Trabeculectomy

If you have glaucoma and medications and laser surgeries do not lower your eye pressure adequately, your ophthalmologist (Eye M.D.) may recommend a procedure called a trabeculectomy. In this procedure, a tiny drainage hole is made in the sclera (the 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 the following:

• 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.

Antimetabolites

Certain medications, called antimetabolites, were originally developed to help treat some kinds of cancer. These same medications have also been found to be helpful when used with some types of glaucoma surgery. The eye’s natural healing process works against the success of the surgery as scar tissue forms. 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. Mitomycin-C 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. 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 new blood vessel formation within the eye;
• 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 untreated and losing your vision.

Bleb Care After Trabeculectomy

Trabeculectomy surgery for glaucoma results in the creation of a drainage “bubble” or filtration site under the upper eyelid. Aqueous fluid flows from the eye into this filtration site bubble, which is called a bleb. The aqueous fluid is absorbed into tiny blood vessels, keeping eye pressure low. The bleb tissue is fragile, and it is important to take care of it to maintain proper functioning. Patients should avoid rubbing the bleb; direct contact with this area should be avoided. Patients should wear protective eyewear when engaging in sporting activities or swimming. A bleb that functions well is often thin and is susceptible to infection. If there is any sign of redness or drainage, call your ophthalmologist (Eye M.D.) immediately. An infected bleb can lead to pain, decreased vision, and potentially even loss of vision or the eye. Patients who have had anti-scarring medication, such as 5-fluorouracil (5-FU) or mitomycin C, are even more prone to infection. Your ophthalmologist will tell you if this is the case for you. Another complication that can occur either early or late is a bleb leak. If you detect any abnormal tearing or a change in visual acuity, you need to have your eye examined by your ophthalmologist as soon as possible. A well-functioning trabeculectomy bleb can last a lifetime. Proper care and maintenance can help ensure that the bleb continues to control your eye pressure.

Glaucoma Drainage Device Surgery

Tube shunts can be implanted into the eye to lower the eye pressure. Typically, the tube is placed in the anterior chamber, which is the fluid filled space between the cornea (clear front part of eye) and iris (colored part of eye). The tube is connected to a plastic plate that is sewn to the sclera, the white part of the eye. Fluid collects overtop of this plate and forms a fluid filled space called a ‘bleb.’ The tube shunt apparatus may have a valve, or it may be non-valved. The tubes shunts with a valve have the advantage of immediate pressure reduction following surgery, as well as the prevention of too low of a pressure (hypotony) which can be dangerous or undesirable for a different reason. Oftentimes patients with valved tubes end up on at least one glaucoma drop following surgery over the long-term. Non-valved tubes have the advantage of being able to achieve lower pressures than their valved cousins; however, to prevent early hypotony, they must be tied off with a degradable suture that will dissolve several weeks later. For this reason, these tubes do not provide immediate pressure reduction. Some of the risks and complications from glaucoma drainage device surgery include the following:

• failure to control intraocular pressure, with the need for another operation;
• Infection;
• Double vision;
• 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.