JUL 2013

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

Issue link: https://digital.eyeworld.org/i/146899

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August 2012 EW NEWS & OPINION 15 Tools & techniques Optimizing KAMRA inlay clinical outcomes by Minoru Tomita, MD, PhD T he final frontier in refractive surgery is presbyopia. For the elderly patient with cataracts, multifocal IOLs, accommodative IOLs, and future investigational lenses make the treatment of presbyopia somewhat straightforward. For the patient who has just reached presbyopic age, the options are many and the ideal treatment is still debatable. When there is a large refractive error, a refractive lens exchange or monovision LASIK can be performed and will usually result in a happy patient with the right temperament. The emmetropic presbyope is perhaps the most challenging refractive patient. Can we justify a refractive lens exchange just to treat presbyopia? Is it proper to create myopia with LASIK in a patient who was 20/20 in both eyes? Is there a better approach? In this month's column, Minoru Tomita, MD, describes the prospects of future presbyopic treatment with the KAMRA corneal inlay. This technology offers the prospects of reversible treatment for presbyopia that can provide functional near vision without the need to blur distance acuity through myopia. The procedure can be performed in the emmetrope, combined with LASIK, or used in a post-refractive patient. This overview gives a great review of this technology with tips for perfecting technique and maximizing outcomes. Richard Hoffman, MD, Tools & techniques editor T he KAMRA corneal inlay (AcuFocus, Irvine, Calif.) for the correction of presbyopia is commercially available in 48 countries and currently in front of the FDA for review. After seven years in clinical trials in the United States and nearly 20,000 inlays implanted worldwide, there have been several advancements in surgical technique for inlay implantation. For all procedures, the inlay is implanted into the patient's nondominant eye and, if necessary, the dominant eye is treated for distance vision. Patient selection and expectation management are critical for achieving excellent outcomes postoperatively. Patients with uncontrolled dry eye, blepharitis, keratoconus, or cataracts are not good candidates for a KAMRA inlay. If dry eye and blepharitis are treated and controlled, these patients can still be considered. KAMRA inlay pocket implantation (PEK) The procedure used in the international clinical trial was implantation of the inlay into a corneal pocket in emmetropic patients using femtosecond laser technology. PEK requires the patient be prepped with the same antibiotic and anesthetics as a LASIK procedure. Preoperatively, an AcuTarget image of the eye intended for implantation should be captured and assessed to determine the ideal inlay placement location. Bilaterally, 78% of the patients can see J2 or better and 88% can see J3 or better. 98% of patients are 20/20 or better. (IE=inlay eye, FE=fellow eye, OU=both eyes) The surgical procedure begins by creating a lamellar pocket at a depth of 200 microns using a femtosecond laser. For optimal results, laser settings should be adjusted to provide the smoothest resection possible with minimal energy. Next, the cornea is marked using a 4 mm ring marker to identify where the inlay should be placed. A custom spatula is then used to dissect the pocket. The inlay is loaded into the forceps with only 1/4 of the inlay protruding beyond the edge of the forceps. The inlay is then inserted into the pocket and centered within the mark made preoperatively. Once the inlay is in the desired location, the inlay is released and the forceps are slowly withdrawn from the pocket. This is a dry procedure, so there is no irrigation of the interface. It is important, when inserting the inlay into a pocket, to insert beyond the centration mark and then pull the inlay into the desired position. This technique removes any folds in the inlay that may have occurred during insertion and simplifies the centration process. Once the inlay is well centered, does not have any folds, and there is no debris in the pocket, the procedure is complete. Combining LASIK and KAMRA inlay implantation (CLK) Most patients that present for presbyopia correction also have some degree of ametropia, and this procedure allows both to be corrected at the same time. This procedure also begins with marking the location where the KAMRA should be placed in the non-dominant eye. Using a femtosecond laser, a 200-micron flap is created. The flap is lifted and the refractive correction performed. The flap is then replaced and the stromal bed irrigated. This concludes the LASIK portion of the procedure. The inlay is loaded into the inlay forceps with approximately 3/4 of the inlay protruding beyond the end of the forceps. Using toothless forceps, the flap is relifted, the inlay is placed on the corneal bed, and the flap is replaced using a dry technique. If the position needs to be adjusted, the flap can be lifted and the inlay can be adjusted. While centration is important, it is more important to minimize flap manipulation. Surgeons should only relift the flap a maximum of two times in order to minimize postoperative edema. Post-LASIK KAMRA implantation (PLK) The inlay can also be used to address presbyopia in patients who have previously undergone LASIK surgery. In these patients, a corneal pocket is created, again with a femtosecond laser in the non-dominant eye at least 200 microns deep in the cornea and 100 microns between the inlay pocket and the LASIK interface. The incision should be created temporally between the previous LASIK flap edge and as close as possible to the limbus to minimize induction of astigmatism. continued on page 16 At one year after PLK, 95% of patients report being satisfied with their vision. Only 8% (2% often, 6% sometimes) of the patients need reading glasses. Source (all): Minoru Tomita, MD, PhD

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