Eyeworld

EW FEATURE 104 Refractive options March 2015 by Michelle Dalton EyeWorld Contributing Writer including loss of quality, loss of contrast, and halos at night." The Raindrop is steeper in the center than in its intermediate areas, Dr. Whitman said, but patients may lose up to a line of distance vision. "They tend to regain a lot of it back over a year's time," he said. While some complain about the KAMRA's visibility, Dr. Whitman said the 2 mm diameter, 30 µm thick Raindrop is imperceptible in a patient's eye. Simply put, the inlays are trying to create a surgical alternative to monovision and multifocal contact lenses, Dr. Lindstrom said. To date, patient satisfaction has been "pretty good" with the 2 inlays furthest along in the studies, said Jeffrey Whitman, MD, in practice at the Key-Whitman Eye Center, Dallas. Those two inlays—the KAMRA (AcuFocus, Irvine, Calif.) and the Raindrop (ReVision Optics, Lake Forest, Calif.)—have shown impressive results in the clinical studies, and are commercially avail- able outside the U.S. "In general, visual side effects are low and very rare," Dr. Whitman said. "The rate of dryness, haze, and glare all are very low, in accordance with making a LASIK flap. But there will be a percentage of people that don't react well to an inlay. They'll denote a foreign body reaction or inflammatory reaction, which usu- ally can be treated with steroids, but there are going to be some people in whom the inlay will have to be removed." Method of action Both monovision and inlays typical- ly treat the non-dominant eye, said Vance Thompson, MD, director of refractive surgery, Vance Thompson Vision, Sioux Falls, S.D. The KAMRA uses a pinhole effect to create a 1.6 mm pupil, while the Raindrop increases depth of focus, Dr. Whitman said. "There is more loss of distance with the Raindrop than there is with the KAMRA, but some would argue—and the data suggests it may be true—that the near may be a little better with the Raindrop and intermediate better with KAMRA," Dr. Lindstrom said. "The Raindrop creates a multifocal cornea so it hits far and near." Another inlay, the Flexivue (Presbia, Irvine, Calif.), changes the refractive index rather than the shape of the cornea, he added, but does result in about a line of dis- tance vision lost. One advantage to the KAMRA is it offers good intermediate vision and a continuous range of vision, but because it creates a pinhole ef- fect, night vision is slightly reduced, Dr. Lindstrom said. Similarly, the Raindrop boasts all the advantages of multifocal lenses, "but it has the potential for all the negatives, too, With pros and cons to each approach, experts suggest careful patient selection is the key to success S urgical correction of pres- byopia remains one of the "Holy Grails" of ophthal- mology. Monovision—cor- recting 1 eye for distance and the other for near—is a fairly well understood concept. Today, the corneal inlay is fast approaching regulatory approval in the U.S., and understanding the advantages and disadvantages is integral to provid- ing better patient outcomes, experts say. The "best way" to differentiate between the 2 approaches is to think of corneal inlays as "modified mono- vision" and standard monovision as just "monovision," said Richard L. Lindstrom, MD, founder of Minne- sota Eye Centers, Minneapolis. "Whether you're doing mono- vision or modified monovision with an inlay, you take the usually dominant eye and target it for dis- tance—20/12 if you can," he said. In standard monovision, the fellow eye is corrected for near, so the patient is likely to have "very blurry" distance vision, with some loss of binocu- larity and stereopsis, he said. But as long as surgeons do not correct above –2 (and preferably closer to –1.5 D) in the near eye, patients can use spectacles to regain distance vision and stereopsis. In modified monovision, good distance vision is retained in the near eye, with less loss of binocular summation for distance and stereopsis. AT A GLANCE • Corneal inlays can improve near vision without compromising distance. • Both monovision and corneal inlays treat the non-dominant eye. • Assessing biological compatibility 12–24 months after inlay implantation is recommended. • Corneal inlays can be removed if patients cannot adapt. Correcting presbyopia: Monovision or corneal inlays? One day postoperative hydrogel intracorneal lens for presbyopia placed in a pocket at 400 µm depth. Visual acuity at one month, 1 year, and 5 years after surgery: 20/25 and J2. Source: Richard L. Lindstrom, MD The Raindrop is 2 mm in diameter and 30 µm thick. Source: Revision Optics continued on page 106 There is also the VisAbility Implant and VisAbility Implant System (VIS) from the Refocus Group (Dallas). It is made of 4 small, clear plastic implants that are insert- ed below the surface of the sclera. The implants work through the vaulting of the sclera, according to the company's website. "This vaulting of the sclera also lifts the underlying ciliary mus- cles surrounding the crystalline lens," material from the company said. "Lifting of the ciliary muscles

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