Contact lens with a hydrogel coating thereon

A method for making coated contact lenses, comprising the steps of:

• (1) obtaining a contact lens precursor which has a concave surface and an opposite convex surface and comprises a lens bulk material and carboxylic acid groups on and/or near the anterior and posterior surfaces;
• (2) immersing the contact lens precursor in an aqueous solution in a container, wherein the aqueous solution comprises from about 0.01% to about 5.0% by weight of at least one hydrophilic copolymer that is a statistical copolymer of formula (I)
• in which
• T′ and T″ independent of each other are H or a terminal group;
• each R0 independent one another is H or CH3;
• each R0′ independent of one another is H or C1-C4 alkyl;
• B1, B2 and B3 independent of one another are O or NR′;
• R′ is H or C1-C4 alkyl;
• D1, D2 and D3 independent of one another are a C1-C12 alkylene divalent radical;
• D0 is a C1-C12 alkylene divalent radical or a divalent radical of -D4-O-D5-B4—CH2—;
• B4 is —O— or
• D4 is a C1-C12 alkylene divalent radical;
• D5 is a C2-C6 alkylene divalent radical or a divalent radical of
• D6 and D7 independent of each other is a C2-C6 alkylene divalent radical;
• d1 is zero, 1 or 2;
• PEG is a polyethyleneglycol group of
• in which R″ is H or C1-C4 alkyl;
• t2 is an integer from 3 to 100;
• PC is a zwitterionic group of
• in which t1 is an integer of 1 to 5 and 1R, 2R and 3R independently of one another are C1-C8 alkyl or C1-C8 hydroxyalkyl;
• a, b, c, and d independent of one another are an integer of from 5 to 100, wherein (a+c)/(a+b+c+d)≤0.40 and a/c is from 2.5 to 0.4;
• and
• (3) heating the aqueous solution with the contact lens precursor therein at a temperature of from about 100° C. to about 140° C. for at least 30 minutes to form a coated contact lens having a hydrogel coating thereon, wherein the hydrogel coating is covalently attached onto the anterior and posterior surfaces through linkages each formed between one carboxylic acid group and one epoxy group, wherein the hydrogel coating comprises a crosslinked polymeric material comprising polymer chains derived from the hydrophilic copolymer,
• wherein the contact lens has a water-break-up time (WBUT) of at least 10 seconds.