Corneal Donor Tissue Preparation for Descemet's Membrane Endothelial Keratoplasty

Abstract

Descemet's Membrane Endothelial Keratoplasty (DMEK) is a form of corneal transplantation in which only a single cell layer, the corneal endothelium, along with its basement membrane (Descemet's membrane) is introduced onto the recipient's posterior stroma(3). Unlike Descemet's Stripping Automated Endothelial Keratoplasty (DSAEK), where additional donor stroma is introduced, no unnatural stroma-to-stroma interface is created. As a result, the natural anatomy of the cornea is preserved as much as possible allowing for improved recovery time and visual acuity(4). Endothelial Keratoplasty (EK) is the procedure of choice for treatment of endothelial dysfunction. The advantages of EK include rapid recovery of vision, preservation of ocular integrity and minimal refractive change due to use of a small, peripheral incision(1). DSAEK utilizes donor tissue prepared with partial thickness stroma and endothelium. The rapid success and utilization of this procedure can be attributed to availability of eye-bank prepared precut tissue. The benefits of eye-bank preparation of donor tissue include elimination of need for specialized equipment in the operating room and availability of back up donor tissue in case of tissue perforation during preparation. In addition, high volume preparation of donor tissue by eye-bank technicians may provide improved quality of donor tissue. DSAEK may have limited best corrected visual acuity due to creation of a stromal interface between the donor and recipient cornea. Elimination of this interface with transplantation of only donor Descemet's membrane and endothelium in DMEK may improve visual outcomes and reduce complications after EK(5). Similar to DSAEK, long term success and acceptance of DMEK is dependent on ease of availability of precut, eye-bank prepared donor tissue. Here we present a stepwise approach to donor tissue preparation which may reduce some barriers eye-banks face in providing DMEK grafts.

Quantitative Analysis of Endothelial Cell Loss in Preloaded Descemet Membrane Endothelial Keratoplasty Grafts

“…11 Briefly, the tissue was stabilized with the endothelium side up on the Barron Punch Cutting Block (Katena, Denville, NJ, USA). A partial thickness 9.5mm trephination was performed.…”

“…6–10 Surgeons have been slow to convert to DMEK because of the steep operative learning curve and the technical difficulty of donor corneal tissue preparation. 11, 12 Any damage to the DMEK tissue can lead to endothelial cell loss (ECL) and may contribute to the higher rates of graft detachment and failure. 4, 5, 13 …”

“…10, 11, 14, 15 Eye banks began providing pre-stripped DMEK tissue around 2013; however, more tissue preparation is still needed by the surgeon in the operating room prior to surgery which can damage the fragile tissue. The optimal tissue delivery would be one where the tissue was completely stripped, trephined, and stored in the injector ready to go on the day of surgery.…”

Six-Month Results of Descemet Membrane Endothelial Keratoplasty in 100 Eyes: First Clinical Results from Turkey

“…In general practice, the 9.5 mm technique is preferred for donor graft preparation. 13 In our study, we evaluated whether there is a difference between the 9.5 mm and 8 mm techniques. Although contact with the endothelial layer during the 8 mm preparation technique might cause concern about increased ECD loss, we did not observe any significant increase in loss.…”

Evolving Techniques in Corneal Transplantation

“…The host is prepared by stripping away the diseased DM and endothelium [55]. Several instruments are used to insert DMEK grafts into the host cornea, including glass pipettes [56] and intraocular lens injection cartridges [46, 54•].…”