Eyeworld

22 November 2018 EW NEWS & OPINION Research highlight by Maxine Lipner EyeWorld Senior Contributing Writer ural, so even if you do a nano-thin DSEK, you're not going to get the kind of visual results as quickly as you will with DMEK," he said. One of the early obstacles with learning to perform DMEK included the fact that surgeons would have to strip the Descemet's tissue off the donor tissue in the operating room, which came with the risk of tearing and destroying it, Dr. Terry ob- served, adding that the answer here was having the eye bank prestrip the tissue for surgeons, akin to what happened for DSEK. "DSEK didn't take off until they had precut tissue from the eye bank," he said. "DMEK also didn't climb until there was pre- stripped tissue by the eye banks so surgeons didn't have to risk damag- ing this at the time of surgery and canceling the case." Considering preloaded tissue Knowing that many practitioners are put off by the somewhat risky parts of the DMEK process, such as trephinating the tissue, staining with trypan blue, and loading this into an injector, Dr. Terry set out to conquer the issue. "I said to the eye bank, 'Let's see if we can preload tissue, where we do everything for surgeons, and all they have to do is take the tube out and inject the tissue,'" he said. Included in the consecutive case series were 111 eyes with endothe- lial failure that were treated with donor tissue that was prestripped, prestained, pretrephinated, and pre- loaded in a Straiko modified Jones tube, Dr. Terry noted. "We found that out of the 111 cases, there were no primary graft failures at all," he said, adding that in 16 cases it was necessary to place another air bubble and in two others a second rebubble was needed. The endothelial cell loss at 3 and 6 months, respectively, was 26.9% and 30.9%, Dr. Terry report- ed. "That's a little less cell loss than we were getting when we were doing our own loading," he said. One intriguing finding here was the sense that Dr. Terry had that the preloaded tissue seemed to unscroll easier than previous tissue that had been prepared by the practitioner. "The unscrolling times were much Performing DMEK with preprepped and preloaded tissue W hen performing Descemet's mem- brane endothelial keratoplasty (DMEK) surgeons can attain equally good results with prestained, preloaded donor tissue, without hav- ing to do it on their own, according to Mark A. Terry, MD, director of corneal services, Devers Eye In- stitute, Portland, Oregon. Results from a study published in Cornea indicated that the outcomes were no different than if the surgeons had gone through the trephination, loading, staining, and other steps themselves. 1 DMEK obstacles While the total number of DMEK procedures continues to grow, its predecessor, Descemet's stripping endothelial keratoplasty (DSEK) remains the preferred procedure, Dr. Terry said. Today, 26% of all endo- thelial keratoplasties performed are DMEK and 74% are DSEK. "Those numbers should be reversed since the data shows that DMEK gives better visual acuity with faster visual recovery," Dr. Terry said. Unfortu- nately, he finds that many practi- tioners are reluctant to try DMEK since the tissue is only 7–10 mµ thick and very delicate. "It scrolls up like a rug," he said. "If you touch it directly, you'll kill the endotheli- al cells." On the other hand, even very thin DSEK tissue is easier to manipulate since you can touch this without doing as much damage, he noted. While DSEK is a good pro- cedure, it still adds tissue to the cornea, Dr. Terry pointed out. "It has a stromal interface, which is not nat- Locked and preloaded Prestained, preloaded DMEK tissue makes it easier and more efficient for surgeons to perform the procedure, according to Dr. Terry. Source: Mark Terry, MD

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