Eyeworld

73 EW GLAUCOMA June 2017 teens during the follow-up period. The device is effective in its ability to create and maintain blebs. Our blebs are still standing and holding with a high success rate at 5 years. I think this is a very important con- tribution—the device is introduced ab externo, which is invasive, but its results warrant its use. Our success rate is 96%; failure was seen in 1/23 patients whose IOP did not drop below 20% from baseline." Physicians uncomfortable with trabeculectomy or cautious about the adverse events associated with the procedure may now have a new, less complicated option. "The MicroShunt will offer an alternative to the gold standard of modern surgery, which is trabeculectomy, as a primary procedure, but may not be as effective in all refractory cases or as a secondary procedure. There is an ongoing FDA trial comparing the InnFocus MicroShunt to trab- eculectomy, and the results will be revealed in 6 months," Dr. Batlle said. "Known complications of fil- tration surgery (trabeculectomy) and valves include blebitis, exuberant bleb, endophthalmitis, choroidals, and Tenon's cyst, and have been a real challenge to the gold standard. The InnFocus offers maximum IOP lowering by bypassing the trabecular meshwork, Schlemm's canal and the aqueous veins, and by draining to a bleb. It can treat all stages of glauco- ma and is associated with a minimal follow-up, no suture lysis, quick vision recovery, a needleable device, and no cataract progression." EW References 1. Acosta AC, et al. A newly designed glaucoma drainage implant made of poly(styrene-b-isobutylene-b-styrene): biocompatibility and function in normal rabbit eyes. Arch Ophthalmol. 2006;124: 1742–9. 2. Batlle JF, et al. Three-year follow-up of a novel aqueous humor microshunt. J Glauco- ma. 2016;25:e58–65. Editors' note: Dr. Batlle has financial interests with InnFocus, Allergan, and Ivantis (Irvine, California). Dr. Riss has no financial interests related to her comments. Contact information Batlle: jbatlle55@gmail.com Riss: isabelleriss@orange.fr pseudophakic, nine phakic, and 12 cataract patients. Their mean visual acuity in the test eye was 20/60 (range: light perception vision to 20/20) and their mean number of glaucoma medications was 2.2 ± 0.9 medications (range: one to four medications). The patients' ancestral heritage was mixed: black, Hispanic, Arawak Indian, white, or a combina- tion thereof. Success was defined as a patient with an IOP ≤21 mm Hg and an IOP reduction from baseline of 20% or greater, with no reoperation for glaucoma (trabeculectomy, another drainage implant) or loss of light perception vision. Complete success was a patient who was not on sup- plemental medical therapy to obtain controlled levels of IOP, while quali- fied success was defined as a patient who required supplemental medical therapy to maintain levels of IOP. Needling of the bleb or post-surgical injection of an anti-fibrotic were not considered failures. "You can see in the initial post- op period that the shunt reduced the IOP more when it was combined with cataract surgery," Dr. Batlle said. "But after 2 years, this differ- ence disappeared altogether. In the years 3 to 5, we actually had an identical set of data for the com- bined group as for those who had a single procedure. Flow is related to the diameter of the tube—the wider the tube lumen, the higher the flow. This tube is set to give us a pressure postoperatively of about 6 mm Hg, but as we saw in our study, IOP continues to increase to the low immune system without generating a foreign body response as would occur with silicone. SIBS is a new concept in organic chemistry. It is a molecule with an ultra stable carbon backbone strongly bonded to its side chains. The backbone and side chains avoid ethers, esters, amides, urethanes, ureas, carbonates, labile c-bonds, and double bonds. It pro- vokes insignificant myofibroblast production and tissue reactions, and no neovascularization when placed in the subconjunctival space, as seen in rabbit models. This explains the ability to have it coexist in the sub- conjunctival space without extru- sion or encapsulation, by matching the compliance of ocular tissue. SIBS was first used in drug eluting coro- nary stents," Dr. Batlle said. 5-year data In the 5-year outcomes update, reported at the ESCRS Winter Meet- ing, of a published 3-year study 2 conducted by Dr. Batlle in which 23 primary open angle glaucoma patients received InnFocus Micro- Shunts, IOP remained steady at 12.3 mm Hg, which was well within the zone of optimal IOP control, for 5 years' duration. Glaucoma medications at year 1 were 0.3 ± 0.8 medications per patient and 0.9 ± 1.5 medications by year 5. The IOP percentage reduction was 55% in year 1 and 48% in year 5. The study patients were aged 59.8 ± 15.3 years (range 30–81 years) with a baseline fully medicated IOP of 23.8 ± 5.3 mm Hg (range: 18.5–38 mm Hg), and were comprised of two the MicroShunt is wedged into the pocket. The fin keeps the device from migrating into the anterior chamber, it prevents fluid from flowing around the device, and it provides stability. Finally, the distal end of the device is tucked under Tenon's capsule and the conjunctiva is closed, providing additional hold. "Most of the time if the pa- tient is looking down and doesn't move, you are not going to lose the anterior chamber. We have the same postoperative strategy as after cataract surgery. There is hardly any inflammation postoperatively and no cases of severe hypotony," Dr. Riss said. The InnFocus device is thin and soft to conform to the curvature of the eye. The lumen is sufficient- ly large enough (70 µm) to pass sloughed endothelial cells, and narrow and long enough (8.1 mm) to prevent hypotony. InnFocus versus XEN Although the XEN Gel Stent (Aller- gan, Dublin) and InnFocus Micro- Shunt create a similar pathway for aqueous flow, there are several fac- tors that set them apart. "The Micro- Shunt is implanted ab externo while the XEN is implanted ab interno," Dr. Riss said. "Although InnFocus does not fall under the definition of an ab interno MIGS device, it has been termed a MIGS device by the Food and Drug Administration. It is placed in a subconjunctival/Ten- on's flap, where hemostasis can be controlled and its position ensured. Placement of the XEN stent, howev- er, does not allow control of hemo- stasis or the ability to place it under the Tenon's capsule. The MicroShunt has a 70 µm lumen whereas the XEN has a 45 µm lumen, so there is less chance of clotting with the larger lumen. Also, there is more than 15 years' history using the special ma- terial that makes up the shunt, SIBS, supporting its long-term stability in the body." According to Dr. Batlle, what sets the InnFocus apart from the XEN stent has everything to do with its material makeup: poly(sty- rene-block-isobutylene-block-sty- rene) (SIBS). 1 "The InnFocus MicroShunt is a very innovative microshunt, made of a special material that is accepted by the Dr. Batlle consults with a patient about InnFocus. Source: Juan Batlle, MD

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