In–vivo investigations of corneal posterior stroma and endothelium three years after implantation of a lamellar keratoprosthesis–prototype

Abstract

Abstract: : Purpose: In corneae with its main opacity in the anterior part of the stroma a lamellar type of of keratoprosthesis may have several advantages over the conventional penetrating ones. This study deals with the in–vivo behaviour of the retroprosthetic corneal stroma and the endothelial cells following the implantation of lamellar keratoprosthesis. Methods: 6 New Zealand white rabbits were supplied with a lamellar keratoprosthesis. The optical part of the device is made out of a transparent silicon material. The haptic ring of a newly devoloped foam with interconnecting pores of surface modified silicon with a pore size of 100 – 200 µm. Examinations with an in–house development of an in–vivo confocal laser–scanning system was performed three years after surgery. To evaluate keratocyte as well as endothelial cell morphology and density examinations had performed under general anasthesia. Results: Keratocyte morphology and density could be evaluated in all 12 eyes of 6 animals. In the eyes following surgery mostly due to technical reasons the image quality in the confocal planes has been slightly reduced comparing with the untreated corneae. In all eyes it was possible to count the keratocyte numbers per focal plane as well as the endothelial cells. There were no statistical differents in cell count (keratocytes: 400/mm2 ; endothelial cells: 2500/mm2) and there were no visible differents in cell morphology in both cell populations. Conclusion: Our results can be regarded as prove of principal of lamellar keratoprosthesis made out of surface modified silicon which remain in place for a period of three years. Prototypes for human use are on its way.

Keywords: keratoprostheses • microscopy: confocal/tunneling • cornea: stroma and keratocytes