[Viability of corneal endothelium after long-term storage at +4 degrees C in Optisol]

For successful corneal transplantation endothelial cell function of at least 50% is considered necessary. Corneal grafts are often evaluated by morphological criteria, such as endothelial cell size or density. Donor corneas with a storage time longer than 10 days are usually excluded from transplantation. The viability of the endothelium of 35 human donor corneas was evaluated after storage for up to 27 days at +4 degrees C in Optisol storage medium by using the Janus green photometry technique. The results were compared with the endothelial cell density counted. We demonstrated that the human corneal endothelium remains satisfactorily viable (minimum 68% viable cells) for a period of at least 27 days and that morphological changes do not sufficiently reflect the functional intactness of the cornea. Morphological irregularities should be interpreted as a form of compensation by a viable endothelial cell layer.