An IOP control system for implantation in an eye of a patient is disclosed. The IOP control system includes a drainage tube configured to convey aqueous humor from an anterior chamber of an eye and includes a pressure-driven valve system in fluid communication with the drainage tube and configured to control flow rates of the aqueous humor. The valve system includes a plurality of pressure-driven valves arranged to operate in cooperation with each other. The IOP control system may include an electronic pump system to further regulate flow.
