A drainage device for draining the aqueous humor present in the anterior chamber of the eyeball comprises a drainage tube (10) extending axially along a tube axis between a distal end (10') and a proximal end (10"). The distal and proximal ends are at least partially open and are beveled in the same direction. A support flange (30) extends from the proximal end (10") of the drainage tube (10) and comprises a plate-shaped portion (32) having an upper surface (32') and a lower surface (32"). The proximal end (10") of the drainage tube (10) is sloped so as to make its opening face the upper surface (32') of the plate-shaped portion.
