OCT 2013

EyeWorld is the official news magazine of the American Society of Cataract & Refractive Surgery.

Issue link: https://digital.eyeworld.org/i/194331

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84 EW SECONDARY FEATURE Microinvasive glaucoma surgery October 2013 Steps to adopting the iStent for comprehensive cataract surgeons by Maxine Lipner EyeWorld Senior Contributing Writer Tips for getting started T hese days cataract surgeons are doing more than straightforward phacoemulsification. Many are also become adept at inserting the iStent (Glaukos, Laguna Hills, Calif.) for glaucoma patients in need of both procedures, according to Richard A. Lewis, MD, Sacramento, Calif. "The data suggests that about 20% of cataract patients that have glaucoma are on medication," he said, adding that for many this brings with it compliance problems as well as cost issues. This can make insertion of the iStent, which may alleviate or reduce the need for medication, potentially invaluable in this population, he said. While it only adds a few extra minutes onto phacoemulsification, as with anything new there can be a bit of a learning curve. We culled some secrets to early success with the iStent for comprehensive anterior surgeons. Preparing for success Dr. Lewis says the challenge that a lot of anterior surgeons face is that they don't routinely do gonioscopy and therefore may not be as comfortable with all of the anatomy of the eye. "You have to know the anatomy and know the angle structure so that you can identify the meshwork in the canal," he said. "Sometimes anterior segment surgeons are just treating areas of pigment and not realizing that that's not necessarily where the trabecular meshwork is." To better ensure success he recommended practicing gonioscopy and getting comfortable with it both in the office and in the operating room, adding that practitioners need to learn to reposition their patients following phacoemulsification so that the head is rotated away from and the microscope tilted toward the surgeon. Then the microscope is placed in the non-dominant hand. Jonathan D. Solomon, MD, Solomon Eye Physicians & Surgeons, Bowie, Md., said that when starting out with the iStent, picking the right patient can go a long way toward Stent next to the I/A tip following placement Source: Jonathan D. Solomon, MD success. He recommends initially selecting patients who have a welldefined angle structure, with a fair amount of pigment to the trabecular meshwork, wide-open angles, and who tend to be relatively relaxed about surgery. "Those who are going to tolerate the cataract procedure as a whole, who can follow instructions in general, would do best," Dr. Solomon said, noting that the iStent should be properly placed by spending the time necessary and doesn't demand that much more of the patient than cataract surgery alone. Dr. Solomon stressed, however, that reasonable expectations for glaucoma outcomes are important here. "You don't want to start with someone who is going to need very low pressures either," he said. You're not going to take a patient on three medications who still has pressures in the mid 20s and drop it down to a 9, he said, adding that for these early patients in particular you want to make sure they understand that. "[With] patients on multiple medications, if you can reduce that dependence, they'll love you for life," he said. Indeed, in a review of his first 60 patients, Dr. Solomon and his team have seen a decrease in IOP of 23% (evaluated at eight weeks) from presurgery levels, along with a reduction of one medicine bottle. Surgical secrets When it comes to the iStent surgery, Dr. Solomon recommended pressurizing the eye a little more than you would following traditional cataract surgery. That way you don't tend to see a spillover of blood in the anterior chamber. "Pressurize the eye a little bit," he said. "Instead of down at 14, 15, or 16, bring the pressure up to 20, 22, 23, just so that you can keep hyphema at bay." During the insertion process, first it's a matter of properly identifying the trabecular meshwork, Dr. Lewis said. "If you put the iStent in an area where there is a lot of drainage, near a collector system, you're going to get more [pressure reduction] than if you throw it in there wherever you can," he said. "Put it near an area of pigment— pigmented meshwork is a target because that's an area of higher flow." When initially inserting the iStent it's important to commit to the injection process. "The tendency is to back off as you're injecting it forward," Dr. Lewis said. "You have to hold your position otherwise it comes in tilted and isn't fully in the angle." Dr. Solomon recommended attacking insertion from a relatively steep angle so that you get under the trabecular meshwork with the stent.

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