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43 EW FEATURE April 2018 • Intersection of refractive surgery and MIGS Dr. Brubaker added that from a placement standpoint, he thinks the CyPass has the shortest learning curve. "The gonioscopic challenge with the CyPass is that the surgeon has to make sure to not press down on the lip of the corneal wound during placement," he said. "Be- cause the CyPass is inserted in the more posteriorly located supraciliary space, the surgeon needs to raise the wrist and the handle of the inserter to prevent downward force on the corneal lip." Dr. Brubaker said that this helps to avoid distortion of the cornea, making visualization difficult. "Another challenge with the CyPass is recognizing differenc- es in iris root appearances among patients," he said. "Rather than focusing on the apparent insertion of the iris at the more posterior root, it is crucial to target insertion of the CyPass just below the scleral spur." This is a constant anatomic feature that can reliably direct CyPass place- ment in every case, he said. With the other trabecular mesh- work targeted MIGS such as gonios- copy-assisted transluminal trabec- ulotomy (GATT) and Kahook Dual Blade (KDB, New World Medical, Rancho Cucamonga, California), one can rely on the techniques used in learning the iStent, Dr. Brubaker said. "A good feel for the location and depth of the meshwork and canal are particularly helpful during one's progression toward these more advanced MIGS," he said. "Both of these procedures require the use of interocular microincision forceps under gonioscopic visualization." He added that this is a technique that can be helpful in these pro- cedures but also if repositioning is necessary with the CyPass or iStent. Finally, Dr. Brubaker said that the use of the XEN Gel Stent is on a different spectrum when compared to internal MIGS. "The (indirect) gonioprism is only used to guide initial targeting of the needle," he said. "The stent is injected with direct visualization." He added that the learning curve with the XEN is making sure the stent is well placed. Advanced placement just under the conjunctiva is a technique that usu- ally requires more than a handful of cases before this can be mastered, Dr. Brubaker said. Skills needed to implant vs. skills needed to manage According to Dr. Huang, the skills to manage postoperatively are different than the skills needed for implantation. "The benefit of MIGS procedures is they often have lower rates of complications compared to traditional filtering surgery, such as hypotony, which can be difficult and time consuming to manage," she said. "However, MIGS proce- dures are not free of complications." Less invasive MIGS procedures such as trabecular meshwork bypass stents (iStent) may be easier to man- age than procedures that resemble traditional surgery, Dr. Huang said, such as gel stents (XEN), which may even require postoperative bleb needling and injections of anti-fi- brotics. Significant postoperative care can be a barrier to adoption of MIGS procedures, she said. "There is a spectrum of MIGS, and refractive surgeons should take into account postoperative care when deciding what devices they are comfortable implanting," Dr. Huang said. Dr. Patterson said that in these cases it's important for the surgeon to be comfortable managing hy- phema, shallow chamber, choroidal folds, and other issues that may arise. He added that he has no prob- lems with the majority of his MIGS patients, but you do need more chair time with certain patients. Dr. Brubaker said that most sur- geons initially focus on performing the procedure itself, but once these techniques are learned, postoper- ative management becomes more crucial. With the iStent, success resolves around appropriate glauco- ma medication management in the postoperative period to avoid IOP spikes, he said. With the CyPass it is crucial to prepare the patient for the likely delayed visual recovery due to early hypotony and myopic shifts. With trabecular meshwork ablating procedures, Dr. Brubaker said, the surgeon needs to be prepared to deal with postoperative hyphema. "While this usually self clears, it is important to prepare patients for this possibility and have a clear understanding when these need to be surgically washed out." Finally, with the XEN, the postoperative management is crucial for success, he said. "Having a firm comprehen- sion of bleb management is critical for success." "I think the bigger barrier to adoption varies by procedure," Dr. Brubaker said. "With internal MIGS, I think the challenge pendulum swings toward the technical proce- dure itself, while the more aggres- sive MIGS such as GATT and XEN have a potentially more difficult postoperative course." "It is important for surgeons to understand that the follow-up care is as important, and possibly more important, than the actual proce- dure," Dr. Samuelson said. "Glau- coma cannot be cured, it can only be managed." He said that adequate surveillance postoperatively is man- datory for this reason. "I would discourage surgeons from adopting MIGS if they are unwilling to be accountable for appropriate postoperative surveil- lance," he said. "While it is true that many patients are co-managed in to- day's medical environment, proper co-management still requires careful correspondence with the referring doctor and coordination of care, to be certain that steroids are dis- continued in a timely fashion and those patients developing a steroid response are adequately monitored and treated." Dr. Samuelson added that it's important to move on to more " There is a spectrum of MIGS, and refractive surgeons should take into account postoperative care when deciding what devices they are comfortable implanting. " —Linda Huang, MD continued on page 44 Check us out on Instagram at: EyeWorldNews Follow EyeWorldNews on Instagram for ophthalmic photos and videos!

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