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Trabeculectomy Surgery

Glaucoma is caused by a build-up of fluid in the eye (called aqueous humour, or just aqueous). This causes pressure in the eye (called intraocular pressure or IOP) to increase, which damages the optic nerve and leads to vision loss. A trabeculectomy is an eye operation that improves drainage of fluid out of the eye. This page describes how a trabeculectomy works and the surgery involved.

What is a trabeculectomy?

A trabeculectomy is an operation which helps to drain fluid out of the eye and into a small blister (called a bleb) under the surface of the eye (the conjunctiva). The operation creates a kind of trap door for the fluid to pass through, bypassing the normal drainage channel. Drainage of aqueous is improved and this reduces IOP.

How will it help with my glaucoma?

The lower IOP reduces pressure on the optic nerve, which means vision loss is less likely to happen. However, any vision already lost to glaucoma can’t be recovered, and the glaucoma is not cured.

This type of treatment is for people with moderate to advanced glaucoma, and is a fairly common operation when eye drops aren’t working very well.

What does the surgery involve?

The surgery is usually done under local anaesthetic, which means you’ll be awake but your eye will be numb. It usually lasts one to two hours. You will probably be able to go home the same day or the next day.

What happens after surgery?

The bleb will not normally be permanently visible after surgery, but while the eye is healing it will probably be red and swollen.

You will be seen by your ophthalmologist the day after surgery, and given antibiotic and steroid eye drops to improve recovery. You must continue to take all eye drops as directed, including for your other eye if you have glaucoma in both eyes. You’ll be asked to attend several follow-up appointments after the surgery to check the eye is healing well and the device is working. It is very important to attend all appointments.

It will take your eye several weeks to recover from the surgery, so you’ll need to take some time off work and avoid some types of physical activity.

It is possible that your prescription for glasses may change after surgery. You should wait for three months before changing glasses, while the eye is adjusting and healing.

What are the benefits?

Trabeculectomy is a safe procedure, although as with all operations there is some risk, for example of infection. For most people with glaucoma, the surgery reduces IOP well. This means fewer eye drops and a better chance of protecting vision.

What are the alternatives?

There are other treatments available for glaucoma which may be recommended to you, for example, eye drops, aqueous shunt or MIGS.

Download our free trabeculectomy booklet

If you want to know more about trabeculectomy, our free booklet is a great place to start. You can download a digital edition or order the print version to be delivered to your door.

We are here to help

Our glaucoma helpline advisors are also on hand to answer any questions you may have and provide support whenever you need it.

Call 01233 64 81 70 or email

(Monday – Friday, 9.30am – 5.00pm)