An exemplary embodiment provides a biocompatible polymer composition suitablefor making intraocular lenses, especially posterior chamber phakic lenses,that includes a hydrogel having an equilibrium water content of less than about55 wt. %. The hydrogel has a refractive index greater than about 1.41 and a sodiumion flux between about 16 to about 20 µeq-mm/hr/cm2.