Biological Safety Test of Seoultype Keratoprosthesis

PURPOSE: To perform biological safety test of the Seoul-type keratoprosthesis (SKpro) according to the international standards. METHODS: Mouse fibroblasts were used to assess the cellular toxicity, and albino rabbits were used for the irritation test, intradermal test, ocular toxicity test, pyrogenic test and transplantation test. Albino guinea pigs were used for the sensitization test, and rats were used for the acute toxicity test and chronic toxicity test. All tests were performed using the SKpro extracts, which was extracted under 121degrees C for 1 hour using a 0.9% normal saline as the solvent. RESULTS: For the cellular toxicity test, all the rat fibroblasts showed cell proliferation inhibition of less than 29%, which proved to be non-cellular toxic. For the irritation test and the intradermal reaction test, none of the albino rabbits showed skin rash, crust or edema. On the ocular irritation test, there were no conjunctival, corneal or iris abnormalities among the albino rabbits. On the sensitization test, none of the guinea pigs showed skin rash, crust or edema. On the acute systemic toxicity test, there were no signs of lethargy or coma among rats. On the pyrogenic test, no temperature increase was observed in the albino rabbits. On the transplantation test, there was no evidence of graft reaction around the cornea. On the chronic toxicity test, complete blood analysis, urinalysis and histological findings 6 month after exposure showed no signs of abnormalities. CONCLUSIONS: The result of this study shows that SKpro is non-toxic and biologically safe.

Clinical, Physical Stability and Histological Biocompatibility of Experimental Seoul Type Keratoprosthesis

In cases that penetrating keratoplasty do not help to improve vision, keratoprosthesis implantation is necessary. This study was performed to assess clinical and mechanical stability of Seoul type-keratoprosthesis[SKPro], bio-compatibility and effect of amniotic membrane transplantation on clinical and mechanical stability of SKPro. SKPro consists of an optic portion made of PMMA, a skirt of Gore-tex or polyurethane and a haptic of prolene. The skirt of SKPro was covered with recipient conjunctiva completely at postoperative 1 month and melting of covered conjunctiva and exposure of skirt developed at postoperative 2 months and progressed slowly to postoperative 6 months. But retroprosthetic membrane formation, extrusion of SKPro, posterior segment complication such as retinal detachment did not develop and transplanted SKPro showed relatively good clinical stability during 6 months. Pressure loading test showed relatively good mechanical stability under high pressure at postoperative 2 months. Histologic study showed moderate inflammatory reaction and abnormal pattern of collagen and extracellular matrix in lamellar pocket and anterior flap. There was no deposit of collagen in Gore-tex skirt. But histology of posterior flap of lamellar pocket was nearly normal. Group that was transplanted with amniotic membrane twice showed more better stability than once and without amniotic membrane transplantation on clinical and mechanical stability.

Clinical, Physical Stability and Histological Biocompatibility of Experimental Seoul Type Keratoprosthesis

In cases that penetrating keratoplasty do not help to improve vision, keratoprosthesis implantation is necessary. This study was performed to assess clinical and mechanical stability of Seoul type-keratoprosthesis[SKPro], bio-compatibility and effect of amniotic membrane transplantation on clinical and mechanical stability of SKPro. SKPro consists of an optic portion made of PMMA, a skirt of Gore-tex or polyurethane and a haptic of prolene. The skirt of SKPro was covered with recipient conjunctiva completely at postoperative 1 month and melting of covered conjunctiva and exposure of skirt developed at postoperative 2 months and progressed slowly to postoperative 6 months. But retroprosthetic membrane formation, extrusion of SKPro, posterior segment complication such as retinal detachment did not develop and transplanted SKPro showed relatively good clinical stability during 6 months. Pressure loading test showed relatively good mechanical stability under high pressure at postoperative 2 months. Histologic study showed moderate inflammatory reaction and abnormal pattern of collagen and extracellular matrix in lamellar pocket and anterior flap. There was no deposit of collagen in Gore-tex skirt. But histology of posterior flap of lamellar pocket was nearly normal. Group that was transplanted with amniotic membrane twice showed more better stability than once and without amniotic membrane transplantation on clinical and mechanical stability.