Descemet membrane endothelial keratoplasty tissue preparation from donor corneas using a standardized submerged hydro-separation method.

Purpose: To standardize a novel submerged hydro-separation technique for Descemet membrane endothelial keratoplasty (DMEK) graft preparation from donor corneal tissues.

Design: Experimental study, laboratory investigation.

Setting: The Veneto Eye Bank Foundation, Venice, Italy.

Study Population: Fifty-four random human donor corneal tissues unsuitable for transplantation.

Intervention: Donor corneas were laid in a sterile basin partially filled with tissue culture medium. A 25 gauge needle with 1 mL mounted syringe was filled with the tissue culture medium. The needle (with bevel up) was bent to 90 degrees and was inserted in the posterior cornea initiating beneath the trabecular meshwork. It was further advanced toward the midperiphery, ensuring that only the bevel was inserted, considering it as a threshold of insertion. The liquid was injected with a medium to high pressure into the posterior stroma or in the Descemet membrane-stroma interface to create the bubble. The tissues were preserved for 7 days in tissue culture medium at 31°C. Parametrical, physiological and histological analyses were carried out.

Main Outcome Measures: Larger-diameter tissue, no tissue wastage, reproducibility, and preshipment evaluation.

Results: Complete detachment was achieved in all the cases without any tissue wastage. Average diameter of the excised graft was 10.80 (±0.28) mm and endothelial cell loss post preservation was 11.48%. Expression of tight junction protein and regular morphology was observed post preservation. No signs of cell apoptosis were seen. Histological analysis showed elimination of residual stroma in most of the cases.

Conclusions: The submerged hydro-separation method reduces tissue wastage. It allows preshipment evaluation, thus allowing a validated tissue to be transported from the eye banks to the surgeon. Because of the liquid interface, the peeling of the DMEK graft becomes easy for transplantation.