Glaucoma afflicts more than three million Americans and has made an enormous health and financial impact upon the nation; annually, thousands lose their sight to glaucoma, and the economic cost in terms of medical care, lost wages and other negative impacts is in the billions of dollars. Fortunately, glaucoma is treatable with both medications and surgery, with the most recent promising treatment options coming in the operating room. Two relatively recent surgical options, shunt and stent implantation, offer glaucoma patients less invasive opportunities to gain long-term control of their condition. Below is more information about how glaucoma surgery is shifting from a more-traditional approach to shunt- and stent-based options:
Glaucoma surgery- where it began and where it is headed
Not too long ago, the trabeculectomy was considered the surgery-of-choice for all glaucoma patients. This procedure involves the partial removal of the trabecular meshwork. This particular tissue structure normally permits drainage of aqueous humor, the intraocular fluid located between the lens and cornea. Aqueous humor is essential for maintaining proper eye function in healthy individuals; in patients with certain forms of glaucoma, the trabecular meshwork does not provide adequate drainage and this leads to dangerous intraocular pressure build-up.
Trabeculectomy is usually effective, but it requires a several week recovery time. Additionally, the invasive nature of the surgery can lead to infection, abnormally low intraocular pressure, and other serious problems. The surgery can also create scar tissue which can limit the use of trabeculectomy. Though there is still a place for trabeculectomy as a surgical option, surgeons have developed less-invasive procedures for building "fluid expressways" for aqueous humor drainage: optic shunts and stents.
Also called tube shunts, optic shunts for glaucoma are an effective alternative to trabeculectomies. An optic shunt consists of an ultra-thin, non-metallic tube inserted through the surface of the eye; it is joined to a surgically-created collection "basin" that serves as a collection point for aqueous humor. The tubing serves to transfer collected fluid out of the eye and deposits it into the space immediately behind the eye.
Tube shunts involve much less tissue dissection, and they can provide a reliable drainage canal for aqueous humor without the more numerous risks associated with trabeculectomy. At one time, tube shunts were considered a secondary option to trabeculectomy, but with a track record of success, tube shunts have shown themselves to be an excellent first-line treatment for glaucoma.
The latest surgical development in glaucoma treatment is the use of micro-sized stents that are about the width of an eyelash. These stents consist of tiny metallic half-tubes, often made of titanium or nickel, inserted into clogged drainage pathways. Eye stents are not closed tubes nor do they create a new pathway for drainage. Instead, they help keep existing pathways open so the trapped fluid can flow freely.
Surgical insertion of glaucoma stents is a fast, simple outpatient procedure. More than one system of stent placement has been developed, but some systems are designed especially for rapid-fire insertion of stents. The procedure itself lasts no more than about half-an-hour in most instances, and it can be performed using local or general anesthetic depending on patient desires. In addition, patients are able to head home after the surgery, since it is minimally invasive and provides little in the way of infection risk. Benefits of using stents have proven to be overwhelmingly positive, with almost all patients experiencing marked improvement, and most not needing to use prescription eye drops.
The biggest drawback to optic stents is that their drainage effect is less dramatic than other surgical options, though adding multiple stents can help overcome this limitation. In addition, since stents are the newest technology in glaucoma surgery, they do not yet have a body of long-term research to demonstrate their staying power.