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EW CORNEA 128 October 2016 Figure 1E is an example of preloaded DMEK in an IOL cartridge preserved in the transport vial that is filled with the transport media. The entire unit can be used for shipment and can be preserved up to 4 days at room temperature. In the surgical theatre, the transport medium can be removed and the tissue can be restained with trypan blue for easy recognition before the transplant. The IOL car- tridge should be filled with balanced Figure 1: Preloading DMEK grafts in the eye bank. A: Stripped DMEK tissue on vacuum block with endothelial side tri-folded inward. B: DMEK graft is gently moved in the loading chamber of an IOL cartridge. C: DMEK graft is pulled further in the preservation chamber using end-grasping forceps. D: DMEK graft in the IOL cartridge filled with transport medium blocked from its rear and front end using rubber stoppers. E: Entire unit is then preserved in transport vial using transport media. Source: Jaini Parekh salt solution in order to avoid any serum injection that is present in the preservation liquid. The tissue can then be injected inside the recipient eye using a syringe (1 mL). The tissue opens up spontaneously on its own, therefore an air bubble can be used to adhere the tissue to the recipient eye. Results to date Our primary results 2 have shown that tri-folded (endothelium-in) DMEK tissues can be preserved in IOL cartridges filled with preserva- tion media supplemented with dex- tran up to 4 days at room tempera- ture without a high endothelial cell loss and active metabolism. How- ever, the surgical outcome needs to be further evaluated. This technique has been validated using 20 human donor corneal tissues suitable for research. It was also observed that the stripping technique to prepare a DMEK graft offers minimal tissue wastage (almost 100% success rate of peeling). Average time to strip the DMEK tissue was found to be 20 minutes, whereas the loading time was 4.5 minutes, which can be saved in the operating room if the tissues are preloaded. Endothelial cell loss after preservation was 4.35% with 3.55% mortality. The cells showed active metabolism and did not show any damage in terms of cellular morphology or molecular integrity. The tri-folded technique with en- dothelium inward showed that the graft unfolds easily inside the eye in <1 minute. 3 Usually a standard DMEK surgery can take between 20 and 45 minutes (mostly to open the graft and stick it to the stroma of the recipient eye), and if the surgeon has to prepare the tissue in the operating room, the surgical time may reach up to an hour. Preloading the tissue and implanting it with the endo- thelium flapped inward may reduce the overall surgical time by around 45–50 minutes, thus reducing the overall costs of the surgery. Conclusions Preloading DMEK will have a major clinical impact in terms of: 1. Reduced graft preparation issues, simplified surgery with high reproducibility rate, provision of a validated and ready-to-use tissue, reduced surgical time and tissue wastage, cost, and logistical requirements. 2. Ease of handling, meaning that even less skilled surgeons could perform a DMEK, a procedure that is now limited to only a few surgeons. As the tissues will be pre-prepared in the eye banks, the learning curve for the surgeons will only be limited to the trans- plantation technique. 3. Implanting a pre-validated DMEK graft with correct orientation; less cost (the device will be provided by the eye bank, thus reducing the cost of the surgical tools used) and time required for surgery, thus allowing more surgeries to be scheduled on any specific day. 4. Efficient postoperative data; as preloading DMEK grafts will provide validated tissue, postop endothelial graft survival will be easy to record and manage. EW References 1. Ruzza A, et al. Preloaded donor corneal lenticules in a new validated 3D printed smart storage glide for Descemet stripping automat- ed endothelial keratoplasty. Br J Ophthalmol. 2015;99:1388–95. 2. Parekh M, et al. Preloaded tissues for Descemet membrane endothelial keratoplasty. Am J Ophthalmol. 2016;166:120–125. 3. Parekh M, et al. Endothelium-in versus endothelium-out for Descemet membrane endothelial keratoplasty graft preparation and implantation. Acta Ophthalmol. 2016 Jul 16. [Epub ahead of print] Editors' note: The authors are affiliated with the International Center for Ocular Physiopathology (ICOP), Fondazione Banca degli Occhi del Veneto Onlus, Venice, Italy. They have no financial interests related to this article. Contact information Parekh: mohit.parekh@fbov.it New continued from page 127 " Preloading the tissue and implanting it with the endothelium flapped inward may reduce the overall surgical time by around 45–50 minutes, thus reducing the overall costs of the surgery. "

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