EyeWorld India June 2015 Issue

Corneal lamellar surgical procedures June 2015 32 EWAP SECONDARY FEATURE Evolution and implementation of DMEK into practice by Ellen Stodola EyeWorld Staff Writer AT A GLANCE • When beginning DMEK, there is a learning curve, so using the procedure may be more beneficial for high volume surgeons. • There are a number of injection techniques that can be used in DMEK, including IOL injectors or other off-label injectors. Glass material is often deemed better than plastic for success. • The best candidates for DMEK are eyes with corneal edema but no alteration of the anterior segment. Since its introduction, DMEK has been gaining ground, but some still prefer DSEK K eratoplasty procedures have evolved over the years, with a number of breakthroughs in tissue handling, wound healing, and the ways the surgeries are performed. Mark Gorovoy, MD, Fort Myers, Fla. , Francis Price, MD , Price Vision Group, Indianapolis, Mark A. Terry, MD , Devers Eye Institute, Portland, Ore., and Isabel Dapena, MD, PhD , Netherlands Institute for Innovative Ocular Surgery (NIIOS), Rotterdam, the Netherlands, are currently using Descemet’s membrane endothelial keratoplasty (DMEK). They commented on the specifics of the technique, how it compares to Descemet’s stripping automated endothelial keratoplasty (DSAEK), and when each procedure should be used. Since 1998, NIIOS has introduced concepts for posterior The right eye had a DMEK just 6 days before this photo, and the vision is 20/20 without glasses. The left eye had a DSAEK 6 months before the photo, and the vision is 20/25 with a hyperopic glasses refraction. Source (all): Mark Terry, MD lamellar keratoplasty, Dr. Dapena said. In the U.S. these techniques were popularized as deep lamellar endothelial keratoplasty (DLEK) and DSAEK. “In 1998, we described a technique for selective transplantation of Descemet’s membrane through a self-sealing 3.0 mm clear corneal incision, at that time tentatively named DMEK,” she said. “Since then, the DMEK technique evolved into what we now know as the ‘standardized no-touch DMEK technique’ surgery, which can be performed in reproducible steps and with hardly any direct contact with the tissue, which theoretically diminishes the potential damage of the donor endothelium during surgery.” Dr. Price said the first endothelial keratoplasties were difficult because part of the posterior stroma had to be dissected off, and the surgeon had to do a hand dissection of the donor and fit the pieces together. Descemet’s stripping endothelial keratoplasty (DSEK) was a huge breakthrough, he said. The vision was the same but without the problem of slow wound healing or wound rupture postoperatively, and it was a lot easier and safer for patients. “DSEK at this time is still the standard of care in the U.S,” Dr. Price said. Why DMEK? DMEK, which started being used around 2008, increases the degree of difficulty for the surgeon because it is just Descemet’s membrane and endothelium, Dr. Price said. Initially, handling donor prep was a problem, but he said that for many high volume surgeons, the donor loss rate is now less than 1%. “The initial advantage with DMEK was that the vision was better,” he said. When you just transplant Descemet’s and endothelium, you are not inducing any irregularity into the patient’s cornea, Dr. Price said, but no matter how you cut a DSEK graft, there is always some irregularity with the way the stroma is cut. When he and his colleagues started DMEK, they were doing it for improved vision, but surgeons tended to still favor DSEK. As data was collected on DMEK, it was shown that rejection rates were lower than for other options. Dr. Price has now done more than 1,700 DMEK procedures in his practice and has only seen 20 rejections. He added that some surgeons are using the ultra-thin DSAEK grafts and are seeing fewer