Eyeworld

81 November 2016 EW MEETING REPORTER A new DMEK technique Donald Tan, MD, Singapore, high- lighted a new technique, hybrid- DMEK (H-DMEK), a variation of DMEK, which adopts the standard Descemet's stripping automated endothelial keratoplasty (DSAEK) procedure but uses the DSAEK stromal tissue just as a carrier. It uses pre-stripping of the Descemet's membrane (DM) from the pre-cut tissue and lays it back loosely onto the stroma. There is coiling of the DSAEK stromal tissue and the DM into the EndoGlide DSAEK inserter. The physician pulls only the DM do- nor tissue into the anterior chamber and leaves the DSAEK stromal tissue behind in the EndoGlide chamber, he said. There are both pros and cons with the H-DMEK technique, Dr. Tan said. Pros include more consis- tency and less stress because of less reliance on tissue characteristics; a more controlled procedure and bet- ter control of donor tissue; shorter learning curve; no need to unscroll and the ability to use with young donor tissue with no risk of tissue eversion; and shorter manipulation time, which can lead to less endo- thelial cell loss. Dr. Tan noted the possible cons, particularly that DSAEK pre-cut tissue is still needed. There is also a requirement of a disposable DSAEK tissue inserter. "There is a bit of a learning curve," he said, like a one-handed DMEK tissue manipula- tion. There is a larger entry wound, so you can have a more unstable an- terior chamber, but that's mitigated by the fact that you're holding onto the tissue, so it evens out, he said. Early results of hybrid-DMEK seem encouraging, Dr. Tan said. Editors' note: Dr. Tan has financial interests with Alcon (Fort Worth, Tex- as), Allergan (Dublin), Bausch + Lomb (Bridgewater, New Jersey), Carl Zeiss Meditec (Jena, Germany), Network Medical Products (Ripon, U.K.), and Santen (Osaka, Japan). Award lecture The R. Townley Paton Award Lecture was given by Mark Terry, MD, Port- land, Oregon, on "The Evolution of Endothelial Keratoplasty: A Personal Journey." He detailed his personal experience with the development of EK, also mentioning the many key contributors in its development, in- cluding surgeons and those involved in industry. Dr. Terry got involved with EK development in private practice. In 1997, he joined an "instrument development advisory board." Although 1998 was a tough year for him both professionally and person- ally, it was this year that he had an epiphany and the following year he began to take his first steps to devel- op these procedures. Dr. Terry dis- cussed the different EK procedures, including DLEK, DSEK/DSAEK, and DMEK, and the advances in each. He stressed the importance of eye banks in the evolution of corneal trans- plantation, and why he thinks that everyone should be doing DMEK. The evolution of corneal trans- plantation over the past 16 years has been astonishing and patients have benefited immensely, Dr. Terry said. DMEK represents pure anatom- ic replacement surgery and takes physicians as far as surgery can go, he said. Standardization and surgical simplification of DMEK should now lead to full acceptance by transplant surgeons. He added his final thoughts for residents and fellows. The "big ideas" that become game changers in surgery rarely come out of the labs of prestigious universities, but usually from individual surgeons who are passionate about what they do and unhappy with the status quo, Dr. Terry said. Don't question whether you can make a difference simply because after you graduate you are in private practice or in a non-academic setting, he added, and don't be afraid to innovate. Dr. Terry said to always put patients first by protecting their safety and rights at every step of innovation. Editors' note: Dr. Terry has financial in- terests with Bausch + Lomb and Moria (Doylestown, Pennsylvania). Donor tissue When it comes to corneal trans- plants, there are many factors to consider before actually doing the transplant, including the quality of donor tissue and if there is any risk of disease transmission. Maria Woodward, MD, Ann Arbor, Michi- gan, highlighted this topic. There is a risk of disease transmission from donor to recipient in corneal trans- plantation, she said, but there are many efforts being made, particular- ly by eye banks, to ensure the tissue used in these transplantations is safe and of high quality. The standards for determining the quality of tissue are very dy- namic, Dr. Woodward said, and they respond to changing conditions and knowledge. She noted that there were recent adjustments to consider Zika virus and malignant melano- mas and their impact on donor tissue that would make the tissue unsuitable for transplant. The risk of transmission is not zero, Dr. Woodward said, but we do whatever possible to minimize risk. Dr. Woodward pointed out the specific donor contraindications to transplantation, both infectious and non-infectious. Infectious contraindications include hepatitis B, hepatitis C, HIV, West Nile virus, congenital rubella, Reye syndrome, viral encephalitis, viral meningitis, rabies, Ebola virus, vaccinia, and Zika. Infectious bacte- rial contraindications include syph- ilis, bacterial meningitis, bacterial endocarditis, and sepsis. Additional- ly, other infectious contraindications include fungal endocarditis and prion diseases. Non-infectious contraindica- tions may include leukemia, lym- phomas, malignant melanoma, Parkinson's disease, amyotrophic lateral sclerosis (ALS), multiple scle- rosis (MS), Alzheimer's disease, and Down syndrome, as well as death View videos from AAO 2016: EWrePlay.org Amar Agarwal, MD, introduces a new PDEK technique employing infusion anterior and posterior to the iris. continued on page 82

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