Materials and Methods
All silicone oils used clinically in recent years are composed of the same basic molecule: polydimethylsiloxane (PDMS). It is transparent with a refractive index of 1.404 and is somewhat lighter than water (specific gravity = 0.97). It is permeable to oxygen and has a high surface tension towards air (21 mN/m) and water (40 mN/m) and, accordingly, does not mix with them. In pure form it largely exhibits those properties an ophthalmologic implant material should ideally posses: chemically largely inert, completely permeable to light in the visible light spectrum, biologically not degradable in tissue, not carcinogenic, mechanically stable, and easily sterilizable due to its high heat resistance (Habal et al. 1980, Kreiner 1987). Other silicone oils, e.g., fluoro- or phenylsilicones, are still in the experimental stage and have properties that make clinical application at present inadvisable (Petersen et al. 1986, Gabel et al. 1987b).
KeywordsRubber Shrinkage Retina Sponge Glaucoma
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