EyeWorld is the official news magazine of the American Society of Cataract & Refractive Surgery.
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E W GLAUCOMA 134 by Ellen Stodola EyeWorld Staff Writer An update on the iStent T h e iStent (Glaukos, Laguna, Hills, Calif.) has been FDA approved for more than a year, but updates on the technology are still exciting because of the way it is evolving and the results so far, experts say. The real late-breaking news surrounding the iStent, said Thomas Samuelson, M D, Minneapolis, is the way it is incorporated into surgical manage- ment of glaucoma. Dr. Samuelson spoke at the 2013 American Academy of Ophthalmol- ogy meeting about new technologies for glaucoma that will hopefully help surgeons intervene earlier than was previously possible. "The goal i s to try to stop glaucoma from progressing," he said, since it is the second leading cause of blindness. Deciding when in the spectrum of glaucoma to use the iStent is a new development. Another important factor is the realization and acceptance that cataract surgery lowers IOP. The fact that phacoemulsification lowers in- traocular pressure has changed glau- coma management, Dr. Samuelson said. The glaucoma spectrum and various treatment options "If we look at the severity spectrum of glaucoma, it's clear there are some patients who will never go blind and never even be symptomatic of their glaucoma while others will become functionally impaired or lose their functionality completely," Dr. Samuelson said in his presentation. Likewise, there is a spectrum of surgical interventions to offer. "We have some surgeries that are extremely safe but only modestly effective and some surgeries that are marginally safe but highly effective." There is not a question about whether a trabeculectomy or tube procedure can effectively lower in- traocular pressure, but the concern with these procedures is safety. "In the past we've been somewhat reluctant to do a trab or a tube on patients on the low end of the severity spectrum for glaucoma," Dr. Samuelson said. However, proce- dures in the "phaco plus" category, including phaco with MIGS proce- dures, could be an option for these types of patients. "We have the opportunity to in- dividualize care like we never have before," Dr. Samuelson said. It be- gins with "the phaco platform" for glaucoma management, which has a modest IOP benefit, is extremely safe, and very predictable. He added that the ancillary effects of pha- coemulsification are beneficial including vision improvement, im- provement in the anterior chamber configuration, improved refractive error, and extremely high patient satisfaction. " We certainly don't want to mess that up with some of the complications that we see with traditional glaucoma surgery," Dr. Samuelson said, adding that he no longer uses trabeculectomy or tubes just for the convenience of getting patients off of their medication be- cause these procedures prove too m uch of a risk for those with early to moderate forms of glaucoma. Trials with the iStent Dr. Samuelson discussed data from an iStent trial sponsored by Glaukos that looked at two major endpoints. The first compared cataract surgery plus the iStent to cataract surgery a lone to see which was more likely to get pressure lower than 21 mm Hg without medication from a base- line of about 25 mm Hg, and the second looked at which group was more likely to get a 20% reduction in pressure without medication. At one year, the data was statis- tically significant in favor of the iStent plus cataract surgery on both endpoints. Comparing the two-year data, the iStent results still proved superior, although the second end- point was no longer statistically significant. Even so, it is important to understand that as a one-year trial, the study wasn't adequately powered through two years. "The beauty of this procedure lies in the safety," Dr. Samuelson said. While traditional glaucoma surgeries are heavy on efficacy, they may focus less on safety. The new combination is extremely safe, even if only modestly effective. "The fact that you can perform a glaucoma operation in conjunc- tion with cataract surgery and have it be comparable in safety to cataract surgery alone with no measurable statistical safety differences is break- ing news," Dr. Samuelson said. Incorporating the iStent into glaucoma treatment Dr. Samuelson spoke about what the incorporation of the iStent into the glaucoma disease spectrum means. "I don't think it needs to be rele- gated to just the early stages of glaucoma," he said. "I think any tool we have that lowers pressure is helpful for all forms of glaucoma." Patients with reasonably con- trolled glaucoma on two or three medicines may choose to have pha- February 2011 March 2014 The iStent is designed to improve aqueous outflow and reduce IOP. It is only 1 mm in length and 0.33 mm in height. The stent is inserted and positioned in the eye with the help of a sterile inserter. Source: Glaukos IOP reduction seems to be inherent to cataract surgery. In this video from Hawaiian Eye 2014, Steven Dewey, MD, discusses clinical employment of this finding and de- scribes which patients benefit most. In this video from Hawaiian Eye 2014, Gary Foster, MD, discusses surgical tips and personal experi- ence with MIGS devices. The operative gonioscopy mirror may be the biggest hurdle, he said. In this video from Winter Update 2014, Steven R. Sarkisian Jr., MD, discusses patient selection and surgical pearls for first iStent cases. Gonio lens use can be tricky. Related videos on ewreplay.org ewreplay.org Winter Update 2014 Monday ewreplay.org Hawaiian Eye 2014 Wednesday ewreplay.org Hawaiian Eye 2014 Tuesday 130-135 Glaucoma_EW March 2014-DL2_Layout 1 3/6/14 4:12 PM Page 134