Structural damage was present in the endothelium of cryopreserved rabbit corneas after thawing, even though the corneas had been frozen as soon as possible after killing the animal. This damage included clarification of the cytoplasm, condensation of the mitochondria accompanied by swelling of the cristae, dilatation of the perinuclear spaces and profiles of rough endoplasmic reticulum, and interruptions in the continuity of cellular membranes. All of these changes, however, were shown to be reversible during rehydration of the frozenthawed tissue in Kinsey medium, in albumin and saline, or in vivo in the aqueous humor of a recipient rabbit eye prepared for penetrating keratoplasty.
Van Horn DL, Edelhauser HF, Gallun AB, Schultz RO. Reversibility of Ultrastructural Freeze-Thaw-Induced InjuryDemonstration in the Endothelium of Cryopreserved Corneal Tissue. Arch Ophthalmol. 1972;87(4):422-426. doi:10.1001/archopht.1972.01000020424012