EyeWorld India June 2015 Issue

June 2015 8 EWAP FEATURE Correcting presbyopia: Monovision or corneal inlays? by Michelle Dalton EyeWorld Contributing Writer 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. With pros and cons to each approach, experts suggest careful patient selection is the key to success S urgical correction of presbyopia remains one of the “Holy Grails” of ophthalmology. Monovision—correcting one 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 providing better patient outcomes, experts say. The “best way” to differentiate between the two approaches is to think of corneal inlays as “modified monovision” and standard monovision as just “monovision,” said Richard L. Lindstrom, MD , founder of Minnesota Eye Centers, Minneapolis. “Whether you’re doing monovision or modified monovision with an inlay, you take the usually dominant eye and target it for distance—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 binocularity 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. To date, patient satisfaction has been “pretty good” with the two 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 available 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 usually 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 typically treat the non-dominant eye, said Vance Thompson, MD , director of refractive surgery, Vance Thompson Vision, Sioux Falls, SD. 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 continued on page 10 One day postoperatively, hydrogel intracorneal lens for presbyopia placed in a pocket at 400 µm depth. Visual acuity at 1 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