Polymeric hydrogel

A polymeric hydrogel comprising a polymeric matrix formed by copolymerizing a nonionic polymerizable monomer with a crosslinking monomer, wherein the polymeric matrix contains a wetting agent and water, at least 50 wt % of the wetting agent is constituted of a polymer chosen from polyglycerin having 8 to 12 hydroxyl groups, and the polymer is water-soluble and has an average molecular weight of 150 to 4000 and satisfies the relationship:

• {(number of ether groups in the polymer+number of hydroxyl groups in the polymer)/number of carbon atoms present in the polymer}≧1/3, wherein the nonionic polymerizable monomer is selected from acrylamide, polyethyleneglycol methacrylate, N,N-dimethylacrylamide, and polypropyleneglycol acrylate, wherein the crosslinking monomer is selected from N,N-methylenebisacrylamide and polyethyleneglycol dimethacrylate.