Silicone hydrogel lenses with water-rich surfaces

A silicone hydrogel contact lens, comprising:

• a silicone hydrogel bulk material covered with an outer surface hydrogel layer having a thickness of at least about 0.1 μm,
• wherein the silicone hydrogel bulk material comprises (i) repeating units derived from a silicone-containing vinylic monomer, a silicone-containing vinylic macromer, a silicone-containing prepolymer, or combinations thereof, and (ii) repeating units derived from a hydrophilic vinylic monomer, and has a first water content, designated as WCSiHy, of from about 10% to about 70% by weight when being fully hydrated,
• wherein the outer surface hydrogel layer comprises polymer chains derived from a copolymer which is a polymerization of a composition comprising (1) 60% by weight or less of at least one reactive vinylic monomer and (2) a phosphorylcholine-containing vinylic monomer, wherein the reactive vinylic monomer is selected from the group consisting of amino-C1-C6 alkyl (meth)acrylate, C1-C6 alkylamino-C1-C6 alkyl (meth)acrylate, allylamine, vinylamine, amino-C1-C6 alkyl (meth)acrylamide, C1-C6 alkylamino-C1-C6 alkyl (meth)acrylamide, acrylic acid, C1-C4 alkylacrylic acid, N,N-2-acrylamidoglycolic acid, beta-methyl-acrylic acid, alpha-phenyl acrylic acid, beta-acryloxy propionic acid, sorbic acid, angelic acid, cinnamic acid, 1-carboxy-4-phenyl butadiene-1,3, itaconic acid, citraconic acid, mesaconic acid, glutaconic acid, aconitic acid, maleic acid, fumaric acid, tricarboxy ethylene, and combinations thereof, and wherein the outer surface hydrogel layer has a second water content higher than WCSiHy and a water-swelling ratio of (a) at least about 150% if WCSiHy≤45% or (b) at least
• 130
• ·
• WC
• SiHy
• 1
• -
• WC
• SiHy
• 
• %
• if WCSiHy>45% when being fully hydrated.