Corneal changes due to alkali burns.

Rabbit corneal epithelium and endothelium were destroyed in vivo with 0.5 normal sodium hydroxide applied to the anterior surface of the cornea for 1 minute. Specimens were studied by transmission and scanning electron microscopy. Cellular necrosis is intense during the first day and healing begins on the third day on both surfaces of the cornea. The epithelial side is covered with new cells in 12 days and the eptihelium is normal on the 21st day, but there is a transformation of part of the corneal epithelium by conjunctival epithelium. On the endothelial side, healing is very slow and for this there seems to be two reasons: (1) Persistent cellular necrosis, (2) Inflammatory reaction which disorganizes the regenerating process. The overstimulation caused by this slow cicatrization leads to the formation of a retrocorneal membrane similar to those observed in human pathology.