Eyeworld

127 EW CORNEA October 2016 by Mohit Parekh, MSc, Alessandro Ruzza, BSc, and Stefano Ferrari, PhD New horizon in the field of endothelial keratoplasty Preloading grafts for DMEK D escemet's membrane endothelial keratoplasty (DMEK) has evolved over the years since it was first introduced in 2006. Var- ious preparation and implantation techniques have been addressed so far. However, there has not been a standard technique for DMEK. Eye banks are confronted with new re- quirements from corneal surgeons as DMEK is gaining popularity in terms of early rehabilitation and better visual outcomes. DMEK validation and standardization both in terms of preparation and implantation is thus becoming essential. At the Veneto Eye Bank Foundation (FBOV), we have seen a gradual increase in the demand for tissues for specific pur- poses like pre-cut DSAEK since 2012. FBOV has also received requests for pre-cut DMEK tissues, and we have seen an interest in these tissues since 2014. In 2015, we reported preloaded tissues for DSAEK using a commercial device, I-Glide (Eurobio, France), which has the capability to transport and transplant pre-cut DSAEK tissue. 1 In 2016, we reported a "proof of concept" for preload- ing DMEK tissues and introduced a modified design for a surgical device that will help to preserve, transport, and transplant a DMEK graft with less manipulation. Preloading DMEK will also be useful to standardize and validate DMEKs with advantages like reduced primary graft failure rates due to deoriented grafts, lowering the high surgical skills quotient, high rehabilitation rate with better visual acuity, low surgical time, costs and logistic requirements. Preloading DMEK tissues The dedicated device as a "proof of concept" is a modified intraocular lens (IOL) cartridge that includes: (a) loading chamber to load the tri-fold- ed stripped DMEK graft with endo- thelium inward, (b) preservation chamber with a funnel pore of 2.2 mm for easy insertion of the DMEK graft in the recipient eye, (c) detach- able stoppers to block the rear and the front end for preservation phase, (d) container to preserve the device, and (e) syringe to hold the device during transplantation. DMEK lenticules can be prepared using a stripping method leaving a hinge behind. The tissues can be punched with an 8.5–9.5 mm diameter blade and folded (overlapped) with endo- thelial side inward (Figure 1A) and loaded in the chamber of the device. The tissue is moved further inside the preservation chamber using end-grasping forceps (Figure 1B and C). The entire unit is then filled with the transport media (tissue culture medium supplemented with dex- tran) and locked from its front and rear end using stoppers (Figure 1D). continued on page 128

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