A method of modifying the surface characteristics of a polymeric hydrogel, and a polymer article formed therefrom, without causing substantial swelling or distortion or the hydrogel. A preferred method includes photoinitating of the surface of the article with a benzophenone and grafting a macromer having a number-average molecular weight greater than 1000 in the presence of UV irradiation. The preferred article is a siloxane-containing hydrogel, especially a soft contact lens.