A prospective 3-year follow-up trial of implantation of two trabecular microbypass stents in open-angle glaucoma

Comparison of Safety and Efficacy of Hydrus and iStent Combined with Phacoemulsyfication in Open Angle Glaucoma Patients: 24-Month Follow-Up

The paper presents the results of a 24-month-long observation comparing the effectiveness and safety of two micro-invasive glaucoma surgery (MIGS) devices: Hydrus Microstent and iStent Trabecular Bypass in combination with cataract phacoemulsification in the treatment of open-angle glaucoma. We also analyzed the impact of preoperative factors on achieving surgical success in both surgical methods. The prospective, comparative, non-randomized study included 65 glaucoma surgeries. In 35 patients (53.8%), an iStent implant procedure was performed, while 30 patients (46.2%) underwent a Hydrus implant procedure. The demographic data was similar in both treatment groups. At 24 months after surgery, the mean IOP in the iStent group was 15.9 ± 3.0 mmHg and in the Hydrus group 16.2 ± 1.8 mmHg. The difference between the mean iStent vs Hydrus after two years of treatment was -0.3 (p = 0.683). At the 24 month follow-up, the average change in the number of antiglaucoma medications used was 71.7% in the iStent group and 79.6% in the Hydrus group. The difference in mean percentage change between groups was 7.9% in favor of Hydrus. Patients under the age of 70 may benefit from a greater risk reduction in the Hydrus group (HR = 0.81), while those over the age of 70 may benefit from a risk reduction in the iStent group (HR = 1.33). IOP cases with >18 mmHg before the surgery have a better chance of surgical success with the Hydrus method (HR = 0.28), and with IOP < 18 mmHg in the iStent group (HR = 1.93). Cases with more drugs (≥3 drugs) are more favorable in the Hydrus group (HR = 0.23), while those with a maximum of two drugs have a better prognosis in the iStent group (HR = 2.23). The most common postoperative complication was the presence of erythrocytes in the anterior chamber (AC), found in 40.0% of operated eyes in the Hydrus group. The profile of observed complications and significant improvement in visual acuity allows us to consider both implants as a safe way of treating patients with early or moderate glaucoma and co-existing cataracts.

Minimally Invasive Glaucoma Surgery: Safety of Individual Devices

Primary open-angle glaucoma progression in those already on maximal medical therapy has traditionally been treated with trabeculectomy, a surgical procedure that carries a high degree of morbidity. In the last few decades, significant advances have been made in the field of minimally invasive glaucoma surgery (MIGS) devices, which aim to defer or prevent trabeculectomy via less arduous surgical techniques in certain types of glaucoma. Although reviews have been published examining the efficacy of various MIGS techniques, no article synthesises the comparative safety of all available devices. We performed a literature review examining the safety of MIGS devices. Fifteen devices were included, variously attempting to increase aqueous outflow through the trabecular meshwork or the suprachoroidal space, shunting into the subconjunctival space, or reducing aqueous production through ciliary body ablation. Notably, the earliest product attempting to increase outflow to the suprachoroidal space, Alcon's CyPass Micro-Stent, was withdrawn from the market due to concerns regarding increased corneal endothelial cell loss at five years post-implantation. All other devices were described as well-tolerated, with the most common adverse effects including hyphaema, intraocular pressure spikes, and device migration or obstruction. MIGS devices are purported to be uniformly safe, and many studies report no statistically significant increased complications beyond those associated with cataract surgery alone. It is important to note, however, the generally poor quality of current studies, with a dearth of randomised, or even prospective, data, and a large proportion of studies funded by device producers.

Long-term outcomes of two first-generation trabecular micro-bypass stents (iStent) with phacoemulsification in primary open-angle glaucoma: eight-year results

Background

The short- and medium-term outcomes of iStent have been extensively studied; however, only few studies have investigated its long-term outcomes. Here, we assessed the long-term efficacy and safety of two iStents with concomitant cataract surgery in glaucomatous eyes while also evaluating measures of disease stability using visual field and optical coherence tomography (OCT) of the optic nerve and the macula throughout 8 years of follow-up.

Methods

This longitudinal, single-center consecutive case series included glaucomatous eyes that underwent implantation of two first-generation trabecular micro-bypass stents (iStent) with concomitant cataract surgery. Eight-year efficacy outcomes included mean intraocular pressure (IOP) and medications, as well as surgical success. Eight-year safety outcomes included best-corrected visual acuity (BCVA), visual field mean deviation (VF-MD), cup-to-disc ratio (CDR), retinal nerve fiber layer (RNFL) thickness, ganglion cell-inner plexiform layer (GC-IPL) thickness, and adverse events.

Results

A total of 62 eyes with primary open-angle glaucoma (POAG) were included. At 8 years postoperative, IOP reduced by 26% from 19.2 ± 3.9 mmHg preoperatively to 14.2 ± 2.4 mmHg (P < 0.001), 91.1% of eyes achieved IOP ≤ 18 mmHg (vs. 51.6% preoperatively), 69.6% of eyes achieved IOP ≤ 15 mmHg (vs. 14.5% preoperatively), and 25% of eyes achieved IOP ≤ 12 mmHg (vs. 1.6% preoperatively). Medication use decreased by 17.9% from 2.8 ± 1.1 preoperatively to 2.3 ± 1.2 (P = 0.018). Surgical success was 90%, as six eyes underwent subsequent glaucoma surgeries. Safety measures of BCVA, CDR, RNFL thickness and GC-IPL thickness remained stable through 8 years postoperative. VF-MD remained stable until postoperative year 5 and subsequently progressed according to the natural history of glaucomatous disease.

Conclusions

Implantation of two iStents with concomitant cataract surgery is an effective and safe treatment option for surgery-naïve POAG eyes, evidenced by significant IOP and medication reductions, reasonable surgical success, and favorable safety outcomes, throughout the 8-year follow-up. Our data additionally supports the efficacy of this combined procedure in stabilizing or slowing disease progression.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40662-021-00263-1.

5-year outcomes of single iStent (G1) trabecular microbypass implantation with phacoemulsification in moderately advanced primary open angle glaucoma

Purpose

To evaluate the safety and efficacy of combined phacoemulsification and single iStent (G1) (iStent, Glaukos Corp. San Clemente, USA), implantation in moderately advanced primary open angle glaucoma (POAG) with 5-years follow-up.

Methods

Retrospective, interventional case series. All subjects had POAG and underwent single iStent implantation+ phaco+IOL by a single surgeon, with 5 years follow-up. Primary outcome measures: reduction in intraocular pressure (IOP) and proportion of eyes achieving at least 20% reduction of IOP at 5 years. Secondary outcome measures: number of glaucoma drops at 1 through to 5 years; change in visual field mean deviation (MD) at year 5 compared to baseline.

Results

35 eyes of 26 patients were included. Mean (sd) medicated pre-op IOP was 18.5 (3.2) mm Hg on mean (sd) 2.3 (1.0) medications. Mean IOP was reduced to 15.9 (4.5) mm Hg on 2.2 (0.9) drops, 15.0mm (4.5) mm Hg on 2.3 (0.9) drops, 15.6 (3.6) mm Hg on 2.5 (1.0) drops, 15.7 (4.43) mmHg on 2.6 (1.0) drops and 14.7 (3.02) mmHg (P<0.001) on 2.7 (1.14) drops (P = 0.06) from 1 through to 5 years. At year 5, 62% of eyes had achieved at least 20% reduction in IOP. MD reduced from -8 (8.1) dB to -10.7 (13.4) dB over 5 years (p = 0.8) at 0.54dB/ annum. One eye required filtering surgery. There were no sight-threatening complications.

Conclusion

This study showed sustained IOP reduction and excellent safety profile for single iStent implantation. Uniquely it provides data for a more severe stage of glaucoma, and also visual field data, which indicated no significant change through 5 years.

Selective Laser Trabeculoplasty Versus MIGS: Forgotten Art or First-Step Procedure in Selected Patients with Open-Angle Glaucoma

Introduction

To evaluate the long-term effect on intraocular pressure (IOP) and glaucoma medication of selective laser trabeculoplasty (SLT) compared to minimally invasive glaucoma surgery (MIGS) in primary open-angle glaucoma (POAG) and its potential in clinical practice.

Methods

A total of 342 consecutive patients (stand-alone procedures) were included. One hundred and five patients underwent SLT treatment (360° SLT, 95–105 spots, Trabeculas SLT ARCLaser, Nürnberg, DE), 107 patients had an ab interno-derived trabeculotomy (Trabectome^®, NeoMedix, Tustin, USA), and 130 patients received iStent inject^® implantation (2 implants-Glaukos, CA, USA). IOP and glaucoma therapy were evaluated preoperatively, 1 day, 6 weeks, 3 months, 6 months, and 1, 2, and 3 years postoperatively. Statistical analysis was performed using a regression model and propensity matching score (reduced cohort number) using SPSS v20.0. Kaplan–Meier analysis was included using the following six criteria: criterion A (IOP ≤ 21 mmHg with or without medication, qualified success), criterion B (IOP ≤ 18 mmHg with or without medication, qualified success), criterion C (IOP ≤ 21 mmHg without medication, complete success), criterion D (IOP ≤ 18 mmHg without medication, complete success), criterion E (IOP ≤ 21 mmHg and IOP reduction > 20% after therapy), and criterion F (IOP ≤ 18 mmHg and IOP reduction > 20% after therapy).

Results

In the matched cohort, the SLT cohort showed an IOP reduction of 31.2% from 19.9 ± 2.3 to 13.7 ± 2.7 mmHg (p < 0.001) 3 years postoperatively; in Trabectome^® IOP decreased by 31.4% from 20.5 ± 1.3 to 13.8 ± 2.0 mmHg (p < 0.001) and in iStent inject^® by 29.9% from 19.5 ± 2.0 to 13.8 ± 2.7 mmHg (p < 0.001). Trabectome^® and iStent inject^® could not demonstrate a significant reduction in glaucoma therapy (Trabectome^®p = 0.138, iStent inject^®p = 0.612); a significant drop was noted in SLT (2.2 ± 1.2 to 1.7 ± 1.2, p = 0.046). SLT and MIGS achieved good to moderate survival rates using criterion A (93.3% SLT, 79.7% Trabectome^®, 77.6% iStent inject^®) and criterion B (74.5% SLT, 48.0% Trabectome^®, 56.2% iStent inject^®). As expected, low survival rates were obtained with non-filtering procedures: criterion C 11.1% in SLT, 6.5% in Trabectome^®, 7.0% in iStent inject^® and criterion D 3.0% in SLT, 4.3% in Trabectome^®, 3.7% in iStent inject^® in 3-year follow-up.

Conclusion

The SLT is a low-complication and effective method for reducing pressure in mild to moderate POAG. SLT is suitable as an initial procedure when setting up a step scheme; MIGS is the treatment of choice as a follow-up for mild to moderate forms of glaucoma and accepted topical therapy. Ethic approval had been given by the Ethikkommission Charité – Universitätsmedizin Berlin, EA4/047/20—retrospectively registered.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40123-021-00347-0.

Five-Year Outcomes Prospective Study of Two First-Generation Trabecular Micro-Bypass Stents (iStent®) in Open-Angle Glaucoma

PURPOSE

To assess 5-year effectiveness and safety of 2 iStent® trabecular micro-bypass stents in eyes with open-angle glaucoma (OAG) not controlled on 1 medication.

MATERIALS AND METHODS

This prospective, interventional, single-arm, multi-surgeon study (NCT #1252862, clinicaltrials.gov) enrolled eyes with OAG, preoperative intraocular pressure (IOP) of 18-30 mmHg on 1 ocular hypotensive medication, and 22-38 mmHg after medication washout. Eyes underwent standalone implantation of 2 iStent devices and were followed through 60 months postoperatively. Efficacy was quantified by mean diurnal IOP and medication usage. Efficacy endpoints included the proportion of eyes with ≥20% IOP reduction versus baseline unmedicated IOP (primary efficacy), and the proportion of eyes with IOP ≤18 mmHg (secondary efficacy) without medication or secondary glaucoma surgery. Safety parameters included visual acuity, cup-to-disc ratio, visual field, and complications and adverse events.

RESULTS

Preoperative mean IOP on 1 medication was 20.6 ± 2.0 mmHg and post-washout unmedicated IOP was 24.1 ± 1.4 mmHg (n = 39). At 5 years postoperative, medication-free mean diurnal IOP reduced to 14.5 ± 2.2 mmHg, constituting a 40% decrease versus preoperative washed-out IOP (p < .0001). In addition, this 5-year medication-free IOP constituted a 30% decrease versus preoperative IOP on 1 medication (p < .0001). At Month 60, 89.7% (26/29) of eyes achieved the primary efficacy endpoint of ≥20% IOP reduction versus baseline unmedicated IOP, and 86.2% (25/29) of eyes achieved the secondary efficacy endpoint of IOP ≤18 mmHg, without medication or secondary glaucoma surgery. Throughout follow-up, 89.7-91.3% of eyes were on no medications. Favorable safety included no secondary glaucoma surgeries, minimal adverse events, and stable visual acuity, cup-to-disc ratio, and visual fields through 5 years postoperative.

CONCLUSIONS

This prospective interventional study demonstrates persistent 5-year reductions in IOP and freedom from medications, together with favorable safety, following implantation of 2 first-generation trabecular micro-bypass stents in eyes with OAG on 1 preoperative medication.

iStent Trabecular Microbypass Stent Implantation with Phacoemulsification in Patients with Open-Angle Glaucoma: 6-Year Outcomes

Purpose

To investigate the long-term safety and efficacy of an iStent trabecular microbypass stent in combination with cataract surgery in eyes with primary open-angle glaucoma (POAG).

Setting

Private practice; Sioux Falls, South Dakota.

Design

Retrospective, consecutive case series.

Methods

This case series included eyes implanted with a single trabecular microbypass stent in combination with phacoemulsification in patients with mild to severe POAG. Data were collected preoperatively and at day 1, week 1, month 1, and up to 6 years postoperatively. Primary outcome measures included mean intraocular pressure (IOP) and number of glaucoma medications. Safety was noted by assessing the incidence of IOP spikes and need for additional surgery.

Results

The study comprised 411 eyes. Mean IOP was reduced to 14.9±4.2 mmHg compared to 18.8±5.6 mmHg at baseline at 6 years postoperative. The mean number of medications was reduced to 1.2±1.0 from 1.4±1.1 at baseline. In eyes with severe stage of disease, there was a mean IOP reduction >6 mmHg at 6 years postoperative. Eyes with baseline IOP ≥18 mmHg achieved a more robust reduction in IOP. Fifteen eyes underwent a secondary glaucoma procedure. There were no intra- or postoperative complications.

Conclusion

Trabecular microbypass stent implantation in combination with cataract surgery provides a sustained IOP reduction in eyes with mild-to-severe POAG. The degree of IOP reduction was more significant in eyes with higher baseline IOP and severe stage of disease.

Use of iStent as a Standalone Operation in Patients with Open-Angle Glaucoma

Purpose

The iStent provides a direct pathway for aqueous outflow from the anterior chamber to Schlemm's canal in patients with open-angle glaucoma (OAG). We performed a meta-analysis to evaluate the effectiveness of iStent as a standalone operation in patients with OAG in reducing the intraocular pressure (IOP) and the number of topical glaucoma medications.

Methods

We searched various databases between January 1, 2000, and September 30, 2019, and included only peer-reviewed, prospective, or retrospective clinical studies in our analyses. Details regarding the IOP and the number of medications at baseline and end point were recorded from each study. Standardized mean differences (SMDs) of IOP and medication numbers were calculated. Furthermore, the success rate (the proportion of IOP ≤18 mmHg and IOP reduction ≥20% at end point) and the complication rate were also summarized. Finally, a subgroup analysis was done based on the iStent generation (first and second), follow-up duration (≤6, 6–18, 18–36, and >36 months), and iStent number (one, two, and three). The outcome measures were aggregated SMDs computed from each study.

Results

A total of 17 studies with 978 eyes were included in this analysis. All studies demonstrated a reduction in IOP after iStent implantation. Aggregated SMDs of IOP revealed a significant reduction (SMD = −2.64, 95% confidence interval (CI): −3.21 to −2.07). The success rate was significantly good, and most of the complication rates were low. The number of medications was also significantly reduced (SMD = −1.71, 95% CI: −2.18 to −1.24). The subgroup analysis revealed a reduction in IOP and medication burden in each category of iStent generation, follow-up duration of up to 42 months, and iStent numbers.

Conclusion

Use of iStent as a standalone procedure does reduce the IOP and the number of glaucoma medications. The benefit of iStent lasts for at least 42 months.

iStent inject trabecular microbypass stent implantation with cataract extraction in open-angle glaucoma: early clinical experience

Background

Retrospective, consecutive case series to evaluate the implantation of two second-generation trabecular microbypass stents in combination with cataract surgery in a real-world, clinical setting.

Methods

The series included 56 eyes implanted with the iStent inject device with phacoemulsification. The series consisted of eyes with primary open-angle glaucoma (n = 52) and pseudoexfoliative glaucoma (n = 4). Primary outcome measures included intraocular pressure (IOP) and number of glaucoma medications. Safety outcomes included the need for secondary surgical intervention and the incidence of IOP spikes ≥10 mmHg and ≥ 15 mmHg.

Results

IOP was reduced by 21% to 14.7 ± 2.9 mmHg (p < 0.01) at 6 months postoperative from 18.7 ± 5.8 mmHg at baseline. Preoperatively, the mean number of glaucoma medications was 1.5 ± 0.9 and reduced by 39% to 0.9 ± 1.2 (p < 0.01) at 6 months. At 6 months, 68% of eyes had an IOP ≤15 mmHg, increased from 30% at baseline. 55% of eyes were medication-free at 6 months, up from 18% at baseline. There were no severe postoperative complications. No eyes underwent an additional glaucoma procedure.

Conclusions

Implantation of the iStent inject device with concomitant cataract surgery effectively provides a sustained reduction in IOP with a markedly improved medication burden out to 6 months postoperative. The safety profile is excellent.

Prospective Studies of Minimally Invasive Glaucoma Surgeries: Systematic Review and Quality Assessment

Glaucoma is a common blinding disease; while there is no cure, effective treatments include medications, laser, and incisional surgery. There is significant interest from patients and doctors to develop safer surgical options throughout the spectrum of disease, to minimize treatment burden in mild glaucoma patients and to minimize risk of complications in patients needing more aggressive treatment. Surgical procedures called Minimally or Micro-Invasive Glaucoma Surgery (MIGS) are growing in popularity. Eighty-seven prospective studies on MIGS were identified and assessed for quality. Most (74%) did not have a control group. Twelve of the highest quality were reviewed. MIGS procedures appeared to have fewer complications, and lowered intraocular pressure, and reduced medication use. Studies were limited by small sample size, narrow spectrum of glaucomatous disease, and/or conflicts of interest. There is a need for high quality, independently funded and performed, comparative studies on the MIGS to help make treatment decisions.

Four-Year Outcomes of Two Second-Generation Trabecular Micro-Bypass Stents in Patients with Open-Angle Glaucoma on One Medication

INTRODUCTION

This study evaluated long-term reductions in intraocular pressure (IOP) and medication following implantation of 2 second-generation trabecular micro-bypass stents (iStent inject®) in eyes with open-angle glaucoma (OAG) not controlled on 1 preoperative medication.

MATERIAL AND METHODS

In this prospective interventional multi-surgeon study, standalone implantation of 2 iStent inject stents was performed in 57 eyes of 57 subjects with OAG, preoperative IOP of 18-30 mmHg on 1 medication, and preoperative post-washout IOP of 22-38 mmHg. The main outcome measures included the proportions of eyes achieving medication-free IOP ≤18 mmHg, IOP ≤15 mmHg, or ≥20% IOP reduction versus preoperative unmedicated IOP. Assessments included IOP, medications, visual acuity, visual field, pachymetry, complications, and interventions. Subjects were followed for 48 months with follow-up continuing in all eyes.

RESULTS

At Month 48 (n=57), 95% of eyes achieved an IOP reduction of ≥20% without medication versus preoperative washout IOP; and although they had eliminated medication, 81% of eyes still had an IOP reduction of ≥20% versus preoperative IOP on 1 medication. Mean 48-month unmedicated IOP decreased by 46% to 13.2±1.6 mmHg vs 24.4±1.3 mmHg preoperatively (p<0.0001), with 95% of medication-free eyes having IOP ≤18mmHg and 82% having IOP ≤15mmHg. Over the course of follow-up, 3 eyes had medication added and 1 eye underwent a secondary glaucoma surgery, and safety parameters were favorable.

DISCUSSION

Standalone iStent inject implantation in OAG patients on 1 preoperative medication resulted in average IOP reduction to ≤15 mmHg with the elimination of medication and favorable safety through 48 months.

TRIAL REGISTRATION

ClinicalTrials.gov identifier, NCT02868190.

Second-generation trabecular micro-bypass stent implantation: Retrospective analysis after 12- and 24-month follow-up

BACKGROUND

The study aimed to investigate the 24-month safety and efficacy of implantation of two second-generation iStent inject trabecular micro-bypass stents with concomitant cataract surgery.

METHODS

This consecutive case series included 164 eyes of 109 patients implanted with the iStent inject® device with concomitant cataract surgery. The series was comprised of eyes with primary open-angle glaucoma (n = 84), pseudoexfoliation glaucoma (n = 42), normal-tension glaucoma (n = 18), and ocular hypertension (n = 20). All 164 eyes reached 9-14 months of follow-up ("12-month consistent cohort"), with a subset of 88 eyes reaching 21-26 months of follow-up ("24-month consistent cohort"). Performance outcome measures included intraocular pressure (IOP) and number of glaucoma medications. Safety outcomes included intra- or postoperative complications, the need for secondary procedures and corrected distance visual acuity. Comparisons of change in continuous (e.g., IOP) and categorical (e.g., proportions of eyes on zero medications) measures between baseline and postoperative times were made with the paired t-test and McNemar's chi-squared test, respectively.

RESULTS

At 12 months postoperatively, IOP was reduced by 25.5% (from 20.0 ± 5.5 mmHg to 14.9 ± 2.0 mmHg; p < 0.001); at 24 months postoperatively, IOP was reduced by 26.6% (from 20.3 ± 6.1 mmHg to 14.9 ± 1.9 mmHg; p < 0.001). At 12 months postoperatively, mean number of glaucoma medications was reduced by 85.0% (from 2.0 ± 1.0 to 0.3 ± 0.8 medications; p < 0.001); at 24 months postoperatively, mean number of medications was reduced by 81.0% (from 2.1 ± 1.1 to 0.4 ± 0.8 medications; p < 0.001). After 12 months, 96.3% of eyes had an IOP ≤ 18 mmHg and 58.5% of eyes had an IOP ≤ 15 mmHg, with 81.1% of eyes free of any medication, compared to 1.8% of eyes medication-free in the 12-month cohort at baseline. After 24 months, 98.9% of eyes had an IOP ≤ 18 mmHg and 53.4% of eyes had an IOP ≤ 15 mmHg, with 72.7% free of medication compared to 1.1% of eyes medication-free in the 24-month cohort at baseline. Overall, a high safety profile was observed with no significant postoperative complications.

CONCLUSIONS

The insertion of iStent inject (comprised of two second-generation trabecular micro-bypass stents) with cataract surgery effectively provides a sustained reduction in IOP with a markedly improved medication burden up to 24 months postoperatively.

Real-world Case Series of iStent or iStent inject Trabecular Micro-Bypass Stents Combined with Cataract Surgery

INTRODUCTION

This real-world retrospective case series assessed 12-month effectiveness and safety following implantation of iStent® or iStent inject® trabecular micro-bypass with cataract surgery.

METHODS

Consecutive patients were implanted with either iStent (comprising 1 stent) or iStent inject (comprising 2 stents), together with cataract surgery. Most patients had primary open-angle glaucoma. Effectiveness outcomes through 12 months included intraocular pressure (IOP) and glaucoma medications. Proportional analyses were completed for eyes achieving IOP ≤ 18 mmHg, IOP ≤ 15 mmHg, or IOP reduction ≥ 20% from preoperative; and eyes on 0 medications or ≥ 2 medications. Safety outcomes included adverse events, secondary surgeries, visual acuity, and visual fields.

RESULTS

This analysis included 137 eyes (67 iStent, 70 iStent inject) with cataract and mild to moderate glaucoma or ocular hypertension. Over 73% of eyes in both groups had early disease, and ~ 22% had prior glaucoma surgery. At 12 months postoperatively, mean IOP decreased from 18.4 ± 4.2 mmHg to 14.2 ± 2.5 mmHg in iStent eyes (p < 0.0001), and from 20.4 ± 5.6 mmHg to 14.4 ± 2.1 mmHg in iStent inject eyes (p < 0.0001). The IOP reduction was significantly greater for iStent inject eyes than iStent eyes (6.0 mmHg versus 4.2 mmHg reduction, p = 0.034). Both groups had high proportions of patients achieving the 12-month IOP endpoints, although consistently greater proportions reached these endpoints after iStent inject than iStent: 95.7% versus 92.5% had IOP ≤ 18 mmHg, respectively; 74.3% versus 71.6% had IOP ≤ 15 mmHg, respectively; and 68.6% versus 62.7% had IOP reduction ≥ 20% from baseline, respectively. Mean medication burden at 12 months decreased from 1.8 ± 0.7 to 0.3 ± 0.5 medications in iStent eyes (84.0% reduction, p < 0.0001), and from 1.3 ± 0.9 to 0.1 ± 0.3 medications in iStent inject eyes (94.7% reduction, p < 0.0001). Significantly more iStent inject eyes were medication-free at 12 months than iStent eyes (92.9% versus 76.1% medication-free, respectively; p = 0.0068). Favorable safety included few adverse events, no secondary glaucoma surgeries, and stable visual acuity and visual fields in both groups.

CONCLUSION

Significant and safe IOP and medication reductions were achieved through 12 months after iStent or iStent inject implantation with cataract surgery. iStent inject eyes had greater absolute IOP reduction and more eyes medication-free versus iStent eyes.

FUNDING

Glaukos Corporation.

One-Year Comparative Evaluation of iStent or iStent inject Implantation Combined with Cataract Surgery in a Single Center

INTRODUCTION

This retrospective consecutive case series assessed 12-month effectiveness and safety of iStent® or iStent inject® trabecular micro-bypass implants with cataract surgery in patients with open-angle glaucoma (OAG) in a real-world clinical setting.

METHODS

Effectiveness outcomes consisted of intraocular pressure (IOP) reduction; glaucoma medication reduction; proportions of eyes achieving IOP < 18, < 15, or < 12 mmHg; and proportional analysis of medication usage. Safety outcomes included adverse events, secondary surgeries, and best-corrected visual acuity (BCVA).

RESULTS

This evaluation included 58 eyes with OAG (35 iStent, 23 iStent inject), with 96.6% of eyes having mild or moderate glaucoma. Diagnoses included primary open-angle glaucoma (the majority; 72.4%), pseudoexfoliative glaucoma, and pigmentary glaucoma. Baseline mean IOP and medications were statistically comparable between groups: 16.1 ± 3.6 mmHg on a mean of 1.8 ± 0.8 medications in the iStent group, and 16.2 ± 3.1 mmHg on a mean of 1.7 ± 0.8 medications in the iStent inject group. Twelve months after stent-cataract surgery, mean IOP was significantly lower in the iStent inject group than in the iStent group (13.1 mmHg vs. 15.4 mmHg, respectively; p < 0.001), and the percent reduction in IOP from baseline was significantly greater in iStent inject eyes than in iStent eyes (19.1% vs. 4.3% reduction, respectively; p < 0.001). At 12 months postoperative, significantly greater proportions of iStent inject eyes than iStent eyes achieved IOP < 18 mmHg (100% vs. 80.0% of eyes, respectively; p = 0.035), IOP < 15 mmHg (73.9% vs. 34.3% of eyes, respectively; p = 0.003), and IOP < 12 mmHg (26.1% vs. 0% of eyes, respectively; p = 0.002). Meanwhile, both groups achieved significant medication reductions at 12 months vs. baseline (94.1% reduction in iStent inject eyes, p < 0.0001; and 72.2% reduction in iStent eyes, p < 0.0001), with the percent reduction being significantly greater in iStent inject eyes than in iStent eyes (p = 0.023). At 12 months, mean number of medications was significantly lower in iStent inject eyes than iStent eyes (0.1 vs. 0.5 medications, respectively; p = 0.021), and significantly more iStent inject eyes (95.7%) than iStent eyes (71.4%) were off medications entirely (p = 0.021). A similarly high safety profile was observed in both groups.

CONCLUSION

iStent or iStent inject implantation with cataract surgery resulted in substantial and safe reductions in IOP and medications through 12 months postoperative. Consistent with prior observations, greater efficacy was observed with iStent inject than with iStent.

FUNDING

The Rapid Service Fees were funded by Glaukos Corporation.

Second-Generation Trabecular Micro-Bypass Stents as Standalone Treatment for Glaucoma: A 36-Month Prospective Study

INTRODUCTION

To evaluate long-term outcomes following stand-alone implantation of two second-generation trabecular micro-bypass stents (iStent inject®, Glaukos Corp., San Clemente, CA, USA) in eyes with predominantly primary open-angle glaucoma (POAG) and considerable preoperative disease burden.

METHODS

Eyes with POAG, pseudoexfoliative glaucoma (PXG), appositional narrow-angle glaucoma (NAG, with open-angle configuration in the area of implantation), or secondary glaucoma were included in this prospective, non-randomized, consecutive case series. All eyes underwent ab interno iStent inject implantation as a sole procedure. Assessments through 36 months included IOP, medications, corrected distance visual acuity (CDVA), secondary glaucoma surgeries, and complications and adverse events.

RESULTS

Two iStent inject stents were implanted in 44 consecutive eyes (POAG = 38, PXG = 4, appositional NAG = 1, secondary neovascular glaucoma = 1) of 31 patients, and 33 eyes had 36-month follow-up data. Preoperative mean IOP was 25.3 ± 6.0 mmHg on a mean of 2.98 ± 0.88 medications, with 75% of eyes on 3-5 medications, no eyes medication-free, and 50% of eyes with history of prior glaucoma surgery. At 36 months postoperatively, mean IOP reduced by 42% to 14.6 ± 2.0 mmHg (p < 0.0001) and 87.9% of eyes achieved an IOP reduction of ≥ 20% versus preoperatively. In addition, 97% of eyes reached IOP ≤ 18 mmHg (vs. 9.1% preoperatively; p < 0.0001) and 70.0% of eyes reached IOP ≤ 15 mmHg (vs. 2.3% preoperatively; p < 0.0001). Mean medication burden decreased by 82% to 0.55 ± 0.79 (p < 0.0001), and 61% of eyes became medication-free. All eyes maintained or decreased their 36-month medication burden versus preoperatively. Safety was favorable, including minimal adverse events and stable CDVA through 36 months postoperatively.

CONCLUSION

This real-world cohort of glaucomatous eyes with substantial preoperative disease burden experienced significant, sustained, safe IOP and medication reductions through 36 months following stand-alone iStent inject implantation.

FUNDING

Article processing charges and writing assistance were provided by Glaukos Corp. (San Clemente, CA, USA).

Three-year outcomes of combined trabecular micro-bypass and phacoemulsification in a predominantly Hispanic population with primary open-angle glaucoma

Purpose: To present long-term, real-world outcomes after implanting one trabecular micro-bypass stent with cataract surgery for primary open-angle glaucoma (POAG) in a predominantly Hispanic patient population. Patients and methods: This retrospective, consecutive case series evaluated intraocular pressure (IOP), medications, and safety through 36 months after implanting one iStent^® during phacoemulsification cataract surgery. Eyes were stratified into 2 subgroups classified by preoperative IOP and surgical goal. The Controlled Group had IOP <18 mmHg on ≥1 medications, and goal to reduce medications. The Uncontrolled Group had IOP ≥18 mmHg and/or maximum tolerated medication load, and goal to reduce IOP. Assessments included IOP, medications, visual fields (VF), retinal nerve fiber layer thickness (RNFL), adverse events, and secondary surgeries. Results: Of 168 total operated eyes, 87 eyes (49 Controlled, 38 Uncontrolled) completed 36 months of follow-up and comprise the Consistent Cohort in this report. At baseline, 79.6% (39/49) of Controlled eyes and 71.1% (27/38) of Uncontrolled eyes were from Hispanic patients. In the Controlled Group desiring medication reduction, mean medications were reduced by 77.3% (2.6 medications preoperatively vs 0.6 at 36 months; p<0.001. All Controlled eyes maintained or reduced medications versus preoperative; no eyes were on ≥3 medications (vs 61.2% preoperatively); and 58.3% were medication-free (vs 0% preoperatively). In the Uncontrolled Group desiring IOP reduction, mean IOP decreased by 31.2% (19.4 mmHg preoperatively vs 13.4 mmHg at 36 months; p<0.001), 91.7% of eyes achieved IOP ≤18 mmHg, 69.4% reached IOP ≤15 mmHg, and 77.8% decreased IOP ≥20% vs baseline. Uncontrolled eyes also experienced a 45.3% medication reduction (2.2 medications preoperatively vs 1.2 at 36 months; p<0.001). Favorable safety included no intraoperative complications, and stable VF and RNFL through 36 months. Conclusion: In this predominantly Hispanic patient cohort, significant IOP and medication reductions were sustained safely through 36 months after iStent implantation during cataract surgery.

Intermediate Results of iStent or iStent inject Implantation Combined with Cataract Surgery in a Real-World Setting: A Longitudinal Retrospective Study

INTRODUCTION

In this real-world, retrospective, comparative study we evaluated 6-month performance and safety in consecutive eyes following implantation of the iStent® or iStent inject® trabecular micro-bypass device with concomitant cataract surgery.

METHODS

Performance outcomes included intraocular pressure (IOP) reduction; glaucoma medication reduction; proportions of eyes achieving an IOP of < 18, < 16, < 14, or < 12 mmHg; and proportions of eyes on 0, 1, 2, or ≥ 3 medications. Safety outcomes included adverse events, secondary surgeries, and best-corrected visual acuity (BCVA).

RESULTS

A total of 73 eyes with open-angle glaucoma and cataract were included in the study; of these, 38 eyes were implanted with the iStent device and 35 were implanted with the iStent inject device. The two groups of patients had similar baseline characteristics, with the exception of mean age and medication burden (both higher in patients receiving the iStent inject device); over 90% of eyes in both groups had early glaucoma. At 6 months after surgery, mean IOP had fallen from 16.5 ± 3.9 to 13.9 ± 2.3 mmHg in eyes with the iStent implant (p < 0.001), and from 17.3 ± 3.0 to 12.7 ± 1.8 mmHg in those with the iStent inject implant (p < 0.001). This reduction was significantly greater in the iStent inject eyes than in the iStent eyes (26.6 vs. 15.8%) (p = 0.005). Significantly more eyes receiving the iStent inject device compared to the iStent device achieved an IOP of < 18 mmHg at 6 months post surgery (100 vs. 86.8%) (p = 0.033). Average medication usage was reduced from 1.8 to 0.4 medications in iStent eyes (p < 0.001) and from 2.3 to 0.4 medications in iStent inject eyes (p < 0.001). Over 70% of eyes in both groups became medication-free by 6 months post implantation. Adverse events in iStent eyes were mild and resulted in no sequelae; two iStent eyes underwent non-penetrating deep sclerectomy during follow-up. No complications or secondary surgeries were noted in iStent inject eyes. All eyes in both groups maintained or showed improved BCVA versus baseline.

CONCLUSION

Significant and safe IOP and medication reductions were observed after iStent or iStent inject implantation with concomitant cataract surgery. Trends toward greater effectiveness and fewer adverse events were observed with the iStent inject device compared with the iStent device.

FUNDING

Article processing charges were provided by Glaukos Corporation.

Comparing iStent versus CyPass with or without phacoemulsification in patients with glaucoma: a meta-analysis

Bacground

The aim of this study was to conduct a meta-analysis to compare the overall intraocular pressure (IOP)-lowering effect of iStent or CyPass as isolated procedures or in combination with cataract extraction.

Materials and methods

Cochrane review manager 5.3 software (RevMan^® 5.3) was used for a meta-analysis of IOPs and the number of antiglaucoma medications in six groups according to the type and number of stents and whether the procedure was isolated or in combination with cataract extraction.

Main results

A total of 33 out of 446 publications retrieved have been enrolled. The mean changes in IOP in the groups with one iStent and more than two iStents with concurrent cataract extraction were -3.78 ± 0.53 mmHg and -3.89 ± 0.73 mmHg, respectively. The mean differences in IOP in the groups with one iStent and more than two iStents without concurrent cataract extraction were -3.96 ± 0.25 mmHg and -7.48 ± 0.55 mmHg, respectively. The mean changes in IOP in the groups with CyPass implantation with and without concurrent cataract extraction were -4.97 ± 1.38 mmHg and -8.96 ± 0.16 mmHg, respectively.

Conclusions

Both iStent and CyPass either in combination with cataract extraction or as isolated procedures effectively decrease IOP. This effect is greatest with isolated implantation of CyPass followed by multiple iStents and then single iStent implantation and lasts up to 2 years.

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

Introduction

The 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).

Methods

This 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.

Results

Preoperatively, 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.

Conclusion

This 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.

Funding

Article processing charges were funded by Glaukos Corporation (San Clemente, CA, USA).

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

Introduction

This 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).

Methods

Prospective 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.

Results

Preoperatively, 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.

Conclusion

IOP 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 Registration

NCT01456390.

Funding

Glaukos Corporation.

Electronic supplementary material

The online version of this article (10.1007/s12325-018-0666-4) contains supplementary material, which is available to authorized users.

Long-term titrated IOP control with one, two, or three trabecular micro-bypass stents in open-angle glaucoma subjects on topical hypotensive medication: 42-month outcomes

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.

Minimally-invasive glaucoma surgeries (MIGS) for open angle glaucoma: A systematic review and meta-analysis

Background

MIGS have been developed as a surgical alternative for glaucomatous patients.

Purpose

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.

Methods

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).

Results

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.

Conclusions

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.

Micro-invasive glaucoma surgery (MIGS): a review of surgical procedures using stents

Over the last decade several novel surgical treatment options and devices for glaucoma have been developed. All these developments aim to cause as little trauma as possible to the eye, to safely, effectively, and sustainably reduce intraocular pressure (IOP), to produce reproducible results, and to be easy to adopt. The term “micro-invasive glaucoma surgery (MIGS)” was used for summarizing all these procedures. Currently MIGS is gaining more and more interest and popularity. The possible reduction of the number of glaucoma medications, the ab interno approach without damaging the conjunctival tissue, and the probably safer procedures compared to incisional surgical methods may explain the increased interest in MIGS. The use of glaucoma drainage implants for lowering IOP in difficult-to-treat patients has been established for a long time, however, a variety of new glaucoma micro-stents are being manufactured by using various materials and are available to increase aqueous outflow via different pathways. This review summarizes published results of randomized clinical studies and extensive case report series on these devices, including Schlemm’s canal stents (iStent^®, iStent^® inject, Hydrus), suprachoroidal stents (CyPass^®, iStent^® Supra), and subconjunctival stents (XEN). The article summarizes the findings of published material on efficacy and safety for each of these approaches.

Implantation of two second-generation trabecular micro-bypass stents and topical travoprost in open-angle glaucoma not controlled on two preoperative medications: 18-month follow-up

Importance

Additional data are sought regarding treatment options for glaucoma, a major cause of global blindness.

Background

The study assessed outcomes following standalone implantation of two second‐generation trabecular micro‐bypass stents and postoperative topical prostaglandin in eyes with open‐angle glaucoma not controlled on two preoperative medications.

Design

The study design is a prospective, nonrandomized, open‐label study at a tertiary‐care ophthalmology centre.

Participants

Subjects had open‐angle glaucoma with preoperative intraocular pressure of 18–30 mmHg on two medications, a medication washout phase, and post‐washout intraocular pressure of 22–38 mmHg. All subjects (N = 53) have been followed for 18 months.

Methods

One day following implantation of two second‐generation trabecular micro‐bypass stents, subjects started topical travoprost. Medication washout was repeated at month 12.

Main Outcome Measures

The main outcome measure was the proportion of eyes with intraocular pressure reduction ≥ 20% versus medicated baseline intraocular pressure with reduction of one medication at 12 months.

Results

At 12 months, 91% of eyes achieved intraocular pressure reduction ≥ 20% with reduction of one medication. All eyes had intraocular pressure ≤ 18 mmHg with reduction of one medication, and 87% had intraocular pressure ≤ 15 mmHg. Mean intraocular pressure on one medication was ≤ 13.0 mmHg (≥ 34% reduction) through 18 months. Mean post‐washout intraocular pressure at month 13 was 33% lower than preoperative unmedicated intraocular pressure. No adverse events occurred through 18 months.

Conclusions and Relevance

In open‐angle glaucoma eyes on two preoperative medications, treatment with two second‐generation trabecular stents and one postoperative prostaglandin resulted in mean intraocular pressure ≤ 13 mmHg with reduction of one medication, with favourable safety. These findings show the utility of second‐generation trabecular bypass with postoperative prostaglandin in patients with open‐angle glaucoma.

Safety and Efficacy of Microinvasive Glaucoma Surgery

Microinvasive glaucoma surgery (MIGS) is emerging as a new therapeutic option for glaucoma patients who wish to reduce their medication burden and avoid the postoperative complications of conventional glaucoma filtration surgery. These devices differ in terms of their efficacy and safety profile. Schlemm's canal devices have the most favorable safety profile at the compromise of modest efficacy, while subconjunctival and suprachoroidal devices are potentially more effective at lowering the intraocular pressure at the expense of a higher rate of complications. This review consolidates the latest evidence on the efficacy and safety of the MIGS devices in clinical use and provides an overview on upcoming devices which would likely also become viable treatment options in the near future. These clinical data would assist a glaucoma surgeon in selecting the most appropriate MIGS device for each patient based on the glaucoma severity and patient expectations.

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

Purpose

To 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.

Methods

This 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.

Results

At 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.

Conclusion

Significant 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.

Outcomes Following Implantation of Two Second-Generation Trabecular Micro-Bypass Stents in Patients with Open-Angle Glaucoma on One Medication: 18-Month Follow-Up

Introduction

The study objective was to evaluate the intraocular pressure (IOP) and medication-lowering effect of 2 second-generation trabecular micro-bypass stents in eyes with open-angle glaucoma (OAG) on one preoperative medication.

Methods

Fifty-seven qualified phakic eyes with OAG on 1 medication, preoperative medicated IOP of 18–30 mmHg, and preoperative unmedicated (post-washout) IOP of 22–38 mmHg underwent implantation of 2 second-generation trabecular micro-bypass stents in a standalone procedure. Evaluations included IOP, best-corrected visual acuity, medication use, fundus and slit lamp examinations, visual field, cup to disc ratio, pachymetry, and complications and interventions. Subjects have been followed for 18 months, and follow-up is ongoing.

Results

At Month 12 postoperative, 100% of eyes had achieved an IOP reduction ≥20% (100% had IOP ≤18 mmHg and 67% had IOP ≤15 mmHg) without medication versus preoperative unmedicated IOP, and 75% had IOP reduction ≥20% without medication versus preoperative medicated IOP. The Month 12 mean unmedicated IOP had decreased by 42%, to 14.2 ± 1.9 mmHg vs 24.4 ± 1.3 mmHg preoperatively, and this reduction was maintained through 18 months (14.4 ± 2.1 mmHg). A high safety profile was observed.

Conclusion

In this prospective, open-label, single-arm study, the standalone implantation of two second-generation trabecular micro-bypass stents in OAG patients on 1 preoperative medication resulted in IOP reduction to ≤15 mmHg and elimination of medication through 18 months, with favorable safety.

Trial Registration

ClinicalTrials.gov identifier, NCT02868190.

Funding

Glaukos Corporation, San Clemente, CA.

Electronic supplementary material

The online version of this article (doi:10.1007/s12325-016-0420-8) contains supplementary material, which is available to authorized users.

Newly Diagnosed Primary Open-Angle Glaucoma Randomized to 2 Trabecular Bypass Stents or Prostaglandin: Outcomes Through 36 Months

Purpose

To examine outcomes through 36 months in phakic eyes with newly diagnosed primary open-angle glaucoma (POAG) naïve to therapy randomized to treatment with two trabecular micro-bypass stents or topical prostaglandin.

Methods

Subjects with POAG naïve to therapy, with intraocular pressure (IOP) ≥21 and ≤40 mmHg, were randomized to implantation of two stents or travoprost. Additional medication was to be prescribed post-treatment for elevated IOP or glaucomatous optic nerve findings. Of 101 randomized subjects, 100 subjects were followed for 24 months and 73 subjects were followed for 36 months. Follow-up on all subjects is ongoing.

Results

In this randomized cohort of 101 POAG subjects, 54 subjects underwent 2-stent surgery and 47 received topical travoprost. Mean pre-treatment IOP was 25.5 ± 2.5 mmHg in stent-treated eyes and 25.1 ± 4.6 mmHg in medication-treated eyes. By 3 years, mean IOP was 14.6 mmHg in stent eyes (with medication added in 6 eyes) and 15.3 mmHg in travoprost eyes (with a second medication added in 11 eyes). In the subset of eyes that did not require additional medical therapy, mean IOP was 14.5 mmHg and 15.7 mmHg in the respective groups. Ninety-one percent of stent eyes had 3-year IOP ≤18 mmHg without additional therapy (62% ≤ 15 mmHg) and 79% of travoprost eyes had 3-year IOP ≤18 mmHg (21% ≤ 15 mmHg). Safety was favorable in both groups.

Conclusions

In this prospective, randomized comparison of subjects with newly diagnosed POAG naïve to therapy, substantial IOP reduction with a favorable low complication rate was shown through 3 years after either 2 trabecular stents implanted as the sole procedure or topical travoprost therapy. These data suggest 2-stent implantation may be a viable initial treatment option comparable to topical prostaglandin in newly diagnosed POAG patients.

Trial registration: ClinicalTrials.gov identifier, NCT01443988.

Funding

Glaukos Corporation, Laguna Hills, CA.

Electronic supplementary material

The online version of this article (doi:10.1007/s40123-016-0065-3) contains supplementary material, which is available to authorized users.

iStent® Trabecular Microbypass Stent: An Update

Due to the high rates of complications and failure experienced with current glaucoma procedures, there is a continuous search for a safer and more effective glaucoma surgery. A new class of procedures termed minimally invasive glaucoma surgeries (MIGS) aim to fill this void by offering an alternative method of IOP reduction associated with markedly reduced complication rates and shorter recovery times. The iStent, a trabecular microbypass stent, is a MIGS device that has quickly gained popularity. The device allows aqueous humor to directly drain from the anterior chamber into Schlemm's canal by bypassing an obstructed trabecular meshwork. This review examines publications about the iStent, focusing on the device's efficacy, safety, and cost when a single iStent or multiple iStents are implanted in combination with cataract surgery or as a solo procedure. Current data suggest that the iStent is a safe and effective tool in the management of mild-to-moderate glaucoma, notable for its limited complications and absence of serious adverse events following implantation. As valuable experience is gained performing ab interno MIGS, increasing familiarity with angle anatomy and iStent placement, and as newer stent designs are developed, there is promise of continual improvement in the surgical management of glaucoma.