Eyeworld

EW FEATURE 86 Advances in corneal inlays • March 2017 AT A GLANCE • Intracorneal inlays have a history that dates back decades, starting as a concept for other refractive indications before settling on presbyopia. • There are three different types of inlays (two of which have FDA approval) with different optical principles to help presbyopes regain some near vision without reading glasses. • In addition to serving a previously untapped market, physicians say inlays are rejuvenating other refractive surgeries as well. by Liz Hillman EyeWorld Staff Writer also said that the KAMRA seems to perform better in patients who are slightly myopic, which is something the surgeon can create to maximize outcomes. Per AcuFocus' Ophthalmic Devices Panel Executive Summary submitted to the FDA, 83.5% of the 478 patients included for evaluation in the pivotal study achieved uncor- rected near visual acuity (UCNVA) of 20/40 or better 1 year postop. 4 At 36 months, 87.1% of the 417 subjects available for evaluation achieved UCNVA of 20/40 or better. Less than 1% of subjects had induced cylin- der because of the procedure, and the mean endothelial cell loss was about 5% but it stabilized by 1 year. As for subjective, patient-reported symptoms, dryness was the most common. As with other procedures, Dr. Durrie said setting patient expecta- tions for the KAMRA is important. While some patients see improve- ment in the first week, it may take 2 or 3 weeks for the majority to start experiencing the effects, with KAMRA The KAMRA, which was approved in April 2015, operates based on the principle of small-aperture optics, much like a camera or pinhole effect. Placed in a femtosecond laser-made pocket in the patient's non-dominant eye and centered over their pupil, this opaque, porous inlay made of polyvinylidene difluo- ride narrows the pupil's aperture size to increase depth of focus. The 3.8 mm inlay with the cen- tral open space of 1.6 mm was ap- proved for presbyopic patients with +0.5 D to –0.75 D of cycloplegic refractive spherical equivalent with 0.75 D refractive cylinder or less. According to AcuFocus, the patient should not rely on glasses or contact lenses for distance vision. Some sur- geons will, however, perform LASIK in sequence with the inlay or simul- taneously, said Daniel Durrie, MD, clinical professor of ophthalmology, University of Kansas, Overland Park. AcuFocus, however, notes that the safety and efficacy of this combi- nation is not known. Dr. Durrie at the time, it was usurped by the success of PRK and LASIK with the excimer laser. "Then we transitioned to the idea that an intracorneal lens might be a useful adjunct for presbyopia," Dr. Lindstrom said. Fast forward to present day. There are two inlays approved by the U.S. Food and Drug Administration (FDA), the KAMRA inlay (AcuFocus, Irvine, California) and the Raindrop Near Vision Inlay (ReVision Optics, Lake Forest, California), and one in clinical trials leading toward FDA approval, the Flexivue Microlens (Presbia, Irvine, California). All three of these inlays have the CE mark. "The first question patients asked eye surgeons 20 years ago was, 'Can you get rid of my glasses, can you get rid of my contacts?' And we could say yes when LASIK was approved," said Ralph Chu, MD, Chu Vision Institute, Bloomington, Minnesota. "Now they ask, 'Can you get rid of my reading glasses?' And we can actually say yes to that now." What's available now and what's coming down the pipeline with these presbyopia-correcting implants I ntracorneal inlays have come a long way since they were first introduced as a concept in 1949 by Jose Barraquer, MD, Bar- celona, Spain. 1 In the decades following, research was conducted on the effect of an implant in the cornea for correction of myopia and aphakia. 2,3 New procedures would even- tually supersede inlays for these re- fractive conditions, but the implants found their market and materials would improve to the point of being well-tolerated within the cornea. Richard Lindstrom, MD, Minnesota Eye Consultants, Minne- apolis, first started working with in- tracorneal inlays 30 years ago using polysulfone lenses for the correction of high myopia. While the outcomes for treating myopia were quite good, Dr. Lindstrom noted that the mate- rial prevented glucose diffusion and resulted in vascularization. "That, however, led us to ap- preciate that if you're going to use a non-permeable material, you need to microperforate it. That was great learning," Dr. Lindstrom said. Following that, Dr. Lindstrom said he worked with a company to develop a hydrogel intracorneal lens for the treatment of myopia and aphakia. While this showed promise History of inlays, the current market, and what's yet to come This early generation polysufone implant placed in 1982 by Peter Choyce, MD, of England to treat high myopia shows early vascularization. It eventually needed to be explanted.

• Blank Page
• Blank Page (1)