EyeWorld Asia-Pacific June 2016 Issue

EWAP CORNEA 55 June 2016 Department of Ophthalmology, University of Minnesota. Using small diameter aperture optics, the KAMRA is placed in a patient’s non-dominant eye within a small pocket created in the cornea with a femtosecond laser. Surgeons ensure proper centration—the most “critical” factor for successful patient outcomes, Dr. Lindstrom said— using the AcuTarget HD, which was developed by AcuFocus to work with the KAMRA to help identify the center of the visual axis for inlay positioning. The Raindrop, which is commercially available in the European Union and had the FDA accept its premarket approval submission in November 2015, is placed under a LASIK-like flap and works much like a multifocal IOL by creating a multifocal cornea. The inlay is thinner at its edges and reaches up to 32 microns at its center to achieve this effect. Dr. Wiley thinks the Raindrop could work best in patients who have a minimal amount of hyperopia. The Flexivue is in a phase 3 clinical trial in the U.S. and has received the CE mark in Europe. This inlay is placed in a pocket created with a femtosecond laser in the cornea. It has a refractive power built in that is carefully selected by the surgeon based on the patient’s needs. Dr. Lindstrom said a potential challenge with the Flexivue and the Raindrop is that a stronger power might be needed as the patient continues to age over time, while the KAMRA is more “one- stop shopping,” he said. The Flexivue could be beneficial to younger patients, Dr. Wiley said, because they could require a lesser power that would then make adjusting to the device easier. Such a patient might require multiple surgeries over time to increase the power with new inlays as needed. A patient who might benefit from the Flexivue is someone who has done well with monovision contact lenses, Dr. Wiley said. All of these inlays are designed to allow nutrients to pass freely through them. On a macro-scale, Dr. Hovanesian said success of the inlays is “remarkably similar,” based on the data. “There are differences [among the inlays] that are important, but from a standpoint of patient results, they’re all fairly similar,” he said. A 3-year follow-up study published in January 2012 in the Journal of Cataract & Refractive Surgery about patients who had received the KAMRA supported the longer-term safety and continued efficacy of the inlay. 1 Of the 32 patients surveyed, 84.5% said they would have the procedure again. As for the learning curve, Dr. Hovanesian said it’s relatively short because “most surgeons performing these inlays are already performing LASIK, using femtosecond lasers, and dealing with corneal flaps.” “What makes these procedures different is that there is a very delicate implant to be handled with implant instruments and a corneal pocket, which is a somewhat different operating environment,” he said. “For most surgeons, these hurdles are fairly easily to overcome. “With inlays it’s the postop care that’s a greater challenge than the technique itself,” he added. Dr. Wiley said that proper patient selection is something surgeons will need to learn as well. Who’s the best candidate? The ideal candidates for inlays, Dr. Hovanesian said, are patients who are generally younger presbyopes, have healthy eyes, and have always had good distance vision without glasses. “These fit patients who are healthy but are 55 years old and are fed up with reading glasses,” he said. “In the past, the only choice for these folks was to give them monovision, but in an ideal world, you wouldn’t compromise their distance vision.” Patients who have already developed presbyopia and are myopic would likely get LASIK to correct their distance vision first and then have an inlay placed for their near vision, Dr. Wiley said. A patient with an existing inlay needing some sort of refractive enhancement later could have LASIK or PRK done, but Dr. Wiley said these procedures would likely happen simultaneously or before. Patients with inlays who develop cataracts later in life will also be able to maintain the inlay with the ophthalmologist selecting the correct IOL to work well with it. Who isn’t a good candidate? “In general, anyone who isn’t a good candidate for refractive surgery is not a good candidate for corneal inlays,” Dr. Wiley said. “That may include people with thin corneas, dry eye disorders, inflammatory or autoimmune disorders, and people who are critical observers and might not … enjoy a different optical system.” Healing, complications, and comparisons In terms of healing, Dr. Lindstrom said surgeons need to manage wound healing of the ocular surface, and there is a neuroadaptive aspect for patients. Dr. Hovanesian said inlay patients might require a longer follow-up period than LASIK patients to ensure they are still tolerating the device well. Dr. Lindstrom said it takes anywhere from a few weeks to a few months for patients to realize the full benefit of the inlays, but Dr. Hovanesian said those who have received it in his practice are still “really excited about how immediate the results are.” continued on page 56