Sponsored by Glaukos
Credited with introducing many of the terms and definitions used to describe MIGS, and as a leader in MIGS research, Iqbal Ike K. Ahmed, MD, FRCSC, has a unique perspective on glaucoma’s transformation into a surgical disease. In a recent interview, while he reflected on the current state of MIGS and all its introduction has wrought, Dr. Ahmed kept returning to two under-appreciated and unintended consequences of procedural management.
- The first is that the availability of safe and effective MIGS options means that clinicians can ask who would benefit. Options breed conversations that improve outcomes.
- The second point is that recent evidence suggests a strong possibility of reducing medication burden after MIGS. Quality of life is an important outcome in glaucoma management.
“We have to remember what our goals of glaucoma therapy are,” Dr. Ahmed said. “In the past, we would think about IOP as the only modifiable risk factor and the traditional metrics, but we weren’t necessarily focused on what outcomes mattered to patients, which is quality of life. In this respect, the shortcomings of drops, I think, are very well established.”
Joining Dr. Ahmed in the interview was Sahar Bedrood, MD, PhD, another pioneer in MIGS research. From her perspective, the MIGS era has catalyzed interest in understanding the root causes and drivers of glaucoma pathology. The iterative process of building a more detailed understanding of the aqueous outflow pathway has suggested benefits associated with targeting obstruction at the source. However, to date, there is not a good way to image the pathway. If researchers are able to provide that, Dr. Bedrood said, it would provide insight on how best to harness the best attributes of each MIGS device and technology.
“The anatomy that we're actually targeting with MIGS is the angle, but the truth is, we actually still don't know a whole lot about the angle. We also don't know how the downstream system—the Schlemm canal, all the vessels, the episcleral veins, the collector channels—how all of those are actually functioning. We're just seeing the tip of the iceberg in terms of developing imaging for those purposes, but once we get there, we will have a better sense of where and how to target the anatomy.”
Following is a transcript of their interview, which has been edited for length.
What has been the impetus behind the growth of the MIGS market from when it was almost non-existent a decade ago to where it is today?
Dr. Bedrood: The most important thing is that the concept of intervening earlier in a minimally invasive manner has become more acceptable. And a big reason for that is the innovation that’s behind MIGS. The continual contribution of new devices spurred new techniques, and each of those things allowed us to have different conversations with patients. We’ve also learned what endpoints are important to study, and we are now getting data suggesting greater visual field preservation with MIGS, that patients are more likely to be off medications postoperatively, and they will also have a reduced chance of needing a secondary procedure. The growth of MIGS has really happened because innovation sparked discussion, which led us to the data.
Dr. Ahmed: One of those endpoints we certainly learned about is the potential to reduce medication burden. The real opportunity in early surgical intervention is a greater chance to get patients off drops. In the past when our surgical options were all invasive, that was less of a consideration. It also emerged at the right time in history when there was an unmet need. The technology was right, the investments were right, clinicians had the right mindset, and the field was undergoing the skill transfer between cataract and glaucoma specialists.
What do you think will be the next important breakthrough for MIGS?
Dr. Ahmed: It has yet to be proven, but one theoretical outcome of intervening early in glaucoma is that improving outflow might prevent or reduce the development of irreversible secondary damage to the anatomy, with consequences for disease progression and loss of vision. Before the introduction of iStent infinite, why were MIGS procedures generally not as successful in more advanced glaucoma?
Dr. Bedrood: We have learned a tremendous amount about the complex aqueous outflow system through and because of MIGS. But the truth is, there is still a lot we do not know, including where exactly the obstruction is occurring. We can rely somewhat on clinical judgement and study data to identify patients for certain procedures, but it’s not based on solid evidence. The next big evolution for MIGS will be ways to image or view the outflow system to know where to target. It will be then that we can start to really talk about the effects MIGS surgeries have on the anatomy and whether we are addressing the cause of pathology.
Is the endpoint to achieve a paradigm where topical therapy for glaucoma is abandoned in lieu of procedural options?
Dr. Bedrood: Short answer, no, but what MIGS allows is a better ability to individualize the approach to treatment. Because we have options that are safe for use in milder glaucoma, we can consider whether adding a third or fourth medication would be useful—and in some cases whether even one or two medications are providing enough benefit. In my practice, it is my goal to get existing patients down to the minimum number of drops necessary and use drops as a supplementary treatment to procedural intervention, so that we are providing the best chance to preserve the ocular surface and reduce side effects. Drops will continue to have a role in glaucoma management, but they are no longer the default option for all patients.
Dr. Ahmed: We started this conversation talking about what has changed with MIGS. Well, this is it: the ability to ask questions that lead to outcomes that are better for our patients. Are we in a world where we think about whether drops are the first line? And are we in a world where we can think about if there is a good chance of getting someone off drops with surgery—whether that’s one drop or two or three? Are we at a point in glaucoma care delivery where if we have a patient with a concomitant cataract, we should be thinking about addressing two issues in the same procedure? In my view, yes to all of the above. But regardless of what I think, we at least can ask and study those questions.
Dr. Bedrood: We haven’t even mentioned drug delivery devices and what they could possibly add. The obvious application is for patients for whom surgery is less than desirable or as an alternative to drop instillation to improve compliance. But I wonder what it would look like to combine drug delivery devices and MIGS, taking advantage of complementary mechanisms of action with procedural and pharmacologic approaches.
How do you define the “Interventional Mindset”?
Dr. Bedrood: Interventional glaucoma is a new era of glaucoma treatment where we are thinking proactively, aiming to prevent progression rather than slowing it. We're treating disease earlier with procedural intervention or with some kind of sustained release trying to get better quality of life outcomes for patients by getting them off their daily burden of drops in some way, even if that reduction is one drop. And by trying to restore and utilize the anatomy that's still functioning, we hope to halt progression earlier in the disease process.
Dr. Ahmed: Mindset is really the key word, because this is bigger than one procedure or one technology. It's really a shift from the traditional approach, where the ophthalmologist was in a reactive posture, watching for progression before intervening in a step-wise fashion, typically with drops and more drops before going on to surgery; to being proactive, to predicting which patients need to be addressed and dealing with them early on using diagnostics, using clinical history, big studies, and clinical judgment to identify patients who would benefit from intervention. Prior to the MIGS era, many glaucoma specialists were really trying their hardest to delay and possibly avoid surgery. With MIGS, we’ve flipped that mindset to asking when not to perform surgery based on the individual patient in the chair. We can possibly change that patient’s journey. We must accept that we don’t know which eyes will progress and which won’t. They’re all at risk, and if we have something safe, why consider it? We shouldn’t be indiscriminate in using MIGS, but if we can do something safely, especially as we gather more evidence on the various approaches, we can actually change the way that the disease course unfolds. We see this already with laser, with greater visual field preservation compared to topical therapy and we see less secondary surgery. Several studies are now looking at visual field as an endpoint, and I suspect that data will add significantly more to the extraordinary amount we have learned about glaucoma because of the MIGS era.
