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EW FEATURE 54 MIGS roundup • July 2017 AT A GLANCE • Hypotony and bleb-related problems are potential concerns with some of these procedures. Early results with the XEN have shown good safety and lower risk of some complications. • Generally, using one of these procedures does not preclude a surgeon from choosing another option in the future. • Antifibrotic agents are important to use with trabeculectomy and the XEN, but are not generally used with tube shunts. by Ellen Stodola EyeWorld Senior Staff Writer the patient works in a dirty environ- ment, a trabeculectomy would not be ideal because this puts the patient at risk for infection. Tubes, he said, have the least risk of infection. An- other example Dr. Grover gave was patients who scuba dive. In these patients, a tube shunt would be bet- ter. Dr. Grover added that in patients who are on blood thinners and can't be taken off this medication, it's risky to do a tube or trabeculectomy, and a XEN may be a better choice because of the lower risk of a sudden drop in pressure. The XEN creates a bleb, so this could put the patient at risk for bleb-related complications. But Dr. Grover noted that these problems have not been seen in Europe where the XEN has been approved for a longer period of time. Patients who are more prone to scar tissue formation tend to do better with glaucoma tubes, he added, and would not do well with a trabeculectomy or the XEN. If the patient has mild/moderate glaucoma to early advanced glauco- ma, Dr. Grover noted that his gen- eral approach is to try to open up their own drain, but if that doesn't work, then he tells patients he has to create a new drain. Right now, the safest, most predictable, and least invasive way of creating a new drain is the XEN, he said. Experts discuss use of trabeculectomy, tube shunts, and XEN Gel Stent A lthough trabeculectomy, tube shunts, and the XEN Gel Stent (Allergan, Dublin, Ireland) work by creating a pathway for aqueous humor to drain into the subconjunctival space, these are all very different options for different types of patients. Patient factors, such as disease severity, and more can play into which procedure a glaucoma surgeon chooses. Kateki Vinod, MD, New York Eye and Ear led to the development of MIGS pro- cedures that seek to optimize safety." The eye is like a faucet and drain, Dr. Grover said, in that it makes water and drains water. The majority of open-angle glaucoma is thought to be caused by drainage problems through the trabecular meshwork. Dr. Grover said his ap- proach is to tell patients that he will try to open their own drain, but if that's not possible, a new drain will need to be created, which can be done with a tube shunt, trabeculec- tomy, or the XEN Gel Stent. The problem is that the aqueous is not supposed to be in the subconjunc- tival space, so when it is, it creates an aggressive scarring response. To address this, Dr. Grover said that mitomycin-C (MMC) or a drainage implant can be used. All innovations with trabs and tubes are designed to trick the eye to not act as aggressive- ly to aqueous in the subconjunctival space, he said. Dr. Grover thinks that the XEN could help create a more predictable outflow pathway. "It's the best of both worlds between [tra- beculectomy] and tube," he said. Ideal patients for each option Dr. Grover said the ideal procedure often depends on the patient, and he noted that certain cases may be more clear-cut than others. In partic- ular, he considers patients' activity and where they live. For example, if Comparing glaucoma procedures Monthly Pulse MIGS roundup T he topic of this Monthly Pulse survey was "MIGS roundup." We asked, "Which of the following newly available glaucoma technologies do you find most exciting?" The majority of the respondents to this survey chose the CyPass, followed closely by the XEN45. When presented with the scenario of a patient needing cataract surgery with moderate glaucoma on several topical agents, the majority of respondents said they can't say what they would do, as each patient is unique. The second most popular answer was "Bypassing the trabecular meshwork (iStent)." When asked about their experience with MIGS, most said they have been performing MIGS and plan on continuing. Finally, we asked about efficacy with currently available MIGS procedures, and the majority said, "I am satisfied with safety, but not efficacy." Infirmary of Mount Sinai, New York, and Davinder Grover, MD, Glau- coma Associates of Texas, Dallas, discussed aqueous drainage into the subconjunctival space and shared their thoughts on when to use each of these options and the advantages and disadvantages they offer. Aqueous drainage into the subconjunctival space The subconjunctival space is the site of aqueous drainage in traditional filtering glaucoma surgery, includ- ing trabeculectomy and tube shunt surgery, Dr. Vinod said. "Procedures targeting the subconjunctival space offer the advantage of achieving lower intraocular pressures than trabecular meshwork and Schlemm's canal-based surgeries can, as the latter are limited by downstream resistance to outflow and episcleral venous pressure," she added. However, bleb-related problems, such as leaks and infections, may occur with operations that involve aqueous drainage to the subcon- junctival space. "Such complications have become less common as a re- sult of refinements in our trabeculec- tomy technique, including more diffuse application of antifibrotic- soaked sponges and, more recently, subconjunctival injection of antifi- brotics," Dr. Vinod said. "The risk of these and other complications associated with trabs and tubes has

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