Glaucoma surgery (trabeculectomy)

What is glaucoma surgery?

Trabeculectomy is the most common type of surgery used to treat glaucoma and causes minimal scarring. 

Glaucoma is a condition where there is damage to the optic nerve, which carries visual signals from the eye to the brain. Damage is usually caused by a build-up of fluid (aqueous humour) within the eye. This causes the pressure inside the eye to rise. If left untreated, glaucoma can lead to severe loss of vision or even blindness.

Our ophthalmologists recommend trabeculectomies for moderate to advanced glaucoma, and if eye drops or medications are not alleviating intraocular pressure.

Preparing for glaucoma surgery

Glaucoma surgery may be carried out under either local anaesthetic (the area will be numbed and you will be awake) or general anaesthetic (you will be asleep throughout).

Most surgery is performed as a day case, so you would usually return home on the same day. The operation will generally last for less than an hour.

What does glaucoma surgery involve?

First, your surgeon will make a small hole into the sclera (white part of the eye) to create a small blister (bleb). The fluid in your eye will drain into the bleb, bypassing the blocked drainage system and reducing intraocular pressure. The bleb is typically made underneath your eyelid, so you won’t notice it.

During the procedure a drug, mitomycin C, may be applied to reduce scarring after the operation. It helps to keep fluid draining from the eye.

By reducing the pressure in your eye with a trabeculectomy, the pressure on your optic nerve decreases, making vision loss less likely. However, this treatment will not restore the vision you’ve lost already. 

After a trabeculectomy, you will most likely go home on the same day, but it can take several weeks for you to recover fully. 

Your glasses or contact lenses prescription may change after a trabeculectomy, so you may need another eye test three months after your procedure.

Alternative treatments

Eye drops are the main non-surgical treatment for glaucoma. If they’re not effective, there are other options apart from trabeculectomy.

These include laser treatment and many other types of newer glaucoma surgeries, collectively known as MIGS (minimally invasive glaucoma surgeries), which can be used to reduce the pressure in your eyes. Your consultant will be able to discuss these alternatives with you and advise on the most appropriate course of action.

Risks of glaucoma surgery

Surgery is usually a safe procedure and it’s effective in reducing the pressure within the eye. Occasionally the pressure in the eye may drop too low, so further surgery may be needed. This is the most common complication of trabeculectomy. Other complications are rare, but may include:

• infection
• bleeding
• blurring or loss of vision
• discomfort
• collection of fluid under the retina
• double vision

Your consultant will discuss the potential complications with you in more detail.