Effects of various eye drops on corneal wound healing after superficial keratectomy in rabbits.

PURPOSE

The effects of various eye drops on corneal wound healing, particularly in the subepithelial haze area, were investigated histologically following superficial keratectomy in rabbits.

METHODS

Mechanical superficial keratectomy was performed in rabbit eyes. Tranilast, betamethasone, hyaluronic acid, and diclofenac eye drops were administered after the procedure. Physiological saline was used as a control. Corneas were excised 1, 2, 3, and 4 weeks after keratectomy, labeled with 3H-thymidine or 3H-proline, and subjected to autoradiography.

RESULTS

In the control and diclofenac groups, corneal haze occurred 3 weeks after keratectomy. Histological examination revealed an accumulation of proliferating keratocytes and active synthesis of collagen in the subepithelial area. In the tranilast and betamethasone groups, formation of corneal haze was reduced compared to the controls. The proliferation of keratocytes and the production of collagen in the corneal stroma were inhibited by these drugs. In the hyaluronic acid group also, corneal haze was decreased. In this group, although the proliferation of keratocytes was activated compared to the controls, abnormal accumulation of keratocytes in the subepithelial area was not detected.

CONCLUSIONS

Tranilast and betamethasone decrease the formation of subepithelial haze by inhibiting keratocyte proliferation and synthesis of extracellular matrix in the corneal stroma. Hyaluronic acid, on the other hand, inhibits subepithelial haze by promoting physiologic wound healing.