Eyeworld

EW FEATURE 100 Advances in corneal inlays • March 2017 by Ellen Stodola EyeWorld Senior Staff Writer AT A GLANCE • Currently, the KAMRA inlay is placed in a corneal pocket, while the Raindrop inlay is placed under a flap. • The Raindrop inlay is indicated to be placed under a corneal flap at 30% thickness. • The KAMRA corneal pocket should be around 200 to 250 microns deep, with many indicating that deeper is better. Experts discuss considerations when implanting different corneal inlays W hen implanting cor- neal inlays, creating the ideal tunnel or flap for the inlay is especially important for the success of the procedure. Daniel Durrie, MD, Durrie Vision, Overland Park, Kansas; Phillip Hoopes Jr., MD, Hoopes Vision, Salt Lake City, and Luke Rebenitsch, MD, ClearSight, Oklahoma City, commented on how they think the femtosecond laser has impacted this process and key differences between using pocket and flaps for the differ- ent inlays. need to understand wound healing, he again stressed. The inlay doesn't cause excessive wound healing on its own, but rather it's the combination of dissection with the femto laser. Dr. Hoopes said he has expe- rience using the iFS laser (Abbott Medical Optics, Abbott Park, Illi- nois), WaveLight FS200 laser (Alcon, Fort Worth, Texas), and the Femto LDV Z4 laser (Ziemer, Port, Switzerland) in making pockets for the KAMRA inlay. "Each of these femtosecond lasers has been able to make the pocket without difficulty," he said. "Currently, we have used the iFS laser for the flap creation for placement of the Raindrop." Dr. Hoopes thinks that any of the Femto has revolutionized implanting of corneal inlays One thing everyone has to under- stand, Dr. Durrie said, is that when doing corneal inlays, regardless of what brand it is, a foreign object/ material is being introduced into the cornea. The goal for the inlays is to have the inlay do its job but not have excessive wound healing inter- fere with that. "That's why femto- second preparation is so important," he said. Outside the U.S., ophthalmol- ogists have learned the impact of excessive wound healing around the inlay, Dr. Durrie said. With the KAMRA (AcuFocus, Irvine, Califor- nia), for example, there's no inlay in the visual axis so any excessive wound healing around the inlay changes the corneal curvature, and causes loss of some reading vision, he said. Meanwhile, if the inlay is in the center and there is excessive wound healing, you could lose best corrected vision. "The focus should be how to avoid excessive wound healing," Dr. Durrie said. Incidence is rare and has become significantly lower with the understanding of femto and how parameters are different using a deeper pocket in the cornea than when physicians became used to doing a flap. The anterior lamellar layers are tightly packed, Dr. Durrie said, so it's like cutting something very stiff. You can cut a precise area by splitting the lamellar with the femto. As you go deeper in the cornea, it's like cutting through a sponge, and the layers are not as tightly packed, he said. The femto laser makes microscopic air bubbles that have a tendency not to stay in the plane as well when tissue isn't as tightly packed, Dr. Durrie said, so you need to move spots of femto closer together the deeper you go and lower the energy as well. "The good news is all of the femtosecond companies are learn- ing this," he said, noting that many companies are modifying the tech- nology to maximize the ability of the lasers to do pockets. Cornea inlays work well but you Implanting corneal inlays Monthly Pulse Update on intracorneal inlays T he topic of this Monthly Pulse survey was "Update on intracorneal inlays," which was dis- tributed as part of the current feature "Advances in corneal inlays." We asked about plans to offer or not offer corneal inlays now that they are FDA approved in the United States. The majority of respondents to this survey said, "Even though I do refractive surgery including PRK and LASIK monovision, I will continue to not offer corneal inlays." When asked to make a recommendation for a 50-year-old plano presbyope patient who wanted surgical correction, a majority responded that they would only recommend reading glasses. When asked about the positive features they see in corneal inlays, the majority of respondents selected all three features: they blur distance less than monovision; they do not negatively affect stereoacuity as much as monovision; and they are removable. When asked about recommendations for a 48-year-old patient who was 20/20 uncorrected at a distance and wanted to surgically correct their presbyopia but did not want refractive lens exchange, a majority opted for none of the surgical options. Dr. Rebenitsch demonstrates how he places a KAMRA inlay in a combined LASIK and KAMRA procedure. Source: Luke Rebenitsch, MD

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