Drs. Blake Williamson and Christy Benson Talk Standalone MIGS, Including Clinical Data, Real-World Outcomes, and Future Implications for Glaucoma

Blake Williamson, MD, MPHS, MS and Christy Benson, MD provide valuable insights into the evolving landscape of glaucoma treatment, particularly the role of standalone MIGS in enhancing patient care and surgical outcomes.

Hey everybody, and welcome to this podcast. We’re talking about iStent infinite in a standalone procedure setting, and I’m very happy to have a guest on today, Dr Christy Benson. Christy, how are you doing?

Christy Benson, MD:

Good. I’m doing great.

Blake Williamson, MD, MPH, MS:

I thought maybe we’d just start by  introducing yourself; talk about where you practice and what your practice is like, just for all the listeners.

Christy Benson, MD:

Sure. My name is Christy Benson. I practice in Des Moines, Iowa. I practice at a community hospital, which would be considered a safety net hospital. So I treat a lot of glaucoma and I see patients of all nationalities from all over the world. And again, lots of glaucoma.

Blake Williamson, MD, MPH, MS:

And I’m Dr. Blake Williamson, for those I haven’t met, and I mostly specialize in refractive and cataract surgery here in Baton Rouge, Louisiana. But I do a lot of cataract surgery, so as a result of that, I’m doing a lot of MIGS. And now we have standalone MIGS too, so I’m doing even more. So we’re going to be talking about that.

So really the development of microinvasive glaucoma surgery revolutionized the treatment of glaucoma by addressing the unmet need for a procedure for patients with mild to moderate glaucoma who would benefit from early surgical management. Now MIGS has evolved with the introduction of a standalone implantable device, the iStent infinite by Glaukos. And so I thought maybe what we could do, Dr Benson, is begin our discussion on how standalone MIGS meets that unmet need in treating glaucoma. How does it provide a better option in glaucoma management?

Christy Benson, MD:

I’ve been in practice for about 9 years now, outside of residency, and until the iStent infinite came along, there were a lot of patients who would come to me and their pressures weren’t at goal, not sure if they’re taking their drops or not, they’re either having side effects and I’ve done as many SLTs as I could. And if I’ve already done their cataract surgery and/or put a stent in, I was kind of out of options and would have to send these patients out for either a tube or a trab. But again, a lot of these patients, are setting them up for a surgery that has a high complication profile.

So now I have this ability that I can offer this standalone procedure for patients who’ve already had their cataracts taken out, who’ve already maxed out what I can do with topical meds, and now I’m able to offer a very minimally invasive surgery that can lower their eye pressure in a safe and effective way. So it’s been kind of a game changer for me. So I’ve been doing the standalone iStent infinite since about October of 2022, and just trying to think back to what things were like before I had that option, it was referring these patients out to the glaucoma practices for either tube or trab, and now I can offer this option and it’s fantastic, in my opinion.

Blake Williamson, MD, MPH, MS:

Yeah, I think my experience mirrors yours. I assume you’re not glaucoma fellowship trained, right?

Christy Benson, MD:

Nope. I’m a comprehensive ophthalmologist, and so I don’t feel comfortable doing tubes or trabs anymore because I stopped doing them when I got out of residency. And so I wasn’t able to manage those patients after I’d maxed out the SLTs and the iStent at the time of cataract surgery. And then I didn’t have any other good options after that.

Blake Williamson, MD, MPH, MS:

Yeah, same. It seems like if you drive through Baton Rouge, you get your cataract taken out. So many of my patients were already pseudophakic, right. And as a result of that, it’s like, “All right, well we have other options.” There’s some stripping procedures and that type of thing, but then you’re removing the trabecular meshwork, and you might need that for other things like drug elution and that type of thing? Or maybe you’re someone who really believes in leaving the anatomy as intact as possible. And so for all those reasons, I think that a stenting standalone procedure has been welcomed. And as a result, hopefully we’re buying people time before they need a more invasive incisional procedure, if ever, right?

Christy Benson, MD:

Yeah. I’ve had a lot of patients recently that are in the mid to late eighties range, and they had their cataracts taken out maybe 20 years ago when they didn’t have any stents, and maybe they didn’t even have glaucoma back then. And I have that 80 into the nineties range; a lot of them can’t get drops in throughout the day due to memory issues, maybe they’ve got arthritis. And so to have that as an option for the pseudophakic patients in a safe procedure is really a godsend to be able to offer that.

Blake Williamson, MD, MPH, MS:

Yeah, totally. And so really I think that the unbundling of this from cataract surgery, the fact that you can do it without it has been huge. And maybe talk a little bit about your outcomes, your clinical outcomes. How have they changed for the better over time? I feel like when iStent first came out, you and I came out really at the exact same time, and so first generations of iStent could be difficult to get in for some people, and they kind of left it. And I feel like now that the learning curve has become shorter and shorter and with the infinite, the fact that we’ve been in this space for so long and we’re more comfortable in the angle, I feel like maybe my outcomes are better. I don’t know about you.

Christy Benson, MD:

Yeah, I definitely can mirror that. I remember struggling with that first generation stent. You had to backhand, remember, the snorkel, and sometimes the angle of what you had to do, the backhand maneuver to get that in was challenging. But I remember I knew it was important, so I kept trying to work at it and get better and better. And then when they came out with the second generation, iStent inject, that was much easier. And then when they came out with iStent inject W, that was even easier yet. And then now with the infinite, I think they’ve made some design modifications, now they have that silicone sleeve, and so you don’t get the anterior chamber shallowing. I also believe that the trocar is a little bit shorter, and so there is a little more stability when you’re implanting it.

And so yeah, I feel the same way, that the outcomes are better because we’re getting better with that space and we’re getting better with positioning. Because half the battle is getting the patient positioned properly and getting your good visualization. And so the more that you work in that space, the better that you get.

And then I also think Glaukos has done their due diligence by keeping modifying the design of their device to make it just that much easier to get it in the right space and position and to have that stability. So I think it goes both sides. I think we’re getting better, but I also think Glaukos keeps modifying and improving their devices.

Blake Williamson, MD, MPH, MS:

Yeah, and I think that’s reflected in the literature as well. When we reviewed the clinical data associated with standalone MIGS, the devices achieved better results than most surgeons really anticipated. For example, in a prospective multi-center 12-month pivotal that studied the iStent infinite, the results were really impressive, especially in those patients with open angle glaucoma who had failed prior surgical intervention.

So maybe let’s discuss a little bit about that pivotal study. Are there any numbers or data points that jumped out at you when looking over that pivotal trial?

Christy Benson, MD:

I just know with the pivotal trial, these were really sick eyes that they were dealing with. A lot of them had failed, I think two procedures. I can’t remember the exact amount. I think a lot of them were on two to three meds. Again, these were not the standard eyes that were in a lot of other mixed trials, and I know that the outcomes were also really phenomenal. And I would just say that I’ve done my own retrospective analysis of the first year of my early stents, and I’ve had similar results with my own patients.

Blake Williamson, MD, MPH, MS:

Yeah. I think you’re exactly right. Patients enrolled in that study had a significantly higher preoperative treatment burden. Some of the stats that I don’t have memorized but that I have jotted down to discuss that I think are important to mention is just some of the average patient characteristics in that pivotal trial. 73% of patients had greater than 20% reduction in IOP. 47% had greater than 30% reduction in IOP, which is pretty amazing—and 91% of patients in the failed prior surgery group reduced or maintained medications at 12 months. So about 16 was the mean diurnal IOP in patients who did not have an IOP-related SSI corresponding to a mean reduction of about six millimeters of mercury. So really sustained efficacy throughout the course of the study. Exceptional intraoperative and postoperative safety was demonstrated even among patients who had failed filtering surgeries.

So only about 4% of eyes required secondary surgical interventions through that standalone MIGS group through 12 months. And most of all, the safety rang through. There was zero cases of hypotony, zero explants, zero cyclodialysis clefts. And so to me, I think that speaks to not only the efficacy, but the safety.

So really, maybe talk to me about what point in your treatment protocol do you move on from topical meds to a more invasive ‘surgical procedure’? So would you consider a standalone MIGS procedure before proceeding to a more invasive procedure? Why or why not?

Christy Benson, MD:

So every patient is a little bit different. I really like to get to know my patients and what their struggles are. I want to get a sense of are they taking their drops? Do they have dementia? Are they having difficulties remembering to get the drops in? Do they have arthritis? Sometimes I’ll actually have the patients show me putting the drops in. And if you’ve ever asked your patient that question, you’ll be surprised to actually watch them, and maybe they’re not getting any of the drops that they think they’re getting in their eye. You’re watching them do it and you have these physical limitations and challenges. And then I like to keep a close log of what drops they’ve been on, what reactions they’ve had, if any, and to get a good gestalt of my patient when they’re coming into the chair, noting maybe we’ve done SLT once or twice. Did they have a stent when they had their cataract surgery?

And so just getting a good gestalt of my patient, of are they progressing? Are they able to get the drops in? Are they having side effects? And now with the infinite, and if they are meeting any of those criteria of, “Hey, they’re not getting their drops in,” “Hey, they’re having all these side effects,” I’m very confident in recommending the infinite as a standalone procedure if they’ve already failed SLT, or maybe they failed a first generation stent that I implanted eight years ago.

I usually like to be pretty aggressive with my glaucoma patients because I never know what’s coming around the corner with either their health or maybe they’re going to get a visual field defect. And so if I’m noticing signs of progression and I’m getting concerned about compliance or side effects, then I know that I have to do something different. And now the infinite is what I offer, and I’m pretty confident going through the discussion and talking about the safety profile, talking about the statistics.

I also would say that success for an operation like that looks different for each patient. Some of them it’s preventing progression. Some of them it’s getting off a drop. So I guess every patient is slightly different and every goal is different as well, and I think that’s what makes glaucoma a unique disease to treat. There’s not a one size fits all, and every patient has a different goal. There’s so many factors that go into the treatment and the management.

Blake Williamson, MD, MPH, MS:

Yeah. To me, I think it gives me peace of mind. It’s kind of a low bar to meet versus my ICL patients or my custom lens replacement patients who are paying a lot of money for a refractive result where they have to get out of glasses. Any little halo or glare, you’re hearing about it. And so it’s like how do you define success in a MIGS procedure? People always talk about failures, and it’s like, “Well, gosh, what do you mean by that?” Did we delay an AGV by 3 years? Because to me, I don’t know, I don’t know that that’s a failure. If I had 3 years without an AGV and you delayed the progression of the disease, even though I’m on the same drops, even though my pressure doesn’t really change too much, you delayed a more invasive procedure by years. And so God forbid, to me that sounds like a pretty low bar, but even that is success. And so I think that you’ve got to shoot your shot. I think that’s important.

Maybe talk about some of your real world results. You mentioned what you’re seeing in your own patients, but do they mirror that of the pivotal trial? Are you mostly getting people off drops with this and that’s what you’re talking about? Or is it mostly IOP reduction? I know it’s different for every patient, but maybe just what you see in general.

Christy Benson, MD:

Yeah. Every patient is a little bit different. I’ve had some patients that they’ve had a 12 point pressure reduction. I’ve had some patients where maybe you only got that three to four point pressure drop. So I would say that the results vary, but I would say the vast majority of my patients that I’ve done the infinite on, basically I’ve maxed out their treatments with either the drops that they can tolerate, SLTs previously, and then I take them in for surgery for the infinite. And usually at that three month mark, I’m seeing a significant reduction. And usually I can either prevent them from adding that third drop or maybe even take away some of the drops. And so I guess that’s the hardest thing to analyze about the data, because in some patients, they were able to come off all their drops. Some patients, they were able to come off one drop. Some patients, they were just able to not add a third.

And so again, just like what we said, the success is different for each patient because the goal is different for each patient. I have not had a single complication from any of the infinite procedures that I’ve done. And I’m trying to just think, off the top of my head, how many I’ve done since I started doing them in October of 2022. I’ve probably done somewhere between 30 and 40, just off the top of my head. So I’ve done a fair amount and I’ve had really good results. And the more that I do, the more confident I am to recommend the procedure for my patients.

Blake Williamson, MD, MPH, MS:

Yeah. And I think that I’m seeing a lot of that as well. It’s very rare that I am unhappy with whatever result I’ve been given. And I frame that in the context of glaucoma, which is a chronic progressive disease for which there’s no cure. And so even if you don’t get that patient off that drop that you had talked about, maybe you’re able to show a reduction in pressure and talk about how that’s useful as well. So all of your results I think could be related very easily within the context of a disease that doesn’t necessarily have a cure. So I think that’s important to talk to patients about that.

So where do you see the future of standalone? It’s showing promising results, and I think it’s been an untapped area in the field of surgical glaucoma, and it took years, most of my career so far, to get surgeons to start to understand that, gosh, when you’re already inside the eye, why not go ahead and put a stent in? Well, now we’re asking surgeons, “Well, you don’t have to do it with cataract surgery. You can take them to the OR just for glaucoma surgery.” So do you see that evolving and more and more surgeons getting on board with this, or do you think there’s still going to be barriers and your comprehensive non-glaucoma people will be hesitant, unlike me and you?

Christy Benson, MD:

I do think there are some barriers, and I hope that that changes. I hope that you and I doing this podcast will get the word out that you and I are comprehensive ophthalmologists, we’re doing standalone cases not in the setting of cataract surgery, and we’re having good results. And honestly, these patients that I’m doing for standalone procedure, they’re some of my happiest patients. You’re not getting those … I mean, just like what you said about the cataract surgery patients with the glare halos. They’re happy when I can finally say, “Your pressures are at target.” And for years we’ve been struggling with drops, SLT, and then now I can finally say, “Hey, you’re finally at target. We finally got there.” And we wouldn’t have been able to get there without this procedure.

So I’m hopeful that the mindset can change with time, as more education gets out there and people feel more confident, the more that they do and the more experience that they can have with it.

Blake Williamson, MD, MPH, MS:

Yeah. And I think that there’s other devices in the standalone space too, and we’re mostly focusing on the iStent infinite because frankly that’s what you and I have both had a lot of success with, and I’m sure you too have done other procedures that are standalone successfully. And so patients out there or surgeons out there can consider many such devices, but I think that what they’re going to find is that the safety and the data and everything involving with the iStent infinite is pretty compelling and hard to rival. But I just think that spending time in that space, even the standalone patient, is key for all of us.

And so maybe I’ll just give you the floor to bring us home. Any take home messages for surgeons regarding the standalone MIGS devices?

Christy Benson, MD:

So I would say don’t be afraid to have the discussion with your patient about the standalone options for infinite, especially ones that they’re coming in time and time again and their pressure is not at target and maybe they’re pseudophakic. Don’t be afraid to offer that as a treatment option.

And when I first started having these discussions with patients, I thought, “No patient is going to want this procedure because I’m not offering it at the same time as cataract surgery.” So with cataract surgery, it’s an easy sell, but I don’t know that I’ve had a single patient actually say no when I went through the risks and benefits.

So that’s one thing I guess that surprised me, was that I think we forget sometimes how frustrated our glaucoma patients are feeling at home. Maybe they’re feeling overwhelmed with their drops. They don’t like the way the drops make their eyes feel. And so when you offer this other solution, they actually get excited and they’re really up for it. And usually the family too is really encouraging too, because if they can prevent progression, if they can maybe get off some of their drops, I would say that my patients are not only for it, but they’re excited about it.

And then also, to me, it’s a fun surgery to do because I can see the improvement in the pressures. And again, these are patients that have failed prior surgeries, have failed prior laser. This isn’t a first line treatment. So these are patients that are frustrated anyway, and so it’s been really fun to be able to offer that and have this solution and option that isn’t a tube and isn’t a trab. So it’s safe, it’s effective, and you can offer it earlier on than, say, you would a tube or trab, because back in residency when we would have those discussions, you waited until you absolutely had to, just because of the high risk profile. So now with the safe profile, you can offer it earlier. And like I said, these patients are happy.

Blake Williamson, MD, MPH, MS:

Very cool. Thanks Dr Benson. I appreciate it. Those are great pearls and I’ve enjoyed talking to you, and I hope that the listeners will come away with a few things that they can implement in their practice to better serve our patients who are suffering from glaucoma.

Christy Benson, MD:

Great. Thank you.