Glaukos’s iStent infinite Trabecular Micro-Bypass System is the first FDA-cleared microinvasive implantable device that can be used in combination with cataract surgery or as a standalone treatment option for glaucoma patients not undergoing concomitant cataract surgery. Manjool Shah, MD, associate professor of ophthalmology and program director of the glaucoma fellowship at New York University Langone Health in New York City, has used the iStent infinite for some of his glaucoma patients because, compared to its predecessor, it has the ability to target more of the outflow system; it has improved ergonomics, injector design, and delivery system; and it can be used for standalone microstenting.
The iStent infinite includes 3 titanium stents preloaded into an autoinjection system that allows surgeons to inject stents across a span of up to approximately 8 clock hours around Schlemm’s canal. The stents are designed to lower intraocular pressure (IOP) by restoring the natural physiologic outflow of aqueous humor. It has a similar mechanism of action to its predecessor, Glaukos’s 2-stent iStent inject W Trabecular Micro-Bypass System.
“Physicians now have the opportunity to treat patients with glaucoma before using more invasive procedures,” says Jay Katz, MD, FACS, chief medical officer of Glaukos in Aliso Viejo, California. “While using minimally invasive glaucoma surgery procedures in situations where patients also have cataracts has been hugely advantageous, it has limited patients with glaucoma to just 1 opportunity for this microinvasive intervention. A standalone trabecular bypass option gives many more patients the chance for a microinvasive treatment option before the potential need for a more invasive, higher risk incisional surgery,” he adds. Many countries outside of the United States have had a standalone option for years.
“By targeting a broad area of the conventional outflow system through microstents, we can potentially achieve profound intraocular pressure reduction and stabilization with a concomitant reduction in medication dependency,” Dr. Shah says.
How It Works
The iStent infinite has a completely redesigned injector system that is intended to provide smooth stent deployment with an unlimited number of delivery attempts. “This gives surgeons the ability to be confident in optimal placement,” Dr. Shah says.
It also has an autoretracting introducer tip designed for seamless entry through a corneal incision and provides protection against viscoelastic egress during implantation. This helps maintain a stable anterior chamber, allowing a larger space for the safe, precise insertion of iStent infinite, Dr. Katz says. In addition, the handpiece has an 8° angled insertion tube designed to minimize incision interference and provide greater access to deliver stents widely. A sleeve around the injector provides a stable anterior chamber during stent insertion, which facilitates visualization.
iStent infinite can deliver continuous long-term IOP control in patients with glaucoma who have failed prior medical and surgical intervention.1 It offers an intermediate alternative to more invasive procedures and minimizes complications and follow-up.1,2
Looking Ahead
The iStent infinite isn’t indicated for any specific stage of glaucoma. Traditionally, trabecular meshwork–based microstents have been used in mild to moderate open-angle glaucoma. However, the iStent infinite FDA Investigational Device Exemption study3 demonstrated efficacy in patients with higher disease burden and more complex prior surgical histories, Dr. Shah says. This indicates an opportunity to implement canal-based microstenting beyond the traditional stent patient.
“One could make the argument that the iStent infinite can play a role relatively early on in the disease journey, when distal outflow has not completely atrophied and improved conventional outflow can have disease-modifying effects,” Dr. Shah says. “One can also make the argument for its use later in the disease process, again as demonstrated by clinical trial data.3 We can move beyond disease severity and instead focus on patients’ goals, such as intraocular pressure stabilization, medication reduction, and delaying onset of medication initiation or stacking additional medications.” GP
References
2. Baker ND, Barnebey HS, Moster MR, et al. Ab externo microshunt versus trabeculectomy in primary open-angle glaucoma: 1-year results from a 2-year randomized, multicenter study. Ophthalmology. 2021;128(12):1710-1721. doi:10.1016/j.ophtha.2021.05.023
3. Sarkisian SR Jr, Grover DS, Gallardo MJ, et al. Effectiveness and safety of iStent infinite trabecular micro-bypass for uncontrolled glaucoma. J Glaucoma. 2023;32(1):9-18. doi:10.1097/IJG.0000000000002141
