A simple, practical, and safe method for evaluating donor corneas prior to their use for grafting is based on the fact that trypan blue, a vital stain, is taken up only by dead or damaged endothelial cells, the normal cells remaining unstained. Individual units are available which allow one to prepare a sterile solution of the dye instantaneously for each cornea. No harmful effects have been observed either in extensive experimental tests or by clinical experience.
Stocker FW, King EH, Lucas DO, Georgiade NA. Clinical Test for Evaluating Donor Corneas. Arch Ophthalmol. 1970;84(1):2-7. doi:10.1001/archopht.1970.00990040004002