The healing of linear nonperforating wounds in rabbit corneas of different ages.

Linear nonperforating incisions were made in the corneas of 2-week-old and 2-year-old rabbits. The resulting wounds were examined by light microscopy and transmission and scanning electron microscopy. A corneal incision of a 2-week-old rabbit produced a wide gaping wound caused by retraction of the cut stromal lamellae away from the incision. The wound became wider with time as the developing eye enlarged and the cut lamellae retracted further. Polymorphonuclear leukocytes, presumably from the tear film, penetrating into the wound area before it was covered over by the sliding epithelium. Most of the leukocytes disappeared by 3 days after wounding. Three to six layers of fibroblasts appeared beneath the epithelial plug. The tissue eventually rebuilt approximately one third of the corneal depth lost to the wound. The stroma of the wounded region did not return to its normal width, but the epithelium was thicker than that of the unwounded cornea. An incision in a 2-year-old rabbit cornea produced a narrow V-shaped wound that did not change shape with time. This wound was repaired by fibroblasts resulting in collagenous repair tissue being the same depth as the normal stroma. There appears to be no evidence for wide gaping wounds in humans in the literature, as was found in this study in rabbits.