What is a trabeculectomy?

A trabeculectomy (trab-ec-u-lec-tomy) operation may be recommended if your glaucoma continues to progress despite using eye drops and/or having had laser treatment. The goal of trabeculectomy surgery is to help lower and control your eye pressure.

The trabeculectomy is an operation to create an alternative drainage channel in the white of your eye (sclera) to allow aqueous fluid (natural fluid) to drain from your eye into a reservoir called a bleb underneath the top eyelid, and then to be absorbed by the body. This new pathway bypasses the blocked natural drain (trabecular meshwork) of your eye.

We understand how precious your vision is… Ms Pearsall will guide you through your personalised treatment plan.

Remember we are with you every step of the way.

How do I know I need a trabeculectomy?

The eye pressure is known as intra-ocular pressure (IOP). If your IOP remains high, then further irreversible loss of vision from glaucoma may occur. This operation will not improve your vision or cure glaucoma, but aims to prevent or slow down further visual loss from glaucoma damage.

What happens next?

Welcome – When you arrive at your treatment clinic, you will be warmly welcomed and signed in by one of our friendly reception team members and directed to the clinic. You will be seated in our clinic reception and offered complimentary tea and coffee. Your eye health journey with Ms Pearsall will begin..

Eye Health check

Using the latest state-of-the-art technology she will be able to capture detailed measurements of your eyes, discuss your work and hobbies with you and what is important to you. She will ensure your surgical plan is the most optimal for you.

Your appointment will lasting about 1.5 hours (and includes about 20 minutes to allow your pupils) to dilate – see below). examine your eyes and conduct a sight test to check the quality of your vision.

Dilating the eyes causes blurred vision and sensitivity to light, so you won’t be able to drive; so it’s important to make sure you organise a lift or arrange transport to/from the hospital.

Please feel free to ask any questions you may have about your surgery at any time.

You’ll need to bring your current glasses, a list of your current medications, record book (if you’re diabetic or taking Warfarin) and a contact number of a relative/friend. If you wear contact lenses these should not be worn for at least 48 hours before your appointment.


What happens at the pre-assessment?

1. Vision test – we will check your vision using the same letter chart as your optician

2. Eye pressure – It is important to check the pressure side your eye.

3. Visual field test – to check the quality of your peripheral vision

4. Corneal thickness measurement (CCT) – to measure the thickness of the clear tissue at the front of your eye

5. A full eye health check looking at all structures of the eye in detail.

6. Pupils dilated – Drops are placed in each eye to make the pupils larger so we can examine the eye. (It usually takes about 30 to 40 minutes for your pupils to dilate). It can affect your vision and sensitivity to light for up to four hours, so you will not be able to drive yourself home after the appointment.

7. Eye diagnostics – optic disc and retinal scans or photographs – to analyse the structures of the eye

8. General healthcare – we will check your blood pressure and temperature, discuss your current health and what regular medication you are taking (both prescription and non-prescription).

We will talk you through the best option for you explaining everything thoroughly and answering any questions you may have.

Consent – We take time to discuss with each of our patients the details of your glaucoma surgery, the benefits that you should get from the surgery and also the risks of surgery. We’ll check that you understand everything and ask you to sign a consent form, which lets us know you give your permission for your surgery to go ahead. Please let us know if you have a lasting power of attorney (LPA) or require support for giving consent.

How do I book the surgery?

The final stage of your appointment is to book a date for your surgery. Your eye advisor will talk through the next steps with you and help you choose a time and date to suit you – this is usually about two weeks following your appointment.

Confirmation of your appointment

You will receive written confirmation of your appointment date and information on cataract surgery. We will provide a comprehensive patient information booklet on glaucoma surgery, which includes what you can expect at each stage of your patient journey.

Your glaucoma surgery

It is very normal to be anxious about your surgery, but please be reassured that we will support you through every step on your surgery day; put your mind at ease, explain what is happening and discuss any concerns you may have, making you as comfortable as possible.

Before your operation

You should continue any eye drops and tablets for your glaucoma as prescribed until the time of your surgery, unless directed otherwise. If you take any blood thinning medicines for example Warfarin, it is very important to tell us, as this may need adjusting prior to your operation.

You will be asked to attend a pre-operative assessment appointment. For this appointment please bring with you an up to date list of your current medications and a brief summary of your medical history, available from your GP if you are unsure. During this visit your general health and suitability for anaesthetic will be assessed and any investigations for example blood tests will be undertaken if required.

Average time for glaucoma surgery is 45 minutes – but you will be at the hospital on the day of your surgery for about 2 to 3 hours

Advice and recommendations for your surgery day

The time given for your appointment is the time you should arrive at the hospital and NOT the time of your surgery.

It’s important to make sure you organise a lift or arrange transport . If you’re struggling to find transport please speak to your eye hospital receptionist

We recommend eating a light meal before you arrive at the hospital.

Please take all your medications as normal, unless we have specifically advised you not to.

You should wear comfortable and loose fitting clothing – you will not need to wear a hospital gown.

We recommend you wear dark coloured clothing – we use iodine during surgery and this can sometimes run down your neck and may stain lighter clothing.

Remove all make-up before arriving at the hospital.

Please try not to bring any valuables with you – we have lockers and areas for you to leave bags etc during surgery, but we cannot guarantee their safety.

We are here to support you, make you feel at ease and make your surgery day as stress-free as possible.

1. Welcome – You will receive a big smile and warm welcome from one of our friendly reception team. They will check you in and take you to the patient waiting area. There will be complimentary tea, coffee and biscuits for you and your family/friends/carer.

2. Arranging pick up – Our reception team will ask contact details of the person who will be picking you up after your surgery and we will give them a ring when you’re ready to go home. Your family/friends/carer is also welcome to wait in the reception area once you are called through to the surgical ward – this is normally about a 2 to 3 hour wait.

3. Nurse pre-surgery check – You’ll be called through to the surgical ward where you’ll be greeted by one of our skilled and friendly nurses, who will spend about 5 to 10 minutes with you. They’ll take your blood pressure and temperature and check all is OK for your surgery to go ahead.

4. Surgical ward – the nurse will show you through to the surgical ward. It is very important for your pupil is constricted, and so there will be up to 45 minutes waiting time on the surgical warder the drops to work.

5. Consultant pre-surgery check – Ms Pearsall will check through your details and make sure you’re all OK with everything before taking you through to surgery. Please feel free to ask any further questions you may have… An arrow will be drawn above the eye you are having surgery on – don’t worry, this is standard procedure for all surgical operations.

6. Pre-surgery – One of the surgery team will call you through to the surgery preparation room to get you ready for surgery. The nurse will administer anaesthetic drops to numb your eye. We give you a couple pieces of protective clothing to pop on before surgery – a cap and shoe covers. If you wear a hearing aid we ask that this is removed at this point and the nursing team will look after this and give it back to you straight after your surgery. The nurse will make sure you understand what will happen next and you can ask any questions you may have to make sure you are happy with everything.

Will I feel anything?

Trabeculectomy surgery can be carried out under either a local anaesthetic or a general anaesthetic. These choices will be discussed with you prior to your admission to hospital

If you choose to have a local anaesthetic the surgery is done as a day case using an injection beside the eye a few minutes before the start of the operation. This makes the eye numb, and usually blurred as well.

How is a trabeculectomy procedure performed?

Your surgery

The nursing team will take you through to the operating theatre and help get you comfortable on the operating bed.

  • The area around your eye will be cleaned using an iodine based solution; this can stain light clothing, so we advise you to wear dark clothing on your surgery day.
  • A sterile sheet is placed across your head and chest; this does not lie directly on your face or head, but is held above your face and body using a bar fixed to the operating bed. The sterile sheet sticks to the skin around the eye to create a sterile zone around your eye area.
  • The surgeon uses a special microscope with a very bright light, which magnifies your eye. You will be looking at this very bright light throughout the surgery and this is all that you will be able to see.
  • Obviously, we will ask you to keep still during the surgery and our patients don’t find this an issue. If you need to move, to sneeze for example, that’s fine, just let the surgeon know – just think of it like the dentist where you have to keep your head still for a few minutes. And, as a matter of fact, many of our patients have said that they found eye surgery a much better experience than going to their dentists!
  • It’s important to keep the eye moist during surgery and so water is used to irrigate the eye and this sometimes runs down your face onto your ear or neck. This is why we ask that any hearing aids are removed before your surgery.
  • The procedure lasts, on average, about 45 minutes, that’s all, and most of our patients are (pleasantly) surprised when our surgeon lets them know it’s finished!
  • We have asked hundreds of patients to describe what they feel or experience during surgery and the feedback is that they just see a very bright light or bright colours and don’t feel anything. If you experience any strange or unpleasant sensation during surgery please let Ms Pearsall know and they will give you some more anaesthetic drops.
  • The sheet is removed very carefully from around your eye at the end of the surgery – this feels similar to a sticky plaster being taken off, so there is a small amount of discomfort, but this only lasts for a second or two.
  • At the end a patch is taped over the eye, which is left on until the next day. This is to help protect the eye and prevent infection.
  • One of the nursing team will support you as you get off the operating table and take you through for your post-op check.


If you have had sedation or a general anaesthetic, you will be taken to the recovery area in the operating suite, where you will be carefully monitored until you are considered safe to transfer back to your bed on the ward. This time can vary from person to person, but is generally less than an hour.

Surgery all done – take a deep breath and smile!

Benefits of a trabeculectomy surgery

The most obvious benefit of the surgery is to lower pressure inside your ey and ultimately to prolong useful vision. The vision will not improve. Often vision is temporarily worse as the level of pressure inside the eye stabilises. the benefit is long term (years), rather than immediate.

How successful is the surgery?

The success of trabeculectomy surgery is based upon a patient’s IOP being less than 21mmHg a year after surgery. The national average shows that 66% of patients achieve this. However you will be reassured to know that, we have a success rate of greater than 95%.

Factors that can reduce the success of trabeculectomy surgery are:

  • Young age.
  • Ethnic group.
  • Uveitis (inflammation within the eye).
  • Previous eye surgery.
  • Previous severe eye injury.
  • Rubeotic glaucoma where there are abnormal blood vessels on the iris.
  • Natural healing process causing scarring.
  • Diabetes.
  • Some eye drops, including multiple use of eye drops.
The use of antimetabolites (anti-scarring drugs)

The main reason for trabeculectomy failure is that the newly created drainage site can scar and heal up. The previous mentioned risk factors can influence this. Antimetabolites are drugs that prevent scar tissue forming and enhance the success rate of the operation.

The most commonly used antimetabolites are 5 Fluorouracil (5FU) and Mitomycin C (MMC). These can be used at the time of surgery and 5FU can be used in the out-patients clinic and given as an injection around the drainage bleb.

What are the risks of trabeculectomy surgery?

_ Your eyes are very delicate and, as with all surgery, there are possible side effects that can arise either during surgery, shortly after, or many months after. In most cases the complications can be treated and in a small proportion of cases, further surgery may be needed. Very very rarely some complications can result in loss of sight.

Listed below are some more serious possible complications:

  • Vision: Sight may take several weeks to return to normal. Some patients will find their vision is not quite as sharp after surgery. The benefit is slowing (or stopping) the rate of deterioration of glaucoma. However, the operation cannot be totally guaranteed to stop the loss of vision in your eye. Eye surgery for any condition ALWAYS carries a small risk that vision may be worse or the eye may become blind after the operation.
  • The most serious problem that can occur is bleeding inside the eye (called “suprachoroidal” haemorrhage). This may require further treatment, and may ultimately lead to loss of vision and even blindness, but occurs in less than 1 in 1000 patients.
  • An infection inside the eye can be very serious and also cause loss of vision or blindness. This happens in less than 1 in 1000 patients and may require further urgent treatment.
  • A trabeculectomy operation itself will make your eye more prone to infection, even in years to come. If your eye becomes painful or red or the vision becomes blurred, you should seek immediate medical help.
  • After the operation the IOP may be too high or too low. This may require pressure lowering eye drops, additional treatment in the out-patient clinic, or the need for further surgery.


Other complications that can occur:

  • Inflammation inside the eye can occur; this is treated with eye drops.
  • Some patients are aware of the drainage bleb under their upper eyelid or that there is slight drooping of the eyelid, this usually settles down.
  • This usually settles within a few weeks, but some patients experience long-term discomfort. These symptoms are usually mild and can be controlled with artificial tears.
  • As your eye settles and heals you may need a change of glasses, to get your best vision. About 10% of patients notice that their vision is reduced by one line on the eye chart a year after the operation, as cataract formation may be increased by trabeculectomy surgery.
  • Further surgery may be required to make the operation succeed, or to correct low pressure. It is not unusual for an additional procedure of some sort to be required – usually this is a much shorter procedure than the trabeculectomy itself.
Why do we use antimetabolites (anti-scarring drugs)?

The main reason for trabeculectomy failure is that the newly created drainage site can scar and heal up. The previous mentioned risk factors can influence this. Antimetabolites are drugs that prevent scar tissue forming and enhance the success rate of the operation.

The most commonly used antimetabolites are 5 Fluorouracil (5FU) and Mitomycin C (MMC). These can be used at the time of surgery and 5FU can be used in the out-patients clinic and given as an injection around the drainage bleb.

What happens after your operation?

The nurses will give you some eye drops to take home and use several times a day for a few weeks. These treat inflammation (redness and soreness) and prevent infections. If your eye(s) is/are painful after the operation, you can take painkillers which are suitable for young people, such as paracetamol or ibuprofen.

If you wear glasses, you will need to continue wearing them. We will need to see you the day after surgery and regularly at the clinic to measure the pressure in your eye.

Immediately after your operation, your eye will be covered by a protective eye pad. Eye drops are not usually required in your operated eye until the day after surgery. Any eye drops that you use in your other eye must be continued as normal.

The morning after your operation the protective eye shield will be removed. Your eye will be cleaned and examined and eye drops started. The eye drops you will need to use in your operated eye will be different from the drops that you used prior to your operation.

Drops will need to be used for approximately three months after your operation. Each time you attend the out-patient clinic any changes to your eye drops will be discussed with you.

Can I wear contact lenses afterwards?

Cannot be worn due to the bleb.

Should I wear sunglasses?

Wear for comfort if your eye feels sensitive to light and wear sunglasses in bright sunlight with UV protection.

Should I wear my glasses?

No restrictions. Avoid buying new glasses for 2-3 months after surgery as your glasses prescription can change during this time as your eye heals.

Can I go walking?

No restrictions.

How shall I sleep?

Try to sleep on your un-operated side. Tape the plastic eye shield provided over your eye every night for 2 weeks to avoid accidentally rubbing your eye whilst asleep.

Can I wash my hair?

No need to avoid but don’t allow soapy / dirty water to go into your eye.

Can I have a shower or bath?

No need to avoid but back wash advised to avoid getting shampoo into your eye. It may be easier to have someone else wash your hair for you.

What can I do after trabeculectomy surgery?

Following surgery you are able to read and watch television as normal as these activities will not harm your eye. It is however, important to avoid strenuous activity during the first few weeks after surgery as a general guide below are the ‘do’s and don’ts’. If in doubt please ask

Wearing contact lenses?

Cannot be worn due to the bleb.

Can I drive?

This is dependent on your vision in both eyes and you will be advised at clinic.

Can I go away on holiday?

Discuss with your doctor/nurse as it is very important to attend your follow up appointments.

Can I wear make-up?

Avoid for 1 month then use new make-up. Never share eye make-up with someone else.

Can I do household chores?

Avoid for 1 – 2 weeks but this depends upon your intra-ocular pressure.

Can I be intimate with my partner?

We would recommend avoiding sex for 2 weeks.

Can I go to the gym?

Avoid for 3 months.

Can I play sports?

Avoid for 3 months.

Can I run or jog?

Avoid for 3 months.

Can I swim?

Avoid until all your stitches have been removed, approximately 3 months then after that wear goggles.

It is most important that you do not bump, rub or press on your eye after surgery.

When can I go back to work?

The length of time you will need off work depends upon a number of factors. These include the nature of your job, your vision and the IOP in your operated eye. Most people need 1 – 2 weeks off after surgery. If your job involves heavy manual work or you work in a particularly dusty/dirty environment you may require longer off.

Contact us immediately if…

The information above is intended as a guide only, as each patients experience will be different. Do not wait until your next appointment, but contact us immediately on 020 3137 3237, if you have:

  • Redness.
  • Vision disturbance such as double vision.
  • Loss of vision.
  • Increasing Pain.