EyeWorld is the official news magazine of the American Society of Cataract & Refractive Surgery.
Issue link: https://digital.eyeworld.org/i/233841
30 EW REFRACTIVE SURGERY January 2014 Refractive editor's corner of the world Raindrop corneal inlay shows promise for all degrees of vision correction by Ellen Stodola EyeWorld Staff Writer Early results for the inlay indicate potential for the future C orneal inlays continue to incite much interest and show promise. The concept of creating a corneal flap or partial corneal incision, placing the inlay, and replacing the flap/closing an incision seems pretty straightforward. Given the limitations of presbyopic treatments, corneal inlays seem to fill an unmet need— a presbyopic solution that is minimally invasive, reversible, and preserves any residual accommodation a patient may still possess. The potential pool of candidates for these procedures is quite large. However, after years of careful clinical studies and subsequent manufacturer modifications, we are still left in the cycle of clinical studies and perhaps more modifications. Thanks to Drs. Steinert and Waring for updating us on the topic of corneal inlays for this month's "Refractive editor's corner of the world." I look forward to the day when we will have the opportunity to offer these technologies to our patients on a routine basis. Presbyopia, as those of us of age have come to learn, is a challenge we should be able to solve. Kerry Solomon, MD, refractive editor can give near and intermediate vision with little to no compromise to distance vision. he Raindrop (ReVision Optics, Lake Forest, Calif.) is just one of several corneal inlays in development for the treatment of presbyopia. Roger Steinert, MD, chair, Department of Ophthalmology, University of California, Irvine, and director, Gavin Herbert Eye Institute, Irvine, Calif., spoke at the 2013 American Academy of Ophthalmology meeting about the advancements and results of the Raindrop so far. He followed up with input on what's to come from the inlay. George Waring IV, MD, assistant professor of ophthalmology, and director of refractive surgery, MUSC Storm Eye Institute, and medical director, Magill Vision Center, Charleston, S.C., commented on the Raindrop and other presbyopia inlays. "We all know that the current options for presbyopia correction are less than fully satisfactory," Dr. Steinert said at the meeting. There are options like monovision and multifocality, but there is a struggle to find an alternate technology that Dr. Steinert explained in his presentation that the Raindrop is a physiological and transparent corneal inlay. It is a hydrogel and is biocompatible, with a water content and refractive index that is the same as the cornea so that nutrients can flow through it. He added that it is only 2 mm in diameter and approximately 30 µm thick, which varies depending on the power. The inlay is easily inserted under a flap and can be removed if the results are not satisfactory. "It reshapes Bowman's layer and the anterior cornea," Dr. Steinert said. "This gives a gradient of power with smooth transitions for near, intermediate, and distance." "The easiest way to think about the different presbyopic inlays is by mechanism of action because they've changed names and design so many times through the years," Dr. Waring said. "The Raindrop is unique in that it's a permeable hydrogel lenticule that allows for nutrient flow and fluid flow. This is a space occupying lenticule that is the only one of its kind on the market." T What is the Raindrop? The Raindrop Near Vision Inlay is a 2 mm hydrogel corneal inlay. He explained that the Raindrop has the same refractive index as the cornea, meaning that it has no refractive power but creates a hyperprolate shape of the cornea to help increase the depth of focus and provide a broader range of vision. Dr. Waring said that this is different from the other inlays, like the KAMRA (AcuFocus, Irvine, Calif.), which uses a small aperture, or others that have refractive power. How to insert the inlay To insert the Raindrop inlay, Dr. Steinert said to start by making a flap at one-third of the depth of the corneal thickness, which typically is about 150 µm, that initially reshapes the front in a parallel manner. "The key that makes this work so well optically is remodeling of the cornea that goes on anteriorly with epithelial hyperplasia and remodeling to give this prolate shape and hence the term profocal," he said. What preop refractive error or range of errors is ideal? At the 2013 AAO meeting, Dr. Steinert spoke about recent results of studies that were undertaken to determine what preoperative refractive error or range of errors is ideal for implanting the Raindrop. Source: ReVision Optics