Coalescence of endothelial cells in the traumatized cornea. I. Experimental observations in cryopreserved tissue.

After thawing, cryopreserved rabbit corneas were stained with trypan blue and cellular damage was evaluated with the specular microscope using indirect illumination. Thereafter, the cornea was maintained at 35 degrees C, and specular microscopy, performed from the endothelial side, was used to observe the same area of endothelium for several hours. Dead endothelial cells interfered with specular reflection and appeared as dark areas devoid of cellular definition. Viable cells, presumably damaged by freeze-thaw injury, began to effect repair within one hour after thawing and coalesced to form a single larger cell. Our photographic evidence suggests that coalescence of injured corneal endothelial cells represents an important step in the early repair process, resulting in a reduction of the total number of cells but enabling damaged cells to survive.