Private iStent MIGS glaucoma surgery London

What is iStent MIGS?

The iStent inject W (Glaukos Corporation) is the world's smallest medical implant. Each stent is a 360-micron heparin-coated titanium tube with a flanged inlet that sits flush against the trabecular meshwork and a 230-micron snorkel that passes through the meshwork to deliver aqueous humour directly into Schlemm's canal. Two stents are placed at clock-hour positions chosen by the surgeon to drain into the most patent collector channels.

The procedure belongs to the family of micro-invasive glaucoma surgery (MIGS). MIGS is defined by an ab interno (from inside the eye) approach, minimal disruption of tissue, an excellent safety profile, fast recovery and a modest IOP-lowering effect that suits mild-to-moderate disease. iStent inject W is the most widely used trabecular MIGS in the UK; alternatives include Hydrus Microstent (Alcon, an 8-mm nitinol scaffold within Schlemm's canal), OMNI / iTrack canaloplasty (catheter-based circumferential viscodilation of Schlemm's canal), Kahook Dual Blade goniotomy and Trabectome trabeculectomy. Subconjunctival MIGS such as the XEN gel stent operate on a different physiological principle and are reserved for more advanced glaucoma.

iStent works by bypassing the trabecular meshwork — the principal site of resistance to aqueous outflow in primary open-angle glaucoma and pseudoexfoliation glaucoma. By restoring a more physiological pathway from the anterior chamber to the collector channels and the episcleral venous system, the implant reduces IOP without creating a bleb on the conjunctiva (as in trabeculectomy) and without external tubing (as in glaucoma drainage devices). The result is glaucoma surgery with a recovery profile close to that of cataract surgery alone. Read more: Glaucoma (condition) · Glaucoma surgery overview · Private cataract surgery London.

Who is a candidate for iStent inject W?

The strongest UK 2026 indications are visually significant cataract plus mild-to-moderate primary open-angle glaucoma, pseudoexfoliation glaucoma or pigmentary glaucoma controlled on one to three topical medications, where reducing the drop burden, levelling the diurnal IOP curve and avoiding the long-term ocular-surface side-effects of preserved drops have direct quality-of-life value. Standalone iStent inject W (without cataract surgery) is reserved for ocular hypertension and mild POAG with drop intolerance, allergic conjunctivitis from prostaglandin analogues, demonstrated poor compliance or simply patient preference for a one-step physiological solution.

• Mild-to-moderate POAG, pseudoexfoliation glaucoma or pigmentary glaucoma with visually significant cataract — combined phaco + iStent is the gold-standard UK 2026 first-line surgical step.
• Ocular hypertension or mild POAG with drop intolerance — standalone iStent inject W is a sensible alternative to a third or fourth medication or selective laser trabeculoplasty (SLT).
• Drop compliance failure — documented missed doses, dexterity, cognitive or polypharmacy issues.
• Glaucoma planning a refractive lens exchange — iStent at the same anaesthetic preserves long-term IOP control and protects the optic nerve.

iStent is not the right operation for advanced glaucoma with split fixation visual fields, near-total cup, IOP > 30 mmHg on maximum tolerated medical therapy, primary angle-closure glaucoma without first dealing with the angle, neovascular glaucoma, uveitic glaucoma with active inflammation, or steroid-induced glaucoma where the steroid can be stopped. These cases are usually better served by trabeculectomy, the PreserFlo MicroShunt, an Ahmed or Baerveldt drainage device, or cyclodiode laser, depending on the clinical picture.

How is the procedure performed?

iStent inject W is performed as a day-case procedure under topical and intracameral local anaesthetic, usually in 5–10 minutes added to the end of a 10–15-minute phacoemulsification cataract operation, or as a 10–15 minute standalone case. Step-by-step:

1. Anaesthesia and prep — topical proxymetacaine plus intracameral preservative-free lidocaine; sterile drape and lid speculum.
2. Cataract surgery (combined cases) — standard 2.4–2.75 mm clear corneal phacoemulsification with intra-ocular lens implantation in the bag.
3. Gonioscopic visualisation — the surgeon tilts the patient's head and the microscope, places a Swan-Jacob direct gonio prism on the cornea and visualises the nasal trabecular meshwork at high magnification.
4. iStent placement — the pre-loaded injector is advanced through the same clear-corneal incision, two stents are deployed at separate clock-hour positions in the nasal trabecular meshwork (typically 2–3 clock hours apart) and reflux of blood from Schlemm's canal confirms patency of the collector channels.
5. Closure — the anterior chamber is reformed with balanced salt solution, the wound is hydrated and a topical antibiotic-steroid combination is started.

Patients walk out the same day, drive within 24–48 hours (combined phaco) or 24 hours (standalone iStent), and resume office work in 1–3 days.

UK 2026 private iStent and MIGS price table

Procedure	UK 2026 price (per eye)	Best for
iStent inject W (standalone)	£3,000–£4,500	OHT, mild POAG, drop intolerance
iStent inject W + phaco-cataract	£4,500–£6,500 all-inclusive	Visually significant cataract + mild-moderate POAG / PXF
Hydrus Microstent + phaco	£5,000–£7,000	Alternative trabecular MIGS, longer scaffold
OMNI / iTrack canaloplasty + phaco	£5,500–£7,500	Canal-based, no implant; pigmentary, PXF
Kahook Dual Blade goniotomy + phaco	£4,000–£5,500	Implant-free MIGS; younger patients
PreserFlo MicroShunt	£5,500–£7,500	More advanced POAG; subconjunctival
Trabeculectomy (gold-standard subconjunctival)	£6,500–£9,500	Moderate-advanced POAG; lowest target IOP
Selective laser trabeculoplasty (SLT) for comparison	£500–£1,200	First-line laser alternative to drops

Prices are UK 2026 self-pay, all-inclusive (consultant glaucoma surgeon, theatre, anaesthetist, hardware, structured 12-month follow-up). Prices vary by central London (premium), Greater London and regional centres.

What is included in the all-inclusive private iStent fee?

• Consultant glaucoma surgeon — UK GMC-registered consultant ophthalmologist with glaucoma subspecialty fellowship and a published MIGS volume.
• Pre-operative work-up — visual acuity, refraction, slit-lamp examination, dilated fundus exam, gonioscopy, applanation tonometry, central corneal pachymetry, OCT of the optic nerve and macula (RNFL and ganglion cell complex), fundus photography, Humphrey 24-2 SITA-Faster visual fields and biometry (combined phaco cases).
• Hardware — the iStent inject W device pair (or Hydrus / OMNI hardware where appropriate); the intra-ocular lens (combined cases).
• Theatre — CQC-registered day-case theatre, scrub and circulating teams, monitored sedation as needed.
• Anaesthetic — topical and intracameral local; consultant anaesthetist where general or sub-Tenon's block is preferred.
• Drops — topical antibiotic-steroid combination for 4 weeks; lubricants.
• Structured 12-month follow-up — day-1, week-1, week-4, 3 months, 6 months and 12 months; gonioscopic stent inspection, IOP, OCT and visual fields at the 6 and 12-month points.
• Out-of-hours emergency cover — 24/7 consultant access for any pressure spike, infection or unusual symptom in the first 90 days.

NHS vs private iStent in the UK in 2026

The NHS funds combined phaco + iStent at MIGS-commissioned trusts in line with NICE IPG575 and local Integrated Care Board policy, predominantly for moderate-to-severe POAG, pseudoexfoliation glaucoma and pigmentary glaucoma where the patient also has visually significant cataract. Standalone iStent inject W for ocular hypertension or mild POAG without cataract is funded inconsistently across the UK and is often only available privately in 2026.

Choose the NHS pathway when your glaucoma is well-controlled enough to wait the 6–18 months that the local trust takes to bring you to theatre, your visual field is stable on serial perimetry, you are happy with your existing drops, and you have no work or care commitments that make timing critical. Choose the private pathway when same-week consultant glaucoma review and theatre within 2–4 weeks matters — documented drop intolerance, polypharmacy, dexterity issues, work travel, NHS waits longer than the consultant deems safe for your nerve, or the wish to combine bilateral surgery with the same surgeon at the same anaesthetic.

Insurance cover for iStent in 2026

Bupa, AXA Health, Aviva, Vitality and WPA all cover iStent inject W combined with medically indicated cataract surgery in 2026, with pre-authorisation. Coverage rules are device- and indication-specific:

• Combined phaco + iStent — covered as a single CCSD code-bundle when the cataract is the dominant indication and the iStent is at the same anaesthetic.
• Standalone iStent inject W for OHT or mild POAG — usually self-pay; some insurers reimburse on appeal where drops have failed or caused documented intolerance.
• Pre-existing exclusions — moratorium policies will check for pre-existing glaucoma diagnosis. Discuss with your insurer's pre-authorisation team before booking.
• Excess — standard policy excess applies; the clinic billing team confirms the excess at the time of pre-authorisation.

What does the evidence say?

iStent has been studied in more randomised controlled trials than any other MIGS device. Headline outcomes from the UK and international evidence base:

• iStent inject pivotal trial (FDA, n=505) — combined iStent inject + phaco vs phaco alone; at 24 months, 76 per cent of iStent patients achieved an unmedicated IOP ≤ 80 per cent of baseline vs 62 per cent control; mean IOP fell from 24.8 to 17.1 mmHg.
• HORIZON Hydrus 5-year trial — combined Hydrus + phaco vs phaco alone; 65 per cent of Hydrus patients were medication-free at 5 years vs 46 per cent control, with a halving of the rate of incisional glaucoma surgery.
• UK iStent inject real-world data — 30–35 per cent IOP reduction, 60–70 per cent of patients off all drops at 12 months in mild-to-moderate POAG and pseudoexfoliation glaucoma.
• NICE IPG575 — trabecular stent bypass micro-surgery for open-angle glaucoma is supported with normal arrangements for clinical governance, consent and audit.
• EGS Guidelines 5th Edition — MIGS is endorsed for mild-moderate POAG combined with cataract; trabeculectomy and tubes remain the reference operation for advanced disease.

Risks and what can go wrong

• Transient IOP spike in the first 24–72 hours (1–5 per cent) — usually managed with topical or oral pressure-lowering medication.
• Hyphaema (blood in the anterior chamber, 1–3 per cent) — clears with rest in days.
• Stent malposition or obstruction (1–2 per cent) — gonioscopic review at the 4-week visit; revision is rare.
• Insufficient pressure-lowering effect — some patients still need 1–2 drops; conversion to a higher-tier glaucoma operation is < 5 per cent at 2 years in mild-moderate POAG.
• Cataract-related risks (combined cases) — posterior capsule rupture, vitreous loss, dropped lens fragments, cystoid macular oedema and endophthalmitis — collectively < 1 per cent at experienced centres.
• Endophthalmitis — sight-threatening intra-ocular infection; rate < 1 in 1,000.

Recovery timeline

• Day 1 — Eye review, IOP check, antibiotic-steroid drops started; mild gritty sensation.
• Days 1–3 — Resume reading, screens and office work; avoid heavy lifting and dusty environments.
• Week 1 — Slit-lamp review, gonioscopy of the stents, IOP; clear plastic eye-shield at night for 7 nights.
• Weeks 2–4 — Drops tapered as IOP allows; resume gym, swimming and contact sport at week 2–4.
• Month 3 — OCT optic nerve, IOP, refraction; many patients are off most or all drops.
• Month 6 & 12 — Visual fields, OCT and gonioscopic stent check.

How to choose a London iStent clinic in 2026

1. CQC registration and Good rating — check the clinic's published CQC report.
2. Consultant glaucoma fellowship — the operating surgeon should hold a UK glaucoma fellowship and be a UKEGS member.
3. Published MIGS volume — ask for the surgeon's annual iStent / MIGS volume; look for > 50 cases per year.
4. Clear written quotation — itemised, all-inclusive, with structured 12-month follow-up.
5. Transparent re-operation policy — clarity on the cost and pathway if a higher-tier operation (PreserFlo, trabeculectomy) is later needed.
6. OCT and visual-field tracking — serial structural and functional follow-up with comparison to baseline at every 6-month visit.
7. Out-of-hours consultant access — 24/7 cover for any pressure spike or unusual symptom in the first 90 days.

Frequently asked questions

How much does private iStent MIGS cost in London in 2026?

Standalone iStent inject W typically costs £3,000–£4,500 per eye in London in 2026. Combined with private cataract surgery (the commonest UK route) the all-inclusive fee is £4,500–£6,500 per eye, covering the consultant glaucoma surgeon, the iStent inject W device, the intra-ocular lens, theatre, anaesthetist, drops and structured 12-month follow-up.

Will iStent get me off my glaucoma drops?

The pivotal iStent inject trials and UK real-world series report that 60–70 per cent of mild-to-moderate POAG and pseudoexfoliation glaucoma patients are off all glaucoma drops at 12 months after combined phaco + iStent. Some patients still need one drop, particularly if they started on three or four. Standalone iStent in OHT and mild POAG typically reduces IOP by 20–30 per cent and lets the consultant simplify or stop the drop regimen.

Is iStent better than SLT (selective laser trabeculoplasty)?

SLT is a 5-minute outpatient laser that lowers IOP by 20–25 per cent for 1–5 years and is usually offered first-line per NICE NG81 and the LiGHT study. iStent inject W is a more durable intra-ocular procedure that combines naturally with cataract surgery and produces a similar or slightly larger drop in IOP with greater medication-freedom rates. Most UK glaucoma surgeons step from drops to SLT and then to combined phaco + iStent at the time of cataract surgery.

Can I have iStent if I have already had cataract surgery?

Yes. Standalone iStent inject W can be performed in pseudophakic eyes through a fresh clear-corneal incision; recovery is similar. The all-inclusive private fee is £3,000–£4,500 per eye.

What is the difference between iStent and Hydrus Microstent?

Both are trabecular MIGS devices. iStent inject W is a pair of 360-micron flanged titanium stents implanted at two clock-hour positions. Hydrus Microstent is a single 8-mm nitinol scaffold that holds open three clock hours of Schlemm's canal. The 5-year HORIZON trial showed Hydrus reduced the rate of incisional glaucoma surgery in mild-moderate POAG. Both are reasonable choices; the surgeon will recommend based on angle anatomy, baseline IOP target and clinic experience.

Will I see better after iStent?

Standalone iStent does not change refraction. Combined phaco + iStent typically delivers the same visual benefit as cataract surgery alone, with the additional benefit of lower IOP and fewer drops. Patients usually achieve driving-standard vision in 24–72 hours.

How long does the iStent device last?

iStent inject W is permanent and is left in place for life. Heparin-coating and the small implant size mean late occlusion is rare. Five-year and 7-year follow-up data show durable IOP reduction.

Can iStent be combined with refractive lens exchange (RLE)?

Yes. Patients with glaucoma or ocular hypertension who are planning RLE can have iStent inject W at the same anaesthetic for long-term IOP control. The all-inclusive UK 2026 self-pay fee is similar to combined phaco + iStent: £4,500–£6,500 per eye, plus the premium IOL upgrade if a trifocal or EDOF lens is chosen.

What if iStent does not work for me?

If IOP rises later or the visual field continues to progress, the next surgical step is usually a higher-tier operation: PreserFlo MicroShunt, XEN gel stent, trabeculectomy with mitomycin C, or a glaucoma drainage device (Ahmed, Baerveldt, Paul). The presence of an iStent does not interfere with any of these subsequent operations.

Is iStent painful?

No. The procedure is performed under topical and intracameral local anaesthetic; you will feel pressure but not pain. After surgery the eye is usually a little gritty and tender for 24–48 hours, controlled with simple analgesia.

When can I drive, work and travel after iStent?

Driving is permitted once both eyes meet the DVLA visual standard, typically 24–72 hours after combined phaco + iStent or 24 hours after standalone iStent. Office work resumes in 1–3 days. Air travel is fine from 24–48 hours; there is no gas in the eye, unlike retinal-detachment surgery.

Does my private medical insurance cover iStent?

Bupa, AXA Health, Aviva, Vitality and WPA cover iStent inject W combined with medically indicated cataract surgery in 2026 with pre-authorisation. Standalone iStent for OHT or mild POAG is usually self-pay. The clinic billing team typically obtains pre-authorisation in 24–48 hours.

Sources and editorial methodology

This guide is compiled from UK 2026 self-pay tariffs published by major London CQC-registered glaucoma centres, NICE IPG575 (trabecular stent bypass), NICE NG81 (Glaucoma: diagnosis and management), Royal College of Ophthalmologists glaucoma commissioning standards, UKEGS consensus position statements, EGS Guidelines 5th Edition, AAO Preferred Practice Pattern (Primary Open-Angle Glaucoma), the FDA pivotal iStent inject trial, the HORIZON 5-year Hydrus trial, the COMPASS / COMPASS-XT trials and the UK MIGS-CC real-world series. Reviewed by a UK GMC-registered consultant ophthalmologist with glaucoma subspecialty fellowship. Last updated May 2026. Prices are provider-published and inclusive of consultant, theatre, hardware and structured 12-month follow-up unless stated otherwise.

Book your private iStent MIGS consultation in London

Same-week consultant glaucoma assessment. Theatre slots within 2–4 weeks at CQC-registered London centres. Bupa, AXA, Aviva, Vitality and WPA pre-authorisation in 24–48 hours.