Abstract: A glaucoma filtration implant is constituted by a generally tubular body section having an oblong external diameter formed of a continuous convex curve. The device preferably has flow resistance structure provided by a portion of the internal lumen having a reduced diameter. The flow resistance structure may have a length of up to 5000 &mgr;m and a diameter in the range 15 to 50 &mgr;m, the diameter being selected so as to achieve a pressure drop along the flow resistance structure in the range 5 to 15 mm Hg. The internal conduit for liquid flow also may include a removable flow inhibitor, which can be removed after implantation by a laser, such as an ophthalmic YAG laser. The device is made of biocompatible materials.