Optimization and histological validation of DMEK graft preparation with specific instruments

Abstract

Purpose

To assess the learning curve and technique standardization of Descemet membrane endothelial keratoplasty (DMEK) preparation with a purpose-specific instruments at The Basque Transfusion and Human Tissue Centre.

Methods

Twenty corneas not eligible for transplantation from 18 donors were prepared by an eye bank technician without previous surgical experience. The technique was monitored and standardized and three differentiated steps were characterized: “cleaning”, “stripping” and “pulling”. Preparation time, number of tears at every stage of the technique and donor demographics were measured. Tissue damage was catagorized into five graft morphological types. To evaluate microscopic tissue damage, electron microscopy images were taken from three pre-specified areas of the donor cornea: graft periphery, trabecular meshwork and denuded stroma.

Results

Viable grafts resulted in 14 out of the 20 preparations. A positive trend was found between graft usability and the experience of the operator. Small peripheral round tears were the most common findings overall and in the viable grafts subset. Radial and round tears occurred most frequently during the stripping and the cleaning phase, respectively. Univariate analyses showed no correlation between preparation time, donor age and gender and culture medium.

Conclusion

DMEK preparation with a purpose-specific instruments may have a relatively short learning curve, suggesting feasibility for eye bank technicians without previous surgical experience.