| abstract |
An ophthalmic lens is described that is suitable for periods of prolonged use of at least one day in the eye, without a clinically significant amount of swelling of the cornea, and without substantial user discomfort. The lens has a balance of oxygen permeability and permeability to ions or water, the permeability to ions or to water being sufficient to provide good movement over the eye, so that there is a good exchange of tears between the lens and eye. The preferred lens is a copolymerization product of a macromer with oxygen permeability and a monomer with ions. The invention encompasses contact lenses for extended use, which include a core having oxygen transmission and ion transmission paths that extend from the inner surface to the outer surface. |