Minimally invasive glaucoma surgery (MIGS) procedures, once done mainly in combination with cataract surgery, are now regularly being used as standalone interventions in both phakic and pseudophakic patients.1 There are more options for standalone MIGS than ever before. Of note, a recent study demonstrated that even after patients had failed prior incisional surgeries or cilioablative procedures and had intraocular pressure (IOP) greater than 24 mmHg on multiple medications, they could still have a significant drop in pressure with the iStent infinite (Glaukos).2 This study showed that the trabecular meshwork can still be bypassed, even after a filtering procedure; the TM is not completely dormant. This significant IOP-lowering was a surprise to many conventionally minded ophthalmologists and has been instrumental in changing hearts and minds about standalone trabecular microbypass.
As the glaucoma treatment paradigm shifts, surgeons will increasingly encounter patients who previously underwent standalone MIGS and later present for cataract surgery. This scenario raises a few considerations regarding optimal intraoperative planning and long-term IOP management.
When a patient has glaucoma and is on medication, and they also have a cataract—even if their intraocular pressure (IOP) appears controlled—it is inappropriate to forgo a MIGS procedure during cataract surgery, even if the patient has previously undergone MIGS. There is a common assumption that cataract surgery alone will lower IOP, but this effect is inconsistent, particularly in glaucoma patients who have already had MIGS.
This population remains understudied, and in my daily practice, I continue to see patients who experience permanent vision loss after a general ophthalmologist performed cataract surgery without addressing their glaucoma. Often these patients were only borderline controlled on medications, and the assumption that cataract surgery would further reduce their IOP proved incorrect. The number needed to treat to justify intervening should be 1—because even 1 case of preventable vision loss is too many. So, if a patient has already had standalone MIGS and is still on medication or inadequately controlled, it is essential to seriously consider additional intervention at the time of cataract surgery. This article outlines a practical framework for surgical planning and decision-making in this unique population, based on my experience as a glaucoma specialist frequently managing such cases.
Tailoring the Second MIGS: A Case-by-Case Approach
When selecting an appropriate MIGS option to pair with cataract surgery in these patients, the key variables are the nature of the original MIGS procedure, current IOP status, severity of disease, and medication burden.
If the prior MIGS involved canaloplasty alone—such as a viscodilation with the Omni Surgical System (Sight Sciences) or iTrack (Nova Eye Medical)—and there was minimal or no goniotomy, I typically find that there is room for a stent. Even in cases where 180° of nasal trabecular meshwork (TM) was treated previously, it is feasible to do cataract surgery and then implant the iStent inject or iStent infinite (Glaukos) temporally by repositioning the chair to the cephalic position or sitting on the opposite side and adjusting the patient’s head to allow access to the inferior or temporal angle. This approach provides flexibility and can expand the treated area of the outflow system.
If the prior MIGS involved a goniotomy or a trabecular stent, another angle procedure may still be viable depending on the treated sectors. I have, in selected cases, removed an existing stent to make room for another angle procedure such as canaloplasty with or without goniotomy with the Omni device. More commonly, I perform canaloplasty after a previous iStent inject plus phacoemulsification combination. The reverse sequence—iStent infinite followed by canaloplasty—is also possible.
The Role of ECP and Suprachoroidal Approaches
In some situations, especially when angle space is limited or when a more posterior approach is desired, endoscopic cyclophotocoagulation (ECP) offers an attractive alternative. Ciliary ablative procedures avoid the angle, and ECP is safe and well tolerated for reducing aqueous production, particularly in pseudophakic patients.3 I believe that ECP is due for a resurgence as more surgeons recognize its value in combination cataract surgery.
Similarly, suprachoroidal MIGS is becoming increasingly relevant. AlloFlo Uveo Bio-Spacers (Iantrek) fit in almost every part of the treatment paradigm. It creates a cyclodialysis cleft into the supraciliary space, bypassing the TM entirely, and you can titrate it based on the severity of the glaucoma. Although I primarily use this in pseudophakic eyes, combining the AlloFlo Uveo Bio-Spacer procedure with cataract surgery is a promising option. These procedures offer a pressure-lowering strategy that doesn’t rely on an already manipulated or damaged TM.
Together, ECP and suprachoroidal MIGS provide new dimensions of treatment beyond the canal and subconjunctival space and may be especially valuable for patients who have exhausted other options.
Addressing More Advanced Disease
The variables of disease severity, number of medications, and target pressure all play a role in decision making. If the patient who has already had standalone MIGS presents with significant progression and elevated pressure, I consider more aggressive surgical options. In such cases, it’s not unreasonable or inappropriate to consider cataract surgery combined with a subconjunctival filtration procedure. I favor the Xen gel stent (AbbVie) in these cases. I want to have the best refractive outcomes possible, and that is the filtering
procedure that will create the least astigmatism.
In patients with very high pressure, I may stage the procedures. That is, I may first perform a subconjunctival filtration procedure to gain pressure control and defer the cataract surgery until later. Once the eye is stable, I can revisit MIGS or ECP as needed. ECP standalone after phaco is perfectly appropriate and I do a fair amount of that; I get a lot of referrals for that. Obviously, you would also have access to the supraciliary space.
Leveraging Procedural Pharmaceuticals
Procedural pharmaceuticals, such as iDose TR (Glaukos) or Durysta (AbbVie), can also play an important role. In patients on multiple medications or with higher IOP, combining cataract surgery with a sustained drug delivery implant can reduce the postoperative drop burden and help maintain IOP control. I have used iDose in combination with iStent infinite, iStent inject, Omni surgical system, ECP, or goniotomy, tailoring the choice based on patient needs and medication tolerance.
It is not unusual for a patient to ultimately receive several stents over time—especially when procedures are staged. For instance, a patient may receive iStent inject at the time of cataract surgery and later receive iStent infinite if further pressure control is needed. Given that the TM is functionally segmented, multiple stents may access distinct outflow channels and improve overall efficacy.
Conclusion
With the growing use of standalone MIGS in phakic patients, glaucoma specialists are increasingly challenged with managing these patients when they later develop cataracts. The traditional assumption that cataract surgery alone will lower IOP is unreliable in this population. Instead, careful selection of a supplemental MIGS procedure—based on prior interventions, glaucoma severity, and angle anatomy—is essential to maintain long-term disease control and protect vision.
Whether through trabecular bypass, viscodilation, goniotomy, suprachoroidal devices, ECP, filtration surgery with Xen, or procedural pharmaceuticals, surgeons now have a broad range of options to individualize treatment. The key is to avoid complacency. Cataract surgery in glaucoma patients—particularly those with a history of MIGS—demands a deliberate and proactive surgical strategy. GP
References
1. Micheletti JM, Brink M, Brubaker JW, Ristvedt D, Sarkisian SR. Standalone interventional glaucoma: evolution from the combination-cataract paradigm. J Cataract Refract Surg. 2024;50(12):1284-1290. doi:10.1097/j.jcrs.0000000000001537
2. Sarkisian SR, 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
3. Francis BA, Berke SJ, Dustin L, Noecker R. Endoscopic cyclophotocoagulation combined with phacoemulsification versus phacoemulsification alone in medically controlled glaucoma. J Cataract Refract Surg. 2014;40(8):1313-1321. doi:10.1016/j.jcrs.2014.06.021