An exemplary embodiment provides a biocompatible polymer composition suitable for making intraocular lenses, especially posterior chamber phakic lenses, that includes a hydrogel having an equilibrium water content of less than about 55 wt. %. The hydrogel has a refractive index greater than about 1.41 and a sodium ion flux between about 16 to about 20 &mu；eq-mm/hr/cm2.
