Aqueous shunts in glaucoma

Glaucoma remains a major cause of blindness worldwide and all currently available medical, laser, and surgical therapies have substantial failure rates. Among surgical therapies for glaucoma, aqueous shunts are being increasingly employed for those cases in which prior conventional filtering surgery has failed to control intraocular pressure (IOP). Common denominators of the three currently popular shunts include their construction from materials to which fibroblasts cannot tightly adhere and an equatorial explant plate connected to the anterior chamber or vitreous cavity via a silicone-rubber tube. Few randomized clinical trials have been published comparing aqueous shunts to conventional filtering surgery, or to each other. It is important and timely to assess their relative safety and efficacy as a guide to continuing clinical use and to further evolution of these devices. At present there is insufficient evidence to conclude that outcomes of trabeculectomy differ substantially from those of aqueous shunts in similar patients.