Plano and refractive keratectomy. Comparison of the wound healing response.

PURPOSE

To compare the extension of the subepithelial low dry mass layer after plano and refractive keratectomy, in order to know more about the factors that influence the corneal wound healing response.

METHODS

Thirty rabbits assigned into two groups were treated on one eye each with plano and refractive keratectomy, respectively. In each group five rabbits were sacrificed after 10 days, 4 weeks and 21 weeks, respectively. The corneal buttons were excised, freeze-sectioned and freeze-dried. On the freeze-dried sections microradiography was performed. In the treated eyes the superficial stroma showed qualitatively underneath the epithelium areas with low dry mass, whose extension was measured by a modified planimetry.

RESULTS

The difference between the extension of subepithelial low dry mass areas in the plano and the refractive keratectomy group was small but statistically significant at 4 weeks. Within the refractive group the extension of low dry mass was significantly higher at 4 weeks compared to 21 weeks.

CONCLUSION

A flat surface ablation may cause a less pronounced healing response when compared to a steep curve refractive treatment.