The keratoprosthesis: improved biocompatibility through design and surface modification.

Due to poor biocompatibility, the success of keratoprostheses has been limited. We compared a newly-designed PMMA intracorneal keratoprosthesis, covalently coated with type-I collagen, with an identical, uncoated keratoprosthesis were retained for 15 months, the uncoated implants had more extensive adjacent corneal melting, greater inflammatory response, and more epithelial downgrowth than their collagen-coated counterparts. Electron microscopy showed that stromal collagen fibers had attached to the surface of the coated implants, but not to that of the uncoated ones. Intracorneal keratoprostheses covalently coated with type-I collagen may offer superior biocompatibility and become significantly incorporated into corneal tissues.