Contact lens and process for preparation thereof

An oxygen-permeable contact lens consisting essentially of a polymer having an organic polysiloxane skeleton and a three-dimensional crosslinked structure, said polymer comprising structural units comprising (A) a residue represented by the following formula:

• ##STR14## wherein R.sub.1 and R.sub.2 each stand for an organic residue, (B) a residue connected to residue (A) comprising at least one compound selected from the group consisting of unsaturated carboxylic acids, monoalkyl esters of unsaturated dicarboxylic acids, monoalkyl and dialkyl esters of unsaturated tricarboxylic acids, hydroxyalkyl esters of unsaturated carboxylic acids, acrylamide, methacrylamide, vinyl ethers, and styrene derivatives having an active hydrogen atom, (C) a polydimethylsiloxane residue connected to residue (A) modified with an active hydrogen-containing functional group, which is represented by the following general formula:
• ##STR15## wherein l and m stand for an integer of 0 to 200, n is an integer of 1 to 200, and R.sub.4 stands for ##STR16##
• in which p is an integer of 1 to 30, q and r stand for an integer of 0 to 30, s is an integer of 1 to 25 and t is an integer of 0 to 30,
• copolymerized with (D) a residue of at least one compound selected from the group consisting of alkyl esters of acrylic acid, alkyl esters of methacrylic acid, fluorine-containing acrylates, fluorine-containing methacrylates, acrylates and methacrylates having an alicylic hydrocarbon group, aryl acrylates and methacrylates, halogen-containing aryl acrylates and methacrylates, styrene, styrene derivatives, dialkyl esters of unsaturated dicarboxylic acids and trialkyl esters of tricarboxylic acids wherein unit (A) connects an organic polysiloxane skeleton to a skeleton consisting of the residue of unit (D) through unit (B).