Development of emulsification-resistant silicone oils: can we go beyond 2000 mPas silicone oil?

PURPOSE To develop new blends of emulsification-resistant silicone oil based on high molecular weight (HMW) silicone oil for use as an endotamponade in vitreoretinal surgery. METHODS Viscosity and elasticity of various silicone oil blends (Siluron 1000, Siluron 2000, Siluron 5000, 7% HMW + Siluron 1000, 10% HMW + Siluron 1000, and 15% HMW + Siluron 1000; Fluoron GmbH, Ulm, Germany) were measured using a piezoelectric axial vibrator. Emulsification was induced using a sonication device. Pluronic 10%, plasma, and serum were used as emulsifiers. The emulsion area was photographed and measured using ImageJ software (developed by Wayne Rasband, National Institutes of Health, Bethesda, MD; available at http://rsb.info.nih.gov/ij/index.html). RESULTS Viscosity increased proportionally to HMW concentrations. Fluid elasticity was optimum using 10% HMW. Emulsification was at a minimum when using 10% or 15% HMW blends. CONCLUSIONS A new silicone oil-based tamponade was developed with a viscosity similar to Siluron 5000 (at 37°C) but with significantly less emulsification tendency than Siluron 5000 or Siluron 2000. HMW concentration increases the fluid elasticity, thereby reducing the emulsification tendency.