Glaucoma drainage devices are an option in the management of complicated glaucomas that carry a high risk of failure from conventional filtering surgery. Examples include the glaucomas associated with aphakia or pseudophakia, neovascular glaucoma, and glaucomas associated with trauma, uveitis, epithelial downgrowth, iridocorneal endothelial syndrome, vitreoretinal disorders, and penetrating keratoplasty. Modifications in the various implant designs have been developed to limit the occurrence of postsurgical complications such as hypotony, serous and hemorrhagic choroidal detachment, tube and plate avulsion, tube exposure, and corneal endothelial damage.