Effect of a collagen shield on cat corneal epithelial wound healing

We have previously demonstrated that a corneal bandage lens made from porcine scleral collagen may be useful in treating various ocular surface problems. In order to determine whether the collagen shield would accelerate epithelial healing, a 7 mm diameter circular area in the center of the left cornea of ten domestic cats was mechanically deepithelialized. In five of the cats, a 14.5 mm non-cross-linked collagen shield was then placed on the cornea covering the wound. Another shield was applied 24 hr after surgery. The wound size was determined immediately after surgery and at 8-hr intervals until wound closure. Using analysis of variance for experiments with repeated observations, there was a significantly greater healing response in the treated group than in the control group. There was, however, no significant difference in slope between the two groups, suggesting that the shield did not increase the speed of epithelial cell migration. Rather, the effect of the shield was most pronounced during the first 8 hr after wounding. In contrast to that of the treated group, the mean defect radius of the control group was larger at t = 8 hr than at t = 0 hr. The earlier wound closure exhibited by the treated group, which may be due to protection and lubrication of the epithelial cells at the margins of the fresh wound, suggests that the collagen shield may be useful in treating corneal surface conditions of which deepithelialization is a component.