Hydrogel copolymers which are hydrated polymerization products of monomeric mixtures comprising polysiloxane prepolymers and hydrophilic comonomers are useful for forming biomedical devices, particularly ophthalmic devices including contact lenses, intraocular lenses and ophthalmic implants. The copolymers have a desirable combination of oxygen permeability, tensile modulus, and water content, especially for soft contact lenses.
