Unmet Needs of Standalone Glaucoma Surgery
The MIGS treatment paradigm is evolving, and it is being rapidly adopted by providers.
In the era of interventional glaucoma, it is important for providers to intervene early in the disease state and select a procedure that would best serve them in the future.
“It behooves us to pursue a glaucoma intervention such as a standalone surgery as opposed to continuing or adding more drops,” explains Valerie Trubnik, MD, FACS, a glaucoma and laser cataract surgeon in practice in Manhasset, New York. “Patients, providers, and insurance carriers need to be made aware of the myriad limitations and side effects of conventional treatment with drops and open up the option for procedural intervention.”
However, several barriers are present. “We need to overcome the inertia we feel from insurance carriers as well as both patients and providers (comprehensive ophthalmologists and optometrists) on adopting this newer approach,” she explains noting that published studies and other media will help reach a broader audience.
A recent study1 showed that a large proportion of US patients that are undergoing cataract surgery have comorbid glaucoma, but not all of these patients are treated for their glaucoma at the time of cataract surgery. “We must utilize safe standalone procedures even after cataract surgery,” Dr Trubnik says.
While some minimally invasive standalone procedures are available for use such as goniotomy and canaloplasty, if a surgeon wants to potentially avoid adverse events such as a hyphema the options are limited. For example, the Hydrus (Alcon) is not approved for a standalone procedure and the iStent infinite (Glaukos) is FDA-cleared for use in both standalone and in combination with cataract surgery (for patients who have failed both medical and surgical therapy). “Our focus is to intervene earlier and stop progression, hence we must utilize this technology earlier,” she notes.
While glaucoma surgery has come a long way in the last decade, Jacob W. Brubaker, MD, a glaucoma specialist in practice in Sacramento, California, notes that several areas of standalone options are still needed. “A big unmet need is being able to treat patients that have exhausted their trabecular meshwork (TM) options, with a standalone option that is still ab interno and also a suprachoroidal option (potentially the iSTAR Medical’s MINIject™ Implant which is in clinical trials) is something that would be nice to have,” he says.
Standalone surgery also can be used in post cataract patients and post prior MIGS in some cases depending on what previous surgery was performed and the remaining anatomy. “If the TM is still intact in certain clock hours, implantation of a stent into Schlemm’s canal may still be possible. This opens more possibilities for treatment that may not have existed before,” Dr Trubnik says.
Identifying Patients
For success with standalone procedures, optimal patient selection is crucial. “These are patients who are on several drops,” she says, noting that both the physician and the patient should have realistic goals and expectations (for example, reducing the need for 1 or 2 drops).
The patient’s experience can be an indicator. “If we have patients that are struggling to take the drops and/or progressing on the current therapy pre- or post-cataract surgery, they are good candidates for a standalone procedure. Good initial candidates may be patients who have failed selective laser trabeculoplasty (SLT) and/or DURYSTA (bimatoprost intracameral implant, Allergan/Abbvie) and are looking to stay off the drops,” she says.
Dr Brubaker explains that as patients come into clinic there are several areas in which standalone may be a good option. “Typically, you are treating the patient with some degree of medications. Opening up the possibility of doing a standalone procedure comes down to either elevated eye pressure in spite of the medical therapy or intolerance to eye drops. If you are seeing someone who is not tolerating their medication, or their eye pressure is high, despite their medications, now you really have to move on to surgical procedure.”
Patients who don’t yet have a cataract or who already had cataract surgery do not have another option except to do a standalone procedure. “If a patient is not tolerating their medications and their pressure is just a little bit high that is a great opportunity to do an iStent infinite,” Dr Brubaker explains.
iStent infinite Pivotal Trial
The prospective, multicenter, single-arm, open-label clinical trial2 showed that the iStent infinite standalone surgery achieved clinically significant intraocular pressure (IOP) reduction and favorable safety in patients with OAG uncontrolled by prior surgical and medical therapy. For the study, 72 patients (72 eyes) with preoperative mean medicated mean diurnal IOP (MDIOP) of 23.4±2.8 mm Hg on a mean of 3.1±0.9 IOP-lowering medication classes were enrolled, with 61 eyes with failed prior surgery(ies) (Failed-Surgery subgroup) and 11 eyes uncontrolled on maximum tolerated medical therapy (MTMT subgroup).
Of all enrolled patients, 76.1% met the responder endpoint (73.4% Failed-Surgery, 90.9% MTMT), with mean reduction (SE) in MDIOP at month 12 of 5.9(0.6) mm Hg [5.5(0.7) mm Hg Failed-Surgery subgroup, 8.1(0.9) mm Hg MTMT subgroup]. For patients on the same or fewer medication(s) as baseline, 53.0% achieved ≥30% MDIOP reduction without surgical interventions/other events.
Real World Experience
Dr Brubaker discusses the iStent infinite with appropriate candidates and explains that this is a less invasive option. “I tell them all we are doing is a small incision and putting these 3 micro stents in your eye which is designed to help lower their eye pressure,” he says. He also shares that if it is unsuccessful, it will be time to move on to a more invasive surgery.
Dr Trubnik has used the standalone iStent infinite in patients with refractory glaucoma. “Patients tolerate the procedure exceptionally well with almost immediate visual recovery. In the patients that I have done, their IOP was lowered to target, and I was able to stave off the need for an incisional surgery,” she says.
Future Outlook
Additional research evidence is essential for more widespread acceptance of the use of standalone surgeries earlier in the process. “We need to start thinking and acting like interventional cardiologists,” says Dr Trubnik. “When there is a blockage of the coronary artery, they do not attempt to treat the condition solely with medications, they get to the crux of the problem by dilating the vessels and placing a drug eluting stent. As ophthalmologists, we also need to restore physiologic outflow and bypass the area of limited flow. Standalone procedures need to be the standard of care. We no longer question the need for coronary stents, why should it be any different when it comes to the eye?”
Dr Brubaker concurs that more studies will provide the data needed to further support this approach. “The iDose TR trial should be a pivotal study in swaying the pendulum more toward earlier intervention. We saw this with The Laser in Glaucoma and Ocular Hypertension (LiGHT) Trial3 with SLT that as we get the data, as we have that proof, that is what really sways adoptions of therapy. If we can get that same data on the MIGS standalone procedures that will start to sway practice patterns and insurance coverage to the point that we can start to treat these patients earlier in the disease.”
References
- Radcliffe N. The case for standalone micro-invasive glaucoma surgery: rethinking the role of surgery in the glaucoma treatment paradigm. Curr Opin Ophthalmol. 2023;34(2):138-145. doi:10.1097/ICU.0000000000000927
- Sarkisian SR Jr, Grover DS, Gallardo MJ, et al; iStent infinite Study Group. Effectiveness and safety of iStent Infinite Trabecular Micro-Bypass for Uncontrolled Glaucoma. J Glaucoma. 2023;32(1):9-18. doi:10.1097/IJG.0000000000002141
- Gazzard G, Konstantakopoulou E, Garway-Heath D, et al; The LiGHT trial group. Laser in Glaucoma and Ocular Hypertension (LiGHT) Trial: Six-year results of primary selective laser trabeculoplasty versus eye drops for the treatment of glaucoma and ocular hypertension. Ophthalmology. 2023;130(2):P139-151. doi:10.1016/j.ophtha.2022.09.009
