Medication and laser surgery are common forms of treatment for glaucoma. But if these don’t work, other forms of treatment have to be used.

In these cases, trabeculectomy surgery is usually the first option, which helps to slow the progression of glaucoma and lower the pressure in the eye (intraocular pressure). With a high success rate, it can prevent further vision loss, and in some people, can even improve the quality of life by reducing the need for eye drops.

What happens during a trabeculectomy?

Trabeculectomy is a type of surgery that involves removing a piece of the trabecular meshwork —an area of tissue in the eye that’s responsible for draining the aqueous humour from the eye (which in turn keeps a regular intraocular pressure).

This surgery usually takes about 45-60 minutes, often under local anaesthetic, during which the surgeon will carefully remove some tissue and create a flap in the sclera (the white layer of the eyeball). This flap is created to prevent all the fluid from leaking out too quickly, and is sewn in place with sutures to serve as an adjustable valve. The stitches can then be released painlessly to help get the target pressure in the eye.

The surgery is always performed under the upper eyelid, and the area above this will become a reservoir of aqueous fluid (called a bleb). This can look like a bubble when the top lid is lifted, but is entirely normal.¹

Sometimes, the formation of scar tissue can cause the newly created channel for drainage to close, which means that the intraocular pressure can no longer be lowered. Eye surgeons can use a powerful agent called mitomycin-C during the surgery to prevent this from happening.

After a trabeculectomy, it’s not unusual to experience some watering of the eye and a gritty sensation. The eye may be red and swollen, and there may be blurring of vision for a few days. The stitches may also cause some temporary soreness and irritation, but this all usually subsides within a few days.² If there is drooping of the eyelid, it usually resolves over a period of time. Typically, there is no sensation from the presence of the drainage bleb.³

Who should have a trabeculectomy?

Any surgery is not without risk so before trabeculectomy surgery is considered, most ophthalmologists will try medical therapy first. Many patients’ glaucoma can be well controlled with pressure-lowering eye drops, and often do not require surgery. Trabeculectomy is recommended when eye drops and/or laser treatment is not successful.

Sometimes there are barriers to using medications: for example, side effects, cost, or physical impairments may prevent a patient from using topical treatment, such as glaucoma eye drops.

Trabeculectomy is commonly advised when the potential benefits outweigh the surgical risks. The goal is to control the high intraocular pressure that is causing progressive damage to the optic nerve and loss of vision.⁴

How to prepare for a trabeculectomy

As with any surgery, it’s important to prepare beforehand. Your eye surgeon will provide detailed instructions on how to prepare, but in the meantime, here are some of the steps you may be asked to take:⁵

• Tell your ophthalmologist about any medication you take
• Continue your prescribed eye drops and medication, unless advised otherwise by your ophthalmologist
• Get treated for conditions such as blepharitis (eyelid inflammation) to minimise the risk of post-operative infection

Trabeculectomy recovery and aftercare

After the surgery, the eye will be padded for usually one day to prevent injury. You will typically be discharged from the hospital on the same day or one day after the procedure, but you won’t be able to drive home yourself. People in office jobs may need to take a couple of weeks off to recover, and those involved in heavy manual labour in dusty environments may need to take four weeks of medical rest leave.³

There may be some initial redness, swelling, and blurred vision during this recovery period, and the eyelid may droop a little. Luckily, these symptoms typically resolve themselves over two to three months.

To help protect against any accidental injury, sometimes a shield may need to be worn for a week or two. Patients will also need return to the clinic for stitch removal in 2-3 weeks post-surgery, and post-operative antibiotic eye drops and other medications may be prescribed and should be used as directed.³

Risks of trabeculectomy

Serious complications from trabeculectomy are rare, though can occasionally occur. For example, the eye can sometimes become infected, but this is treatable with antibiotics. A more serious complication is a sudden drop in eye pressure during the early post-operative period, which happens when large amounts of aqueous humour from the eye leaks out. It is often painless or associated with a dull throbbing sensation in the eye.

If you feel any of these signs or symptoms, it’s important to seek medical attention as soon as possible.

How successful are trabeculectomies?

The success rate of trabeculectomy varies according to age, ethnicity, type and severity of glaucoma, previous surgeries, and general health. One study found that 90% of patients still had successful results two decades after the operation, and that two-thirds of patients required no glaucoma medication.³

Another study supported these findings with an overall success rate of 78%-97%, claiming that trabeculectomy can reduce IOP significantly and reduce the need for glaucoma medication.⁶

Most people are able to achieve control of eye pressure after the operation, and many no longer require glaucoma eye drops afterwards. Clinical trials have also shown that the surgery is consistently more effective in reducing intraocular pressure compared to medications and laser.³

Ultimately, if you have any questions about your trabeculectomy surgery, your first port of call should be your ophthalmologist. They’ll be able to take you through the process in detail, and will be able to answer any questions you have.

If you’re interested in learning more about the treatment options for glaucoma, head over to our treatment resource page.