Inefficacy of collagen shields in the rabbit corneal wound-healing process

A controlled study in the rabbit eye was performed to clarify the suitability of collagen shields in accelerating the wound healing process in damaged cornea. After a standardized bilateral keratectomy, the spontaneous evolution of the healing process in the right eye (control eye) was compared with the evolution in the left eye, treated with a collagen shield (a shield of the 12- or 24-h type). The healing area was measured by planimetry after fluorescein staining at 0, 24, 48, and 72 h after keratectomy. Histological and immunohistochemical analysis of the healing process was also performed. Reepithelization of the damaged cornea was almost complete at 72 h, and there were no differences in the time course of the healing process between control and treated eyes. There was an important polymorphonuclear infiltration in treated eyes, mainly composed of eosinophiles, which was not present in control eyes. This indicates a subacute inflammatory immunological reaction. It is concluded that the usefulness of collagen shields should be reappraised, especially in injured corneas.