Glaucoma drainage devices have traditionally been reserved for refractory glaucoma. However, there is an increasing body of evidence to suggest the use of these implants at an earlier stage in the surgical management of glaucoma. We describe the mechanics behind their function as well as the various implants available. The implants vary in size, surface area and composition and hence the surgical implantation of these devices are described in detail. The knowledge of such devices and their potential complications is fundamental for the successful management of patients who undergo aqueous-shunt surgery. Careful patient selection and optimal postoperative management is critical to the successful patient outcomes.