Experimental assessment of endothelial viability of grafts

Purpose Endothelial quality of penetrating keratoplasty or posterior lamellar grafts (be they manually, mechanically or femto laser dissected) remains of paramount importance for the graft survival in recipients, especially when the recipient endothelial cell peripheral reserve is weak or absent (bullous keratopathy) Methods 1/Review of the literature on the available methods to measure the endothelial quality. 2/presentation of a new concept: experimental quantification of the actual endothelial cell density of cell deemed viable, thus representing the actual number of cells capable of surviving in the recipient eye. This method uses a live/dead assay coupled with the microscopy analysis of the whole endothelium. A comparative series of graft pre-cut for DMEK versus intact organ cultured paired corneas will illustrate our method Results For the first time the exact number of viable endothelial cells can be directly measured. The notion of viable endothelial cell density is introduced. Though it cannot be a routine technique but only a laboratory one, the method can be -and perhaps should be- applied for all kind of graft preparation during its experimental development. Lamellar posterior grafts are good candidates. As expected, the viable ECD is lower than the ECD determined with the routine method used in eye banks, even the most precise ones Conclusion The new notion of viable ECD may participate in our understanding of the dramatic endothelial cell loss ineluctably observed shortly after all types of grafts