork to guide trabecular micro-bypass stent (iStent) implantation in patients who underwent phacoemulsification. Thirty-four eyes from 30 patients who underwent iStent implantation after phacoemulsification from May 2014 to February 2015 were included in our retrospective study. All iStents were implanted via the "landing strip" technique. A 25-gauge microvitreoretinal blade was used to bisect the trabecular meshwork to less than 1 clock-hour, effectively creating a landing strip. The iStent applicator was pressed along the landing strip and then the stent was released into the trabecular meshwork. Of the 34 eyes with iStent implantation, 27 (79.4%) eyes had primary open-angle glaucoma, 6 (17.6%) eyes had pseudoexfoliation glaucoma, and 1 (2.9%) eye had ocular hypertension. At 6-month follow-up (n=17), the mean number of hypotensive medications decreased from 2.2±1.2 at baseline to 0.8±1.3 (P=0.05) and mean intraocular pressure decreased from 19.7±4.1 mm Hg at baseline to 16.7±2.1 mm Hg (P=0.58). Two eyes (5.9%) required subsequent trabeculectomy. The "landing strip" technique appears to be an effective way to assist with iStent implantation.

Efficacy of two trabecular micro-bypass stents combined with topical travoprost in open-angle glaucoma not controlled on two preoperative medications: 3-year follow-up.

PurposeTo evaluate the long-term intraocular pressure (IOP)-lowering effect and safety parameters following treatment with two trabecular micro-bypass stents and topical prostaglandin in phakic eyes with open-angle glaucoma (OAG) not controlled on two preoperative medications.MethodsThis prospective, single-arm, unmasked study enrolled 39 qualified phakic eyes with OAG not controlled on 2 medications, preoperative medicated IOP of 18–30 mmHg, and IOP following medication washout of 22–38 mmHg. Two trabecular micro-bypass stents were implanted as a standalone procedure, and travoprost was started on postoperative day 1. Evaluations included IOP, best-corrected visual acuity, medication use, fundus and slit-lamp examinations, visual field, cup:disc ratio, central corneal thickness, and ocular complications. Data through 18 months were summarized previously. Thirty-seven of the original 39 subjects have been followed for 3 years postoperatively; follow-up is continuing for 5 years.ResultsAt 3 years postoperative, 97% of eyes had achieved an IOP reduction of ≥20% from baseline with a reduction of 1 medication. Eighty-six percent of eyes had IOP of ≤18 mmHg with a reduction of 1 medication. Mean medicated IOP decreased to 14.0±2.6 mmHg on 1 medication versus 22.4±2.3 mmHg on 2 medications preoperatively. The mean unmedicated IOP decreased to 17.7±1.7 mmHg at 37 months from 25.3±1.9 mmHg preoperatively. Long-term postoperative adverse events included cataract surgery in 3 eyes due to cataract progression, and trabeculectomy in 1 eye due to uncontrolled IOP of 23 mmHg. No intraoperative or device-related adverse events occurred.ConclusionSignificant and sustained reduction in IOP and medications with a favorable safety profile was shown through 3 years after implantation of 2 trabecular micro-bypass stents combined with postoperative travoprost in phakic OAG eyes uncontrolled on 2 preoperative medications. These findings demonstrate the long-term performance and safety of trabecular bypass stents in combination with topical prostaglandin for OAG patients.

Minimally invasive glaucoma surgery as primary stand-alone surgery for glaucoma.

Recently, many new devices and procedures have been developed to lower intraocular pressure in a less invasive and purportedly safer manner than traditional glaucoma surgery. These new devices might encourage an earlier transition to surgery and reduce the long-term commitment to topical glaucoma medications with their associated compliance and intolerance issues. Although often seen as an adjunct to cataract surgery, a growing body of evidence suggests that primary minimally invasive glaucoma surgery may be a viable initial treatment option. New studies have shown that primary ab interno trabeculectomy (Trabectome, NeoMedix Inc., Tustin, CA, USA), trabecular micro-bypass stent insertion (iStent and iStent Inject, Glaukos Corporation, Laguna Hills, CA, USA), canalicular scaffolding (Hydrus, Invantis Inc., Irvine CA, USA), the ab interno gel Implant (XEN, Allergan, Dublin, Ireland) or supraciliary stenting (CyPass Micro-Stent, Alcon, Fort Worth, TX, USA) may lower the lowering intraocular pressure and/or topical medication burden in phakic or pseudophakic patients with glaucoma. This effect seems to last at least 12months but reliable cost-effectiveness and quality of life indicators have not yet been established by investigator-initiated randomized trials of sufficient size and duration.

Safety and Efficacy of Two Trabecular Micro-Bypass Stents as the Sole Procedure in Japanese Patients with Medically Uncontrolled Primary Open-Angle Glaucoma: A Pilot Case Series.

Purpose. To evaluate efficacy and safety of a trabecular micro-bypass stent system when used as the sole procedure in Japanese patients with medically uncontrolled primary open-angle glaucoma (POAG). Design. Prospective nonrandomized interventional pilot study. Methods. Ten eyes of 10 Japanese patients with medically uncontrolled POAG taking three ocular hypotensive medications were treated using only the implantation of two iStent trabecular micro-bypass stents. Each patient continued to take the same ocular hypotensive medications used preoperatively throughout the study. Intraocular pressure (IOP) and endothelial cell density (ECD) were determined at baseline and at 1, 3, and 6 months postoperatively. Best-corrected visual acuity (BCVA) was measured at baseline and 6 months after surgery. Results. Mean IOP was 22.0 ± 3.0 mmHg at baseline and 16.9 ± 3.6 mmHg at 6 months, which represented a mean reduction of 5.1 mmHg or 23.2%. No significant changes were observed in the ECD and BCVA. Complications that occurred during the early postoperative period included hyphema, peripheral anterior synechiae, and occlusion of the stent by the iris. Conclusion. Implantation of two trabecular micro-bypass stents as the sole procedure in Japanese POAG patients effectively reduced IOP and exhibited a favorable safety profile. Clinical Trials Registration number is UMIN000004002.

PP031 iStent® For Open Angle Glaucoma: Standard Or Emerging Care?

INTRODUCTION:Increased intraocular pressure (IOP) in open angle glaucoma (OAG) may lead to optic nerve damage due to progressive obstruction of aqueous humor drainage. Among surgery options, trabecular micro-bypass stent (iStent®) was recently introduced. This Health Technology Assessment (HTA) aimed to assess the effectiveness and safety of iStent®, combined or not with cataract surgery, in patients with mild-to-moderate OAG.METHODS:A systematic review (SR) was performed from 2000 to August 2016. Studies reporting data at three months or more on IOP and hypotensive medication use following iStent® implant were eligible. Governmental databases on safety issues were reviewed. The project involved an interdisciplinary group of experts.RESULTS:Two HTA reports, one SR, four randomized controlled trials (RCTs) and nine observational studies (OSs) were included. Compared to cataract surgery alone, implantation of iStent®combined with cataract surgery was associated with a decrease in IOP at 12 months in RCTs (-1.37 mmHg; 95 percent Confidence Interval, CI: - 2.76 to .03 mmHg, p = .055). Results from RCTs and OSs on the effect of iStent® combined or not with cataract surgery suggest also a 12-month positive effect on IOP (mean reduction: 1.5 to 9.5 mmHg) and on mean number of medications (reduction: .3 to 2.0) compared to baseline. Scattered results were found on the proportion of patients who no longer use glaucoma medications. Small sample size, short duration of follow-up, and potential conflicts of interest were among studies limitations. The most common adverse events reported were posterior capsular opacification, decrease in visual acuity, and stent obstruction or malposition.CONCLUSIONS:Appraisal of the effectiveness and safety suggests that iStent® implantation combined to cataract surgery in mild-to-moderate OAG is an emerging practice. Uncertainties related to clinical benefits, safety and care organization need to be clarified before an introduction as a standard of medical practice.

Clinical investigation of new glaucoma procedures.

This article reviews recent studies evaluating the efficacy and complication profiles of novel glaucoma procedures promoting aqueous outflow. Literature from the 2015 to 2016 review period includes abundant data regarding new and emerging glaucoma procedures. Notable findings from recent randomized clinical trials include titratability of intraocular pressure with multiple trabecular microbypass stents (iStent; Glaukos, Laguna Hills, California, USA) and greater reduction in intraocular pressure and medication usage following intracanalicular scaffolding (Hydrus Microstent; Ivantis Inc., Irvine, California, USA) combined with phacoemulsification vs. phacoemulsification alone. A supraciliary microstent (CyPass Micro-Stent; Transcend Medical, Inc., Menlo Park, California, USA) received approval from the Food and Drug Administration after a pivotal trial demonstrated its efficacy and safety. Early studies of investigational subconjunctival filtering devices (XEN Gel Stent; AqueSys, Inc., Aliso Viejo, California, USA and InnFocus MicroShunt; InnFocus Inc., Miami, Florida, USA) offer promising evidence, but late complications are as yet unknown. Newer glaucoma procedures targeting different aqueous outflow pathways have improved the safety profile of glaucoma surgery while preserving modest efficacy. Most can be combined with phacoemulsification, allowing for simultaneous treatment of comorbid cataract and glaucoma. Well-designed randomized clinical trials with extended follow-up remain necessary to evaluate the long-term efficacy and late complications of these novel procedures.

Differential Canalograms Detect Outflow Changes from Trabecular Micro-Bypass Stents and Ab Interno Trabeculectomy.

Recently introduced microincisional glaucoma surgeries that enhance conventional outflow offer a favorable risk profile over traditional surgeries, but can be unpredictable. Two paramount challenges are the lack of an adequate training model for angle surgeries and the absence of an intraoperative quantification of surgical success. To address both, we developed an ex vivo training system and a differential, quantitative canalography method that uses slope-adjusted fluorescence intensities of two different chromophores to avoid quenching. We assessed outflow enhancement by trabecular micro-bypass (TMB) implantation or by ab interno trabeculectomy (AIT). In this porcine model, TMB resulted in an insignificant (p > 0.05) outflow increase of 13 ± 5%, 14 ± 8%, 9 ± 3%, and 24 ± 9% in the inferonasal, superonasal, superotemporal, and inferotemporal quadrant, respectively. AIT caused a 100 ± 50% (p = 0.002), 75 ± 28% (p = 0.002), 19 ± 8%, and 40 ± 21% increase in those quadrants. The direct gonioscopy and tactile feedback provided a surgical experience that was very similar to that in human patients. Despite the more narrow and discontinuous circumferential drainage elements in the pig with potential for underperformance or partial stent obstruction, unequivocal patterns of focal outflow enhancement by TMB were seen in this training model. AIT achieved extensive access to outflow pathways beyond the surgical site itself.