EyeWorld is the official news magazine of the American Society of Cataract & Refractive Surgery.
Issue link: https://digital.eyeworld.org/i/78719
12 EW NEWS & OPINION February 2012 Clarity for KAMRA by Daniel S. Durrie, M.D. T he KAMRA corneal inlay by AcuFocus (Irvine, Calif.) is gaining traction as a great option for treating presby- opia in markets that have access to it, such as Europe, the Mid- dle East, and Asia-Pacific. The inlay works based on the principle of small aperture optics and provides improved depth of focus to improve near vision while having minimal impact on distance vision. The KAMRA inlay is the result of decades of study on corneal inlays. Jose Barraquer is accredited to be the first to experiment with corneal implants in 1949.1 A series of improvements took place, but early generations of inlays suffered from poor predictability, loss of acu- ity over time, haze, corneal thin- ning, and decentration.2-4 The development of new biocompatible materials and experimentation with optimal placement, however, have changed the history of corneal in- lays and the treatment of presby- opia. I first started working with hy- drogel inlays to correct aphakia in 1985. The porous nature of the hy- drogel material made these well tol- erated by the cornea, whereas inlays made out of polysulfone caused corneal thinning and melting due to their poor permeability. This was one of the first indications that in order for an inlay to be tolerated by the cornea, the biological principals of the cornea must be maintained. That includes an inlay of material that allows glucose to go through the cornea and nourish the corneal epithelium. The KAMRA inlay has gone through six design iterations, starting with the original design that was made from Dacron fabric and was 25 microns thick. Over time, the platform has transitioned to polyvinylidene fluoride, a highly biocompatible material that is used routinely in IOL haptics. Further, the inlay has been reduced in size to just 5 microns thick in the current de- sign. The number of microperfora- tions has increased from 1,600 to The KAMRA corneal inlay Source: AcuFocus 8,400, and these are arranged in a pseudorandom pattern to allow for appropriate nutrient flow and to minimize light scatter. Although melts occurred in a prior generation of inlay and with an earlier proce- LASIK continued from page 11 Placing Dr. Tanzer's outstanding LASIK patients undergoing vision tests and evaluation at the Naval Medical Center San Diego Source: Naval Medical Center San Diego results in context for the civilian population, Douglas Koch, M.D., professor of ophthalmology, Cullen Eye Institute, Baylor College of Medi- cine, Houston, pointed out that the Navy is performing LASIK on person- nel that have outstanding potential for excellent outcomes. In the film, Dr. Koch cautioned viewers that not everyone can expect those kinds of results and that the only way to de- termine a patient's potential out- come is by undergoing a very thorough screening process. Dr. Koch also noted that "the studies conducted by Dr. Schallhorn and others in the military have greatly benefited the civilian population by helping us better understand how to get the best outcomes for all pa- tients, military and civilian." The Navy's outcomes and well- documented studies made a com- pelling case that advanced LASIK could withstand the most extreme rigors of ground warfare and avia- tion. This opened the door for LASIK in space, with NASA approving LASIK for astronauts in 2007. The documentary, "LASIK: On the Frontlines," is currently under re- view for broadcast on a national tele- vision network. As these programs tell a compelling story, ASCRS has decided to move forward with the sale and distribution of them through its producer, Patient Educa- tion Concepts, in an effort to satisfy the numerous requests for the pro- grams it has received from members. Both programs can be viewed on PEC's website, www.patientedcon- cepts.com, and are available for pur- chase for $49.95 plus $5.00 shipping by calling PEC at 800-436-9126. EW ABOUT THE AUTHOR John Ciccone is director of communications for the American Society of Cataract and Refractive Surgery. Contact him at 703-591-2220. dure, to date there have been no flap melts in the current clinical trial that will be submitted for approval next year. In addition to the evolution in materials and design, numerous