Silicone preparations possess a wide variety of physical characteristics that are uniquely suited for ophthalmic use. Their optically clear fluids may serve as substitutes for aqueous and vitreous. Their rubber preparations, though opaque, yield fine cords or tubes that may provide more permanent drainage channels for aqueous. Their solid and optically clear preparations may provide intraocularly placed optical lenses; the procedure of siliconizing cloth and providing a uniform and thorough coating of each fiber permits the use of the physical properties of the cloth and the biological properties of the silicones; such preparation may be of value in reinforcing the sclera. Indeed, if these compounds are tolerated by the eye, the variety of situations wherein their mechanical or refractive properties may be used in ocular conditions is very great. Stone1reported tolerance of the rabbit eye to silicone fluid injected in the vitreous. These attractive features suggested an investigation