Corneal Endothelial Permeability After Silicone Oil Exposure: Role of Low-Molecular-Weight Components and Catalyst

AbstractSilicone oils induce corneal and retinal pathologic changes by undefined mechanisms that may relate to certain components. Low-molecular-weight components have often been postulated to cause these ocular toxicities. Several types of additives that occur as contaminants or by-products in crude silicone oils were tested for their effects on rabbit corneal endothelial permeability. A purified oil plus various additives was perfused to fill about 75% of anesthetized rabbit anterior chambers. In vitro endothelial permeabilities to inulin and dextran were determined after 1 week. A long-chain silanol-terminated polydimethylsiloxane (viscosity, 1000 cps) at 2 mg/ml, a catalyst (tetramethylammonium siloxanolate) at 1 mg/ml, and a mixture of a series of linear compounds (hexamethyldisiloxane [MM] through hexacosamethyldodecasiloxane [MD 10M]) each at 10 mg/ml, resulting in the largest permeability increase. A mixture of two short-chain silanol-terminated compounds (15–35 cps plus 80 cps, each at 1 mg/ml) w...