Many of the surgical procedures performed in humans with glaucoma are not effective in dogs due to the difference in the pathophysiology of this disease between species. For instance, common glaucoma procedures performed in humans such as trabeculoplasty, iridotomy, and trabeculectomy do not control the intraocular pressure in dogs, and can actually make it worse. Because dogs most commonly have closed angle glaucoma, the surgery of choice is to increase outflow (make a new drain) and decrease inflow (turn off the faucet). Candidates for this surgery are dogs affected with glaucoma that are no longer medically controlled or acute cases where some vision remains. Dogs that do not have the potential for vision are unfortunately not reasonable candidates for this surgery. The surgery of choice involves two procedures: cyclophotocoagulation and placement of an anterior chamber shunt.  Cyclophotocoagulation refers to partial destruction of the ciliary body (faucet) using a diode laser. Anterior chamber shunt placement involves inserting a valved Ahmed shunt into the anterior chamber to facilitate aqueous drainage (the yellow arrow in the picture below points to the shunt located in the anterior chamber of the eye). This surgery tends to have a good success rate, with 75% of dogs maintaining comfort and vision at 1 year post-operatively.