EyeWorld India December 2014 Issue

49 EWAP DEVICES December 2014 efficacious procedure for lowering pressure,” Dr. Gedde said. “But there are well-known significant risks associated with them.” He reserves invasive surgery for patients who cannot be controlled medically or through noninvasive procedures like laser. “Anyone who needs a profound pressure lowering or can’t tolerate medication undergoes trabeculectomy or tube shunts. Of course, failed MIGS or failed previous surgeries are candidates as well,” Dr. Ahmed said. Dr. Samuelson said he tends to use the EX-PRESS device “for most of my incisional filtration glaucoma procedures now” and the Baerveldt for tube shunt procedures, but acknowledged other surgeons are equally adamant about using Ahmed implants. Still, the decision to perform incisional surgery must remain individualized to the particular patient, Dr. Gedde said. “It really is a judgment call on when to pull the trigger and recommend incisional surgery,” he said. What the evidence shows Advances in ocular imaging mean glaucoma specialists are “increasingly more capable of detecting structural changes,” Dr. Gedde said, and as soon as he has evidence of progression, he escalates therapy. “Some patients have such advanced disease that if they progress further, even by a small amount, it may have a very meaningful impact on their functionality,” Dr. Samuelson said. “Trabeculectomy and aqueous drainage devices have excellent efficacy, and for those patients with advanced disease they remain the ‘go-to’ procedures. Even so, while there are exceptions, I don’t believe trabeculectomy and tube shunts are safe enough to be used as the first incisional procedure for those with early to moderate disease, especially phakic eyes.” With “multiple, well-designed, randomized control trial” results now published, Dr. Ahmed said “there’s still a lot of evidence coming out in this area,” and these procedures “will continue to have a big role.” With the safety of less invasive methods “now fairly well established,” Dr. Samuelson saves the “more aggressive transscleral procedures for patients that are on the more advanced end of the disease.” The XEN Gel Stent (AqueSys, Aliso Viejo, Calif., U.S.) procedure—dubbed “MIGS plus” by Dr. Ahmed—“seems to have a bit more power than our traditional MIGS procedures,” but does create a bleb, and its efficacy is “approaching what trab can achieve,” he said. “Most studies” have shown the EX-PRESS and trabeculectomy “have similar results,” Dr. Ahmed said, although the former can eliminate the need for iridectomy. Dr. Samuelson, however, “has become pretty bullish on devices for surgery. There are those that believe the EX-PRESS adds unnecessary expense, but I use it for most of my filtration procedures because I’ve grown fond of the additional precision that it allows.” The device “augments a trabeculectomy,” Dr. Gedde said. “It eliminates the need to remove a small piece of limbal tissue underneath your trabeculectomy flap, and an iridectomy is not performed. There have been studies that suggest there’s a faster visual recovery than trabeculectomy alone.” He also cited the potentially lower risk of hypotony-related complications, but conceded “the long-term safety and efficacy isn’t different from trabeculectomy.” The newer Ahmed glaucoma valve modified with a polyethylene shell (M4) differs from traditional drainage devices in that it’s “designed to have fibrous tissue growing on the end plates, and the blood vessels provide some great surface area for aqueous to absorb into it,” but there is limited clinical experience reported. All about the pressure The bottom line for these experts—target pressure is key. If that cannot be achieved with other options available, incisional surgery is the only real option. “The only way we’re going to be able to get these patients low enough is with a bleb,” Dr. Ahmed said. “But if the patient can tolerate a pressure in the mid-teens and is going to have cataract surgery as well, then my preference would be to try a mixed procedure, either through Schlemm’s canal or in the suprachoroidal space.” Procedures that retain the physiologic flow are preferred, and may provide enough pressure lowering that the patient only needs one medication. Dr. Samuelson often describes two scenarios to patients—one option is a more efficacious surgery that has more risk, but is likely to allow discontinuation of all medications, and the second option involves a safer procedure (MIGS), but less pressure reduction likely, still requiring one or two medications. “Most of the time they take the safer option of a MIGS procedure.” For those with advanced glaucoma, however, “getting low levels of pressure is more feasible with trabeculectomy and tube shunt surgery than these newer procedures,” Dr. Gedde said. Aiming for a target pressure of 15 mmHg or even 12 mmHg is ideal, Dr. Ahmed said. “If someone is still progressing at 15 mmHg, then they need to come down to below 12 mm Hg. I’m going to get their pressure as low as I can to preserve as much vision as I can.” Whether they are using a drainage device or a shunt, Dr. Samuelson recommends surgeons “be familiar with the 1 or 2 devices you like the best because one of the things that makes them effective is consistency and familiarity.” EWAP Editors’ note: Dr. Ahmed has financial interests with AMO, Alcon, AqueSys, Glaukos, Ivantis (Irvine, Calif., U.S.), and Transcend Medical (Menlo Park, Calif., U.S.). Dr. Gedde has financial interests with Alcon and Allergan (Irvine, Calif., U.S.). Dr. Samuelson has financial interests with AMO, Alcon, AqueSys, Glaukos, Ivantis, and Transcend Medical. Contact information Ahmed: ike.ahmed@utoronto.ca Gedde: sgedde@med.miami.edu Samuelson: twsamuelson@mneye.com