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Glaucoma Experts | Sept/Oct '17

The MIGS Fellowship Gap

With the growing prevalence of glaucoma worldwide and the well-known and widespread problem with patient noncompliance, effective, affordable, and convenient treatments are in high demand.1 Microinvasive glaucoma surgery (MIGS) procedures, with their high safety and efficacy profiles, meet this need nicely. However, most doctors are not exposed to MIGS during their residencies.

In this day and age of subspecialization, I believe it is more important for comprehensive and refractive cataract surgeons to learn MIGS in residency than to learn trabeculectomy and tube shunt procedures. MIGS can be used to target the outflow pathway of choice, whether canal-based, suprachoroidal, or subconjunctival. By using MIGS devices, either alone or in combination, comprehensive cataract surgeons will be well equipped to treat the majority of glaucoma patients in their practice. The few end-stage cases or patients for whom multiple MIGS treatments failed can be referred to a glaucoma specialist comfortable performing more invasive procedures.


I am a living example of this new normal concept for surgical glaucoma. I work in a high-volume practice, seeing 50 patients or more per day, and I have a huge glaucoma population. Yet, because I perform multiple MIGS procedures, over the past year I can count on one hand the number of patients I sent for tube shunts. I believe that this will become standard if comprehensive surgeons treat glaucoma appropriately by addressing it at the time of cataract surgery, much like they would astigmatism. I often tell my refractive colleagues, “Glaucoma is the new astigmatism.”


Treating patients with glaucoma is an inevitable part of ophthalmic practice, and providing patients with the best care possible requires the use of MIGS. Accepting this idea is the first step in getting started. Unfortunately, most surgeons are not exposed to MIGS in residency and will, thus, need to find another learning opportunity.

If you are currently in residency, however, I recommend speaking to your glaucoma fellows and attendings about your desire to learn MIGS during training. Prove to them your seriousness, first by having an exhaustive knowledge of angle anatomy and the aqueous outflow pathway and then by demonstrating your facility with intraoperative gonioscopy. If you encounter resistance, be respectful but remain persistent. This was my approach a few years ago, and it led to my becoming one of the first three residents in the United States certified to use the iStent (Glaukos).

For those already in practice, there is a wealth of information available that can aid in building a knowledge base for MIGS procedures. Eyetube houses many surgical videos featuring MIGS devices, and articles can be found across several ophthalmology publications. Speaking to colleagues, especially glaucoma surgeons with high volumes of MIGS cases, is also very useful. These individuals are the masters who can explain the nuances not found in written texts or videos. Additionally, some MIGS manufacturers host training programs; Glaukos, for example, certifies surgeons to use the iStent with comprehensive online training modules followed by hands-on wet labs and proctored cases.

Clinically, I suggest beginning with a MIGS device that has a favorable safety profile and targets the natural trabecular outflow pathway, such as the iStent.2 This greatly decreases the probability of adverse events. Additionally, identifying the correct patients for your learning phase is critical. The ideal candidates for your first cases are low risk: patients with mild to moderate disease whose primary goal is to reduce their medications. As with most new technologies, there is a learning curve with the iStent, and surgeons should keep their expectations in check even after completing the initial certification process.

You may get humbled a bit, and that’s OK. Accept it and move on. Even if the outcomes for your first few patients result in a modest drop in pressure, no harm has been done and you still have plenty of real estate for further glaucoma surgeries down the road. The eye will already be open for cataract surgery, and the patient will reap the benefits of having the cataract removed and a new lens implanted. The refractive outcome will not be affected, and the experience will serve to increase your comfort in the angle.

Surgically, it is imperative to get comfortable in the angle. Many surgeons try new technologies such as the iStent, and, if their outcomes are not immediately as good as expected, they assume it is the device at fault, rather than the technique. They fail to take into account the learning curve. I, too, got discouraged early on; however, I had simply not spent enough time in the angle. I was not good enough yet.

I have since chosen to explore other MIGS devices, and doing so has greatly increased my comfort in the angle. This cross-training also helped to improve my technique with the iStent. My placements are easier, my targeting is better, and my outcomes are greatly improved. Inexperienced surgeons may not see the outstanding drops in pressure reported by other surgeons using the iStent until they become proficient. For some, this may take only a few cases, but for others it may require many more.


Many surgeons, myself included, do not like to slow down and learn something new. But the fact is that the MIGS space is projected to be a $700 million industry by 2020—clearly, MIGS is here to stay. Technology evolves, and surgeons must evolve with it. They must also recognize the unique opportunity of cataract surgery to help patients who have concomitant glaucoma. Despite the lack of exposure in residency, surgeons can—and should—educate themselves about MIGS and add these procedures to their armamentariums. Patients with glaucoma need treatments that take into account their quality of life. A lack of training in residency does not need to be a barrier to providing this service.

1. Tham YC, Li X., Wong TY, Quigley HA, Aung T, Cheng CY. Global prevalence of glaucoma and projections of glaucoma burden through 2040: a systematic review and meta-analysis. Ophthalmology. 2014;121(11):2081-2090.

2. Samuelson TW, Katz LJ, Wells JM, Duh YJ, Giamporcaro JE; US iStent Study Group. Randomized evaluation of the trabecular micro-bypass stent with phacoemulsification in patients with glaucoma and cataract. Ophthalmology. 2011;118:459-467.

Blake Williamson, MD, MPH
Blake Williamson, MD, MPH
  • Comprehensive ophthalmologist, Williamson Eye Center, Baton Rouge, Louisiana
  • blakewilliamson@weceye.com; Twitter @blakewilly
  • Financial disclosure: None acknowledged
Nathan M. Radcliffe, MD | Section Editor
Nathan M. Radcliffe, MD | Section Editor
  • Director, Glaucoma Service, New York University New York Eye Surgery Center
  • drradcliffe@gmail.com
  • Financial disclosure: None