Trabeculectomy

Glaucoma is an eye condition that’s most common in those aged 50 and over. It causes damage to the nerve that carries visual information from the eyes to the brain (optic nerve).

This damage is caused by pressure inside the eye (intraocular pressure). Although high pressure in the eye is common in glaucoma, this condition can also occur with normal pressure levels.

There are several different types of glaucoma, but all of them are treated by reducing pressure in the eye. In most cases, glaucoma can be effectively treated with regular eye drops. However, in some cases, surgery is needed. Trabeculectomy is the most common glaucoma surgery.

What is trabeculectomy surgery?

Trabeculectomy surgery is an operation to reduce pressure in the eye. It is used to stop or slow down the progression of glaucoma.

Although it cannot reverse existing damage to the eye, the main benefit of this surgery is to prevent further damage to the eye and vision loss.

During trabeculectomy surgery, a small flap is cut into the white part of your eye (sclera) under your upper eyelid. Fluid inside the eye can then drain out of the flap and into a tiny blister hidden by the upper eyelid. This reduces pressure inside the eye.

The blister is called a bleb and is a bubble-like pocket on the surface of the eye. The fluid that collects here is naturally absorbed by the body.

Signs of needing trabeculectomy surgery

You may need trabeculectomy surgery if your glaucoma is not well-controlled with other treatments, namely regular eye drops and/or laser therapy. You may also need trabeculectomy surgery if you can’t tolerate eye drops eg due to an allergy.

Your doctor will determine whether your glaucoma is well-controlled at your regular check-ups, which will include measuring the pressure in your eye.

Is trabeculectomy surgery right for you?

If your glaucoma is well-controlled using less invasive treatments, trabeculectomy surgery will not be recommended.

Trabeculectomy surgery also may not be recommended if there’s a high risk that the surgery will not be successful. This is determined on an individual basis; however, certain situations and conditions increase the likelihood that a trabeculectomy will not be successful. This includes:

• A past trabeculectomy that failed
• Certain types of glaucoma, specifically uveitic glaucoma and neovascular glaucoma in its active stage
• Severe scarring to the front covering of the eye (conjunctiva) eg due to chemical burns

Trabeculectomy surgery is performed under an operating microscope. Your surgeon will make a small cut into the covering of the front part of your eye (conjunctiva). The conjunctiva will then be peeled back to expose the white part of your eye (sclera).

A small cut will be made into the sclera to create a flap located under your upper eyelid. Underneath the flap, a small hole is made into the eye and a tiny piece of the coloured part of your eye (iris) is removed. This creates a route for fluid to drain out of your eye.

The flap is then loosely placed back down and kept in the correct position using very small stitches. Next, a small sponge will be used to apply a drug called mitomycin C on the wound site. This helps reduce scarring. Finally, the conjunctiva is placed back down and stitches are used to hold it in place.

Once your operation is complete, you’ll be given an injection containing steroids and antibiotics into your eye. This helps reduce inflammation and the risk of infection. Your eye will be covered with a pad and a plastic shield.

The operation results in a bubble-like reservoir called a bleb that sits on the surface of the eye under the upper eyelid, hidden from view. Fluid drains into the bleb and is absorbed by the body via blood vessels that supply the eye.

Before your trabeculectomy

You will have a formal consultation with one of our experienced consultant ophthalmologists (a doctor who specialises in treating the eyes). You will also need to complete a questionnaire about your medical history, any medications and/or supplements you are taking and any symptoms you have.

Your consultant ophthalmologist will explain:

• The risks and benefits of trabeculectomy surgery
• What will happen before, during and after your trabeculectomy
• Your options for anaesthesia
• How to take care of your eye during your recovery

If your surgery is being performed under a general anaesthetic, you will be advised on how long you need to fast for before your surgery ie when you will need to stop eating and drinking anything other than water.

If you smoke, you will be advised to quit smoking before your surgery and during your recovery as smoking increases the chances of complications and infection.

Your care team will also let you know whether there are any diagnostic tests that you need before your operation, such as blood tests and/or scans, and whether you need to temporarily stop taking certain medications (eg blood thinners such as warfarin).

Who will be involved?

Your surgery will be performed by one of our expert consultant ophthalmologists. If you have a general anaesthetic, this will be administered by one of our experienced anaesthetists.

Before, during and after your surgery, you will also be cared for by a team of highly skilled nurses.

How long does a trabeculectomy take?

A trabeculectomy takes around 1 hour to complete.

Your anaesthetic options

Your consultant will advise you on your options for anaesthesia, namely local anaesthesia or general anaesthesia.

If you have a general anaesthetic, you will be asleep during your surgery. If you have a local anaesthetic, you will remain awake but will not feel any pain.

In most cases, a local anaesthetic will be recommended. However, you may have a general anaesthetic if your consultant thinks it’s preferable based on your medical history, or you have a strong preference for general anaesthesia and are fit enough to tolerate it. 

Pain during and straight after surgery

During surgery, you will be under general or local anaesthesia and, therefore, will not feel any pain.

After surgery, pain is uncommon, although you may feel some tenderness or mild discomfort. This can be relieved by taking paracetamol.

What happens straight after surgery

If you have a general anaesthetic, you will be taken to a recovery ward where you will be closely monitored overnight as the effects of the general anaesthesia wear off.

If you have a local anaesthetic, you will also be monitored in a recovery ward, but in most cases, you will be able to go home after a few hours.

Your hospital stay

In most cases, a trabeculectomy is performed under a local anaesthetic as an outpatient procedure. This means you will not need to stay overnight in hospital.

However, if you have a general anaesthetic, you will most likely need to stay overnight in hospital until the effects of the general anaesthetic wear off.

Before you go home, your care team will provide you with detailed instructions on how to look after your eye and what you can and cannot do. They will also let you know when to return the next day for your follow-up appointment.

You should arrange for someone to take you home after your trabeculectomy surgery as you may feel tired and your eye will be covered so your vision will be impaired.

For the first 24 hours after your surgery you can take paracetamol if you feel any eye discomfort. You should keep wearing your pad and plastic eye shield — these can be removed the next day.

After your pad and eye shield are removed, you should apply the eye drops prescribed to you as instructed by your consultant. Avoid getting any shampoo, soap or other products in your eye.

If your eye feels sticky, clean it by pouring water that has been boiled and cooled over the eye and gently wipe your eyelids with a clean tissue. Do not rub your eyes or apply any pressure to your eyeball, especially in the area around your wound site. 

You should continue to wear an eye shield at night for the first 2 weeks. When sleeping, try to sleep on the opposite side of your body to the side that was operated on.

During the first 2 weeks of your recovery, you should also avoid any strenuous activities, such as vigorous exercise, sexual intercourse, bending and lifting, as these can increase the pressure in your eyes and impair your recovery.

You should also avoid swimming for the first 2 weeks to reduce the risk of infection and irritation of your wound site.

You can usually return to work after 2 weeks. However, it takes 6–8 weeks to fully recover from trabeculectomy surgery.

Vision changes after trabeculectomy surgery

It’s normal for your vision to be blurry after trabeculectomy surgery. Blurry vision usually returns to normal within 8 weeks.

If you wear glasses, you’ll most likely need a new prescription to correct your vision. However, you will usually be advised to wait 3 months before getting new glasses to ensure your vision has settled after surgery.

You should not drive while you have blurry vision. 

Your vision and eye health will continue to be closely monitored after your surgery with regular appointments for the first 1–2 months.

Every surgery comes with risks and the potential for complications, such as excessive bleeding, infection and tissue damage. All eye surgeries also come with an increased risk of developing cataracts earlier in life.

For trabeculectomy surgery, it’s common to experience blurry vision for up to 8 weeks after surgery. Some individuals also experience a gritty sensation in the eye, which usually improves as the eye heals. However, sometimes, long-term dry eye can develop — this can be treated with lubricating eye drops.

Your risk of infection immediately after surgery and in the long term is raised due to the flap on the surface of your eye. Signs of infection include redness and pain in the eye and a sticky discharge. Inform your care team immediately if you notice these signs.

Trabeculectomy surgery also comes with the risk of your eye pressure becoming too high due to inflammation and scar tissue around the surgery site, or your eye pressure becoming too low due to fluid draining out of the eye too quickly.

On average, 3 years after trabeculectomy surgery, pressure in the eye remains reduced in around 90% of cases.

Alternative treatments to trabeculectomy surgery

Trabeculectomy surgery is not usually recommended unless regular eye drops and/or laser treatment have been unsuccessful. However, a trabeculectomy is not the only surgical option.

Less invasive types of eye surgery to help reduce pressure in the eye are collectively known as minimally invasive glaucoma surgery (MIGS). They include surgery to implant devices called stents, and laser surgery called selective laser trabeculoplasty to increase drainage through the eye’s natural drainage system. 

If trabeculectomy surgery fails or is not suitable, an alternative surgery called aqueous shunt implantation can be performed, where a shunt (a small tube connected to a plate) is inserted to drain fluid from the eye.