Keratocyte activity in wound healing after epikeratophakia in rabbits

Epikeratophakia is a refractive surgical procedure for the correction of aphakia, high myopia, or keratoconus. To solve clinical problems associated with epikeratophakia, a basic knowledge of its postoperative healing process is needed. The authors investigated keratocyte activities, particularly cell proliferation and collagen synthesis, during wound healing after epikeratophakia in rabbits. Epikeratophakia was done on rabbit corneas with a homologous cryolathed keratolens. Ten, 16, 28, 45, 63, 90, 254, and 360 days after the operation, the corneas were excised, labeled with either 3H-thymidine (10 microCi/ml) or 3H-proline (10 microCi/ml) for 4 hr and examined histologically and by autoradiography. Keratocytes in keratolenses were killed during the freezing process. On postoperative day 10, a few keratocytes migrated to the edge of the keratolens from the host stroma. On days 16 and 28, keratocytes in the keratolens and host stroma near the junction between the host and the keratolens incorporated 3H-thymidine, suggesting active proliferation. The proliferating activity was no longer seen after day 45. The repopulation of keratocytes was almost complete on day 90 and gradually returned to normal through day 360. Keratocytes in the keratolens and host stroma beneath the keratolens showed a higher 3H-proline incorporation than the control from days 16-254 with the highest activity at around 4-9 weeks after surgery. These results suggest that remodeling of collagen fibers continues for a long postoperative period after epikeratophakia.