EyeWorld Asia-Pacific December 2016 Issue

December 2016 EWAP CORNEA 55 by Mitchell Gossman, MD Comparison of methods for performing DSAEK Exploring the methods practicing ophthalmologists use when performing DSAEK A survey was performed of 23 ophthalmologists who volunteered to participate from the ranks of participants of the eyeCONNECTIONS online community and volunteers in North America. Responses are anonymous in order to encourage candor. The first five survey questions, covering the topics of anesthesia preference, incision size, and removing Descmet’s, were summarized in the August 2016 issue of EyeWorld . The sixth question in the survey was, “What diameter graft for Fuchs’ in a normal-sized cornea?” 7.5mm 0 7.75mm 0 8.0mm 48% 8.25mm 22% 8.5mm 26% 8.75mm 0 9.0mm 4% 9.25mm 0 9.5mm 0 The seventh question was, “What diameter graft for endothelial failure (e.g., post-phaco decompensation) in a normal-sized cornea?” 3.0mm 4% 3.5mm 9% 4.0mm 39% 4.5mm 4% 5.0mm 35% 5.5mm 9% 6.0mm 0% Graft size is a tradeoff. Some advantages of a larger graft are: a larger optical zone; more endothelial cells, which lowers the risk of graft decompensation; more forgiving of decentration; and a greater distance of the central donor from the aberrations induced by the graft edge, such as edema and folds. Disadvantages of a larger graft are: greater compression and potential for cell loss during folding and insertion; more tedious unfolding; and potential for peripheral anterior synechiae at the graft edge. On the other hand, advantages of a smaller graft are: simpler unfolding; easier access to the anterior chamber for fluid and air injection; less compression during insertion with possible endothelium damage; and the potential for a smaller incision size. Disadvantages of a smaller graft include fewer endothelial cells and the potential for greater visual significance of imperfect centration. Since much of the visual disability of Fuchs’ dystrophy is related to the optical effects of guttae and not just corneal edema, a smaller graft may be satisfactory for improved vision, and in fact, studies have shown that smaller graft size is not associated with lower final endothelial cell count. The eighth question was, “What method do you use to insert the donor lenticule into the anterior chamber?” Busin glide 30% Commercial insertion device, e.g., EndoGlide 28% Folding forceps 17% Push in along Sheets glide with needle 25% Suture pull-through 0% Folding forceps are relatively straightforward, but it can be challenging to keep track of which side is up and require a wider incision of at least 50% of the graft diameter. EndoGlide and others are elegant and fast and can insert a graft through a small incision, but there is an associated expense. Sheets glide method is fast, easy, quick, and there is little ambiguity about graft orientation, but there may be endothelial loss from the endothelial side gliding along the surface. Busin glide is reusable and offers the potential for a smaller incision, but especially with larger grafts, the folding process may result in graft compression with resulting endothelial cell loss. Personally I started with folding forceps and moved to the Busin glide method and have found incision sizes can be very small, even 3.5 mm, without compromised graft function and results, and only one suture suffices. The ninth question was, “If the corneal incision is secure without a suture, do you still suture the corneal incision?” Yes 83% No 17% With a smaller incision, you may find that the incision is watertight, and as with clear cornea cataract surgery, there can be high confidence that a sutureless incision is watertight, especially when small. Sutureless is more convenient to the patient, OR time and cost is less, and less astigmatism is induced. However, the consequences of a leaky incision with DSAEK could be Mitchell Gossman, MD continued on page 56