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MIGS devices lead glaucoma surgical innovation in 2016


A single event stood out in everyone’s mind when Ophthalmology Times asked experts to think back on the year in glaucoma surgery: the July 29 approval by the U.S. Food and Drug Administration (FDA) of the CyPass Micro-Stent.

A single event stood out in everyone’s mind when Ophthalmology Times asked experts to think back on the year in glaucoma surgery: the July 29 approval by the U.S. Food and Drug Administration (FDA) of the CyPass Micro-Stent.

The CyPass, developed by Transcend Medical of Menlo Park, provides an alternative to the only other minimally invasive glaucoma surgery (MIGS) device currently in the U.S. market, the iStent Trabecular Micro-Bypass Stent System sold by Glaukos.

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“There has been really a revolutionary change in our field since the introduction of the iStent,” said Andrew Iwach, MD, executive director, Glaucoma Center of San Francisco, San Francisco.

Since winning approval June 25, 2012, the iStent has soared in popularity, with implantations overtaking trabeculectomy as the most commonly billed glaucoma procedure in Medicare, Dr. Iwach said.

CyPass and iStent both provide surgical relief of IOP without creating a filtering bleb and its attendant risks.

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The CyPass acts as a conduit between the anterior chamber and the supraciliary space, while the iStent bypasses the inner wall of Schlemm’s canal and allows aqueous humor more direct access from the anterior chamber to the collector channels at the outer aspect of Schlemm’s canal. 


Other MIGS devices achieved milestones on the route to the U.S. market in 2016.

  •       Allergan announced the FDA granted approval of its Xen Glaucoma Treatment System, a gelatin micro-stent that works by subconjunctival filtration. At the American Society of Retina Specialists (ASRS) annual meeting, the company presented data showing promise for the device both with cataract surgery and as a standalone procedure for mild to moderate primary open-angle glaucoma (POAG), and for use with mitomycin-C. The Xen also already has approval in Europe where it is indicated for the reduction of IOP in patients with primary open-angle glaucoma for whom previous medical treatments have failed.

InnFocus MicroShunt


  •       The InnFocus MicroShunt achieved promising 3-year results, published in the Journal of Glaucoma. The MicroShunt goes in the anterior chamber through an ab externo scleral needle track tunneled posteriorly to the limbus. Some authors consider the MicroShunt not to be a MIGS device because it must be implanted with a fornix-based conjunctival incision.

  •       While the company made no major announcements in 2016, Ivantis continued with its trial of the Hydrus Microstent, whose 556 patients make it the largest MIGS trial ever, according to the company. Placed inside Schlemm’s canal during cataract surgery using the cataract incisions, it increases outflow by allowing aqueous to bypass the trabecular meshwork, and by dilating the canal. “The initial results have been quite promising,” said Robert Stamper, MD, professor of ophthalmology,University of California, San Francisco.

Big money is at stake in these products. Alcon (a subsidiary of Novartis) acquired Transcend Medical, which developed the CyPass, in February 2016. That follows Transcend’s October 2015 settlement of a patent infringement lawsuit by Glaukos, which requires Transcend to pay royalties to Glaukos.

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In July 2016, Santen acquired InnFocus for $225 million, just months after Allergan’s September 2015 purchase of AqueSys, which developed the Xen, for $300 million.

The investment in MIGS devices bodes well for glaucoma specialists and their patients, said Joel Schuman, MD, chairman ophthalmology, New York University, New York. “I think all of those different approaches give us the ability to choose for each patient the best option,” he said.

Other approaches

Meanwhile, other surgical approaches to reduce IOP made the news in 2016 as well. A Cochrane Database Systematic Review (2016 Aug 15;(8):CD011693) examined Trabectome, an electrosurgical approach to ab interno trabeculectomy (AIT) that improves aqueous drainage through plasma-mediated ablation and disintegration of the trabecular meshwork.

The surgeon gains access to the trabecular meshwork and Schlemm’s canal through insertion of Trabectome tip (NeoMedix), which is fitted with an electrode, through a 1.6 mm clear-corneal incision, leaving the conjunctiva undisturbed. “There is currently no high-quality evidence for the outcomes of ab interno trabecular bypass surgery with Trabectome for open-angle glaucoma,” the reviewers concluded. “Properly designed RCTs are needed to assess the long-term efficacy and safety of this technique.”

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The Trab360 (Sight Sciences), used in a similar approach, also received some attention in trade journals during 2016.

The Kahook Dual Blade (New World Medical) is a single-use, ophthalmic blade that makes parallel incisions in the trabecular meshwork and inner wall of the Schlemm’s canal. Launched in 2015, it continued to get reviews throughout 2016.

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Also in 2016, the inventors of the gonioscopy-assisted transluminal trabeculotomy published a retrospective review in the Journal of Glaucoma (2016 Oct. 6 [Epub ahead of print]) finding that the procedure appears to be safe and successful in treating 60% to 70% of open-angle patients with prior incisional glaucoma surgery.



Ab-interno Canaloplasty (ABiC) continued as a subject of conversation in 2016, along with endoscopic cyclophotocoagulation.

Laser treatments for glaucoma also continued to advance in 2016, with refinements of selective laser trabeculoplasty (SLT) including micropulse laser trabeculoplasty (MLT), titanium-sapphire laser trabeculoplasty (TSLT), and pattern-scanning laser trabeculoplasty (PSLT).

MLT delivers energy in repetitive microsecond pulses with periodic cooling periods to prevent coagulative damage to the trabecular meshwork.

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TSLT uses a 790 nm wavelength laser emitting near-infrared energy in pulses from 5 ms to 10 ms on the theory that this form of energy penetrates more deeply into the juxtacanalicular meshwork and the inner wall of Schlemm’s canal. There it is selectively absorbed by pigmented phagocytes, preserving meshwork tissue.

In PSLT, a computer applies a sequence of patterns onto the trabecular meshwork to ensure that consecutive treatment steps are pieced together without overlap or excessive gaps.

A randomized controlled trial published in Acta Ophthalmologica (2016 Oct 26 [Epub ahead of print]) pitted pattern-scanning laser trabeculoplasty (PSLT) against selective laser trabeculoplasty (SLT). PSLT reduced IOP slightly more than SLT, and patients reported much less pain with PSLT. No serious adverse events were reported in either group.

Reimbursement relief

Perhaps as important as these technical accomplishments to glaucoma specialists in 2016 was the news that the Center for Medicare and Medicaid Services (CMS) has backed off from plans to cut reimbursement for trabeculectomy.

In November 2015, CMS announced that a routine review had revealed that surgeons had trimmed about 15 minutes off from the hour duration the procedure used to last. It proposed cutting reimbursement starting at 19% for each trabeculectomy code in 2016, and in 2017 reaching 25% for Current Procedural Terminology (CPT) code 66170 (trabeculectomy) and 33.3% for CPT code 66172 (trabeculectomy with scarring from previous surgery).

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The cuts exceeded those proposed by the Relative Value Update Committee (RUC), which surveys physicians not only about the time a procedure takes, but also about the intensity of work required. The RUC had proposed a reduction in work value from 2015 to 2016 of 7% in code 66170, and a reduction from 2015 to 2016 of 21.5% in code 66172.

Advocates from the AAO and the American Glaucoma Society lobbied hard, said David Glasser, MD, assistant professor of ophthalmology, Johns Hopkins School of Medicine, Baltimore, Maryland, and spokesman for the AAO.

Advocacy efforts


“It involved advocacy efforts in Congress and participating in a refinement panel in which the specialty societies can petition CMS and offer their rationale for why a decision was incorrect,” he said. “On multiple fronts, we advocated for the RUC’s evaluation because it was based on established protocol that had been considered reasonable for the last several years, and indeed CMS accepted that argument.”

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For 2017, the reimbursement levels will be restored to the levels recommended by the RUC, Dr. Glasser said.

However, the advocates for glaucoma specialists were not able to reverse CMS’s decision to bundle reimbursement for aqueous shunt with a graft into one code, reducing the total amount of reimbursement, Dr. Glasser said. Additionally, a loophole involving corneal tissue remains closed.

Related: Aqueous drainage tube provides trabeculectomy-like efficacy

The experience underscores the importance of surgeons responding to RUC surveys with accurate information, he said.

Overall, the year shaped up as a positive one for glaucoma surgeons.

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