Reutlingen University 1 article published in JoVE Chemistry Synthesis of Soft Polysiloxane-urea Elastomers for Intraocular Lens Application Natascha Riehle*1,2, Sibylle Thude*3, Andreas Kandelbauer1,2, Günter E. M. Tovar3,4, Günter Lorenz1,2 1Reutlingen Research Institute, Reutlingen University, 2School of Applied Chemistry, Reutlingen University, 3Fraunhofer-Institute for Interfacial Engineering and Biotechnology IGB, 4Institute of Interfacial Process Engineering and Plasma Technology IGVP, University of Stuttgart This study describes synthetic routes for aminopropyl-terminated polydimethylsiloxanes and polydimethyl-methyl-phenyl-siloxane-block copolymers and for soft polysiloxane-based urea (PSU) elastomers. It presents the application of PSUs as accommodating an intraocular lens. An evaluation method for in vitro cytotoxicity is also described.