Surface treatment agent for ophthalmic device

A method of treating a surface of a silicone hydrogel, including a step of treating the surface of the silicone hydrogel with a copolymer, the copolymer containing:

• a constituent unit based on a hydrophilic monomer “a” represented by the following formula (1);
• a constituent unit based on a silicone monomer “b” represented by the following formula (2) or the following formula (3);
• and a constituent unit based on a thermally reactive monomer or photoreactive monomer “c”,
• wherein the constituent unit based on the thermally reactive monomer or photoreactive monomer “c” is methacryloyloxybenzophenone, 4-(4-azidobenzoyloxymethyl) vinylbenzene, or glycidyl methacrylate, and
• the copolymer is capable of dissolving at 0.5% (w/v) in hot water at 60° C., and incapable of dissolving at 1% (w/v) in water at 20° C.:
• in the formula (1), R1 represents a hydrogen atom or a methyl group, L1 represents an organic group having 2 to 6 carbon atoms, and the organic group may optionally contain one ether bond and/or one hydroxy group, and R2 to R4 each independently represent a hydrocarbon group having 1 to 3 carbon atoms;
• in the formula (2), X1 represents a (meth)acryloyloxy group, a 3-(2-hydroxyethyloxycarbonyl)-2-methylenepropanoyloxy group, a 3-(2-hydroxyethyloxycarbonyl)-3-butenoyloxy group, or a 3-(2-hydroxyethyloxycarbonyl)-2-propenoyloxy group, L2 represents an organic group having 2 to 6 carbon atoms, and the organic group may optionally contain one ether bond and/or one hydroxy group, R5 to R13 each independently represent a methyl group or an ethyl group, and n1 represents 0 or 1;
• in the formula (3), R14 represents a hydrogen atom or a methyl group, L3 represents an organic group having 2 to 6 carbon atoms, and the organic group may optionally contain one ether bond and/or one hydroxy group, n2 represents an integer of from 4 to 20, and R15 to R17 each independently represent an alkyl group having 1 to 8 carbon atoms.