Andrew A. Dahl, MD, FACS
Andrew A. Dahl, MD, is a board-certified ophthalmologist. Dr. Dahl's educational background includes a BA with Honors and Distinction from Wesleyan University, Middletown, CT, and an MD from Cornell University, where he was selected for Alpha Omega Alpha, the national medical honor society. He had an internal medical internship at the New York Hospital/Cornell Medical Center.
Melissa Conrad Stöppler, MD
Melissa Conrad Stöppler, MD, is a U.S. board-certified Anatomic Pathologist with subspecialty training in the fields of Experimental and Molecular Pathology. Dr. Stöppler's educational background includes a BA with Highest Distinction from the University of Virginia and an MD from the University of North Carolina. She completed residency training in Anatomic Pathology at Georgetown University followed by subspecialty fellowship training in molecular diagnostics and experimental pathology.
William C. Shiel Jr., MD, FACP, FACR
Dr. Shiel received a Bachelor of Science degree with honors from the University of Notre Dame. There he was involved in research in radiation biology and received the Huisking Scholarship. After graduating from St. Louis University School of Medicine, he completed his Internal Medicine residency and Rheumatology fellowship at the University of California, Irvine. He is board-certified in Internal Medicine and Rheumatology.
In this Article
- Glaucoma facts
- What is glaucoma?
- How common is glaucoma?
- What causes glaucoma?
- What are glaucoma risk factors?
- What are the different types of glaucoma?
- What are glaucoma symptoms and signs?
- How is glaucoma diagnosed?
- How often should someone be checked (screened) for glaucoma?
- What is the treatment for glaucoma?
- Glaucoma medications (eyedrops)
- Glaucoma surgery or laser
- Can glaucoma be prevented?
- What is in the future for glaucoma?
- Find a local Eye Doctor in your town
Glaucoma surgery or laser
There are several forms of laser therapy for glaucoma. Laser iridotomy (see the section above on angle-closure glaucoma) involves making a hole in the colored part of the eye (iris) to allow fluid to drain normally in eyes with narrow or closed angles. Laser trabeculoplasty and Selective Laser Trabeculoplasty (SLT) are laser procedures performed only in eyes with open angles. Laser trabeculoplasty does not cure glaucoma, but may be done instead of increasing the number of different eyedrops, or may be recommended when a patient is already using multiple eyedrops (maximal medical therapy). In some cases, it is used as the initial or primary therapy for open-angle glaucoma. This procedure is a quick, relatively painless, and safe method of lowering the intraocular pressure. With the eye numbed by anesthetic drops, the laser treatment is applied through a mirrored contact lens to the angle of the eye. Microscopic laser burns to the angle allow fluid to better exit the drainage channels.
Laser trabeculoplasty is often done in two sessions, weeks or months apart. Unfortunately, the improved drainage as a result of the treatment may last only about 2 years, by which time the drainage channels tend to clog again. There are different types of laser trabeculoplasty including argon laser trabeculoplasty (ALT) and selective laser trabeculoplasty (SLT). ALT is generally not repeated after the second session due to the formation of scar tissue in the angle. SLT is less likely to produce scarring in the angle, so, theoretically, it can be repeated multiple times. However, the likelihood of success with additional treatments when prior attempts have failed is low. Thus, the options for the patient at that time are to increase the use of eyedrops or proceed to surgery.
Laser cyclo-ablation (also known as ciliary body destruction, cyclophotocoagulation or cyclocryopexy) is another form of laser treatment generally reserved for patients with severe forms of glaucoma with poor visual potential. This procedure involves applying laser burns or freezing to the part of the eye that makes the aqueous fluid (ciliary body). This therapy destroys the cells that make the fluid, thereby reducing the eye pressure. This type of laser is typically performed after other more traditional therapies have failed.
Trabeculectomy is a delicate microsurgical procedure used to treat glaucoma. In this operation, a small piece of the clogged trabecular meshwork is removed to create an opening and a new drainage pathway is made for the fluid to exit the eye. As part of this new drainage system, a tiny collecting bag is created from conjunctival tissue. (The conjunctiva is the clear covering over the white of the eye.) This bag is called a "filtering bleb" and looks like a cystic raised area that is at the top part of the eye under the upper lid. The new drainage system allows fluid to leave the eye, enter the bag/bleb, and then pass into the capillary blood circulation (thereby lowering the eye pressure). Trabeculectomy is the most commonly performed glaucoma surgery. If successful, it is the most effective means of lowering the eye pressure.
Aqueous shunt devices (glaucoma implants or tubes) are artificial drainage devices used to lower the eye pressure. They are essentially plastic microscopic tubes attached to a plastic reservoir. The reservoir (or plate) is placed beneath the conjunctival tissue. The actual tube (which extends from the reservoir) is placed inside the eye to create a new pathway for fluid to exit the eye. This fluid collects within the reservoir beneath the conjunctiva creating a filtering bleb. This procedure may be performed as an alternative to trabeculectomy in patients with certain types of glaucoma. Mini shunts without a reservoir are also used to improve safety and reduce the postsurgery chance of pressures that are too low.
In the past few years, minimally-invasive glaucoma surgery (MIGS) has been under development. Various devices such as the Trabectome, the IStent, the Cypass Microstent, the Xen glaucoma implant, and the Hydrus Microstent have been either approved for human use or are in advanced clinical trials. These provide alternative surgical procedures used to lower eye pressure. These procedures are directed at creating openings in the trabecular meshwork, the drainage ring in the wall of the angle of the eye. These surgeries are less invasive than trabeculectomy and aqueous shunt surgery, but may not lower pressure as much.p>
The surgeon sometimes creates other types of drainage systems. While glaucoma surgery is often effective, complications, such as infection or bleeding, are possible. Accordingly, surgery is usually reserved for cases that cannot otherwise be controlled.
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