Development of a Newly Designed Double-Fixed Seoul-Type Keratoprosthesis

OBJECTIVE: To develop a newly designed double-fixed keratoprosthesis (Seoul-type keratoprosthesis [S-KPro]) and to assess its mechanical stability and biocompatibility. METHODS: Twenty-five rabbits were divided into 4 groups by fixation technique, amniotic membrane (AM) implantation, and skirt material. The eyes were studied with the use of slitlamp, light, and electron microscopy. Stress testing was performed. In addition, 2 human subjects underwent S-KPro implantation. Best-corrected visual acuity was checked, and ophthalmic examination was performed. RESULTS: The average retention period of the group receiving double-fixated polyurethane-S-KPro with AM was longer (>24 weeks) than that of the others. Fibroblast invasions were found in polyurethane pores but not in polytetrafluoroethylene (Gore-Tex) pores on light microscopy. The minimal pressure that induced aqueous leakage was greater than 250 mm Hg in all of the tested eyes. Two human subjects have maintained a good postoperative condition for 18 and 8 months. CONCLUSIONS: The double-fixation technique of applied S-KPro and AM appears to be helpful in improving the stability of the keratoprosthesis. Polyurethane with relatively large pore size (40 microm) may be used successfully as a material for the keratoprosthesis skirt. CLINICAL RELEVANCE: Our results may be important for improving the clinical outcome of keratoprosthesis.