Long-term follow-up of a supradescemetic keratoprosthesis in rabbits: an immunofluorescence study.

Objective: To evaluate the long-term clinical and immunohistological outcome of two different non-penetrating keratoprosthesis (KPro) implanted in non-injured rabbit corneas.
Materials and Methods: Three rabbits underwent implantation of a pHEMA-MMA(34) synthetic cornea in the supradescemetic space, and PMMA synthetic corneas in the supradescemetic space and within the central stroma. Animals were followed for at least 24 months before euthanasia. Periodic evaluation was performed with slit-lamp examination and photography. At the end of the follow-up, histological examination including hematoxylin eosin staining and immunocharacterization against collagen IV, alpha smooth muscle actin (α-SMA) and macrophages was performed.
Results: The pHEMA-MMA(34) implant was not extruded, and remained transparent until the end of follow-up. This material did not induce any cell infiltration, corneal scarring or tissue remodeling in the surrounding stroma as shown by immunofluorescence. In contrast, synthetic corneas made of PMMA-induced myofibroblast differentiation, stromal remodeling and macrophage infiltration. This reaction was even more significant in the rabbit with the PMMA implant within the corneal stroma.
Conclusion: pHEMA-MMA(34) was clinically biocompatible, and did not induce any inflammatory reaction or scarring when implanted in the supradescemetic space. This material showed more promising biocompatibility results than for PMMA, whether implanted within the central cornea stroma or in the supradescemetic space.