EyeWorld India March 2012 Issue

March 2012 26 EW FEATURE Implantable telescope gives hope to advanced AMD patients by Faith A. Hayden EyeWorld Staff Writer The implantable miniature telescope and vision treatment program can help some end-stage AMD patients Source: VisionCare Ophthalmic Technologies AT A GLANCE • The implantable miniature telescope can help some end-stage AMD patients regain functional vision • The telescope is not for everyone, and includes many contraindications • The telescope has been approved for use in the U.S. by the FDA, and Medicare applies Device and treatment plan approved by FDA and Medicare I magine being told by one esteemed ophthalmologist after the next that there’s no hope—that the end-stage AMD wreaking havoc on your eyes, your vision, and your entire life, is irreversible. Imagine being told that you’ll never see the faces of your grandchildren, you’ll never again read a book or a newspaper, and you’ll always need assistance pouring coffee. For most end-stage AMD patients, this is the prognosis. But now, thanks to an implantable miniature telescope and vision treatment program approved both by the FDA and Medicare, it doesn’t always have to be. Developed by VisionCare Ophthalmic Technologies (Saratoga, Calif., USA), the mini telescope is inserted into the patient’s worst eye by a cornea specialist. The implant enlarges images by approximately 2.2 or 2.7 times their normal size and projects them into healthier areas of the retina instead of the macula alone. This reduces the blind spot and allows the patient to better view objects that were previously unrecognizable. “There can be complications, which is why the device is restricted to cornea-trained surgeons,” said Kathryn A. Colby, MD, PhD , Massachusetts Eye and Ear Infirmary, Boston, Mass., USA. The procedure is complex, requiring proper wound construction, anterior chamber management, and device insertion after phacoemulsification for a successful surgery. Complications include surgical trauma to the corneal endothelium. “It’s critical that surgeons not view this first-of-a-kind device simply as a larger IOL,” stated an article co-authored by Dr. Colby in the Archives of Ophthalmology (2007;125(8):1118-1121). “One must create an adequately large incision at the limbus, use an appropriately steep downward entry angle to avoid corneal touch, and make a large-diameter (>7-mm) capsulorhexis to accommodate the stiff haptics of the carrier plate with minimal intraoperative manipulation. Meticulous attention should be paid to surgical detail to avoid iris prolapse and a flat anterior chamber.” The surgery, though, is just the beginning. Like a knee or hip replacement, the patient has to go through months of physical, or in this case visual, rehabilitation to learn to use the device correctly. “The brain isn’t used to seeing one large image and one regular size image,” said Susan A. Primo, OD, MPH, FAAO, director, Vision and Optical Services, Emory Eye Center, Atlanta, Ga., USA. “Patients are not really using two eyes at the same time, they’re using one eye for detail and specific activities, that’s the telescope eye, and the fellow eye, which is the non-implanted eye, for walking around and other activities like going up and down stairs.” This rehab process, called the CentraSight treatment program, involves a comprehensive team of doctors including a retina surgeon, cornea surgeon, low- vision specialist, and occupational therapist, and four distinct steps: diagnosis, candidate screening, implantation, and rehabilitation. Candidate screening is critical, and doctors interviewed estimate that only 25% of those screened will continue on to implantation. “There’s many things in the anterior segment of the eye that would eliminate them as candidates,” said Dr. Colby. “The eye has to be a normal eye with the exception of AMD. The corneal endothelium needs to meet a certain minimal level of number of cells in order to proceed with the surgery, and that’s FDA mandated. The anterior chamber has to be large enough to accommodate the telescope, which does protrude above the pupillary plane. The patient can’t have any issues that compromise the integrity of the lens capsule, for example pseudoexfoliation or a history of trauma, because the device needs to sit within the capsular bag to be stable.” To make use of the telescope and make the potential risks of surgery worth it, patients have to improve with an external simulating device that tests their ability to adapt and use the device. It also assesses the potential field of view with the implanted eye at that magnification. “If they don’t improve with the magnification they aren’t CentraSight implantable telescope technology helps improve vision in end-stage AMD Source: James Gilman, CRA