Scrolling of the Donor Cornea in Dependence of Temperature and Osmolarity for Descemet Membrane Endothelial Keratoplasty

Background After preparation of a graft for Descemet membrane endothelial keratoplasty (DMEK), the diameter of the graftʼs scroll varies significantly. In particular, narrow scrolls may complicate DMEK surgery. In this study we investigated how temperature, osmolarity, and deswelling of the donor tissue influence scrolling diameter. Material and Methods In this study we examined donor corneas that could not be used for transplantation. The diameter of the DMEK donor scrolls was measured after graft preparation by reflected light microscopy under different conditions: (1) The diameter of the roll was measured in Ringerʼs solution at temperatures of 5 °C, 24 °C and 35 °C. (2) To study the effect of different culture conditions we used 6% dextran-containing medium for 10 min, 20 min, 16 h and 24 h, and hyper- and hypoosmolar fluids (5% NaCl or aqua dest) for 5 min each. Results The median donors age was 62 years. The median endothelial cell density of the donor corneas was 1679 cells/mm2. The median diameter of the DMEK scroll was 1.35 mm in Ringerʼs solution at 24 °C (IQR, 1.04 – 1.89). In Ringerʼs solution at different temperatures, the scrolling diameter changed between 0.02 mm and 0.29 mm. The change in osmolarity resulted in a difference of 0.02 mm to 0.46 mm. Deswelling with dextran resulted in a change of scrolling diameter between 0.02 mm and 0.09 mm. Summary In this experimental case series, the diameter of the DMEK scroll did not change due to changes of temperature, osmolarity or deswelling. Influencing the graftʼs scroll to standardize and simplify the DMEK surgery remains an interesting goal for future studies.