c.Contacting a plurality of hydrophilic crosslinked particles formed from a polymer including polyoxyethylene glycol, polyvinylpyrrolidone, polyvinyl alcohol with an aqueous medium containing water soluble polymerUS5941909Aug 7, 1997Aug 24, 1999Mentor CorporationComprising flexible elastomeric hollow shell and filling material comprising high molecular weight polyacrylamide polymer; biocompatible,