Seoul-type Keratoprosthesis: The Deelopment of New Keratoprosthesis using Internal Scleral Fixation Method

ABSTRACT

Most of keratoprostheses that had been developed did not show consistent successful results due to the high rates of complications including extrusion. We performed this study to develop a newly designed keratoprosthesis using internal scleral fixation and access the mechanical stability and biocompatibility of the keratoprosthesis (Seoul-type keratoprosthesis, S-Kpro). The S-Kpro has the advantage of double fixation-the Gore-Tex skirt is anchored to the cornea and the prolene haptic is anchored internally to the sclera, simultaneously. And the human amniotic membrane(AM) was covered over the cornea and prosthesis to improve the biocompatibility. The 24 rabbits were divided into four groups group 1(S-Kpro) with scleral and corneal fixation and AM transplantation, group 2 with scleral fixation and AM transplantation but without corneal fixation, group 3 with corneal fixation and Am transplantation but without scleral fixation, group 4 with scleral and corneal fixation but without Am transplantation. The average retention period of group 1(S-Kpro) was 12.3 weeks, which was significantly longer than other groups. The implanted eyes withstanded the intraocular pressure of as high as 200 to 250mmHg. The retroprosthetic membrane was not observed in all cases but retinal detachment and proliferative vitreoretinopathy were developed, and they are thought to be related with the extrusion of the prosthesis. The fibrovascular tissue invasion was not found in the Gore-Tex pores. These results suggest that double fixation technique using internal scleral fixation and AM transplantation is helpful to improve the stability of the kratoprosthesis. The further experiment with total vitrectomy, different species of animals and Gore-Tex with the large-sized pores would be needed.