US Patent 7939579 Hydrogels and methods of manufacture

Hydrogels, methods of preparing hydrogels, and ophthalmic lenses comprising hydrogels are described. Fully hydrated embodiments of the hydrogels have relatively high water content and oxygen permeability, along with relatively low modulus of elasticity. Embodiments of the hydrogels in substantially dehydrated condition are adapted to lathe cutting at or above room temperature. Embodiments of contact lenses made with the silicone hydrogels have low on-eye water loss.