Corneal epithelial preservation.

While clinical experience has demonstrated that current storage techniques are adequate for the preservation of human endothelial cells, increased use of donor epithelium in cases of severe disturbance to epithelial and stromal integrity requires a reexamination of storage effects on the epithelial layer. Measurement of human and rabbit metabolite levels in stored corneas indicates that the epithelium is maintained in a normal state only if the eye is cooled promptly. If cold storage is delayed for as little as one hour after death, glucose levels in the stroma and aqueous fall below levels known to be required for preservation of epithelial integrity. The fundamental time of interest in preservation of donor corneal tissue is in the interval between death and cooling of the eye. If prompt enucleation is not possible, ice should be applied to maintain viability of the epithelium.