EGRESS ROUTE OF EMULSIFIED 20-CENTISTOKES SILICONE OIL FROM ANTERIOR-CHAMBER OF RABBIT

Silicone oil is used in recent clinical practice, however, it may caus e adverse reactions in the eyes. When the high viscosity silicone oil is contaminated with low molecular weight silicone oil, the contaminat ion may cause ocular toxicity or elevation of the intraocular pressure . To obtain information on the distribution of this preparation, emuls ified 20 centistokes silicone oil was injected into the anterior chamb er of rabbit eyes. The silicone oil droplets were visualized by light and electron microscopy by using oil soluble phthalocyanine blue. This copper containing dye remains in the tissue after removal of the sili cone oil by organic solvents. Two and 4 weeks after an injection, the silicone emulsion was observed as numerous small vacuoles with blue pr ecipitate at the margin of vacuoles within elongated trabecular endoth elial cells, fibroblasts along the route of uveoscleral outflow and ce lls of the iris. Three hours after the injection, only a few vacuoles were present in these cells. These results demonstrated that the emuls ified silicone oil leaves the anterior chamber through the conventiona l and unconventional routes. Phagocytosis by the trabecular endothelia l cells and fibroblasts along the uveoscleral route caused an accumula tion of the emulsified silicone oil in these cells. With chronic expos ure to emulsified silicone oil, changes in the trabecular meshwork may lead to a reduction in the outflow of aqueous humor and cause glaucom a.