Abstract: Novel polymers for biomedical use, especially rigid gas permeable contact lenses that are based on bulky side-chain siloxane cross linkers. The siloxanes, either alone, or as copolymers with bulky and non-bulky mono-functional polymerizable siloxanes, fluoro monomers, such as hexafluoroisopropyl methacrylate, and hydrophilic monomers, result in transparent, high oxygen permeable polymers possessing excellent lathing and milling characteristics.

Abstract: A curable composition comprising (1) 0.1 to 20 parts by weight of a silicon compound having a silanol group or a functional group for forming a silanol group upon hydrolysis and no radically polymerizable group, such as ?-glycidoxypropyltrimethoxysilane, (2) 100 parts by weight of radically polymerizable monomers and (3) 0.01 to 20 parts by weight of a photochromic compound, wherein the radically polymerizable monomers include a radically polymerizable monomer having an epoxy group in the molecule, such as glycidyl methacrylate. This curable composition is capable of forming a photochromic coating layer which shows excellent photochromic properties such as high color development density and fast fading rate, is free from the dissolution of the photochromic compound, exhibits high adhesion to a substrate through a simple pre-treatment and has excellent hard coating applicability.

Abstract: The invention relates to a coating material containing a binding agent and a cross-linking agent as well as a thixotropic agent based on ureas and/or ureas derivatives, whereby the coating material additionally contains a wetting agent that improves the wettability of the thixtropic agent.