Background Pretreatment with chemical agents could alter the surface chemistry of the silicone gel,which makes it suitable for epithelial migration onto its surface and thus enhances the cytobiocompatibility.This study aimed to evaluate the biological response of the ceal stroma to porous silicone gel pretreated with different chemical agents in vivo.Methods The porous silicone gels were treated with a mixed acid solution containing 23.2％ H2SO4 and 0.8％ K2Cr2O7 for 10 or 15 minutes or with 30％ H2O2 for 15 minutes.Discs (4 mm in diameter) were inserted into interlamellar stromal pockets of New Zealand white rabbits and followed up for a period of 3 months.Clinical evaluations such as ceal infiltration,edema and neovascularization were performed daily.At 3 months,the fibroplasias and collagen deposition were examined under light and scanning electron microscopy (SEM) and by immunohistochemical analysis.Results Pretreatment of the discs obviously decreased conjunctival congestion,discharge,cea edema,and the extent of neovascularization.More fibroblasts migrated into the pretreated discs than into the control,and collagen was deposited,indicating that the biocompatibility of the ceal replacements was enhanced by the chemical pretreatments.From immunohistochemical analysis,Type Ⅰ collagen deposition in the pretreated silicone discs was greater than in the control.Conclusions Chemical treatment of silicone gel is effective in decreasing rabbit ceal inflammation,encouraging fibroblast in-growth,and enhancing tissue compatibility.Pretreated gels show good biological stability when used as a skirt material in Keratoprosthesis (Kpros).