Abstract: A cylindrical plug for insertion through the punctum and into the canaliculus to block the flow of tears therethrough comprises an insert of a material which when hydrated expands and changes shape, conforming at least to a portion of the canaliculus crossection and contacting the walls of the canaliculus, thus blocking flow. The plug can be inserted in a dry state and hydrating in situ or hydrated, either partially or fully, prior to insertion.

Abstract: A cylindrical plug for insertion through the punctum and into the canaliculus to block the flow of tears therethrough comprises an insert of a gelatinous material which when hydrated expands and changes shape, conforming at least to a portion of the canaliculus crossection and contacting the walls of the canaliculus, thus blocking flow. The gel plug can be inserted in a dry state and hydrating in situ or hydrated, either partially or fully, prior to insertion.

Abstract: An injectable or implantable material for soft tissue augmentation comprising a hydrogel containing both hydrophobic and hydrophilic domains is prepared by copolymerizing a hydrophilic monomer, such as water soluble N-vinylpyrrolidone with non-water soluble monomers, such as N-vinyl carbazole, its derivatives, or a non-water soluble derivative of N-vinylpyrrolidone. Also suitable for injection into direct contact with body tissue are hydrogels prepared by cross-linking polyvinylpyrrolidone. The hydrogel may be either solid or composed of particles. The hydrogel may also be enclosed within a flexible porous or nonporous envelope.