Randomized Evaluation of the Trabecular Micro-Bypass Stent with Phacoemulsification in Patients with Glaucoma and Cataract

doi:10.1016/j.ophtha.2010.07.007

Ophthalmology

Volume 118, Issue 3, March 2011, Pages 459-467

Presented at: the American Academy of Ophthalmology 2009 Annual meeting, October 2009, San Francisco, California; and in part at the American Society of Cataract and Refractive Surgery 2010 Annual Meeting, April 2010, Boston, Massachusetts.

https://doi.org/10.1016/j.ophtha.2010.07.007 Get rights and content

Objective

To assess the safety and efficacy of the iStent trabecular micro-bypass stent (Glaukos Corporation, Laguna Hills, CA) in combination with cataract surgery in subjects with mild to moderate open-angle glaucoma.

Design

Prospective, randomized, open-label, controlled, multicenter clinical trial.

Participants

A total of 240 eyes with mild to moderate open-angle glaucoma with intraocular pressure (IOP) ≤24 mmHg controlled on 1 to 3 medications were randomized to undergo cataract surgery with iStent implantation (treatment group) or cataract surgery only (control). Fifty additional subjects were enrolled to undergo cataract surgery with iStent implantation under protocol expansion. Data in this report are based on the first 240 eyes enrolled.

Intervention

Implantation of the iStent trabecular micro-bypass stent in conjunction with cataract surgery or cataract surgery only.

Main Outcome Measures

The primary efficacy measure was unmedicated IOP ≤21 mmHg at 1 year. A secondary measure was unmedicated IOP reduction ≥20% at 1 year. Safety measures included best-corrected visual acuity (BCVA), slit-lamp observations, complications, and adverse events.

Results

The study met the primary outcome, with 72% of treatment eyes versus 50% of control eyes achieving the criterion (P<0.001). At 1 year, IOP in both treatment groups was statistically significantly lower from baseline values. Sixty-six percent of treatment eyes versus 48% of control eyes achieved ≥20% IOP reduction without medication (P = 0.003). The overall incidence of adverse events was similar between groups with no unanticipated adverse device effects.

Conclusions

Pressure reduction on fewer medications was clinically and statistically significantly better 1 year after stent plus cataract surgery versus cataract surgery alone, with an overall safety profile similar to that of cataract surgery alone.

Financial Disclosure(s)

Proprietary or commercial disclosure may be found after the references.

Section snippets

Study Design

This was a prospective, randomized, open-label, multicenter, controlled US Investigational Device Exemption clinical trial conducted at 29 US investigational sites (see Appendix 1, available at http://aaojournal.org). Patients were randomized into 1 of 2 treatment groups: stent implantation in conjunction with cataract surgery (treatment group) or cataract surgery alone (control group). We report the first year of follow-up on all randomized patients. The study protocol was approved by the

Enrollment and Disposition

Enrolled in the randomized phase of the study between April 2005 and June 2007 were 240 eyes, which constituted the ITT population. No site enrolled more than 15% of subjects, and 10 sites enrolled 10 or more subjects. Of the 117 randomized to iStent implantation in conjunction with cataract surgery, 111 of these underwent cataract surgery with stent implantation. In the remaining 6 subjects randomized to the treatment group, a stent was not implanted because of complications of cataract

Discussion

The iStent has been shown to improve aqueous outflow by means of a patent channel created through the trabecular meshwork into Schlemm's canal via ab-interno placement of the device. The ocular hypotensive efficacy seen with the stent in this study is consistent with the trabecular bypass mechanism of action and results described in previous work.31, 32, 33, 34 Reduction in IOP and medications was shown in earlier trials involving iStent implantation only or iStent implantation in conjunction

Acknowledgments

The authors acknowledge Gary D. Novack, PhD, for medical writing.

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Trabecular Procedures Combined with Cataract Surgery for Open-Angle Glaucoma: A Report by the American Academy of Ophthalmology
2024, Ophthalmology
To determine the intraocular pressure (IOP) reduction of various trabecular procedures (a form of minimally invasive glaucoma surgery [MIGS]) combined with cataract surgery compared with cataract surgery alone, to compare the safety of the various trabecular procedures, and to highlight patient characteristics that may favor one trabecular procedure over another.
A search of English-language peer-reviewed literature in the PubMed database was initially conducted in February 2021 and updated in April 2023. This yielded 279 articles. Twenty studies met initial inclusion and exclusion criteria and were assessed for quality by the panel methodologist. Of these, 10 were rated level I, 3 were rated level II, and 7 were rated level III. Only the 10 level I randomized controlled trials (RCTs) were included in this assessment, and all were subject to potential industry-sponsorship bias.
The current analysis focuses on the amount of IOP reduction (in studies that involved medication washout) and on IOP reduction with concurrent medication reduction (in studies that did not involve medication washout). Based on studies that performed a medication washout, adding a trabecular procedure to cataract surgery provided an additional 1.6 to 2.3 mmHg IOP reduction in subjects with hypertensive, mild to moderate open-angle glaucoma (OAG) at 2 years over cataract surgery alone, which itself provided approximately 5.4 to 7.6 mmHg IOP reduction. In other words, adding a trabecular procedure provided an additional 3.8% to 8.9% IOP reduction over cataract surgery alone, which itself provided 21% to 28% IOP reduction. There was no clear benefit of one trabecular procedure over another. Patient-specific considerations that can guide procedure selection include uveitis predisposition, bleeding risk, metal allergy, and narrowing of Schlemm’s canal. There are no level I data on the efficacy of trabecular procedures in subjects with pretreatment IOP of 21 mmHg or less.
Trabecular procedures combined with cataract surgery provide an additional mild IOP reduction over cataract surgery alone in hypertensive OAG subjects. Additional research should standardize outcome definitions, avoid industry sponsorship bias, and study the efficacy of these procedures in normotensive OAG.
Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.
Prospective, Randomized Controlled Trial of Cataract Surgery vs Combined Cataract Surgery With Insertion of iStent Inject
2024, Ophthalmology Glaucoma
To evaluate the efficacy and safety of combined cataract surgery with insertion of an ab interno trabecular microbypass device (iStent Inject, Glaukos Corporation) compared to cataract surgery alone in patients with mild-to-moderate glaucoma.
Prospective, randomized, assessor-masked controlled trial at a single centre.
Eyes with visually-significant cataract and mild-to-moderate glaucoma with preoperative intraocular pressure (IOP) of 12 to 30 mmHg on 0 to 3 ocular hypotensive medications.
Participants eyes were randomized (2017–2020) 1:1 to combined cataract surgery with iStent Inject (treatment group, n = 56) or cataract surgery alone (control group, n = 48), and followed up for 2 years.
The co-primary effectiveness endpoints were the number of ocular hypotensive medications and IOP at 24-months post-surgery. The secondary effectiveness endpoints were ocular comfort as measured by the Ocular Surface Disease Index (OSDI) and vision-related quality of life as measured by the Glaucoma Activity Limitation Questionnaire (GAL-9) at 24-months. Safety measures included postoperative visual acuity, any unplanned return to the operating theatre, adverse events, and complications.
Participants (67.3% male) were aged 53 to 85 years, and treatment groups were similar in terms of mean medicated IOP (treatment group 17.7 mmHg ± 4.0; control group 17.1 mmHg ± 3.1), and number of ocular hypotensive medications (treatment group 1.69 ± 1.05; control group 1.80 ± 1.22) at baseline. At 24 months, the number of ocular hypotensive medications were 0.7 ± 0.9 in the treatment groups compared to 1.5 ± 1.9 in the control group, with an adjusted difference of 0.6 fewer medications per eye in the treatment group (95% CI 0.2–1.1, P = 0.008). In the treatment group, 57% of eyes were on no glaucoma medications compared to 36% in the control group. There was no significant difference in IOP between the 2 groups beyond the 4-weeks. There were no differences in patient-reported outcomes between the 2 groups. The visual outcomes and safety profiles were similar between the 2 groups.
Combined cataract surgery with iStent Inject achieved a clinically- and statistically-significantly greater reduction in ocular hypotensive medication usage at 24-months compared to cataract surgery alone, with no significant difference in IOP.
Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.
Effect of Preoperative Trabecular Meshwork Pigmentation and Other Eye Characteristics on Outcomes of Combined Phacoemulsification/Minimally Invasive Glaucoma Surgery
2024, Ophthalmology Glaucoma
To investigate associations between pigmentation of the trabecular meshwork (PTM) and other preoperative eye characteristics and outcomes of minimally invasive glaucoma surgery combined with phacoemulsification (Phaco/MIGS).
Retrospective interventional case series.
Academic glaucoma clinic patients with symptomatic cataract and glaucoma treated with combined Phaco/MIGS.
Analyzing preoperative PTM, intraocular pressure (IOP), IOP-lowering medications and visual acuity (VA) data in relation to Phaco/MIGS outcomes.
Pigmentation of the trabecular meshwork and other preoperative eye characteristics in relation to Phaco/MIGS success defined as postoperative IOP between 5 and 21 mmHg and IOP reduction of ≥ 20% and/or a reduction of ≥ 1 IOP-medications compared to baseline, and final IOP, IOP-lowering medications and VA.
A total of 265 eyes (172 patients, mean age, 73.5 [standard deviation, 10.0], range 35–95 years, male 40.0%) were identified and categorized with high PTM (108 eyes, 40.8%) or low PTM (157 eyes, 59.2%). The high PTM group, compared with the low PTM group, demonstrated higher preoperative IOP (16.7 [standard error 0.4] vs. 15.2 [0.4] mmHg, P = 0.009), included more eyes with primary open-angle glaucoma (POAG, P = 0.03), fewer eyes with normal-tension glaucoma (NTG, P = 0.01), and fewer eyes with mild stage glaucoma (P = 0.001). Compared to baseline, final IOP decreased by 6.5 [2.4]% and 13.4 [3.0]% (P = 0.075) to 13.5 [0.3] mmHg and 13.6 [0.4] mmHg (P = 0.77) in the low and high PTM groups, respectively, and IOP-lowering medications decreased by 34.6 [4.9]% (n = 116) and 18.1 [7.3]% (n = 85), respectively (P = 0.062). Surgical success was 59.9% and 58.3%, respectively (P = 0.87). It was positively associated with higher preoperative IOP (hazard ratio 1.08 [95% confidence interval 1.04–1.12] P < 0.0001) and higher number of preoperative IOP-medications (1.20 [1.05–1.37] P = 0.007), negatively associated with history of selective laser trabeculoplasty (SLT, 0.40 [0.23–0.68] P = 0.0009) and longer axial length (0.87 [0.80–0.94], P = 0.0006), but was not associated with PTM.
Higher PTM was associated with POAG rather than NTG, with more severe glaucoma and higher preoperative IOP, but not with Phaco/MIGS success. Surgical success was positively associated with higher preoperative IOP and number of IOP-medications and negatively associated with history of SLT and longer axial length. These findings may help guide glaucoma surgeons in surgical planning and patient counseling.
The author(s) have no proprietary or commercial interest in any materials discussed in this article.
Intraoperative iStent versus postoperative selective laser trabeculoplasty in early glaucoma patients undergoing cataract surgery: A retrospective comparative study
2024, Journal Francais d'Ophtalmologie
To compare the efficacy and safety of iStent inject® versus 360° selective laser trabeculoplasty (SLT) in patients with early glaucoma undergoing cataract surgery.
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.
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.
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.
Comparer l’efficacité et la sécurité de l’iStent inject® par rapport à la trabéculoplastie sélective au laser sur 360° (SLT) chez des patients atteints de glaucome léger et opérés de la cataracte.
Une étude rétrospective non randomisée a été menée sur 73 yeux répartis en deux groupes : chirurgie de la cataracte + iStent peropératoire (n = 40) versus chirurgie de la cataracte + SLT postopératoire à un mois (n = 33). Le critère d’évaluation principal était une baisse de la pression intraoculaire (PIO) ≥ 20 % entre l’état préopératoire et 6 mois après la chirurgie. Les critères d’évaluation secondaires étaient une baisse de la PIO à 1, 6 et 12 mois, et le nombre moyen de médicaments hypotonisants à 6 et 12 mois postopératoires.
La PIO moyenne initiale était de 19,1 mmHg sans différence significative entre les deux groupes. Le nombre moyen de médicaments hypotonisants était plus élevé dans le groupe iStent (n = 1,95) que dans le groupe SLT (n = 1,53 ; p = 0,04). À 6 mois, 18 (60 %) patients du groupe SLT et 20 (51 %) patients du groupe iStent ont obtenu une baisse de la PIO ≥ 20 % sans différence significative entre les deux groupes (p = 0,431). À 6 mois, aucune différence dans le nombre moyen de médicaments hypotonisants n’a été constatée entre les deux groupes (–0,92 et –0,89 dans les groupes iStent et SLT, respectivement). Des résultats similaires ont été constatés à 12 mois.
Nos résultats suggèrent une sécurité et une efficacité similaires entre l’iStent peropératoire et la SLT 360° postopératoire pour abaisser la PIO et réduire les collyres hypotonisants chez des patients atteints de glaucome léger et opérés de la cataracte. Le choix du traitement doit être fondé sur l’expérience de l’ophtalmologiste et sur la balance coût-bénéfice.
Review by the French Glaucoma Society on the roles of new surgical techniques in glaucoma
2023, Journal Francais d'Ophtalmologie
La prise en charge chirurgicale du glaucome a été enrichie depuis quelques années par l’arrivée de nouvelles techniques chirurgicales regroupées sous le nom de chirurgies mini-invasives du glaucome (minimally invasive glaucoma surgery [MIGS]). L’objectif de ces nouvelles techniques est de réduire la pression intraoculaire (PIO) tout en limitant les risques de complications liées à la réalisation d’une chirurgie filtrante classique et en permettant une récupération visuelle plus rapide. Les MIGS peuvent être classées en trois grandes catégories en fonction de la voie utilisée afin de favoriser l’écoulement de l’humeur aqueuse : la voie trabéculaire, la voie supra-choroïdienne et la voie sous-conjonctivale. Les MIGS utilisant la voie sous-conjonctivale sont également appelées MIBS pour minimally invasive bleb surgery. Ces nouvelles techniques ne remplacent pas la chirurgie filtrante classique qui reste la technique de référence mais offrent aujourd’hui de nouvelles alternatives pour la prise en charge chirurgicale des patients glaucomateux en association ou non à la chirurgie de la cataracte.
The surgical management of glaucoma has been enriched in recent years by the arrival of new surgical techniques as a group known as MIGS (minimally invasive glaucoma surgery). The objective of these new techniques is to reduce intraocular pressure (IOP) while limiting the risk of complications of conventional filtering surgery and allowing faster visual recovery. MIGS can be classified into three main categories depending on the route used to promote the outflow of aqueous humor: the trabecular route, the suprachoroidal route and the subconjunctival route. MIGS using the subconjunctival route are also called minimally invasive bleb surgery (MIBS). These new techniques do not replace conventional filtering surgery, which remains the gold standard technique, but now offer new alternatives for the surgical management of glaucoma patients in combination with cataract surgery or as stand-alone procedures.
Minimally Invasive Glaucoma Surgery: Latest Developments and Future Challenges
2023, Asia-Pacific Journal of Ophthalmology
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.

View all citing articles on Scopus

: Manuscript no. 2009-1734.

: Financial Disclosure(s): The author(s) have made the following disclosure(s): TWS: C, O to Glaukos, and C to Alcon, Allergan, AMO, AqueSys, iScience, Ivantis, Pfizer, QLT, and Santen. LJK: C, O to Glaukos, C to Allergan, Alcon, Pfizer, and Lumenis; JW: E, O to Glaukos; Y-JD: C, O to Glaukos and C to Ivantis; JEG: E, O to Glaukos. All the investigators were consultants to Glaukos for the conduct of this study. In addition, Drs. Bacharach, Buznego, Cantor, and Nichamin are equity owners of Glaukos.

: Funding: Glaukos Corp.

: This study was registered with clinicaltrials.gov as NCT00323284.

^⁎: Group members listed online in Appendix 1 (available at http://aaojournal.org).

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Original articleRandomized Evaluation of the Trabecular Micro-Bypass Stent with Phacoemulsification in Patients with Glaucoma and Cataract

Objective

Design

Participants

Intervention

Main Outcome Measures

Results

Conclusions

Financial Disclosure(s)

Section snippets

Study Design

Enrollment and Disposition

Discussion

Acknowledgments

Ophthalmology

Am J Ophthalmol

Can J Ophthalmol

Am J Ophthalmol

Ophthalmology

Am J Ophthalmol

J Cataract Refract Surg

J Cataract Refract Surg

J Cataract Refract Surg

J Cataract Refract Surg

Am J Ophthalmol

Am J Ophthalmol

J Cataract Refract Surg

Ophthalmology

Ophthalmology

Ophthalmology

J Cataract Refract Surg

J Cataract Refract Surg

Prevalence of open-angle glaucoma among adults in the United States

Arch Ophthalmol

The number of people with glaucoma worldwide in 2010 and 2020

Br J Ophthalmol

Global data on visual impairment in the year 2002

Bull World Health Organ

Ocular Hypertension Treatment Study Group: The Ocular Hypertension Treatment Study: a randomized trial determines that topical ocular hypotensive medication delays or prevents the onset of primary open-angle glaucoma

Arch Ophthalmol

The Glaucoma Laser Trial (GLT) and Glaucoma Laser Trial Follow-Up Study: 7. Results

Am J Ophthalmol

Original article
Randomized Evaluation of the Trabecular Micro-Bypass Stent with Phacoemulsification in Patients with Glaucoma and Cataract