Comparative evaluation of iStent versus iStent inject W combined with phacoemulsification in open angle glaucoma

PURPOSE

The study aimed to compare the 12-month post-operative outcomes of iStent and iStent inject W (inject W), and the factors associated with their success in open-angle glaucoma.

METHODS

This single-center, retrospective comparative case series evaluated the medical records of patients who underwent iStent (comprising 1 stent) or inject W (comprising 2 stents) implantation with cataract surgery for primary open-angle glaucoma and normal tension glaucoma between January 2019 and March 2022. The 12-month post-operative efficacy outcomes included intraocular pressure (IOP), glaucoma medications, and survival analysis of the probability of success. "Failure" was defined as any of the following conditions compared to baseline: 1) IOP elevation, 2) increased glaucoma medication, or 3) IOP decline not exceeding 20% when glaucoma medication scores were comparable, and 4) need for additional glaucoma surgery. The safety outcomes included intra- and post-operative adverse events and changes in the best-corrected visual acuity and visual field.

RESULTS

The study comprised 55 eyes in the iStent and 105 in the inject W groups. At 12 months, treatment success was achieved in 66.0% of iStent and 78.4% of inject W eyes. The mean IOP was lower, and the percent reduction from baseline was equal in iStent-treated eyes (8.0% reduction, 14.8 mmHg to 13.7 mmHg, P<0.01) and inject W-treated eyes (11.9% reduction, 15.0 mmHg to 13.8 mmHg, P<0.01) (between-group comparison, P = 0.23). The mean medication burden decreased significantly from 2.5 to 1.1 for iStent (55.0% reduction, P<0.01) and 2.9 to 1.7 for iStent inject (46.8% reduction, P<0.01), with no significant differences between the two groups (P = 0.17). Both devices exhibited excellent safety.

CONCLUSIONS

Both devices significantly reduced IOP and glaucoma medication 12 months post-operatively. The outcome measures did not differ significantly between the two groups, and lower baseline IOP was predictive of surgical failure.

Intraoperative iStent versus postoperative selective laser trabeculoplasty in early glaucoma patients undergoing cataract surgery: A retrospective comparative study

PURPOSE

To compare the efficacy and safety of iStent inject® versus 360° selective laser trabeculoplasty (SLT) in patients with early glaucoma undergoing cataract surgery.

METHODS

A retrospective non-randomized study was conducted in 73 eyes divided into two groups: cataract surgery+intraoperative iStent (n=40) versus cataract surgery+postoperative SLT at one month (n=33). The primary endpoint was intraocular pressure (IOP) lowering≥20% between baseline and 6 months postoperatively. The secondary endpoints were IOP lowering at 1, 6 and 12 months, and the mean number of IOP-lowering medications at 6 and 12 months.

RESULTS

The mean baseline IOP was 19.1 mmHg with no significant difference between groups. The mean baseline number of IOP-lowering medications was higher in the iStent group (n=1.95) compared to the SLT group (n=1.53; P=0.04). At 6 months, 18 (60%) patients in the SLT group and 20 (51%) patients in the iStent group achieved IOP lowering≥20% with no significant difference between groups (P=0.431). At 6 months, no difference in the mean number of IOP-lowering medications was found between groups (-0.92 and -0.89 in the iStent and SLT groups, respectively). Similar results were found at 12 months.

CONCLUSION

These results suggest similar safety and efficacy of intraoperative iStent and postoperative 360° SLT in lowering IOP and reducing glaucoma eye drops in early glaucoma patients undergoing cataract surgery. Treatment choice should be based on the ophthalmologist's experience and on the cost-benefit ratio.

Randomised clinical trial for morphological changes of trabecular meshwork between Kahook dual-blade goniotomy and ab interno trabeculotomy with a microhook

We demonstrated whether the difference of trabecular meshwork remodeling occur depending on the incisional cross-sectional area by comparing Kahook dual-blade goniotomy (KDB) and ab interno trabeculotomy with a microhook. Phakic eyes with primary open-angle or exfoliative glaucoma were randomised into a KDB or a microhook group. The primary outcome was an incisional cross-sectional area quantified by anterior segment optical coherence tomography. In subgroup analysis, the number of patients with the unidentifiable incisional area was compared between the groups. Secondary outcomes were the rate of intraocular pressure changes, the laser flare metre values, corneal endothelial cell densities, the number of glaucoma medications, the usage rate per glaucoma medication type and postoperative complications between the two groups. A total of 29 eyes in 29 patients in the KDB and microhook group were included respectively, with an overall mean age of 72.6 ± 8.1 years. The incisional cross-sectional area of the KDB group was significantly larger at 1 week and at 1, 6 and 12 months (p < 0.01) postoperatively. The number of patients with the nonidentified incisional area was higher at 1, 6 and 12 months postoperatively (p ≤ 0.03) in the microhook group. The flare values in the KDB group were higher than those in the microhook group at 12 months postoperatively (p = 0.02). No significant differences were observed in other secondary outcomes. Incisional cross-sectional area remains larger in eyes treated with KDB goniotomy than in those treated with ab interno trabeculotomy with the microhook, whereas KDB goniotomy did not have an advantage in controlling intraocular pressure postoperatively.Trial registration: UMIN000041290 (UMIN, University Hospital Medical Information Network Clinical Trials Registry of Japan; date of access and registration, 03/08/2020).

Minimally Invasive Glaucoma Surgery: Latest Developments and Future Challenges

The development of minimally invasive glaucoma surgeries (MIGSs) was intended to provide safe and modestly efficacious modalities for early intervention of mild-to-moderate glaucoma, with minimal trauma and rapid recovery. They were mainly ab interno procedures that reduce intraocular pressure by facilitating the aqueous outflow by bypassing the trabecular meshwork resistance, reinforcing the uveoscleral flow via the supraciliary space, and reducing aqueous production by the ciliary body. While the cumulating evidence helps shape the role of the available MIGS, the exponential new development and advancement in this field has expanded the territory of MIGS. Apart from developing subconjunctival MIGS filtration devices (Xen gel stent and PRESERFLO MicroShunt), there is a tendency to revisit the "traditional" MIGS for alternative use and to modify the procedures with consideration of the fundamental aqueous outflow physiology. Combined MIGS has also been suggested, based on the theory that their different mechanisms may provide additive or synergistic effects. The advancement of laser procedures is also promising and could supplement unmet needs along the glaucoma treatment algorithm. This review examines the broad array of MIGS, updates the recent findings, discusses their potential alternative applications, and explores future challenges.

Which is More Effective and Safer? Comparison of Propensity Score-Matched Microhook Ab Interno Trabeculotomy and iStent Inject

INTRODUCTION

The purpose of this study was to compare the surgical outcomes between ab interno trabeculotomy (LOT) and iStent inject W implantation (iStent) both combined with cataract surgery, matching the background factors including age, intraocular pressure (IOP), medication score, central corneal thickness (CCT), and axial length.

METHODS

A total of 100 eyes from 75/79 patients with primary open-angle glaucoma were included in the LOT/iStent groups. The background factors were matched between the two groups using the propensity score.

RESULTS

There were no significant differences in age, IOP, medication score, CCT, and axial length, preoperatively. The postoperative medication scores were 1.3 ± 1.2 and 1.2 ± 1.2 in the LOT and iStent groups. The postoperative IOPs were 12.8 ± 2.8 and 13.1 ± 2.4 mmHg in the LOT and iStent groups, respectively. The changes in the medication score were  - 0.64 ± 1.4 and  - 0.44 ± 1.6 in the LOT and iStent groups, respectively. The changes in the IOP were  - 2.1 ± 3.3 and  - 1.5 ± 3.0 mmHg in the LOT and iStent groups, respectively. These values were not significantly different between the two groups. The postoperative IOP and changes in the IOP were significantly associated with preoperative IOP and CCT. There was no significant difference in the occurrence of postoperative complications (hyphema, 11.0% and 6.0%, and transient ocular hypertension, 8.0% and 5.0%, in the LOT and iStent groups, respectively).

CONCLUSION

LOT and iStent have similar surgical outcomes with sufficient safety. Postoperative IOP was significantly associated with preoperative IOP and CCT in both groups.

Minimally Invasive Glaucoma Surgery: A Review of the Literature

Minimally invasive glaucoma surgery (MIGS) has emerged as a novel approach in the glaucoma treatment spectrum, offering a range of diverse procedures and devices aimed at reducing intraocular pressure (IOP). MIGS can be broadly classified into several categories: those that enhance trabecular outflow (Trabectome, iStent, Hydrus Microstent, Kahook Dual Blade, high frequency deep sclerotomy, and gonioscopy-assisted transluminal trabeculotomy), those that augment suprachoroidal outflow (CyPass Microstent and iStent Supra), those that target Schlemm's canal (TRAB360 and the OMNI Surgical System, Streamline, and Ab Interno Canaloplasty), and conjunctival bleb-forming procedures (EX-PRESS Glaucoma Filtration Device, Xen Gel Stent and PreserFlo MicroShunt). MIGS is considered to have a shorter surgical time and fewer severe complications when compared to traditional glaucoma surgeries such as trabeculectomy and glaucoma drainage device implantation (Ahmed, Baerveldt, and Molteno valves). This literature review comprehensively examines the distinct MIGS devices and procedures, their underlying mechanisms, and clinical outcomes, emphasizing the importance of evaluating the efficacy and complications of each approach individually. As the field of MIGS continues to evolve, it is crucial to prioritize high-quality, long-term studies to better understand the safety and effectiveness of these innovative interventions in glaucoma management.

Spotlight on Schlemm's Canal MicroStent Injection in Patients with Glaucoma

Minimally invasive glaucoma surgery (MIGS) has revolutionized glaucoma care with its favorable safety profile and ability to delay or minimize the need for traditional, bleb-based procedures. Microstent device implantation is a type of angle-based MIGS, which reduces intraocular pressure (IOP) through bypass of the juxtacanalicular trabecular meshwork (TM) and facilitation of aqueous outflow into the Schlemm's canal. Although there are limited microstent devices on the market, multiple studies have evaluated the safety and efficacy of iStent^® (Glaukos Corp.), iStent Inject^® (Glaukos Corp.), and Hydrus^® Microstent (Alcon) in the treatment of mild-to-moderate open-angle glaucoma, with and without concurrent phacoemulsification. This review attempts to provide a comprehensive evaluation of injectable angle-based microstent MIGS devices in the treatment of glaucoma.

Ophthalmic surgery in New Zealand: analysis of 410,099 surgical procedures and nationwide surgical intervention rates from 2009 to 2018

BACKGROUND

Surgical intervention rates (SIR) provide a proxy measure of disease burden, surgical capacity, and the relative risk-benefit ratio of surgery. The current study assessed decade trends in ophthalmic surgery and calculated SIRs for all major classes of commonly performed ophthalmic procedures in New Zealand.

METHODS

Retrospective population-based analysis of all ophthalmic surgical procedures performed in New Zealand from 2009 to 2018. National and regional datasets from public and private health sectors and industry were analysed. SIRs were calculated for all major ophthalmic procedures, and subgrouped by patient demographics.

RESULTS

There were 410,099 ophthalmic surgical procedures completed with a 25.3% overall increase over 10 years. Procedures were mostly government-funded (51%, n = 210,830) with 71% of patients aged over 64 years. Cataract surgery (78%, n = 318,564) had the highest mean SIR (703/100,000/year) and increased by 25% during the study period, consistent with population growth in the over 64 years old age group. Vitrectomy surgery had the second highest mean SIR (67/100,000/year) and increased by 50%, well above national population growth during the study period. Other SIRs included conjunctival lesion-biopsy (38/100,000/year), glaucoma (33/100,000/year), strabismus (20/100,000/year), dacryocystorhinostomy (10/100,000/year), and keratoplasty surgery (4/100,000/year).

CONCLUSIONS

This comprehensive review of New Zealand ophthalmic surgery reports increasing SIRs that cannot be explained by population growth alone. Cataract surgery numbers increased year on year consistent with the increase in the over 64 years old population. Vitrectomy surgery growth exceeded that of the national population, including those over 64 years.

Phacoemulsification with and without iStent: A Systematic Review and Meta-Analysis of Comparative Studies

BACKGROUND

The iStent (Glaukos Corporation; Laguna Hills, CA, USA) is one of the minimally invasive glaucoma devices. It can be inserted at the time of phacoemulsification or as a stand-alone procedure to lower the intraocular pressure (IOP).

OBJECTIVE

Our aim was to conduct a systematic review and meta-analysis comparing the effect of iStent insertion at the time of phacoemulsification with phacoemulsification alone in patients with ocular hypertension or open-angle glaucoma.

METHODS

We searched EMBASE, MEDLINE (OVID and PubMed), CINAHL, and Cochrane Library for articles published between 2008 and June 2022 (PRISMA 2020 for the checklist). Studies comparing the IOP-lowering effect of iStent with phacoemulsification versus phacoemulsification alone were included. The endpoints were IOP reduction (IOPR) and the mean reduction in the number of glaucoma drops. A quality-effects model was used to compare both surgical groups.

RESULTS

Ten studies were included, reporting on 1,453 eyes. Eight hundred fifty three eyes had the combined iStent and phacoemulsification, and 600 eyes underwent phacoemulsification alone. IOPR was higher in the combined surgery at of 4.7 ± 2 mm Hg compared to 2.8 ± 1.9 mm Hg in phacoemulsification alone. A greater decrease in postoperative eye drops was noted in the combined group having a decrease of 1.2 ± 0.3 eye drops versus of 0.6 ± 0.6 drops in isolated phacoemulsification. The quality effect model showed an IOPR weighted mean difference (WMD) of 1.22 mm Hg (confidence interval [CI]: [-0.43, 2.87]; Q = 315.64; p < 0.01; I2 = 97%) and decreased eye drops WMD 0.42 drops (CI: [0.22, 0.62]; Q = 42.6; p < 0.01; I2 = 84%) between both surgical groups. Subgroup analysis shows that the new generation iStent may be more effective in reducing IOP.

CONCLUSION

iStent has a synergetic effect with phacoemulsification. The reduction of IOP and glaucoma eye drops was higher when iStent is combined with phacoemulsification compared with isolated phacoemulsification.

Systematic Literature Review of Clinical, Economic, and Humanistic Outcomes Following Minimally Invasive Glaucoma Surgery or Selective Laser Trabeculoplasty for the Treatment of Open-Angle Glaucoma with or Without Cataract Extraction

Introduction

Selective laser trabeculoplasty (SLT) and minimally invasive glaucoma surgery (MIGS) are increasingly used options for mild-to-moderate open-angle glaucoma (OAG) care. While most MIGS devices are indicated for use in combination with cataract surgery only, with phacoemulsification playing a role in lowering IOP, newer technologies can also be used as standalone glaucoma surgery.

Methods

This systematic literature review (SLR) aimed to assess the clinical, economic, and humanistic outcomes of MIGS and SLT for the treatment of OAG and was conducted according to PRISMA guidelines. Studies that assessed MIGS or SLT in at least one treatment arm versus any other glaucoma treatment in adults with mild-to-moderate OAG were included. Clinical, humanistic (health-related quality of life [HRQoL] and patient burden), and economic data were extracted, and the methodological quality of included studies was evaluated.

Results

A total of 2720 articles were screened, and 81 publications were included. Fifty-eight reported clinical outcomes. The majority assessed iStent or iStent inject (n=41), followed by OMNI (n=9), gonioscopy-assisted transluminal trabeculotomy (GATT) or the Kahook Dual Blade (KDB) (n=7), Hydrus (n=6), SLT (n=5), Xen Gel Stent (n=2), PreserFlo (n=1), and iTrack (n=1). IOP reduction was observed across prospective studies, varying from -31% to -13.7% at month 6 and from -39% to -11.4% at year 1 versus baseline. Most adverse events were transient and non-serious. Limited humanistic and economic data were identified.

Conclusion

Given their established efficacy and safety, there is a rationale for wider use of MIGS in mild-to-moderate OAG. Of the MIGS devices, iStent and OMNI have the largest clinical evidence base supporting their sustained effectiveness.

[Micro-invasive glaucoma surgery]

Glaucoma is a severe, rapidly progressing disease that in the absence of proper treatment leads to blindness in 20% of patients. According to the World Glaucoma Association, this disease is the most socially significant in modern ophthalmology and requires searching for new and effective methods of treatment. This article presents the results of research and reviews on this issue, considers both conservative therapy and surgical methods of treatment, analyzes in detail modern methods of micro-invasive eye surgery actively used in clinical practice. The article also describes indications for a various types of interventions, as well as the effect achieved by them and the possible complications, and presents the conclusions about the possibility of using these procedures in wide clinical practice.

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.

A multicenter prospective comparative study evaluating cataract surgery and endoscopic cyclophotocoagulation either with or without iStent inject implantation in Brazilian patients with glaucoma

Purpose

Compare 12-month (12 M) safety and efficacy of endoscopic cyclophotocoagulation (ECP) + cataract surgery (Group 1) versus ECP + cataract surgery + iStent inject trabecular micro-bypass implantation (Group 2) in Brazilian patients with open-angle glaucoma (OAG).

Methods

This prospective, multicenter, comparative case series included patients with OAG and cataract who were randomized to receive treatment in Group 1 or Group 2. Outcomes included mean and percent reduction versus preoperative in intraocular pressure (IOP) and number of glaucoma medications; visual acuity; occurrence of adverse events; and rate of secondary surgeries.

Results

Preoperatively, Groups 1 and 2 had similar mean IOP (mean ± standard deviation 22.1 ± 3.6 and 22.0 ± 2.5 mmHg, respectively) and mean number of medications (3.3 ± 0.6 and 3.4 ± 0.6 medications, respectively). At all follow-up timepoints through 12 M, both groups achieved significant IOP and medication reductions versus preoperative (IOP p < 0.001 and number of medications p < 0.001 for both groups). At 12 M, IOP reductions were 24.2% (Group 1) and 43.6% (Group 2) (p < 0.001); mean medication reductions were 50.2% and 71.5%, respectively. Mean postoperative IOP and number of medications were higher in Group 1 than Group 2 (IOP p < 0.01 all visits, medication p < 0.01 at 6 M and 12 M). Adverse events were generally mild and infrequent in both groups.

Conclusion

Both treatment groups (ECP + phacoemulsification, with/without iStent inject implantation) achieved significant and safe reductions in IOP and medications versus preoperative in Brazilian OAG patients. Percent reductions were significantly greater, and mean IOP and medications were significantly lower, in the group receiving iStent inject.

Clinical trial registration (CTR)

CAAE project identification #20053019.5.0000.5078. Protocol #3.587.147. Clinical Trial Database of the Federal University of Goiás, Brazil. Registration Date: September 19, 2019.

Comparison of Hydrus and iStent microinvasive glaucoma surgery implants in combination with phacoemulsification for treatment of open-angle glaucoma: systematic review and network meta-analysis

OBJECTIVES

To compare the efficacy and safety of two Schlemm's canal-based microinvasive glaucoma surgery (MIGS) devices, the Hydrus Microstent and the iStent Trabecular Bypass combined with phacoemulsification for treatment of open-angle glaucoma.

DESIGN

Systematic review and network meta-analysis.

METHODS

Literature searches were conducted on PubMed, Web of Science, Cochrane Library and ClinicalTrials.gov to identify randomised controlled trials (RCTs) assessing the Hydrus or the iStent implantation combined with phacoemulsification for treatment of open-angle glaucoma until September 2020. Risk of bias was assessed using a six-item modified Jadad scale. Effects were estimated using the intraocular pressure (IOP) reduction (IOPR), the percentage of IOPR and the proportion of medication-free patients at follow-up end. Safety was estimated using the proportions of adverse events. The network meta-analysis was conducted within a Bayesian framework using the Markov Chain Monte Carlo method in ADDIS software.

RESULTS

Six prospective RCTs comprising 1397 patients were identified. Regarding the absolute value and the percentage of IOPR, the Hydrus and 2-iStent implantation combined with phacoemulsification were significantly more effective than phacoemulsification alone. Rank probability analysis revealed the Hydrus might be the best choice to lower IOP. There was no significant difference in the proportion of medication-free patients among groups. The Hydrus and 2-iStent implantation had a higher probability to achieve the medication-free status versus the 1-iStent implantation and phacoemulsification alone. Overall safety profiles were good for each device with the focal peripheral anterior synechiae more frequently reported in Hydrus eyes.

CONCLUSIONS

The Hydrus implantation may have a slight advantage over the 1-iStent or 2-iStent implantation in combination with phacoemulsification to treat open-angle glaucoma. Our findings might be of some uncertainty due to the limited included data. Further studies are needed to investigate whether our findings are robust, including high-quality RCTs to directly compare these MIGS devices.

8-year follow-up of Excimer Laser Trabeculostomy Alone and Combined With Phacoemulsification in Patients with Open Angle Glaucoma

PURPOSE

To describe the 8-year results of excimer laser trabeculostomy (ELT) alone and ELT in conjunction with phacoemulsification (phaco).

SETTING

University Hospital.

DESIGN

Retrospective review.

METHODS

308 nm excimer laser energy delivered via an intraocular fiberoptic probe created channels through the inner wall of Schlemm's canal. Two groups were studied: ELT Alone and ELT + Phaco. Patients were adults with open-angle glaucoma or ocular hypertension on one or more intraocular pressure (IOP) lowering medications and, in the Phaco + ELT group, visually significant cataract. Primary outcome measures: Change of IOP from baseline and number of IOP lowering medications.

RESULTS

164 eyes in two groups, ELT Alone (n=90) and ELT + Phaco (n=74) were followed for 8 years. Baseline IOP in the ELT Alone group was 22.17 ± 7.0 mmHg and in the ELT+ Phaco group 21.9±6.44 mmHg. IOP in ELT Alone decreased to 16.84±5.2 mmHg at 1 year (n=69) and remained at 15.9±3.5 (n=19) at 8 years. IOP in ELT+ Phaco was 14.04±4.1 mmHg at 1 year (n=63) and 13.7±2.8 mmHg at 8 years (n=13). IOP lowering medications at baseline in ELT alone were 1.85±0.8 and decreased to 1.19±1.10 at 1 year and 1.4±1.4 at 8 years. In ELT + Phaco at baseline 1.58±0.8 and decreased to 0.97 ± 0.95 at 1 year and 1.85±0.7 at 8 years.

CONCLUSIONS

ELT demonstrates long-term IOP lowering and decrease in IOP lowering medications. Benefits of this laser based implant-free MIGS procedure include a high safety profile and long-term efficacy.

Parylene-C Microbore Tubing: A Simpler Shunt for Reducing Intraocular Pressure

OBJECTIVE

Current minimally-invasive glaucoma surgery (MIGS) devices promise to control elevated levels of intraocular pressure (IOP) while avoiding many of the downsides of traditional glaucoma surgery. However, there remains room for improvement in performance metrics, including drainage efficacy, device longevity, and time to implant, as outlined by benchmarks set forth by the Audacious Goals Initiative. We introduce a better shunt, which achieves similar or improved pre-clinical safety and efficacy outcomes to commercial MIGS devices, while reducing surgical profile and implantation time.

METHODS

We developed a parylene-based microbore glaucoma drainage device capable of modulating IOP via a minimally-invasive implantation procedure. We surgically implanted microbore tubing in five healthy New Zealand White rabbits and measured IOP levels biweekly using handheld applanation tonometry to assess device efficacy in lowering and maintaining IOP. After 6 weeks, the rabbits were euthanized and eyes were enucleated to evaluate inflammatory and histologic response to a foreign-body implant.

RESULTS

This device is the only one that fulfills the 10-minute benchmark for implantation time compared to other commercial MIGS devices. In 4 of 5 animals implanted, post-op IOP in the experimental eye dropped by an average of 16.17%. Histopathologic evaluation revealed localized evidence of minor inflammatory reaction and tissue irritation, as well as minimal fibrosis along the tube-tissue interface.

CONCLUSION AND SIGNIFICANCE

Based on these findings, this device stands as a promising platform to lowering IOP, particularly in patients with mild to moderate glaucoma requiring no need for cataract intervention, without eliciting a severe biological response.

12-Month Outcomes of Combined Phacoemulsification and iStent Inject in Asian Eyes with Normal Tension Glaucoma: A Single-Centre Experience

PURPOSE

To evaluate efficacy and safety of the iStent inject combined with phacoemulsification in Asian eyes with normal-tension glaucoma (NTG) up to 12 months after surgery.

STUDY DESIGN

Retrospective case series.

METHODS

Retrospective case series of eyes undergoing surgery from April 2017 to August 2019. Outcome measures included intraocular pressure (IOP), number of topical glaucoma medications and adverse outcomes. Data were retrieved from the post-operative day 1 (POD1), week 1 (POW1), month 1 (POM1), month 3 (POM3), month 6 (POM6) and month 12 (POM12) timepoints. Data were analysed at each timepoint for eyes with available clinical data at that visit. Subgroup analysis was performed for a consistent cohort which included only eyes with data at all six follow-up timepoints.

RESULTS

Data from 91 eyes in the collective subject group was analysed. Majority of subjects were male (53, 58.2%) and Chinese (79, 86.8%). Mean age was 73.2 ± 7.2 years. Pre-operatively, mean IOP was 14.3 ± 3.0 mmHg and mean number of medications was 1.5 ± 0.8. Significant IOP reduction was observed at all timepoints except POW1 and POM12. The number of medications was reduced at all timepoints (p < 0.001). By POM12, there was reduction of 1.2 ± 1.0 medications (p < 0.001). Both the collective and consistent cohorts demonstrated a trend towards decreasing surgical efficacy with time, in IOP reduction and decrease in medications. None of the eyes experienced sight-threatening complications.

CONCLUSIONS

Asian eyes with NTG undergoing combined phacoemulsification and iStent inject surgery demonstrated significant and sustained reduction in number of glaucoma medications up to 12 months post-operatively.

Three-Year Outcomes of Second-generation Trabecular Micro-bypass Stents (iStent inject) With Phacoemulsification in Various Glaucoma Subtypes and Severities

PRECIS

This longitudinal case series provides valuable long-term data on the safety and efficacy of iStent inject with concomitant cataract surgery. Patients experienced significant and durable reductions in both intraocular pressure (IOP) and medication burden through 3 years postoperative.

PURPOSE

The purpose of this study was to examine the 3-year effectiveness and safety of iStent inject second-generation trabecular micro-bypass stent implantation with concomitant phacoemulsification cataract surgery in eyes with various glaucoma subtypes and severities.

METHODS

This was a single-center consecutive case series. Three-year outcomes included mean IOP and medications, the proportions of eyes with IOP ≤18, ≤15, and ≤12 mm Hg, and success (absence of secondary glaucoma interventions). Safety included best-corrected visual acuity (BCVA), cup-to-disc ratio, visual field (VF) mean deviation, retinal nerve fiber layer (RNFL), and ganglion cell-inner plexiform layer (GCIPL) thickness, and adverse events.

RESULTS

A total of 124 eyes with different glaucoma subtypes and severities were included. At 3 years postoperative, mean IOP reduced from 16.90±3.85 mm Hg preoperatively to 13.17±2.83 mm Hg (22% reduction, P<0.001) and mean medication burden decreased from 2.38±1.29 medications preoperatively to 1.16±1.22 medications (51% reduction, P<0.001). At 3 years, 96% of eyes achieved IOP ≤18 mm Hg (vs. 69% preoperatively), 80% of eyes achieved IOP ≤15 mm Hg (vs. 40% preoperatively), and 42% of eyes achieved IOP ≤12 mm Hg (vs. 7% preoperatively) with 76% of eyes eliminating ≥1 medication and 37% of eyes eliminating ≥2 medications versus preoperative medication burden. The 3-year cumulative survival rate was 74%. Postphacoemulsification BCVA improvement was preserved, and cup-to-disc ratio, VF mean deviation, and RNFL and GCIPL thickness remained stable. A favorable safety profile included no intraoperative complications and few, transient, postoperative adverse events.

CONCLUSION

Significant and sustained IOP and medication reductions were achieved through 3 years after iStent inject implantation with cataract surgery in a real-world clinical population with mild-to-severe glaucoma, along with favorable safety including stable BCVA, VF, and RNFL and GCIPL thickness.

iStent versus iStent inject implantation combined with phacoemulsification in open angle glaucoma

Purpose

To compare the outcomes of iStent vs. iStent inject implantation combined with phacoemulsification.

Methods

This single center retrospective comparative case series included subjects with open angle glaucoma who underwent iStent or iStent inject implantation combined with phacoemulsification with ≥1 year follow-up. The main outcome measures were in-group and between-group changes in intraocular pressure (IOP) and medication number, proportion of eyes that achieved IOP ≤15 mmHg, and surgical success defined as 20% IOP reduction from baseline at 6/12 months. Univariate/multivariate regression analyses were done to identify predictors of surgical failure.

Results

One hundred ninety-seven eyes of 148 patients were included (122 iStent, 75 iStent inject). Both groups achieved significant IOP and medication reduction at months 6/12 (P < 0.05). At month 6, IOP was significantly lower in iStent inject vs. iStent eyes (P = 0.003), but the difference was insignificant by month 12 (P = 0.172). Medication number was comparable in both groups at months 6/12 (P > 0.05). More iStent inject eyes achieved IOP ≤15 mmHg at month 6 (P = 0.003) and 12 (P = 0.047). Surgical success was comparable in both groups at months 6/12 (P > 0.05). Kaplan-Meier survival analysis showed similar cumulative rate of surgical failure at year-1 in both groups (P = 0.644). The multivariate model identified older age (P = 0.017) and lower baseline IOP (P = 0.002) as the strongest predictors of surgical failure.

Conclusion

Compared to iStent, iStent inject achieved lower IOP at month 6 and higher proportion of eyes achieved IOP ≤15 mmHg at month 6/12. However, surgical success was similar in both groups. Predictors of surgical failure were older age and lower baseline IOP rather than the stent type.

iStent inject: comprehensive review

Microinvasive glaucoma surgeries (MIGSs) are new surgical procedures for treatment of glaucoma. They aim to safely and effectively reduce intraocular pressure (IOP) with minimal trauma to the eye and less complications. The first-generation iStent is the first approved ab interno MIGS implant for management of open-angle glaucoma. It works by allowing aqueous humor to drain directly from the anterior chamber into Schlemm canal bypassing the trabecular meshwork, the major site of outflow resistance. The second-generation iStent inject is the smallest available trabecular device that occupies less than 0.5 mm. It is designed to facilitate the surgical technique and allow simultaneous implantation of 2 stents, aiming for more IOP reduction. This review examines publications about the iStent inject, focusing on the device's efficacy, safety, and comparison with the first generation iStent. Both devices were found to be a safe and effective tool in management of open-angle glaucoma.

Exploiting biomaterial approaches to manufacture an artificial trabecular meshwork: A progress report

Glaucoma is the second leading cause of irreversible blindness worldwide. Glaucoma is a progressive optic neuropathy in which permanent loss of peripheral vision results from neurodegeneration in the optic nerve head. The trabecular meshwork is responsible for regulating intraocular pressure, which to date, is the only modifiable risk factor associated with the development of glaucoma. Lowering intraocular pressure reduces glaucoma progression and current surgical approaches for glaucoma attempt to reduce outflow resistance through the trabecular meshwork. Many surgical approaches use minimally invasive glaucoma surgeries (MIGS) to control glaucoma. In this progress report, biomaterials currently employed to treat glaucoma, such as MIGS, and the issues associated with them are described. The report also discusses innovative biofabrication approaches that aim to revolutionise glaucoma treatment through tissue engineering and regenerative medicine (TERM). At present, there are very few applications targeted towards TM engineering in vivo, with a great proportion of these biomaterial structures being developed for in vitro model use. This is a consequence of the many anatomical and physiological attributes that must be considered when designing a TERM device for microscopic tissues, such as the trabecular meshwork. Ongoing advancements in TERM research from multi-disciplinary teams should lead to the development of a state-of-the-art device to restore trabecular meshwork function and provide a bio-engineering solution to improve patient outcomes.

Influence of oral anticoagulation on success rates and risk of bleeding events after iStent inject implantation combined with phacoemulsification

Purpose

We conducted a retrospective study to evaluate the intraocular pressure (IOP) lowering effect, the success rates, and the risk of bleeding events of patients receiving an iStent inject combined with phacoemulsification under anticoagulation therapy compared with a matched control group.

Methods

In this retrospective study, sixty-four eyes underwent an iStent inject implantation combined with phacoemulsification at two centers. Thirty-two eyes received surgery while under anticoagulation therapy, and another thirty-two eyes served as a control group matched for visual acuity, IOP, and medication score. Success was defined as criteria A and B (IOP < 18/21 mmHg, > 20% IOP reduction, no resurgery) and criteria C (IOP ≤ 15 mmHg, IOP reduction ≥ 40%, no resurgery). The clinical goal of the study was to determine the difference between the study and control groups with respect to IOP, medication score, and the frequency of intraoperative and postoperative bleeding events.

Results

After a mean follow-up time of 1 year, the IOP lowered 28% from 20.1 ± 4.8 to 14.5 ± 3.7 mmHg in the group of 64 eyes. The medication score lowered 38% from 2.1 ± 1.1 to 1.3 ± 1.2. The two groups with and without anticoagulant agents did not significantly differ in postoperative IOP, medication score, success rates, or number of bleeding events.

Conclusion

We conclude that in cataract surgery combined with the iStent inject a discontinuation of anticoagulant agents might not be necessary. It might be a good option in glaucoma surgery when anticoagulation treatment should not be interrupted and the target pressure is not very low.

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.

Minimally Invasive Glaucoma Surgery: Where Is the Evidence?

PURPOSE

The last decade has witnessed an unprecedented growth in glaucoma treatment options through the introduction of minimally invasive glaucoma surgeries (MIGS). The aim of the present review is to provide an understanding of the currently available MIGS and to examine what data are currently available to guide treatment choice.

DESIGN

Meta-analysis and systematic review of randomized and non-randomized control trials.

METHODS

Out of 2567 articles identified, a total of 77 articles were retained for analysis, including 28 comparative studies and 12 randomized control trials. Overall, 7570 eyes were included. When data permitted, the weighted mean difference in intraocular pressure reduction was calculated for comparison purposes.

RESULTS

Weighted mean intraocular pressure reductions from all analyzed studies were: 15.3% (iStent), 29.1% (iStent inject), 36.2% (ab interno canaloplasty), 34.4% (Hydrus), 36.5% (gonioscopically-assisted transluminal trabeculotomy), 24.0% (trabectome), 25.1% (Kahook dual blade), 30.2% (Cypass), 38.8% (XEN), and 50.0% (Preserflo).

CONCLUSIONS

One of the advantages of the heterogenous range of available MIGS options is the chance to tailor therapy in an individualized manner. However, high-quality data are required to make this choice more than an educated guess. Overall, this review confirms the efficiency of assessed MIGS compared with standalone phacoemulsification, but it highlights that only few studies compare different MIGS techniques and even fewer assess MIGS against criterion standard treatments. Current evidence, while non-negligible, is mostly limited to heterogenous nonrandomized studies and uncontrolled retrospective comparisons, with few quality randomized control trials. We suggest that future research should be comparative and include relevant comparators, standardized to report key outcome features, long-term to assess sustainability and late complications, and ideally randomized.

One-Year Outcomes of Second-Generation Trabecular Micro-Bypass Stents (iStent Inject) Implantation with Cataract Surgery in Different Glaucoma Subtypes and Severities

PURPOSE

To assess the 1-year efficacy and safety of the implantation of two second-generation trabecular micro-bypass stents (iStent Inject®) with concomitant cataract surgery in various subtypes and severities of glaucoma.

METHODS

This single-surgeon, consecutive case series from a Canadian academic ophthalmology center included subjects with cataract, glaucoma, and the need to reduce intraocular pressure (IOP) and/or medications. The 12-month outcomes included mean IOP and medication burden as well as the proportions of eyes with IOP ≤ 18, ≤ 15, and ≤ 12 mmHg compared to baseline. Other measures included corrected distance visual acuity (CDVA), cup-to-disc ratio (CDR), visual field mean deviation (VF MD), retinal nerve fiber layer (RNFL) thickness, ganglion cell inner plexiform layer (GCIPL) thickness, and adverse events.

RESULTS

In 118 eyes, mean IOP reduced from 17.00 ± 3.82 mmHg preoperatively to 13.97 ± 2.65 mmHg at the 12-month follow-up mark (17.8% reduction, p < 0.001), and mean medication burden decreased from 2.31 ± 1.33 preoperatively to 1.03 ± 1.10 medications (56% reduction, p < 0.001). After 12 months, 93% of eyes achieved IOP ≤ 18 mmHg (versus 69% preoperatively), 70% of eyes achieved IOP ≤ 15 mmHg (versus 42% preoperatively), and 29% of eyes achieved IOP ≤ 12 mmHg (versus 7% preoperatively). For all eyes, topical medications were either maintained or decreased from baseline, with ≥ 1 medication eliminated from the preoperative regimen for 83% of eyes and ≥ 2 medications eliminated for 36% of eyes. Visual acuity improved significantly, consistent with expectations for cataract surgery, while CDR, VF MD, and RNFL and GCIPL thicknesses remained stable. Safety was favorable, with no intraoperative complications and few transient adverse events postoperatively.

CONCLUSION

iStent Inject implantation with cataract surgery safely reduced IOP and medication burden in a real-world clinical population with mild to severe glaucoma, and stabilized visual field, as well as RNFL and GCIPL thicknesses on OCT.

FUNDING

The Rapid Service Fees were funded by Glaukos Corporation.