What is trabeculectomy?

Trabeculectomy is a type of glaucoma surgery performed on the eye that creates a new pathway for fluid inside the eye to be drained. This is an outpatient procedure performed in the operating room. It is used to prevent worsening of vision loss due to glaucoma by lowering eye pressure.

When performing trabeculectomy, an eye surgeon creates a flap in the sclera — the white part of the eye — underneath the upper eyelid.  Underneath this flap, a pathway is created to allow fluid to drain, which lowers eye pressure. The flap is then placed loosely back down against the sclera to protect the drainage pathway, and the entire surgery site is covered up using the outermost covering of the eye (the conjunctiva).

This process results in a small blister of fluid, called a bleb, on top of the eye’s surface but underneath the eyelid. The fluid inside the blister gets absorbed into blood vessels and does not cause excess tearing. The bleb is hidden by the upper eyelid and generally not noticeable by other people.

Trabeculectomy does not restore vision that has already been lost. The purpose of the procedure is to prevent further loss of vision due to glaucoma.

Why might I need a trabeculectomy?

Glaucoma is an eye disease in which high eye pressure causes damage to the optic nerve, leading to loss of vision.  Without treatment, people with glaucoma lose their peripheral vision, and potentially their central vision over time. If not treated, glaucoma can cause total blindness.

Your eye care team may recommend trabeculectomy to help prevent glaucoma from becoming worse. Trabeculectomy is a possible treatment for both closed-angle and open-angle glaucoma, as well as primary and secondary types of glaucoma.

“At this time, all of the clinically proven treatments for glaucoma involve lowering of eye pressure to prevent worsening of vision loss,” says Johnson. “Most glaucoma patients are able to successfully lower their eye pressure by using eyedrops and/or office-based laser therapy. A small subset of patients may require trabeculectomy if the eyedrops and/or laser therapy do not lower the eye pressure enough, or if there is allergy or other barriers to using eye drops.”

What are the risks of a trabeculectomy?

Most people do well with a trabeculectomy. However, complications from the surgery sometimes happen. Risks include:

• Failure of surgery to control the eye pressure: This generally occurs because of scarring around the surgery site that prevents adequate drainage of fluid from inside the eye. If this happens, the surgery site can sometimes be revised by breaking up scar tissue, or a different surgery can be performed to lower the eye pressure.
• Leaking of fluid from the surgery site: Sometimes this resolves on its own, but sometimes it requires another surgery to repair the leak.
• Low pressure that causes blurry vision: If the trabeculectomy surgery leads to too much drainage of fluid inside the eye, the eye pressure can become too low. This can be temporary, or it can require additional surgery to revise the trabeculectomy.
• Bleeding inside of the eye: Bleeding inside the eye can occur as a result of trabeculectomy and low eye pressure. While very rare, this can cause loss of vision.
• Eye infections: There is a risk that the surgery site could develop an infection that enters the eye and causes loss of vision if not recognized and treated promptly.
• Cataract: The lens inside the eye naturally develops cloudiness with age, called a cataract.  Trabeculectomy is known to speed up the formation of cataracts, but surgery is a common and highly successful way to address this issue.

Your risks may differ according to your age, health conditions and the specific anatomy of your eye. Talk with your eye care provider about all your concerns and about the risks that apply to you.

How do I prepare for a trabeculectomy?

“Talk to your eye doctor about how to prepare for your trabeculectomy,” says Johnson. “Ask whether you need to stop taking any medicines, especially blood thinners, before the procedure. You will need to avoid eating or drinking anything after midnight before the day of the surgery. You may need to avoid strenuous activity for a period of time after surgery.”

What can I expect during a trabeculectomy?

In general, you can expect the following during your trabeculectomy:

• You may be awake during the surgery. You will receive medicine to help you relax. You may also receive an injection or an anesthetic to numb the eye. This will keep you from feeling pain during the surgery.
• In some cases, you may receive general anesthesia to put you to sleep. If so, you will sleep deeply through the surgery.
• You may receive an anti-fibrotic medicine on your eye during and after the surgery. This can help reduce scarring and the chance of the surgery failing to adequately lower the eye pressure in the long term.
• Your surgeon may rotate your eye during the surgery and temporarily secure it with a stitch.
• You may receive antibiotics in your eye.
• Your eye may be covered with a patch and taped shut after the surgery. You will typically be asked to leave this patch in place until you see your doctor in clinic the following day.

What happens after a trabeculectomy?

In most cases, you will be able to go home the same day. Plan to have someone drive you home after the procedure. The area around your eye may be a little sore — you may be able to take over-the-counter pain medicines as directed by your care team.

Caring for your eye during glaucoma surgery recovery may include:

• Taking steroid eyedrops after surgery to promote healing and prevent scarring
• Covering your eye with a shield while you sleep, so you do not accidentally press on the eye
• Protecting the eye by avoiding eye rubbing
• Avoiding heavy lifting, straining or vigorous exercise
• Knowing the rare but serious warning signs of a problem and calling your doctor with any concerns — it’s important to tell your eye care provider right away if you have bleeding, fever, worsening vision, increasing eye pain, thick discharge or severe swelling during your recovery

“You will need continued follow-up care to monitor how you are doing after your surgery,” says Johnson. “The first two months after trabeculectomy surgery involve frequent visits to see your doctor — sometimes every one or two weeks. Your doctor may need to loosen the flap to drain more fluid from the eye by painlessly removing some temporary stitches from the surgery site using a laser or forceps.”

Other surgical options

Trabeculectomy is not the only surgery available for glaucoma. Other options include:

• Stents (tubing) inside the eye to open up the eye’s internal drainage
• Stents (tubing) outside the eye to create a new drainage pathway from inside to outside the eye
• Procedures that remove tissue from the drain inside the eye
• Operating room lasers that slow down the speed at which the eye makes fluid

Before proceeding with any glaucoma surgery, it is important to carefully discuss and consider all options with your care team.