If you have glaucoma and medications and laser surgeries do not lower your eye pressure adequately, your ophthalmologist may recommend a surgical procedure called a trabeculectomy.

In this procedure, a tiny drainage hole is made in the sclera, or white part of the eye. The new drainage hole allows fluid to flow out of the eye into a filtering area called a bleb. The bleb is mostly hidden under the eyelid. When successful, the procedure will lower your intraocular pressure (IOP), minimizing the risk of vision loss from glaucoma. The surgery is performed in an operating room on an outpatient basis.

Some of the risks and complications from trabeculectomy surgery include:

• failure to control intraocular pressure, with the need for another operation;
• infection;
• bleeding in the eye;
• swelling in the eye;
• irritation or discomfort in the eye;
• eye pressure that is too low;
• cataract (in cases where cataract has not already been removed); and
• decreased or lost vision.

Certain medications, called antimetabolites, have been found to be helpful when used with some types of glaucoma surgery. These medications were originally developed to help treat some kinds of cancer.

Mitomycin-C (MMC) and 5-Fluorouracil (5-FU) are the most commonly used antimetabolites for glaucoma surgery. When these antimetabolites are used with other medications that reduce inflammation, the success rate of surgery is greatly improved, especially for patients who are at high risk for excessive scarring.

These medicines may be applied to the eye during or after the surgery to reduce the growth of scar tissue, a common cause of failure in glaucoma surgery. Your ophthalmologist may consider using antimetabolite medicines with your glaucoma surgery if:

• you are having surgery on an eye that has been operated on before;
• you have inflammation in your eye (called uveitis);
• you have glaucoma due to abnormal new blood vessel formation within the eye (called neovascular glaucoma);
• you are having glaucoma and cataract surgery at the same time;
• you are relatively young;
• you have more deeply pigmented skin; or
• your eyes are at risk for postoperative scarring.

In addition to the usual complications of glaucoma surgery, other risks associated with using antimetabolites include:

• eye pressure that is too low;
• leaking incisions;
• slower healing of the cornea;
• blurred vision;
• fluid in or behind the retina;
• thinning of the eye tissues; and
• infection.

If your ophthalmologist has decided to use antimetabolite medications, he or she will explain why they are recommended for you.

While some people may experience side effects from medications or surgery, the risks associated with these side effects should be balanced against the greater risk of leaving glaucoma inadequately treated and losing your vision.