US Patent 7452075 Hydrodynamically operated multifocal contact lens

This invention pertains to a soft contact lens that has a body with a central zone aligned with the optical axis of the eye when a wearer wears the lens. A micro-channel filled with fluid, is positioned at or near the optic zone and is arranged so that when the fluid is pressurized, the micro-channel expands and changes the optical characteristics of the central zone. The pressure in the microchannel is controlled through changes to a reservoir disposed in the lens below the optic zone.