FEB 2014

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

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Page 52 of 114

1. 27 r 1. K 27 E W CORNEA 50 February 2014 E ditors' note: None of the devices discussed in this column are approved for use in the U.S. EyeWorld spoke with clinical investigators. W hen ophthalmologists joke that the three things people cannot avoid are death, taxes, a nd presbyopia, it's a clear indication the disorder is per- vasive among people who reach a certain age. "Our biggest need happens to be the thing we have the fewest treatment options for," said Stephen G. Slade, MD, in private practice at Slade & Baker Vision C enter, Houston. That may change once corneal inlays are approved for commercial use in the United States (all are under investigation); "more and more of my patients want a surgical solution—they don't want to wear reading glasses," said George O. Waring IV, MD, FACS, assistant pro- fessor of ophthalmology, director of refractive surgery at the Storm Eye Institute, and medical director of the Magill Vision Center at Medical University of South Carolina, Charleston. "The surgical manage- ment of presbyopia is emerging as its own (sub)specialty, and corneal inlays are a promising option for corneal-based treatments." In the U.S., there are three corneal inlays being investigated (see sidebar for a description of each), but in the U.S. studies, patients can only be enrolled if they are emmetropic or roughly em- metropic in both eyes, said Robert K. Maloney, MD, in private practice at Maloney Vision Institute, Los Angeles. "For now, there's no one combining the inlays with corrective refractive procedures in a simultaneous surgery in the U.S.," Dr. Maloney said. In his opinion, different inlays will be appropriate for different patients, with some potentially better suited for those with mild levels of myopia (KAMRA, AcuFocus, Irvine, Calif.) and others more suited for people with mild levels of hyperopia as they induce a slight myopic shift (Flexivue Microlens, Presbia, Irvine, Calif.). "What all these inlays are trying to do is provide a better option than monovision," Dr. Slade said. "With monovision, if you make an eye –1, you'll gain six lines of near but lose six lines of distance. The inlays are trying to soften this by eliminating the loss of distance while still im- proving near vision." While monovision is an avail- able treatment for presbyopia, "a lot of people cannot tolerate it," Dr. Maloney said. "If you add depth of focus, your reading vision will im- prove. So the goal is to leave one eye emmetropic and [have] the other produce some multifocality for depth of focus." For patients to be enrolled in any of the current studies (now closed to recruitment), they had to have had monovision experience, Dr. Maloney said. "Another advan- tage of the inlays is they produce much less binocular rivalry than monovision," he said, citing the work of Scott MacRae, MD, and Pablo Artal, MD, who concluded that most people accept about a diopter of binocular disparity. In the ongoing studies, the inlays are "delivering excellent near vision for a small loss of distance," and Dr. Slade predicted "they are going to have different quality of vision although quantity of vision is similar," like the way one type of multifocal IOL has a different near and distance vision profile than another type. Integrating the inlays into practice The "ideal" candidate for an inlay is someone between the ages of 45 and 65, who may have had previous LASIK or is naturally emmetropic, Dr. Slade said. Studies have evalu- ated the inlays either placed under a LASIK flap or inserted into a pocket, both of which have their own set of surgical challenges and benefits, he said. "None of the lenses has passed the real-world U.S. test," he said. "I'm very enthusiastic about the space and the results we've seen to date. I'm looking forward to working with the inlays on a much broader group of patients." Dr. Waring said presbyopic subjects have done very well in the studies, and predicts he'll use inlays to "extend the life of vision correc- tion in post LASIK patients that have become presbyopic or in early pres- byopes with clear lenses—until a lens-based surgery is indicated. We can simultaneously correct congeni- by Michelle Dalton EyeWorld Contributing Writer Exploring corneal inlays Raindrop Near Vision Inlay Source: ReVision Optics Flexivue Microlens Source: Presbia D evice focus The KAMRA Inlay Source: AcuFocus Snapshot overview of the inlays E ach of the corneal inlays works slightly differently, although they are all designed to treat presbyopia through implantation into the non-dominant eye. (All information is from company websites.) KAMRA Inlay, AcuFocus The KAMRA inlay is an opaque circular micro-disc with a small opening (1.6 mm) in the center that features 8,400 high precision, laser-etched micro-openings along the surface of the inlay to help maintain a healthy cornea. AcuFocus claims its small-aperture technology is a superior alternative to options that use a multifocal approach. Flexivue Microlens, Presbia The Presbia Flexivue Microlens is only 3 mm in diameter, approximately 15 microns in edge thickness, and is barely discernible when placed within the corneal stroma. The lens is made of a hydrophilic polymer, similar to materials used in IOLs for more than two decades, ensuring biocompatibility of the device. Raindrop Near Vision Inlay, ReVision Optics The Raindrop Near Vision Inlay is a microscopic hydrogel device that creates a prolate-shaped cornea. The device is placed under a femtosecond laser 4ap and does not require any tissue removal. The hydrogel material comprises nearly 80% water to help ensure effective nutrient diffusion and transfer through the cornea. 50-55 Cornea_EW February 2014-DL2_Layout 1 1/30/14 10:41 AM Page 50

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