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EW FEATURE 46 Intersection of refractive surgery and MIGS • April 2018 AT A GLANCE • The growth of MIGS means more treatment options for patients and a careful consideration of the best match for each individual patient. • Factors that surgeons consider when selecting MIGS include glaucoma severity, IOP goals, medication use, the presence of a cataract, risk profile, insurance, and lifestyle. • In the future, surgeons would like to see certain MIGS options available without concurrent cataract surgery and better choices for low tension glaucoma. by Vanessa Caceres EyeWorld Contributing Writer The risks or side effects associ- ated with certain MIGS procedures are also part of the decision-making process. For example, the CyPass can be associated with a myopic shift, choroidal effusions, and ante- rior chamber shallowing, although rarely, Dr. Grover said. Angle-open- ing MIGS such as the KDB, Trabec- tome (NeoMedix, Tustin, Califor- nia), and GATT have a slightly higher risk of transient hyphema but are still relatively safe, he added. Insurance Selecting the right medical option for a patient doesn't always square with a patient's insurance coverage. "It gets to be challenging," Dr. Bru- baker said. The iStent is well covered through insurance, and the CyPass has some good coverage as well depending on the glaucoma sever- ity, he added. If the best option is not covered by their insurance, Dr. Brubaker will let patients know that they would have to pay out of pock- et and that the choice may be off-la- bel. "Some patients are concerned about filtering devices, and they're willing to try anything to avoid that step. In that case, it's a good option. But not everyone can afford to pay for an off-label device," he said. "Unfortunately, [insurance] is a harsh reality," Dr. Grover said. "Without insurance coverage, it is hard for patients to afford the costs of surgery. This must be in one's mind when discussing surgical Eye Group, Atlanta. She will let pa- tients know this in advance to keep their expectations in check. Another consideration is wheth- er the patient has a cataract. The iStent and CyPass can be performed only at the time of cataract surgery, so that affects procedure and device choices, Dr. Wallace said. Although that can be limiting, she cited sever- al standalone MIGS procedures such as gonioscopy-assisted transluminal trabeculectomy (GATT), ab interno canaloplasty, and the Kahook Dual Blade (KDB, New World Medical, Rancho Cucamonga, California) as possible choices. Risk profile With safety concerns always at the forefront, risk profile is an import- ant consideration for patient selec- tion. "Many of the MIGS procedures seem to be associated with a higher risk of steroid response, so I would be more cautious in a known steroid responder and choose weaker ste- roids and shorter courses of ther- apy," Dr. Wallace said. She is also cautious in patients under consid- eration for GATT who are on blood thinners that can't be discontinued. "For a patient in whom I am planning a GATT, and to a lesser extent an ab externo canaloplasty, I discuss postop hyphema and the need for head up positioning so they have appropriate expectations for vision recovery after surgery," she said. "I think traditionally, most types of MIGS procedures are better for patients with mild or moder- ate primary open angle glaucoma [POAG]," Dr. Grover said. "The ad- vanced stages of POAG likely need a new drainage either with the XEN [Allergan, Dublin, Ireland], InnFo- cus MicroShunt [not yet approved in the U.S.; Santen, Osaka, Japan], or a trab or tube." Like many surgeons, for Jacob Brubaker, MD, Sacramento Eye Consultants, Sacramento, Califor- nia, there's a constant evaluation of a patient's glaucoma severity, current IOP and IOP goal, and medication use. He shared a typical example and how that has changed. "Until recently when there was only the iStent [Glaukos, San Clem- ente, California], it was a matter of what their IOP is right now. If some- one came in with an IOP of 15 on three medications and they had a cataract, even with severe glaucoma, I'd feel comfortable using the iStent to get a little lower IOP," he said. "Now, with the CyPass [Al- con, Fort Worth, Texas], the XEN, and goniotomy, that opens up the spectrum. My algorithm is that patients who are ideal for the iStent are on one or two medications, have mild glaucoma, their IOP is well controlled, and I am confident that I can get them off one drop and get their IOP down to 15," Dr. Brubaker explained. However, if Dr. Brubaker has a patient with a cataract, an IOP in the upper teens or low 20s, and who is on many drops, he will lean toward the CyPass. "There's a higher likelihood of getting them off their medications and getting their pressure a little lower than with the iStent, but there's a higher risk for myopic shifts and hypotony," he said. The level of IOP change needed or the need to come off a certain number of drops can affect what MIGS choice can be used—or if it can be used at all, Dr. Sheybani said. He is also cautious about not getting the IOP too low. "We can always get pressure lower, but it's hard to go low and come back up," he said. For advanced glaucoma, there may not be sufficient IOP lowering or medication reduction with the iStent, as U.S. surgeons are limited to implanting one iStent at a time, said Dana Wallace, MD, Thomas How surgeons match glaucoma patients with MIGS treatment options G laucoma surgeons and comprehensive ophthal- mologists continue to better understand how to effectively match patients with microinvasive glaucoma sur- gery (MIGS) options. "We are still trying to figure out which MIGS is best for which patient and determine the best way to tailor the surgery to the patient," said Davinder Grover, MD, attend- ing surgeon and clinician, Glaucoma Associates of Texas, Dallas. The explosive growth within MIGS creates more options, but it also involves further analysis of the factors needed to match MIGS procedures with each patient. Here are the factors that several surgeons currently use to help with their deci- sion and where they think the need for MIGS is still underserved. Glaucoma severity, IOP goals A great starting point is to think about glaucoma severity and whether the MIGS in question uses or bypasses trabecular outflow, said Arsham Sheybani, MD, assistant professor of ophthalmology and visual science, Washington Universi- ty School of Medicine, St. Louis. "In general, in patients with advanced disease who need lower pressures than where they are at or who need to reduce medications, we typically won't start with the trabecular out- flow pathway," Dr. Sheybani said. Making MIGS choices A GATT performed with a 5-0 prolene suture; the suture has passed nearly 360 degrees around Schlemm's canal and the distal end of the suture can be retrieved prior to creating a 360 degree trabeculotomy Source: Davinder Grover, MD

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