Traditionally, tube shunts were used to control eye pressure in patients in whom traditional eye surgery to relieve fluid pressure (trabeculectomy) had previously failed, or in patients who have had previous surgeries or trauma that caused substantial scarring of the conjunctiva. Tube shunts have also been successful in controlling eye pressure in other types of glaucoma, such as glaucoma associated with uveitis or inflammation, neovascular glaucoma (associated with diabetes or other vascular eye diseases), pediatric glaucoma, traumatic glaucoma, and others.
A multicenter randomized clinical trial (the Tube Versus Trabeculectomy or TVT Study) was conducted in patients who had previous surgery, including, trabeculectomy and/or cataract surgery. Those results showed that after five years, tube shunt surgery had a higher success rate compared to trabeculectomy, with similar reductions in eye pressure and the need for supplemental glaucoma medications.
In recent years, some surgeons are using tube shunts or glaucoma drainage devices as first-line surgery, and forgoing standard trabeculectomy surgery. The cost of tube shunt implantation is somewhat higher than for trabeculectomy; however, some would argue there are fewer risks. To weigh these factors, there is currently an ongoing trial comparing tube shunt versus trabeculectomy in patients who have had no prior ocular surgery. The tube shunt is covered by Medicare and most insurance plans.