A high strength hydrogel having a constant swelling pressure upon implantation and thereafter is formed by preparing a hydrogel solution and then injecting the solution into a mold and cause to gel. The molded gel is then washed in a saline solution from about one day to twelve weeks, after which the gel is irradiated for sterilization purposes, dehydrated and packaged. The pre-treatment with the use of a physiologic solution results in an implant which exhibits a constant swelling pressure profile after implantation.
