Abstract: A pre-assembled, preferably single piece, device and related surgical procedure, to be surgically implanted in an eye for treating refractory glaucoma by draining aqueous out of the anterior chamber using a tubular shunt depended from a flexible band having a main reservoir and at least two wings extended in directions opposite one another away from said main reservoir, said wings each having a neck portion defining a depression in said band and an anchoring head each having a tip end and a lock end, with each said anchoring head gradually increasing in thickness to form a taper from each said tip end to each respective lock end to guide each said anchoring head under and past the extraocular muscles of the eye, which muscles then rest in said depressions locked against each said lock end , said device being further defined by a plurality of circumferential markings regularly placed along said tubular shunt for placement within the anterior chamber according to the size eye of each respective patient, and a l