Ophthalmology · London
iStent inject W for open-angle glaucoma, by a consultant glaucoma surgeon.
Micro-invasive glaucoma surgery, usually combined with cataract surgery - two tiny stents through the trabecular meshwork to lower pressure, reduce your drops, and buy time before bigger surgery.
Indicative pricing
What private phaco + iStent costs in London.
In short
£4,000–£6,500 per eye, home the same day.
| Procedure | Indicative range | Typical duration | Recovery |
|---|---|---|---|
| Phaco + iStent inject W (per eye) | £4,000–£6,500 | 30–45 min | Same day |
| Phaco + Hydrus microstent (per eye) | £4,500–£7,500 | 30–45 min | Same day |
| Phaco + KDB goniotomy (per eye) | £4,000–£6,000 | 30–45 min | Same day |
| Standalone iStent (pseudophakic eye) | £2,500–£4,000 | 20–30 min | Same day |
| XEN Gel Stent (per eye) | £4,500–£7,000 | 30–45 min | Same day |
| Preserflo MicroShunt (per eye) | £5,000–£8,000 | 45–60 min | Same day |
| Consultation only | £250–£400 | 45 min | Same visit |
Prices vary by clinic, by surgeon, by which IOL is chosen, and by which MIGS device is best suited to your eye.
The problem
The right MIGS device, the right surgeon, the right moment.
MIGS is booked badly all the time - one device for every eye, general cataract surgeons doing the odd stent, and no honest talk about XEN or Preserflo when the disease has moved on. We fix all three before you commit.
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Is MIGS actually right for you?
Sometimes cataract surgery alone is enough. Sometimes the disease is too advanced and you need XEN or trabeculectomy. We say so before you agree to a stent.
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Which device fits your eye?
iStent inject W, Hydrus, KDB goniotomy, XEN, Preserflo - each has an honest sweet spot. Not every surgeon offers the full range.
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Want it done properly?
A named consultant glaucoma surgeon, a proper day-case theatre, and structured OCT and field follow-up - not one visit and gone.
When it helps
When iStent inject W is the right step.
The situations we see most, plus the one red flag that means iStent is not enough - you need a bigger operation.
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Mild-to-moderate POAG with cataract
Primary open-angle glaucoma on 1–3 drops, with a visually significant cataract - the classic combined-procedure indication.
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Pseudoexfoliative glaucoma
PXF glaucoma with cataract responds particularly well to trabecular MIGS - the block is at the meshwork.
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Pigmentary glaucoma
Open-angle, meshwork-based resistance - a good candidate for bypass with iStent inject W.
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Drop-intolerance or poor adherence
Ocular surface disease from years of drops, or a patient who genuinely cannot manage a bottle schedule.
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Standalone in pseudophakic eyes
Previous cataract surgery, IOP creeping up on drops - iStent can be placed as a standalone ab-interno procedure.
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Wanting to reduce medication burden
A patient on 2–3 drops keen to drop to 0–1 - a realistic ambition with well-placed trabecular MIGS.
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Early to moderate field loss
Mild-to-moderate optic-nerve damage on OCT and Humphrey field - the disease stage where MIGS earns its keep.
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Red flag: not for advanced disease
Severe field loss, pressures in the 30s, angle-closure or neovascular glaucoma - you need trabeculectomy or a tube, not iStent.
MIGS and surgical options
iStent is one option, not the only one.
What each device on the table actually does - and which fits which stage of disease.
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iStent inject W (Glaukos)
Two heparin-coated titanium stents through the trabecular meshwork into Schlemm’s canal. The most published MIGS device. Typically 20–30% IOP reduction and about one drop off.
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Hydrus microstent (NICE IPG723)
A single 8mm nitinol stent covering roughly 90° of Schlemm’s canal. Some head-to-head evidence suggests slightly greater IOP and drop reduction than iStent.
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Kahook Dual Blade (KDB) goniotomy
Excises 90–180° of trabecular meshwork rather than stenting through it. No implant left behind. A goniotomy-based alternative to iStent.
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GATT (transluminal trabeculotomy)
Gonioscopy-assisted 360° trabeculotomy using a suture or microcatheter. More extensive angle work - useful for younger patients and juvenile glaucoma.
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XEN Gel Stent (Allergan)
Ab-interno subconjunctival stent - more like a mini-trabeculectomy. Greater IOP reduction than trabecular MIGS, at the cost of a bleb and higher revision rate.
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Preserflo MicroShunt (Santen)
Ab-externo subconjunctival shunt for moderate-to-advanced disease. Sits between MIGS and trabeculectomy in effect and risk.
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Trabeculectomy (traditional)
The gold-standard filtration surgery for advanced disease or when target IOP is low. Bigger operation, bigger drop, more follow-up.
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Consultation only
An honest discussion of whether MIGS is needed at all, which device fits, and whether cataract surgery alone might be enough.
Safety and recovery
What to expect afterwards - honestly.
iStent inject W is one of the safest glaucoma surgeries available. The things worth planning are the drop taper, the follow-up schedule and knowing what is normal after.
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Local anaesthetic with light sedation
Combined phaco + iStent is done under the same LA + IV sedation as standard cataract surgery. General anaesthetic is rarely needed.
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A small hyphaema is normal
A little blood in the anterior chamber from Schlemm’s canal is expected and usually clears within a few days without treatment.
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Transient IOP spikes
Pressures can rise briefly in the first days to weeks - checked at the day-one visit and managed with drops if needed.
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Stent malposition is uncommon
A stent occasionally sits proud or clogs. Rarely, a second procedure is needed to reposition or add drops.
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Endothelial cell loss is marginal
Long-term data show cell loss similar to cataract surgery alone - reassuring, and better than earlier CyPass-style suprachoroidal devices.
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Cataract-surgery risks still apply
Posterior capsule rupture, dropped nucleus fragments, endophthalmitis (under 0.1%) and retinal detachment (under 1%) - the standard phaco risks.
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Not everyone reaches target IOP
A fraction of patients do not get enough drop and go on to add a drop back, or escalate to XEN, Preserflo or trabeculectomy.
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Drops for four weeks after
Chloramphenicol and a tapering steroid drop are used for around four weeks - the same schedule as standard cataract surgery.
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Red flags
Sudden painful red eye, sudden loss of vision or a pressure spike with nausea are not normal - call the clinic or attend eye casualty the same day.
Reading your operation note
Your operation note in four parts. Read the last one first.
Whichever device was used, the note the ophthalmologist sends you keeps to the same shape.
A quiet reminder
Surgical language is precise and can read coldly - we translate it for you.
If you would like us to talk you through the note before your review, just ask.
- 01 Header
Indication and device chosen
Why the procedure was done - POAG, PXF, pigmentary - and which device was placed (iStent inject W, Hydrus, KDB and so on).
- 02 Technique
Anaesthetic and surgical technique
LA with sedation, phaco parameters, IOL model and power, and the intraoperative gonioscopy view when the stents were deployed.
- 03 Findings
Stent position and intraoperative IOP
Where each stent sits (clock-hour position), whether blood reflux was seen (a good sign of patency), and any intraoperative complications.
- 04 Impression
Drop plan, review dates, target IOP
Read this first: which drops to continue, which to stop, target pressure, and when to be seen next.
Recognised by major UK insurers
Cover for combined cataract + MIGS varies by insurer - usually funded when medically indicated with documented open-angle glaucoma on drops.
Frequently asked
Everything we get asked about iStent inject W.
Quick answers on how it works, what it costs, how it compares with Hydrus and XEN, and what the recovery actually looks like.
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What is iStent inject W and how does it work?
It is a pair of tiny heparin-coated titanium stents placed through the trabecular meshwork into Schlemm’s canal. They bypass the main site of outflow resistance in open-angle glaucoma, letting aqueous fluid drain more easily and lowering intraocular pressure.
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Who is iStent inject W suitable for?
Adults with mild-to-moderate open-angle glaucoma (primary, pseudoexfoliative or pigmentary) who also need cataract surgery, or pseudophakic patients wanting to reduce drops. It is not suitable for angle-closure, neovascular, advanced or uveitic glaucoma.
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How much IOP reduction and drop reduction can I expect?
On average, roughly a 20–30% reduction in intraocular pressure and one fewer drop - many patients drop from 2–3 drops to 0–1. Results vary with baseline pressure and disease type.
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How much does phaco + iStent inject W cost privately in the UK?
Roughly £4,000–£6,500 per eye for combined cataract surgery and iStent inject W. Hydrus tends to be £4,500–£7,500, KDB goniotomy £4,000–£6,000.
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Is iStent covered by the NHS?
MIGS is commissioned selectively - some Integrated Care Boards fund combined cataract + iStent for specific indications, many do not. In practice most cataract + MIGS in the UK is done privately. We can tell you what your local ICB funds.
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How is iStent different from Hydrus, XEN or trabeculectomy?
iStent inject W and Hydrus are trabecular bypass MIGS - modest IOP reduction, high safety, combined with cataract. XEN Gel Stent and Preserflo are subconjunctival stents that lower pressure more but carry higher revision rates. Trabeculectomy is the gold-standard filtration surgery for advanced disease.
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What is the recovery like?
Identical to standard cataract surgery. Chloramphenicol and steroid drops for around four weeks, no eye rubbing, no swimming for two weeks, and back to office work within days. Driving usually resumes within a week once vision settles.
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What are the main risks?
Minor hyphaema (small bleed in the front of the eye), a short-lived pressure spike, stent malposition, and the standard cataract-surgery risks - capsule rupture, endophthalmitis (under 0.1%) and retinal detachment (under 1%). Serious complications are rare with an experienced glaucoma surgeon.
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