What is trabeculectomy?

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Trabeculectomy: Overview

During trabeculectomy—sometimes also called filtration surgery—a piece of tissue in the drainage angle of the eye is removed, creating an opening. The opening is partially covered with a flap of tissue from the sclera, the white part of the eye, and the conjunctiva, the clear thin covering over the sclera. This new opening allows fluid (aqueous humor) to drain out of the eye, bypassing the clogged drainage channels of the trabecular meshwork.

As the fluid flows through the new drainage opening, the tissue over the opening rises to form a little blister or bubble, called a bleb. The bleb is located where the sclera, or white of the eye, joins the iris, the colored part of the eye. During office visits after surgery, the doctor looks at the bleb to make sure that fluid is still draining out of the new opening. Not all blebs have to be easily seen to work.

How can you care for yourself after a trabeculectomy?


  • Rest when you feel tired. Getting enough sleep will help you recover.
  • Wear your glasses during the day. Wear your eye shield or patch at night for 1 week or for as long as your doctor tells you to.
  • Ask your doctor when it is okay to drive.
  • You can read or watch TV.
  • Do not wear contact lenses for about 8 weeks, or until your doctor says it is okay.
  • Do not wear eye makeup for 2 weeks. You may also want to avoid face cream or lotion.
  • You can shower or wash your hair the day after surgery. Keep water, soap, shampoo, hair spray, and shaving lotion out of your eye, especially for the first week.
  • Do not rub or put pressure on your eye for at least 1 week.
  • Do not get your hair colored or permed for 10 days after surgery.
  • Do not bend over or do any strenuous activities, such as biking, jogging, weight lifting, or aerobic exercise, for 2 weeks or until your doctor says it is okay.
  • Avoid swimming, hot tubs, gardening, and dusting for 1 to 2 weeks.
  • Wear sunglasses if your eyes feel sensitive to light.


  • Your doctor will tell you if and when you can restart your medicines. The doctor will also give you instructions about taking any new medicines.
  • If you stopped taking aspirin or some other blood thinner, your doctor will tell you when to start taking it again.
  • Follow your doctor's instructions for when to use eye drops. Always wash your hands before you put your drops in. To put in eyedrops:
    • Tilt your head back, and pull your lower eyelid down with one finger.
    • Drop or squirt the medicine inside the lower lid.
    • Close your eye for 30 to 60 seconds to let the drops or ointment move around.
    • Do not touch the ointment or dropper tip to your eyelashes or any other surface.
  • Follow your doctor's instructions for taking pain medicines.
  • As your eye heals, your doctor will know if you need to keep taking glaucoma medicines. You may not need any medicines, or you may be able to take less medicine than before. If you do need medicines, follow your doctor's instructions for taking them.
  • If you get constipated, your doctor may recommend laxatives. These medicines help you avoid straining while trying to pass stool. Straining can increase the pressure in your eye.

How well does a trabeculectomy work?

The new opening created by trabeculectomy allows fluid to gather under the tissue that lines the eyeball (conjunctiva), where it is absorbed into the bloodstream.

This procedure lowers pressure inside the eye. But some people need another trabeculectomy surgery or other treatments for glaucoma. Trabeculectomy is less likely to be successful in:

  • Children who have congenital glaucoma.
  • People who have difficult-to-control glaucoma in which new blood vessels grow on the iris (neovascular secondary glaucoma).
  • People who have diabetes.
  • People who have had previous eye surgery.
  • People of African descent.

The long-term effectiveness of trabeculectomy surgery in preventing loss of vision from glaucoma is less certain. It is not a cure. And visual field loss can continue despite surgery.

How do you prepare for a trabeculectomy?

Surgery can be stressful. This information will help you understand what you can expect. And it will help you safely prepare for surgery.

Preparing for surgery

  • Be sure you have someone to take you home. Anesthesia and pain medicine will make it unsafe for you to drive or get home on your own.
  • Understand exactly what surgery is planned, along with the risks, benefits, and other options.
  • If you take a medicine that prevents blood clots, your doctor may tell you to stop taking it before your surgery. Or your doctor may tell you to keep taking it. (These medicines include aspirin and other blood thinners.) Make sure that you understand exactly what your doctor wants you to do.
  • Tell your doctor ALL the medicines, vitamins, supplements, and herbal remedies you take. Some may increase the risk of problems during your surgery. Your doctor will tell you if you should stop taking any of them before the surgery and how soon to do it.
  • Make sure your doctor and the hospital have a copy of your advance directive. If you don’t have one, you may want to prepare one. It lets others know your health care wishes. It’s a good thing to have before any type of surgery or procedure.

What are the risks of a trabeculectomy?

The most common problem after a trabeculectomy is scarring of the opening. Scarring prevents fluid drainage from the eye and interferes with the proper function of the bleb. If the bleb doesn't work or causes problems, more surgery may be needed.

The medicine mitomycin is commonly used during surgery to prevent scarring. It is more commonly used than 5-fluorouracil, but it cannot be used after surgery. 5-fluorouracil can be used during the surgery or injected into the thin tissue (conjunctiva) covering the eye after surgery to prevent scarring.

Other complications of this surgery that may develop soon after surgery include:

  • Bleeding in the eye.
  • Sudden, permanent loss of central vision. This risk depends in part on how much central vision had been lost before surgery.
  • Infection in the eye.
  • High pressure in the eye, causing the space in the front part of the eye (anterior chamber) to collapse (malignant glaucoma). This is rare.

Late complications after a trabeculectomy may include:

  • A cataract that is worse than it was before surgery (common).
  • Continued changes in the nerve at the back of the eye related to glaucoma.
  • Infection.
  • Droopy eyelid (a very slight droop of the eyelid is common).

What can you expect as you recover from a trabeculectomy?

Most people don't have to be admitted to the hospital. But children who have the surgery may stay in the hospital overnight. And in some cases, your doctor may recommend that you stay in the hospital.

Right after surgery, antibiotics may be applied to the eye. They may also be injected under the lining of the eyelid (conjunctiva). After surgery, the eyelid is usually taped shut, and a hard covering (eye shield) is placed over the eye. A dressing is worn over the eye during the first night after surgery. You'll wear the eye shield at bedtime for up to a month. Corticosteroid medicines are usually applied to the eye for about 1 to 2 months after surgery to decrease inflammation in the eye.

You will probably have a checkup with your eye specialist the day after surgery.

Any activity that might jar the eye needs to be avoided after surgery. People usually need to avoid bending, lifting, or straining for several weeks after surgery.

After surgery, people who have problems with constipation may need to take laxatives to avoid straining while trying to pass stools. Straining can raise the pressure inside the eye (intraocular pressure). This can cause problems with the new opening that was made during surgery to drain fluid from the eye. These problems can increase the pressure in your eye even more and increase the risk of infection.

Usually there is mild discomfort after a trabeculectomy. Severe pain may be a sign of complications. If you have severe pain after your surgery, call your doctor right away.

After trabeculectomy: When to call

Call 911 anytime you think you may need emergency care. For example, call if:

  • You passed out (lost consciousness).
  • You have a sudden loss of vision.
  • You have sudden chest pain, are short of breath, or cough up blood.

Call your doctor now or seek immediate medical care if:

  • You have symptoms of an eye infection, such as:
    • Pus or thick discharge coming from the eye.
    • Redness or swelling around the eye.
    • A fever.
  • You have new or worse eye pain.
  • You have vision changes.
  • You have symptoms of a blood clot in your leg (called a deep vein thrombosis), such as:
    • Pain in the calf, back of the knee, thigh, or groin.
    • Redness and swelling in your leg or groin.

Watch closely for any changes in your health, and be sure to contact your doctor if:

  • You do not get better as expected.

After a trabeculectomy: Overview

You had a trabeculectomy to treat glaucoma. Pressure in the eye can lead to vision problems. This type of surgery is one way to lower the pressure in the eye.

After surgery, your eye may be red and irritated. It may also water more than usual or swell a little. Even though your eye may be uncomfortable, it's important not to rub it. Rubbing your eye could damage it.

A dressing is worn over the eye during the first night after surgery. You'll wear an eye shield at bedtime for up to a month.

You will probably be able to return to work or your normal routine 1 to 2 weeks after surgery. In most cases, the new opening (bleb) in your eye will be covered by your upper eyelid and will not be visible.

For a few weeks, you may see your doctor several times a week to check how well fluid is draining out of your eye. Depending on the pressure in your eye, your doctor may cut the stitches around your bleb to change the flow of fluid.

Your eyes may be blurry for up to 6 weeks after surgery. As this goes away, your vision will probably be as good as it was before surgery. But you may need to change your glasses or contact lenses. Certain kinds of glasses and contacts may be better for your eye after this surgery.

If you need them, your doctor will recommend or prescribe pain medicines. The doctor will also give you eyedrops and may prescribe medicines to prevent the bleb from scarring.

Why is a trabeculectomy done?

Trabeculectomy is used to treat open-angle glaucoma and chronic closed-angle glaucoma. Trabeculectomy is usually done when medicine or laser treatment or both have failed to reduce the pressure in the eyes enough to prevent damage to a person's eyesight.

Trabeculectomy is not the first surgery used for treating children who have childhood glaucoma.

What happens on the day of a trabeculectomy?

  • Follow the instructions exactly about when to stop eating and drinking. If you don't, your surgery may be canceled. If your doctor told you to take your medicines on the day of surgery, take them with only a sip of water.
  • Follow your doctor's instructions about when to bathe or shower before your surgery. Do not apply lotions, perfumes, deodorants, or nail polish.
  • Take off all jewelry and piercings. And take out contact lenses, if you wear them.

At the hospital or surgery center

  • Bring a picture ID.
  • You will be kept comfortable and safe by your anesthesia provider. The anesthesia may make you sleep. Or it may just numb the area being worked on.
  • The surgery will take 30 to 90 minutes.

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