Eyeworld

EW FEATURE 42 Corneal lamellar surgical procedures April 2015 Currently, he finds that the DSAEK approach can successfully serve many patients. "You can treat any patient with decompensated en- dothelium," Dr. Busin said, adding that he even selects the procedure for those with bad stroma. "It's the rare case where the cornea doesn't clear properly or there are residual scars that interfere," he said. He still performs DSAEK and may later go on and perform a DALK, leaving the DSAEK in place. "I had several cases where I was undecided whether it would be worth it to do DSAEK or just remove everything and do a PK, and in several instances I've seen that doing DSAEK gives an improvement that you would not expect to start with," he said. "It's worth it to try DSAEK." Dr. Shamie finds that any patient with endothelial disease, except for those with severe cor- neal scarring, can benefit from DSAEK. She typically recommends that patients whose vision drops below 20/40 be referred to a cornea specialist for transplant evaluation, especially if they have higher visual potential. "If the vision drops significantly less than that, they could develop corneal scarring in the anterior layers of the cornea that may not be cleared as quickly by an endothelial keratoplasty," she said. "The more the cornea remains edematous, the more anterior stromal scarring can occur, which can impact the visual outcome long DSAEK continued from page 40 Making room for DSAEK N ot all potential DSAEK patients are the same—some, such as those with anterior chamber lenses in their eyes, may present unique challenges. Here are options for modifying the technique when handling such cases. While the insertion technique is very similar, given that the anterior chamber is crowded with an anterior chamber lens, it is a little more complex, Dr. Shamie said. "If the graft is being inserted using a folding technique, the anterior chamber lens may need to be pushed down to create more space to allow for the graft to open," she said. As maintaining an air bubble in the anterior chamber can be almost impossible, the surgeon may choose to suture the graft so this does not dislocate, Dr. Shamie said. Otherwise, it might sit on the anterior chamber lens or go into the posterior chamber. She recommended scraping the stromal bed of the recipient cornea to encourage the graft adherence, without the need for the air bubble or pressurizing the eye. Also, Dr. Shamie recommended using smaller grafts, given the crowed anterior chamber. Dr. Busin noted that the type of anterior chamber lens in the eye may come into play. If it is an iris-enclavated lens such as the Verisyse (Abbott Medical Optics, Abbott Park, Ill.), this might be an advantage for DSAEK because it lays flat on the iris and blocks the air in the anterior chamber. "At the end of the procedure, you fill the anterior chamber with air to attach the graft and the air doesn't find a way to go into the vitreous cavity," he said. EW term," she said. In addition, for those who have Fuchs' dystrophy, even if Snellen acuity is good, Dr. Shamie finds that if they complain of glare from light's reflection off of guttata or thickened Descemet's, it may be time to make the referral. Going forward, Dr. Shamie is confident that DSAEK will remain a viable transplant option for many. "I don't think that DMEK will ever replace DSAEK 100%," she said. "I think that an excellent endothe- lial keratoplasty surgeon needs to be comfortable and proficient at performing both DSAEK and DMEK to offer patients the appropriate procedure." A patient with Fuchs' dystrophy who has otherwise normal corneal stroma would be best managed with DMEK with its better visual po- tential. However, those with pseu- dophakic bullous keratopathy and a disorganized anterior chamber (tube, iris loss, etc.) tend to be more com- plicated, with more limited visual potential. "In a lot of those patients, DSAEK is the gold standard and will remain the standard," Dr. Shamie said. EW Editors' note: Dr. Busin has financial interests with Moria (Antony, France). Drs. Neff and Shamie have no financial interests related to their comments. Contact information Busin: mbusin@yahoo.com Neff: drneff@carolinacataract.com Shamie: nshamie@yahoo.com Dr. Neff likewise touts outcomes with thinner tissue. "Results have been very good, particularly in thin DSAEK," she said, adding that a high number attain 20/20 acuity. Not only do patients achieve better vision with thin DSAEK, but some have noticed lower rejection rates as well, Dr. Neff said. In a study that Dr. Neff con- ducted, which was published in the April 2011 issue of Cornea, investiga- tors found that thinner endothelial keratoplasty resulted in a significant improvement in best spectacle- corrected visual acuity. "We found that there was a statistically significant difference between tissue thicker than 131 µm and thinner in terms of visual outcomes," Dr. Neff said. She favors tissue that is less than 135 µm thick. However, in general, she is careful about not rejecting tissue solely based on thickness unless there is some other issue with the cut. "If it's a little thicker, I try to match the tissue to a patient who doesn't have 20/20 visual potential to use that tissue," Dr. Neff said. Dr. Shamie prefers using donor tissue under 150 µm. However, if it is slightly thicker, she will not reject it. "I feel a sense of obligation to the donor pool not to reject corneas because that cornea may be wast- ed," she said. On the other end of the spectrum, Dr. Shamie does not like tissue that is thinner than 80 µm because this is harder to handle. Still, she recognizes that there can be advantages to using ultra-thin tissue. "There's some evidence that thinner grafts could potentially lead to faster vision recovery or better visual outcomes," she said. "But you have to weigh that against increased trauma to the thin graft as you're manipulating it for graft insertion." Dr. Busin usually welcomes an extremely thin graft of below 80 µm. As he performs 200 to 300 DSAEKs a year, he prefers to prepare the tissue himself, rather than have it done at the eye bank. This allows him to save a significant amount of money each year. " I don't think that DMEK will ever replace DSAEK 100%. I think that an excellent endothelial keratoplasty surgeon needs to be comfortable and proficient at performing both DSAEK and DMEK to offer patients the appropriate procedure. " –Neda Shamie, MD

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