Abstract: Objective    To evaluate the histopathological results of the porous skirt of new one-piece keratoprosthesis (KPros) made of PHEMA implanted to alkali burned rabbit corneas. Methods    The KPros were inserted into the lamellar pocket of alkali-burned corneas and the corneas were observed clinically, histologically and ultrastructurally at various time, and followed for up to 28 weeks. Results    Histopathologic study suggested that mild inflammatory reaction and no calcification was seen in all specimens. Fibroblasts and deposition of collagen were found in the pores of the discs two weeks after implantation and stable connection with cornea would formed by 16 weeks. TEM (Transmission Electron Microscope) results showed that abundant endoplasmic reticulum could be observed in fibroblast cytoplasm at week 4, which indicated the strong synthetic activity of fibroblast cells. Also, deposition of proteoglycans and other extracellular matrix around the material could be observed under TEM. By week 16, there were large amounts of orderly arranged collagen fiber around the material. The fibroblasts in the pores looked healthy and functionally active under TEM. Conclusion    Along with the proliferation of surrounding tissue, corneal cells could proliferate and migrate into the porous skirt of PHEMA which was implanted into alkali burned rabbit corneas. Corneal cells and other cells could also secrete extracellular matrix and promote its deposition to accelerate the formation of new organizations, and strengthen the connection between cornea and material.

Key words: Keratoprosthesis, Transmission Electron Microscope, Alkali burn, Keratoplasty, Scanning Electronic Microscopy, Polyhydroxyethyl methacrylate