This is a surgical procedure performed for severe cases of glaucoma. With glaucoma, the eye pressure is high, which causes gradual death of the optic nerve. There are many ways to lower the eye pressure. Many doctors begin with medicated eye drops. These work to improve the outflow of aqueous fluid from the eye. Other drops decrease the production of aqueous fluid. Laser therapy (such as SLT) can also be performed to improve fluid outflow. If these methods aren’t working and visual loss is eminent, a glaucoma surgery can be considered. With a tube-shunt, a small plastic tube is inserted into the anterior chamber in the front of the eye. This tube drains or “shunts” excess aqueous fluid to a pocket under the conjunctiva skin of the eye, up under the eyelid. From here, the vitreous fluid percolates back into the body and is absorbed into the blood stream. This drainage pathway is entirely covered by the conjunctiva skin, so there is no drainage to the outside world. This is important as we don’t want to give environmental bacteria an entrance into the eye. Tube-shunt procedures are much more difficult and time consuming than most eye surgeries so are usually reserved for people with advanced or intractable glaucoma.