EyeWorld Asia-Pacific June 2016 Issue

June 2016 EWAP CORNEA 57 by Liz Hillman EyeWorld Staff Writer Report: KPro outcomes improved, but serious complications still significant The clouded cornea of a patient before receiving the Boston keratoprosthesis Eye of a patient immediately following the Boston keratoprosthesis procedures Source (all): William Barry Lee, MD Literature review reveals successes, shortcomings, and areas for future Kpro research A recent literature review that evaluated the outcomes and complications of the Boston type 1 keratoprosthesis (Kpro, Massachusetts Eye and Ear Infirmary, Boston) found that overall success of the device in patients is significantly better than in early trial years but noted that there are still some serious complications to address. This Ophthalmic Technology Assessment, prepared by the American Academy of Ophthalmology (AAO) and published in its journal Ophthalmology , looked at 22 peer- reviewed studies to answer the question: “What are the outcomes and complications of the [KPro] for continued on page 58 artificial corneal transplantation?” The KPro, which the U.S. Food and Drug Administration approved in 1992, is the “most commonly used artificial cornea in the United States and throughout the world,” according to Massachusetts Eye and Ear Infirmary’s website. Data from the Eye Bank Association of America’s Annual Statistic Report reveals that of the more than 76,400 corneal tissues used in transplants in 2014, slightly less than 300 were KPro cases. This, however, was a 15.3% increase over the KPro cases out of overall corneal tissue transplants reported in 2013. The prosthetic is composed of three parts: a polymethylmethacrylate (PMMA) core with human cadaveric tissue (to help suture the device to the recipient cornea), sandwiched between the front PMMA core and a plastic or titanium back plate. William Barry Lee, MD , Eye Consultants of Atlanta, said the KPro is not for every corneal transplant patient. “It is reserved for patients who have undergone multiple human cadaveric corneal transplant rejections or for cases where human tissue would reject such as severe corneal neovascularization or total limbal stem cell loss,” Dr. Lee said. Dr. Lee, the report’s lead author, said that the overall findings reveal that the outcomes of the KPro have “certainly improved dramatically from some of the early publications with the device in the 20th century.” Still, he added, the main challenges of preventing infection and glaucoma control remain. Dr. Lee went on to say that while long-term topical antibiotic use has “dramatically reduced risk of infection,” it’s still possible and, in the end, could result in loss of the eye. Visual outcomes Based on the Snellen chart, patients in 14 of the 16 articles that reported visual acuity had preoperative vision ranging from 20/100 to light perception. After the procedure, Lee et al. found the majority reported vision at 20/200 or better. “In 10 of the 16 articles reporting this information, 54% to 84% of patients reached this target,” the study authors wrote. “Five articles reported visual acuities of 20/40 or better in 11% to 39% of eyes. Four articles reported visual acuities of 20/40 or better in 43% to 69% of eyes. Three of the 16 articles reported best Snellen visual acuities of 20/100 or better in 69% to 81% of patients.” Dr. Lee called this “amazing vision improvement in the vast majority of cases.” The report authors did note that visual acuity was “skewed toward vision improvement because reports of patients with