Eyeworld

120 | EYEWORLD | DECEMBER 2020 G UCOMA by Liz Hillman Editorial Co-Director 3. Approved for specific indications Linda Huang, MD, addressed the hurdle of many MIGS being approved by the FDA for only certain types or severities of glaucoma and/or in combination with cataract surgery. "This may limit the use of certain types of procedures even though patients may still benefit from them. For example, iStent or Hy- drus [Ivantis] is not approved in patients who are pseudophakic, even if the device may be effective in lowering the patient's pressure," Dr. Huang said. 4. The data All three doctors said when new devices and procedures are introduced, there are always safety and efficacy concerns until long-term data shows otherwise. "Certain MIGS devices have been approved for some time and have had longer follow-up times. It is always important to continue to monitor and assess patients for safety and effi- cacy of a device," Dr. Huang said. Dr. Zhang said she thinks many physicians don't think they have adequate long-term data for more modern MIGS. "Someone opposed to MIGS might say 'Look at CyPass,'" Dr. Zhang said, referencing the recall of Alcon's suprachoroidal stent in August 2018. A 5-year post-surgery data study found the potential for endothelial cell density loss if too much of the device extended into the anterior chamber. Dr. Patrianakos brought up another data concern. There are different study designs, different definitions of success, some use wash- out periods and some don't, different years of follow-up, and different experience levels by the surgeons involved in the studies. "One of the things we need to do to solidify MIGS as a procedure is plan for these future studies to be more standardized and make comparisons between studies easier and also compare to traditional glaucoma therapies," Dr. Patrianakos said. Hurdles facing MIGS D epending on what you define as a microinvasive glaucoma surgery (MIGS), you might think it first became available several decades ago with endocyclophotocoagulation (ECP), but many define the MIGS era beginning with the iStent (Glaukos), the first ab interno trabecular microbypass device approved by the FDA in 2012. Since then there has been a steady stream of new devices and procedures classified as MIGS that have entered the market, and some are still in development. Though nearly a de- cade has passed since the more formal MIGS era began, are there still hurdles facing the IOP-low- ering procedures? According to three glaucoma specialists EyeWorld spoke with, the short answer is yes. 1. Comparing it to trabeculectomy Amy Zhang, MD, said one major hurdle is that MIGS are often still compared to trabeculecto- my. "Some say MIGS would be a replacement for trabeculectomy. I don't think that should be the approach one takes with MIGS. I think it should be thought of as a bridge to possibly bet- ter IOP control," she said. "I don't think the gold standard in terms of trabeculectomy pressure lowering can be replaced by one MIGS device. That's one of the biggest challenges, under- standing where MIGS would fit in." 2. Surgeon adoption Thomas Patrianakos, DO, thinks the biggest hur- dle facing MIGS is still surgeon comfort. "Just like with any new procedure that's out there, there's a learning curve, and there will be complications that occur," he said, explaining that the perception of getting over that learning curve and handling complications is still needed for MIGS acceptance by surgeons. He also advised surgeons to not be put off by early complications. "Reach out to colleagues doing the proce- dures, and you'll be surprised that they probably had that same complications happen," he said. About the doctors Linda Huang, MD Glaucoma Institute of Northern New Jersey Rochelle Park, New Jersey Thomas Patrianakos, DO Cook County Health Northwest Chicago Eye Specialists Chicago, Illinois Amy Zhang, MD Assistant Professor of Ophthalmology Kellogg Eye Center University of Michigan Ann Arbor, Michigan

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