Glaucoma surgery (trabeculectomy)
An operation to lower the pressure inside the eye in glaucoma, by creating a new drainage channel so fluid can leave the eye more easily and protect the optic nerve.
✓ Medically reviewed by a GMC-registered consultant · last reviewed September 2026 · next review September 2027 · how we review
In short
- A trabeculectomy lowers eye pressure by creating a new drainage channel and a small reservoir ('bleb') under the eyelid, to slow glaucoma damage.
- It aims to protect the vision you still have; it cannot bring back sight that glaucoma has already taken away.
- Recovery needs patience and many follow-up visits, with intensive drops, possible stitch adjustment and 'needling' to keep the drainage working.
- The channel can scar and the surgery does not always last; serious sight-threatening complications are rare but, including infection, remain a lifelong possibility.
A plain-English summary. The detail — including risks and recovery — is below.
At a glance
A general guide. Your surgeon will give you advice for your situation.
Effectively lowers eye pressure, often more than drops or laser can
Glaucoma already well controlled on drops or laser, where surgery's risks may outweigh the benefit.
Vision is blurry and the eye is red and watery. You use frequent drops to reduce inflammation and scarring, and attend early checks. Avoid rubbing the...
Frequent early reviews to adjust drops, loosen stitches and needle the bleb if needed.
Vision is blurry and the eye is red and watery. You use frequent drops to reduce inflammation and scarring, and...
Frequent visits continue to fine-tune drainage — the surgeon may loosen stitches or 'needle' the bleb if it scars...
The eye and pressure usually stabilise and your glasses prescription can be updated. Many people are able to...
You need ongoing glaucoma monitoring (pressure, optic nerve and visual fields), as the channel can scar later, and...
What is glaucoma surgery (trabeculectomy)?
Glaucoma is a condition where the optic nerve at the back of the eye is gradually damaged, often because the pressure inside the eye is too high. This can slowly and permanently reduce vision, usually starting with the edges of your sight. Lowering the eye pressure is the main way to slow this damage.
A trabeculectomy is an operation that lowers eye pressure by making a tiny new drainage channel in the white of the eye. Fluid drains through this channel into a small blister-like reservoir under the upper eyelid, called a 'bleb', from where it is reabsorbed. An anti-scarring medicine (such as mitomycin C) is often used to keep the channel working.
It is usually offered when eye drops, and often laser treatment, have not controlled the pressure well enough, or when the glaucoma is getting worse despite them. The aim is to protect the sight you still have.
It is important to be realistic. Glaucoma surgery aims to lower pressure and slow further damage — it cannot restore vision that has already been lost, and the new drainage channel can scar over time, so it does not always work permanently.
Types & techniques
There isn't one single operation. The right approach depends on you — which is something to discuss with your surgeon.
Trabeculectomy vs MIGS
| Feature | Trabeculectomy | MIGS |
|---|---|---|
| Glaucoma severity | Moderate to advanced | Mild to moderate |
| Pressure-lowering power | Strong | Usually more modest |
| Creates a bleb? | Yes | No |
| Recovery / follow-up | Several weeks, intensive | Usually quicker |
| Main risks | Hypotony, bleb problems, infection | Generally lower, but less effect |
These are different tools for different stages of glaucoma. Your surgeon recommends based on how advanced the glaucoma is, your target pressure and your eye, not on which is 'newest'.
Preparing for your surgery
- Discuss with your surgeon how advanced your glaucoma is, your target pressure, and why surgery is being recommended now.
- Ask about your other eye and your overall vision, as this affects how much risk is reasonable.
- Tell the team about all eye drops and medicines, including blood thinners, which may need managing around surgery.
- Expect to continue some drops up to surgery unless told otherwise, and arrange a lift home.
- Plan for several weeks of frequent follow-up visits, as this surgery needs close monitoring.
- Arrange help at home, as you should avoid heavy lifting, straining and bending in the early weeks.
- Ask what will happen to your glaucoma drops afterwards, as the aim is often to reduce or stop them.
What happens
A trabeculectomy is usually done under local anaesthetic, sometimes with sedation, so the eye is numb but you are awake; occasionally a general anaesthetic is used. You lie flat and a clip gently holds the eyelids open.
The surgeon lifts a thin flap in the white of the eye and makes a small opening so fluid can drain out under the surface into a reservoir (the 'bleb') beneath the upper eyelid. An anti-scarring medicine is usually applied briefly to help the channel keep working. Fine, sometimes adjustable, stitches control how fast the fluid drains.
The operation usually takes around 45–60 minutes and most people go home the same day. Your vision will be blurry at first, and the early weeks involve intensive drops and several visits to fine-tune the drainage — including loosening stitches or 'needling' the bleb if it starts to scar.
Is this operation right for me?
A good consultation should explore whether it's the right choice for you now — including reasons to wait or consider something else.
May not be suitable if…
- Glaucoma already well controlled on drops or laser, where surgery's risks may outweigh the benefit.
- Very mild glaucoma that may be better suited to laser or MIGS.
- An eye surface or scarring tendency that makes a bleb very likely to fail (a tube may be chosen instead).
- An eye where vision is already lost beyond what surgery could protect, where the balance of risk needs careful discussion.
- Inability to attend the frequent follow-up visits the surgery requires.
Delay surgery if…
- You have an active eye or eyelid infection or significant inflammation.
- Blood-thinning medicines need adjusting and this has not yet been arranged.
- Your pressure is acutely very high and needs stabilising first.
- You cannot arrange the help and follow-up needed for the early recovery weeks.
- Other urgent eye or general-health problems need treating first.
Alternatives to discuss
- Continuing or changing glaucoma eye drops.
- Laser treatment of the drainage (such as SLT) or to reduce fluid production.
- Minimally invasive glaucoma surgery (MIGS) for milder disease, often with cataract surgery.
- A glaucoma drainage device (tube) instead of trabeculectomy in some eyes.
- Close monitoring without surgery if the glaucoma is stable and slowly progressing.
Before you decide
Use this as a shared-decision checklist. The aim is not just “can this be done?”, but whether it is right for you, now, with the risks and alternatives clearly understood.
What matters most to me?
Think about symptoms, daily life, work, caring responsibilities, sport, fertility, travel, appearance and anxiety — the right choice depends on your priorities, not just the medical facts.
What are all my options?
Ask about waiting, monitoring, medicines, rehabilitation, a smaller or larger procedure, a different test, NHS referral, or a second opinion where that would help.
What would make me pause?
Active infection, pregnancy, unstable medical problems, smoking, medicines that increase bleeding, poor support at home, or feeling pressured are all reasons to slow down and get tailored advice.
What happens if I do nothing today?
For some problems, waiting is safe; for others, delay can make treatment harder. A good consultation should explain the trade-off in plain English.
Anaesthetic choices
The safest option depends on the operation, your health, the facility and your surgeon/anaesthetist. Ask what is planned and why.
Benefits
- Effectively lowers eye pressure, often more than drops or laser can
- Aims to slow or halt further glaucoma damage to the optic nerve
- Can reduce or remove the need for daily glaucoma drops in many people
- Helps protect the remaining field of vision
- Can be adjusted in the early weeks (stitch loosening, needling) to fine-tune the result
Risks & complications
- Blurry vision for days to weeks while the eye settles
- A red, watery or gritty eye and an awareness of the bleb
- Some bleeding inside the front of the eye that usually clears within about a week
- A change in glasses prescription as the eye shape settles
- Pressure dropping too low (hypotony), which can blur vision and usually settles but sometimes needs treatment
- The drainage channel scarring so pressure rises again, needing more drops, needling or further surgery
- Cataract forming or worsening in the months to years after surgery
- A leak from the bleb, or a droopy eyelid, or temporary double vision
- Serious bleeding inside the eye (suprachoroidal haemorrhage)
- Serious infection inside the eye (endophthalmitis), which remains a lifelong risk after this surgery
- Lasting reduction in, or loss of, vision
The two complications that can threaten sight — serious bleeding inside the eye and infection (endophthalmitis) — are rare, but endophthalmitis remains a lifelong risk because of the bleb, so you must know its warning signs forever. More commonly, the pressure can fall too low early on (hypotony) or the channel can scar and stop working. Ask your surgeon about your personal target pressure, what happens if the surgery scars, and the red flags that mean you should seek help urgently.
Published figures to discuss
Success and complication rates vary with how advanced the glaucoma is, the eye's tendency to scar, the surgeon and how 'success' is defined (some studies count any drop in pressure, others count being drop-free). Figures from UK audit and patient-information sources are useful guides rather than promises, and African-Caribbean eyes tend to scar more, lowering success.
| Figure | Reported range | How to interpret it | Source / confidence |
|---|---|---|---|
| Good pressure control without further glaucoma drops | Around 7 in 10 in UK national glaucoma surgery audit data | A success measure; some people still need drops, and success can fall later if the channel scars. | Guide sourcesClinical context |
| Pressure too low early on (hypotony) / too much drainage | Common early; UK national survey data reported hypotony in about 24% early after trabeculectomy | Usually settles on its own, but occasionally needs treatment; anti-scarring medicine raises this risk. | Trabeculectomy — review (StatPearls, NCBI)ncbi.nlm.nih.govPublished figure |
| Bleeding inside the front of the eye (hyphaema) | Common early; UK national survey data reported hyphaema in about 25% | Usually clears within about a week. | Trabeculectomy — review (StatPearls, NCBI)ncbi.nlm.nih.govPublished figure |
| Serious bleeding or infection inside the eye | Very rare; NHS sources quote less than about 1 in 1,000 | Sight-threatening; endophthalmitis (infection) remains a lifelong risk because of the bleb. | NHS — Glaucomanhs.ukPublished figure |
These are literature figures, not a personalised prediction. Your own risks and likely benefits depend on your circumstances, your health, and how your care is carried out and followed up.
Recovery — what to expect, and when
Recovery from glaucoma surgery takes patience. Vision is blurry at first and the result is actively managed over several weeks with intensive drops and frequent visits, because how the eye heals largely decides how well the surgery works.
- Blurry vision that gradually improves over the first weeks
- A red, watery or gritty eye and awareness of the bleb
- Needing frequent drops and frequent clinic visits early on
- A change in your glasses prescription as the eye settles
- Vision fluctuating while the pressure stabilises
Aftercare
- Use all prescribed drops (especially anti-inflammatory/steroid drops) exactly as directed, as they protect the new drainage channel.
- Do not rub or press the eye, and wear any protective shield at night as advised.
- Avoid heavy lifting, bending, straining and strenuous activity in the early weeks.
- Avoid swimming and dusty or dirty environments until your surgeon says it is safe.
- Attend every follow-up visit, even if the eye feels fine, as early adjustments matter.
- Ask before stopping or restarting any glaucoma drops in either eye.
- Learn the warning signs of infection and raised pressure, and keep an urgent contact number to hand for life.
- Lift home and help with daily tasks for the first weeks arranged
- All prescribed drops collected and a dosing plan understood
- Protective eye shield ready for sleeping
- All early follow-up appointments booked
- A clear plan for which glaucoma drops to continue or stop
- Written warning signs of infection and raised pressure
- Clinic's urgent/out-of-hours number saved permanently
Scars and how they heal
The surgery is done within the eye's own surface tissues, so there is no skin scar on the face. Instead, a small blister-like reservoir (the 'bleb') forms under the upper eyelid, usually hidden when the eye is open. The body's natural tendency to scar can affect the bleb and is the main reason the surgery sometimes stops working, which is why anti-scarring medicine and close follow-up are used.
⚠ Get urgent help if…
- Sudden or worsening eye pain
- A sudden drop in or loss of vision
- Increasing redness around the bleb, discharge, or a sticky, very red eye (possible bleb infection — an emergency)
- Increasing light sensitivity with a red, painful eye
- Severe headache, eye ache with nausea or seeing haloes (possible raised pressure)
- Any of these, at any time after surgery, should prompt immediate contact with your eye team — bleb infection can occur years later
Who to contact: your surgeon or clinic first (keep their number to hand). For urgent advice when you can't reach them, call NHS 111. In an emergency, call 999.
General guidance — it doesn't replace the specific advice your surgeon gives you.
Results & realistic expectations
A good result is eye pressure brought down to a level that protects your remaining vision, often with fewer or no glaucoma drops, and a stable optic nerve and visual field over time. Long-term audit data suggest that after this surgery most people achieve good pressure control without needing further glaucoma drops, though some still need drops or further treatment.
The key thing to understand is that surgery protects sight rather than restoring it: vision already lost to glaucoma does not come back. The result also is not guaranteed to last, because the drainage channel can scar over months or years, so lifelong monitoring continues.
Many people get long-lasting pressure control from a trabeculectomy, but it is not always permanent. The new channel can scar and stop working months or years later, in which case more drops, a needling procedure, a repeat operation or a drainage tube may be needed. Cataract can also develop or worsen after surgery. Because of all this, and the lifelong risk of bleb infection, you need ongoing glaucoma care indefinitely.
Combining with other procedures
If you also have a cataract, the surgeon may discuss combining cataract surgery with the glaucoma operation, or doing them separately, depending on your eye. Glaucoma surgery sits within a wider treatment plan that also includes drops, laser and, for milder disease, MIGS — your surgeon will explain where surgery fits for you.
Follow-up & long-term care
Follow-up after glaucoma surgery is intensive: expect several visits in the first weeks to adjust drops, loosen stitches or needle the bleb, then regular long-term checks of pressure, the optic nerve and your visual fields. This close follow-up is part of the treatment, not optional. Report pain, redness around the bleb or vision change immediately, however long after surgery.
- Attend lifelong glaucoma monitoring (eye pressure, optic nerve and visual field tests).
- Use any continuing drops exactly as prescribed, and check before changing them.
- Stay alert for bleb infection and raised-pressure warning signs for life.
- Have your sight in the other eye monitored too, as glaucoma often affects both eyes.
- Expect that further treatment may be needed over the years if the channel scars.
Revision and secondary surgery reality
- The new channel can scar and stop working, needing more drops, a needling procedure, a repeat operation or a drainage tube.
- Stitches are often loosened or removed in the early weeks to fine-tune drainage.
- Cataract may develop or worsen after surgery and need separate treatment.
- Because glaucoma is lifelong, ongoing monitoring and possible further treatment should be expected.
Ask your surgeon for their own revision rate, what counts as a revision, and what is included in the written aftercare policy.
What good aftercare looks like
- Frequent early reviews to adjust drops, loosen stitches and needle the bleb if needed.
- Clear instructions on which glaucoma drops to continue or stop, in both eyes.
- Written, lasting warning signs for bleb infection and raised pressure, with an urgent contact route.
- A long-term plan for monitoring pressure, the optic nerve and visual fields.
- An agreed plan for further treatment if the channel scars over time.
What affects the cost
Costs vary a great deal between people and providers, and we don't publish prices. What matters is understanding what drives the cost and making sure your quote is complete. The main things that affect it:
- The type of glaucoma operation (trabeculectomy, drainage tube or combined surgery)
- Whether anti-scarring medicine and any implant or device are included
- The surgeon's experience and seniority
- Whether the many follow-up visits, stitch adjustments and any needling are included
- Whether it is combined with cataract surgery
- Long-term glaucoma monitoring and the policy for further treatment if the channel scars
- Whether the price includes the intensive early follow-up visits, not just the operation
- Whether stitch adjustment and bleb needling are included if needed
- Whether long-term glaucoma monitoring is included or arranged separately
- Any anti-scarring medicine, implant or device used
- The named operating surgeon
- What happens, and what it costs, if the surgery scars and further treatment is needed
- What happens, and what it costs, if a complication such as infection occurs
On the NHS? Glaucoma surgery is routinely funded by the NHS when clinically needed; private care may be chosen for timing or choice of surgeon, but the operation and aftercare are the same.
You're entitled to your total cost in writing — including aftercare and any revision — before you decide.
Consent traps and marketing red flags
These are not small details. They are often where patients lose choice, time to reflect, or realistic expectations.
Consent traps
- Expecting surgery to improve vision rather than protect it.
- Not being told the surgery can scar and may not last.
- No clear, lasting warning about bleb infection, which can occur years later.
- Under-estimating how many follow-up visits and how much drop use the early weeks need.
- No plan for what happens, and who to contact, if pressure rises again or the eye becomes painful or red.
Marketing red flags
- Promising surgery will restore lost vision or 'cure' glaucoma.
- Down-playing the intensive follow-up and adjustment the surgery needs.
- Pushing one technique as 'best' regardless of how advanced the glaucoma is.
- Not mentioning the lifelong risk of bleb infection.
- Quoting only a headline operation price with no long-term monitoring plan.
Choosing a surgeon safely
- Check your surgeon is on the GMC Specialist Register for this area.
- Make sure they practise at a CQC-registered location, and look for membership of bodies like BAAPS or BAPRAS.
- You're entitled to a two-stage consent process with time to reflect (a cooling-off period). The surgeon who will operate must consent you — not a salesperson.
- Be wary of pressure: time-limited offers, discounts or deposits taken before you've had time to think are red flags, not bargains.
- You're entitled to your total cost in writing — including aftercare and any revision — before you decide.
Questions to ask your medical professional
Take this to your consultation. A good surgeon will welcome every one of these.
- How advanced is my glaucoma, and what eye pressure are we aiming for?
- Why is surgery right for me now rather than more drops, laser or MIGS?
- What is my chance of needing further treatment if the channel scars?
- What will happen to my glaucoma drops after surgery?
- What are the exact warning signs of bleb infection or raised pressure that I must watch for?
- How often will I be seen, and who do I contact urgently at any time after surgery?
- Are you on the GMC Specialist Register for this area, and which Royal College or professional body are you a member of?
- Will you be the surgeon who carries out my operation, and who looks after me afterwards?
- What are the risks for someone like me, and how often do your own patients have a problem or need it repeated or redone?
- What does a realistic result look like — and what can this operation not achieve?
- What are my options, including waiting, doing nothing for now, or choosing a different approach?
- Can I have written information, results and aftercare instructions in a format I can use, including any accessibility or communication support I need?
- What is the total cost in writing, including any follow-ups, and how much time do I have to decide?
Frequently asked questions
Is glaucoma surgery available on the NHS?
Will the surgery improve my vision?
Will I be able to stop my eye drops?
What is a 'bleb', and why does it matter?
What happens if the surgery stops working?
How long is the recovery?
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How we made this page
Medically reviewed by a GMC-registered consultant. Written in plain English, checked against NHS, NICE, GMC and relevant Royal College / specialist-society guidance, and kept under review. No clinic paid to appear on this page, and we publish no pricing. This is general information to help you prepare — it is not a substitute for advice from your own clinician. How we review our guides →
Source hierarchy: UK regulator and NHS/NICE guidance first, then relevant Royal College or specialist-society guidance, then peer-reviewed evidence for procedure-specific figures where available.
Sources & standards: NHS — Glaucoma NHS (Cambridge University Hospitals) — Trabeculectomy patient information NICE — Glaucoma: diagnosis and management (NG81) Trabeculectomy — review (StatPearls, NCBI) The National Survey of Trabeculectomy — complications National survey of trabeculectomy — success rates (PubMed)
Reviews reflect patients' experience of care, not clinical outcomes. For procedure volumes and outcome data see PHIN.
Last medically reviewed 2026-09-21. Spotted something wrong or out of date? Report an error in this guide.
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