If trabeculectomy cannot be performed, aqueous shunt surgery is usually successful in lowering eye pressure.
An aqueous shunt, or glaucoma drainage device, is a small plastic tube or valve connected to a reservoir (a roundish or oval plate). The plate is placed on the outside of the eye beneath the conjunctiva (the thin membrane that covers the inside of your eyelids and the white part of your eye). The tube is placed into the eye through a tiny incision and allows aqueous humor to flow through the tube to the plate. The fluid is then absorbed into the blood vessels. When healed, the reservoir is not easily seen unless you look downward and lift your eyelid.