Eyeworld

47 EW FEATURE July 2017 • MIGS roundup Staining of the trabecular meshwork with trypan blue at the point of the incision in the meshwork. The opening in the meshwork exposes the white posterior wall of Schlemm's canal. Note the "flaps" of the blue trabecular meshwork. Source: Reay Brown, MD Intraoperative view of an iStent in good position. The remainder of the stent is pointing to the left and is covered by the trabecular meshwork. Source: Michael Greenwood, MD Tips for success with MIGS According to Dr. Lewis, the key to success with MIGS is getting com- fortable in the operating room with gonioscopy. "The big challenge for non-glaucoma surgeons is that they have to get comfortable using a gonioprism in their non-dominant hand without pushing too hard and getting the optimal view. It requires proper head position and maximiz- ing the magnification. All of these fundamental tips are crucial to get- ting the best view. People who don't take the time to get the best view are compromising their outcomes. Fun- damentals are important even before you implant the device," he said. Before performing MIGS, Dr. Greenwood recommended getting comfortable with the anatomy of the angle. "We encourage surgeons to practice in the clinic and do go- nioscopy so that they can get a good feel for the angle structures. Then start doing them on your routine cataract cases. At the end of the day, taking a couple of extra minutes to practice goniotomy on patients in the operating room can be helpful. Having a good view and being com- fortable with the maneuvers that are needed to do these procedures is the most important aspect of surgery," he said. Reay Brown, MD, Atlanta, said that staining the trabecular mesh- work with trypan blue has helped his technique. "The idea is to stain the meshwork the same way that you would stain the anterior capsule in a case where you have either a dark brown nucleus or a white nucleus," he said. "The idea is to light up the trabecular meshwork by staining it with trypan blue. This is a big help because it shows you where the canal is and it reveals the poste- rior wall as you are implanting the iStent, so you know you are implant- ing it at the right depth. It identifies what you are aiming for, and it also gives you a positive sign that you have found the right channel." Who should perform MIGS? According to Dr. Berdahl, there are three types of surgeons who consid- er incorporating MIGS in their prac- tices, and they all have a different question. "Comprehensive ophthal- mologists question whether they see enough of these patients to perfect their technique. Data indicate that 20% of patients undergoing cataract surgery have a concurrent diagnosis of glaucoma, so I think the answer there is yes. High-volume cataract surgeons question whether they want to get into the MIGS game, and I think that's a fair question. If they don't, I think that's OK. How- ever, even if you don't offer MIGS as a high-volume cataract surgeon, if there is a patient with cataract and glaucoma, you should let him or her know that there is a good option out there. The third surgeon is the glaucoma specialist who questions whether MIGS can get the pres- sure low enough for the advanced glaucoma patients, and the answer is maybe. In general, it is a good place to start because it is so safe. If it doesn't get the pressure low enough, you can move on to a more aggres- sive but riskier glaucoma surgery," he explained. Today, MIGS procedures are allowing surgeons to treat glauco- ma earlier and more safely than traditional glaucoma procedures. "Surgeons are going to find their preferred MIGS surgery," Dr. Green- wood said. "As time goes by and more data become available, we may learn that some are superior to others. Right now, surgeons have to understand what data are available and decide what they think is an equal balance of safety and efficacy for each individual patient." EW Editors' note: Dr. Berdahl has financial interests with Glaukos, Alcon, Allergan, Johnson & Johnson Vision (Santa Ana, California), and New World Medi- cal. Dr. Brown has financial interests with Glaukos. Dr. Lewis has financial interests with Allergan, Glaukos, Alcon, Ivantis (Irvine, California), and Aerie Pharmaceuticals (Irvine, California). Dr. Greenwood has no financial inter- ests related to his comments. Contact information Berdahl: john.berdahl@vancethompsonvision.com Brown: reaymary@comcast.net Greenwood: michael.greenwood@vancethompsonvision. com Lewis: rlewiseyemd@yahoo.com be used with or without cataract surgery, and they will be used for a broader range of glaucoma. Now we are trying to figure out the right candidates for each treatment and how to best facilitate achieving op- timum pressure control. It sounds a lot easier than it is. The bottom line is the way the wound heals." Although MIGS offers benefits compared to traditional glaucoma surgeries, there are still instances in which traditional surgeries are preferred. "If patients are not can- didates for MIGS, I use a trabeculec- tomy approach. Additionally, the use of drainage devices is going to continue. However, MIGS will ulti- mately erode the numbers as we get more comfortable and begin to find ways to more effectively get pressure control. I am still doing traditional surgery, but it's going to be inter- esting over the next 5 years as we adopt these new procedures, begin to achieve good pressure control with a much safer profile, and get full reimbursement," Dr. Lewis said.

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