Private PreserFlo MicroShunt glaucoma surgery UK 2026

What is the PreserFlo MicroShunt?

The PreserFlo MicroShunt (Santen, formerly InnFocus and Allergan) is an 8.5 millimetre biostable polymer drainage device manufactured from SIBS (poly(styrene-block-isobutylene-block-styrene)) — the same biocompatible material used in coronary drug-eluting stent coatings. The shunt has a precision-machined internal lumen of 70 micrometres and external diameter of 350 micrometres, with two side fins at the proximal end that wedge into a 1.0 mm scleral pocket to fix the device and prevent migration. The distal end sits in the anterior chamber 1.0–1.5 mm anterior to the limbus and the proximal end opens into a subconjunctival space approximately 6 millimetres posterior to the limbus, creating a controlled, low-resistance pathway for aqueous humour to drain from the eye into a posteriorly placed bleb.

The defining mechanical property of the MicroShunt is its Hagen–Poiseuille flow resistance. The 70 µm lumen with 8.5 mm length generates an estimated minimum opening pressure of approximately 6 mmHg at physiological aqueous production rates, which is designed specifically to prevent the early post-operative hypotony that complicates classical trabeculectomy in 10–25 per cent of cases. Unlike the XEN gel stent (Allergan), which is 45 micrometres in lumen and 6 millimetres long and is implanted ab interno through a clear corneal incision, the PreserFlo is implanted ab externo through a conjunctival peritomy and a scleral pocket, allowing direct visualisation of the device track and more reproducible positioning. Mitomycin-C 0.2 to 0.4 mg/mL is applied to the subconjunctival space for 2 to 3 minutes prior to implant placement to suppress fibroblast proliferation and preserve long-term bleb function.

The MicroShunt is licensed in the UK and Europe (CE mark since 2012, current Santen ownership since 2022) and in many international markets; in the United States the device received de novo FDA approval in 2024 following the INN-005 randomised controlled trial against trabeculectomy. NICE Interventional Procedures Guidance IPG622 (2018, with subsequent audit data) supports use of the PreserFlo for primary open-angle glaucoma and selected secondary open-angle glaucomas, subject to consultant-led local governance and submission of outcomes to the NICE audit register. In experienced UK hands the MicroShunt is now a routine option in tertiary glaucoma surgical practice, with rapidly accumulating real-world UK data through the United Kingdom and Ireland Glaucoma Society (UKEGS) registry.

UK 2026 PreserFlo MicroShunt pricing, in detail

Private PreserFlo pricing in the UK is driven by the centre's CQC-registered theatre overhead and consultant glaucoma surgeon seniority, the procurement cost of the PreserFlo implant (manufacturer list price ~£950–£1,150 plus VAT), the consultant anaesthetist fee for the sub-Tenon or peribulbar block, the cost of intra-operative mitomycin-C, and the post-operative regime, which is far more intensive than a routine cataract operation: typically 6 to 8 visits over 12 weeks with slit-lamp bleb assessment, IOP, anterior-segment OCT of the bleb where available and one or more needlings or selective suture lysis procedures. Most reputable London providers bundle these into an all-inclusive 90-day package.

For related glaucoma pricing and pathways see our private iStent MIGS glaucoma surgery London, our private SLT laser glaucoma treatment cost UK, our private glaucoma surgery cost UK overview and our glaucoma treatment options: drops vs SLT vs MIGS vs surgery UK.

What a quality UK PreserFlo MicroShunt package should include

• Consultant glaucoma surgeon — a UK GMC-registered specialist with documented glaucoma fellowship and a minimum 30 PreserFlo cases per year. Bleb-forming surgery outcomes correlate with surgeon volume; insist on per-surgeon results, not centre averages.
• Full pre-operative work-up — Goldmann or iCare IOP, gonioscopy (Shaffer or Spaeth grading), pachymetry (central corneal thickness), spectral-domain OCT of the optic nerve head (RNFL and Bruch's membrane opening minimum rim width), macular ganglion cell complex, 24-2 SITA-Faster and 10-2 Humphrey or Octopus visual fields, and disc and bleb photography.
• CQC-registered ophthalmic theatre — a UKAS-accredited ultra-clean ophthalmic theatre with laminar flow, dedicated microscope (Zeiss Lumera, Leica Proveo or equivalent), and immediately available conjunctival forceps, vannas scissors and 10-0 nylon for suture lysis.
• Anaesthetist-delivered sub-Tenon or peribulbar block — a consultant ophthalmic anaesthetist for a controlled, akinetic block; topical-only anaesthesia is inappropriate for the conjunctival manipulation required.
• Mitomycin-C 0.2–0.4 mg/mL for 2–3 minutes — applied to the subconjunctival space prior to implant placement; without mitomycin-C, 5-year bleb survival drops by approximately 30 per cent (Beckers RWE).
• The PreserFlo implant itself — supplied sterile by Santen; the implant cost is non-negotiable and should be itemised on the quotation.
• Day-case admission with same-day discharge — including pre-operative checklist, theatre nursing, recovery room observation, and discharge with eye shield, drops and patient information.
• Full 90-day post-operative regime included — minimum 6 visits (day 1, week 1, week 2, week 4, week 8, week 12) with slit-lamp bleb assessment, IOP, anterior-segment OCT of the bleb where available, and any needling, 5-fluorouracil top-up or laser suture lysis required within the 90 days bundled into the surgical fee.
• Written quotation and consent — an itemised written quotation valid for 60 days, written consent specifying procedure, alternatives, named complications with numeric risks, and confirmation of insurance pre-authorisation or self-pay invoicing.

Evidence base — what the trials and registries show

The PreserFlo MicroShunt has been studied in one large randomised controlled trial against the comparator standard (trabeculectomy) and in multiple large prospective real-world series. The headline trial-vs-trabeculectomy data and the real-world UK and European data should be reviewed in parallel because each tells half of the clinical story:

• INN-005 (Baker et al., Ophthalmology 2021; 514 eyes, 1-year primary) — multi-centre randomised trial comparing PreserFlo with mitomycin-C to trabeculectomy with mitomycin-C in primary open-angle glaucoma uncontrolled on medical therapy. Primary endpoint (≥20 per cent IOP reduction and 6<IOP≤14 mmHg without medication at 1 year) met in 53.9 per cent of PreserFlo eyes versus 72.7 per cent of trabeculectomy eyes; non-inferiority not demonstrated at 1 year but with substantially lower rates of early hypotony, choroidal effusion and post-operative interventions in the PreserFlo arm.
• INN-005 2-year extension (Baker 2022) — complete success closer at 2 years (PreserFlo ~55 per cent vs trabeculectomy ~67 per cent); the gap narrows as the trabeculectomy arm requires ongoing interventions and the PreserFlo arm stabilises.
• European prospective multicentre series (Beckers et al., Ophthalmology Glaucoma 2022; 472 eyes, 3-year follow-up) — real-world UK and European data demonstrating 65–70 per cent complete success at 2 years and a mean IOP reduction from 22 mmHg to 13–14 mmHg with substantially fewer post-operative interventions than trabeculectomy.
• Pillunat et al. (2023) — German multicentre 2-year analysis confirming Beckers findings, with detailed bleb morphology on anterior-segment OCT predicting long-term outcome.
• UKEGS registry data (presented RCOphth Annual Congress 2024 and 2025) — UK real-world outcomes congruent with INN-005 and Beckers, demonstrating shorter theatre time, fewer 90-day interventions and shorter return-to-work intervals than trabeculectomy in matched cohorts.
• Pseudoexfoliation and secondary glaucoma series — smaller series (Schlenker et al., 2023) demonstrate the MicroShunt is effective in pseudoexfoliation glaucoma and pigmentary glaucoma, with caveats on neovascular and uveitic glaucoma where tube shunts remain preferred.
• Combined phaco-PreserFlo — emerging data (Marolo et al., 2024) suggest equivalent IOP outcomes when staged or combined with cataract surgery, with combined cases having a slightly higher needling rate.
• NICE IPG622 audit data — ongoing UK national audit of PreserFlo outcomes via the NICE Interventional Procedures register; audit-based outcomes from high-volume UK centres are consistent with the published RCT and registry data.
• FDA de novo approval (2024) — United States regulatory clearance based on INN-005 with mandatory post-marketing surveillance; expands the global evidence base further.

In short: the MicroShunt is not quite as deep an IOP reducer as a perfectly executed trabeculectomy, but it is dramatically more predictable in the early post-operative period, lighter on the patient (less needling, fewer visits, less hypotony) and produces a comparable IOP at 2 to 3 years in the hands of an experienced UK glaucoma surgeon.

PreserFlo MicroShunt versus trabeculectomy, XEN gel stent and MIGS

The right glaucoma operation depends on the target IOP, the severity of optic nerve damage and visual field loss, the angle status, the lens status (phakic, pseudophakic, vitrectomised), prior conjunctival surgery and patient factors such as drop tolerance, occupation and ability to attend post-operative review. Honest head-to-head comparison:

• PreserFlo MicroShunt vs trabeculectomy — trabeculectomy retains the deepest IOP-lowering ceiling (mid-single-digit IOPs achievable) but with higher rates of early hypotony, choroidal effusion, bleb-related infection and the need for repeated needling. PreserFlo trades a slightly higher post-op IOP (~13–15 mmHg vs ~9–12 mmHg) for a much smoother early course. Prefer trabeculectomy in advanced disease where single-digit IOP is essential.
• PreserFlo vs XEN gel stent 45 — XEN is ab interno (clear corneal entry, no peritomy), the gelatin tube is shorter and narrower, and total IOP reduction is generally a step less than PreserFlo. XEN is preferred in milder disease, combined with phacoemulsification, and in patients who cannot tolerate a conjunctival peritomy.
• PreserFlo vs iStent inject W and Hydrus Microstent — trabecular bypass MIGS bypass the conventional outflow pathway but cannot lower IOP below episcleral venous pressure (~8–10 mmHg). MIGS suit mild-to-moderate open-angle glaucoma combined with cataract; they are the wrong choice when target IOP is mid-teens or lower or when visual field shows moderate or advanced loss.
• PreserFlo vs OMNI canaloplasty and Kahook Dual Blade — angle-based MIGS achieving 20–30 per cent IOP reduction; intermediate between trabecular bypass and bleb surgery. Suitable when bleb-forming surgery is undesirable but more drop reduction is needed than iStent will provide.
• PreserFlo vs tube shunt (Baerveldt or Ahmed) — tube shunts remain the operation of choice in refractory glaucoma, neovascular glaucoma and after multiple failed bleb-forming surgeries. PreserFlo is preferred in primary surgery for open-angle glaucoma; tube shunts dominate after first failure.
• PreserFlo vs selective laser trabeculoplasty (SLT) — SLT is first-line per the LiGHT trial (Gazzard et al., Lancet 2019) and produces 20–30 per cent IOP reduction lasting 2–5 years. Patients should not progress to bleb-forming surgery until SLT (or drops) have failed to achieve target IOP and the disease is documented to be progressing.

For an authoritative head-to-head walk-through, see our editorial briefing on glaucoma treatment options: drops vs SLT vs MIGS vs surgery UK.

Who is a good candidate for PreserFlo MicroShunt?

The PreserFlo is appropriate as primary bleb-forming surgery in adult patients with:

• Primary open-angle glaucoma with progressing optic neuropathy or visual field defect despite maximally tolerated topical therapy and prior selective laser trabeculoplasty.
• Pseudoexfoliation glaucoma with elevated IOP refractory to medical and laser therapy.
• Pigmentary glaucoma in patients younger than the typical trabeculectomy demographic where the more predictable bleb of the MicroShunt is preferred.
• Moderate-to-advanced disease where mid-teens target IOP is required and MIGS are not sufficient.
• Patients with significant drop side-effects (ocular surface disease, prostaglandin-associated periorbitopathy, allergy) where drop independence is a clinical priority.
• Patients who cannot tolerate or comply with the more intensive post-operative needling and bleb-management course of classical trabeculectomy.
• Eyes with healthy conjunctiva (no prior bleb-forming surgery in the planned quadrant, no significant scarring, no chronic conjunctivitis).
• Phakic, pseudophakic and vitrectomised eyes (with appropriate counselling on cataract progression in phakic patients).

Relative or absolute contraindications include angle-closure glaucoma where peripheral iridectomy and lens extraction are first-line, neovascular glaucoma where tube shunt remains preferred, active uveitic glaucoma, prior failed bleb-forming surgery in the planned quadrant, significant ocular surface disease that will compromise bleb survival, inability to attend the intensive 12-week post-operative review schedule, anticoagulation that cannot be safely bridged, and inability to lie flat for 25–40 minutes under akinetic block. Suitability is confirmed only after a full consultant glaucoma assessment with gonioscopy, OCT-RNFL, visual field and lens status assessment.

NHS versus private PreserFlo MicroShunt

The PreserFlo is available on the NHS in tertiary glaucoma surgical units (typically university teaching hospitals and dedicated specialist eye hospitals) under NICE Interventional Procedures Guidance IPG622 (2018, with audit). NHS provision is consultant-led, with local glaucoma multi-disciplinary triage to confirm that medical and laser therapy have been exhausted and that the optic nerve is progressing. NHS waits in 2026 from initial glaucoma diagnosis to surgical listing are typically 12 to 26 weeks, with a further 6 to 12 weeks from listing to operation date at higher-volume centres; in some lower-volume units the MicroShunt is unavailable and trabeculectomy remains the default bleb-forming option.

The private route compresses the timeline to typically 1 to 2 weeks from initial consultation to surgery and offers continuity of consultant care from assessment through to the full 90-day post-operative course (the same surgeon does the case and reviews the bleb at every post-operative visit). Patients with progressing visual field loss who do not wish to wait for NHS listing, who require continuity of named consultant care, who travel internationally and require coordinated overseas follow-up, or who have private medical insurance that funds the procedure routinely choose the private pathway.

Private medical insurance cover for PreserFlo MicroShunt

The PreserFlo MicroShunt is funded by the major UK private medical insurers (Bupa, AXA Health, Aviva, Vitality, WPA) for primary open-angle glaucoma and selected secondary open-angle glaucomas with pre-authorisation, provided that the policy covers chronic eye conditions and that the consultant glaucoma surgeon is recognised by the insurer. The CCSD procedure codes typically used are C66.5 (insertion of glaucoma drainage device) with the appropriate diagnostic code (H40.11 primary open-angle glaucoma, or the relevant secondary glaucoma code), plus the consultant assessment code and any combined cataract phacoemulsification code where staged or combined.

Each PMI provider sets its own annual surgical benefit limit and may apply an excess; pre-authorisation requires documentation of the visual field defect, OCT-RNFL thinning and the clinical justification for bleb-forming surgery over MIGS or repeat SLT. In practice, insurance funding is routinely approved when the consultant clinical letter clearly documents: target IOP, current IOP on maximally tolerated medical therapy, prior SLT, optic disc and visual field progression, lens status, and the reason for choosing PreserFlo over alternatives. The clinic team will prepare the pre-authorisation package on the patient's behalf.

Risks and side-effects of PreserFlo MicroShunt surgery

The PreserFlo MicroShunt is one of the more predictable bleb-forming glaucoma operations available in 2026, but bleb-forming surgery is inherently more complex than cataract surgery and the realistic risks should be set out honestly:

• Procedural and bleb-related risks:
  • Early hypotony (IOP <6 mmHg) — approximately 7 to 10 per cent in INN-005 and Beckers RWE; usually self-limiting over 1 to 4 weeks with a viscoelastic refill or, rarely, choroidal drainage. Markedly lower than the 15 to 25 per cent rate observed with trabeculectomy.
  • Bleb leak — 2 to 4 per cent in the first 90 days; managed with bandage contact lens, autologous serum drops or, if persistent, conjunctival revision.
  • Bleb failure requiring needling — 15 to 25 per cent in year 1; needling is performed at the slit lamp under topical anaesthetic with 5-fluorouracil or mitomycin-C top-up and is included in the 90-day package.
  • Bleb encapsulation (Tenon's cyst) — 5 to 8 per cent; managed initially with needling, escalating to surgical revision if persistent.
  • Bleb-related infection (blebitis or endophthalmitis) — 0.3 to 0.8 per cent per year cumulative risk; lower than trabeculectomy because the PreserFlo bleb is typically more posterior, lower-profile and less prone to dysaesthesia.
  • Choroidal effusion — 3 to 5 per cent in the first month, usually self-resolving over 2 to 4 weeks; rare cases require choroidal drainage.
  • Suprachoroidal haemorrhage — 0.1 to 0.4 per cent; higher risk in highly myopic, vitrectomised or anticoagulated eyes.
• Device-specific risks:
  • Implant exposure or extrusion — 0.5 to 1.5 per cent over 3 years; requires conjunctival revision or scleral patch graft.
  • Implant occlusion (iris or vitreous prolapse, fibrin) — 1 to 3 per cent in the first 3 months; managed with Nd:YAG laser, anti-VEGF (if neovascular), or revision.
  • Implant malposition or migration — <0.5 per cent in experienced hands; the proximal fins generally lock the implant in the scleral pocket.
• Ocular risks — transient corneal oedema (5 to 10 per cent), mild post-operative inflammation (universal, managed with topical steroid taper), cataract progression in phakic eyes (15 to 25 per cent at 2 years — lower than after trabeculectomy), and rare dysaesthesia of the bleb.
• Visual symptoms — transient blurred vision for 2 to 6 weeks, mild ptosis (~5 per cent, usually transient), bleb-related foreign body sensation in 2 to 4 per cent of eyes.
• Treatment burden — minimum 6 to 8 post-operative visits in the first 12 weeks, then 3 to 4 visits per year for life; topical drops (steroid + antibiotic) for 6 to 8 weeks on a taper; no swimming or contact sports for 4 weeks; eye shield at night for 1 week.

The overall safety record of the PreserFlo MicroShunt is excellent in experienced UK hands; serious sight-threatening complications are minimised by appropriate patient selection (avoiding eyes with very thin sclera, active surface disease or uncontrolled inflammation), meticulous surgical technique with mitomycin-C, and a disciplined 12-week post-operative regime. The realistic 90-day burden is lower than after trabeculectomy and the 2-year IOP control is comparable in well-selected primary open-angle glaucoma.

Recovery and the 12-week post-operative pathway

• Day 0 (theatre day) — admission 1 to 2 hours pre-op, sub-Tenon or peribulbar block, 25 to 40 minutes operating time, 1 to 2 hours recovery; discharge with eye shield and drops. No driving for 24 hours after the block.
• Day 1 review — slit-lamp examination, IOP, bleb assessment. Topical antibiotic stops at 2 weeks; topical preservative-free dexamethasone 4 to 6 times daily for 2 weeks, then taper over 6 to 8 weeks total.
• Week 1 to week 2 — IOP and bleb assessment; the bleb is typically diffuse and low; early signs of fibrosis (Tenon's reaction, vascular bleb) prompt early needling with 5-fluorouracil or mitomycin-C top-up.
• Week 4 and week 8 — bleb morphology review, anterior-segment OCT of the bleb where available, IOP titration. Patients return to driving after the eye is comfortable and IOP is stable; most patients return to office work at 1 to 2 weeks and to manual work at 4 weeks.
• Week 12 — final review in the 90-day surgical package; transition to routine 4-monthly glaucoma follow-up with OCT-RNFL and visual field at 6 and 12 months.
• Activity restrictions:
  • No swimming, hot tub or sauna for 4 weeks.
  • No contact sports (rugby, boxing, martial arts) for 6 weeks; cycling and gym from week 3 with care.
  • Eye shield at night for 1 week to prevent inadvertent eye rubbing.
  • No heavy lifting (>10 kg) for 2 weeks; no Valsalva for 4 weeks.
  • Avoid eye rubbing for 12 weeks.
• Drops after surgery — in 55 to 65 per cent of eyes, all glaucoma drops are stopped at week 4 to 6; the remainder will need 1 or rarely 2 drops to reach target IOP. The aim is the lowest drop burden compatible with the individual target IOP.
• Long-term monitoring — lifelong glaucoma surveillance with IOP, OCT-RNFL, gonioscopy and visual field every 4 to 6 months; bleb morphology review at every visit; needling or revision available later if the bleb fails over time.

How to choose a UK clinic for private PreserFlo MicroShunt surgery

• CQC registration and named consultant glaucoma surgeon — verify both the centre's CQC registration and the surgeon's individual GMC entry with glaucoma fellowship and PreserFlo training.
• Per-surgeon case volume — ask for the surgeon's annual PreserFlo case count (target ≥30 per year) and outcomes (IOP at year 1, complete success rate, needling rate, complication rate).
• UKEGS audit participation — participation in the UK and Eire Glaucoma Society audit is a positive quality signal.
• Full pre-operative work-up included — OCT-RNFL, 24-2 and 10-2 visual field, gonioscopy and pachymetry should all be in the package, not separately charged.
• Mitomycin-C 0.2–0.4 mg/mL standard — mitomycin-C is not optional; absence of MMC use is a red flag.
• Anaesthetist-delivered sub-Tenon or peribulbar block — topical-only anaesthesia is inappropriate for bleb-forming surgery; insist on a consultant ophthalmic anaesthetist.
• 90-day post-operative package included — the 6 to 8 follow-up visits plus any needling and laser suture lysis should be bundled; pay-per-visit pricing is a red flag.
• Same-consultant continuity — the operating surgeon should also be the one reviewing the bleb at every post-operative visit; bleb-forming surgery is too operator-dependent for shared follow-up.
• Itemised written quotation — valid 60 days, with itemised components (theatre, consultant, anaesthetist, implant, mitomycin-C, follow-ups, needling allowance).
• Insurance pre-authorisation support — the team should prepare the PMI pre-authorisation letter on your behalf and confirm cover in writing before booking.

Frequently asked questions

How much does private PreserFlo MicroShunt glaucoma surgery cost in the UK in 2026?

UK 2026 self-pay private PreserFlo MicroShunt costs 4,500 to 6,500 pounds per eye, all-inclusive at CQC-registered London glaucoma surgical centres. The fee covers the consultant glaucoma assessment with OCT-RNFL and visual field, the day-case theatre procedure under sub-Tenon or peribulbar block, the PreserFlo implant and mitomycin-C, the consultant anaesthetist fee, and the full 90-day post-operative course including any needling or laser suture lysis. Bilateral staged pathways are typically 8,500 to 12,500 pounds total with the second eye operated 4 to 8 weeks after the first.

What is PreserFlo MicroShunt and how is it different from trabeculectomy?

The PreserFlo MicroShunt is an 8.5 millimetre SIBS biostable polymer tube with a 70 micrometre lumen that drains aqueous from the anterior chamber to a subconjunctival bleb 6 millimetres behind the limbus. Trabeculectomy creates the same outflow but through a scleral flap with no implant, allowing a wider operative IOP range but more variable bleb behaviour. The MicroShunt's lumen and length generate a defined minimum opening pressure (~6 mmHg) that prevents the early hypotony that complicates 15 to 25 per cent of trabeculectomies. Mean IOP at year 1 is approximately 13 to 15 mmHg for PreserFlo versus 9 to 12 mmHg for trabeculectomy, with materially fewer post-operative interventions and a shorter learning curve for the surgeon.

How long does the PreserFlo MicroShunt last?

Bleb survival at 2 years in INN-005 and the Beckers European real-world series is 55 to 70 per cent complete success (target IOP without any drops). Year 3 to year 5 data from the Beckers cohort and ongoing UKEGS audit suggest 50 to 60 per cent retain complete success at 3 years; the remainder typically still benefit with a markedly reduced drop burden compared with pre-operative therapy. Bleb fibrosis can be managed by needling, 5-fluorouracil top-up or mitomycin-C revision; some bleb failures can be salvaged by repeat MicroShunt in another quadrant or tube shunt placement.

Will the NHS provide PreserFlo MicroShunt?

Yes, in tertiary glaucoma units under NICE Interventional Procedures Guidance IPG622 with consultant-led local governance and audit submission. The MicroShunt is most widely available at university teaching hospitals and dedicated specialist eye hospitals; some lower-volume district general hospital glaucoma services continue to default to trabeculectomy. NHS waits in 2026 are typically 12 to 26 weeks from glaucoma diagnosis to listing and a further 6 to 12 weeks to operation; the private pathway compresses this to 1 to 2 weeks from consultation.

PreserFlo MicroShunt versus XEN gel stent — which is better?

The MicroShunt and XEN are both bleb-forming subconjunctival drainage devices but differ in implant material, lumen, length and surgical approach. XEN is 45 micrometres gelatin and 6 millimetres long and is inserted ab interno through a clear corneal incision; PreserFlo is SIBS, 70 micrometres lumen, 8.5 millimetres long and inserted ab externo through a conjunctival peritomy and scleral pocket. PreserFlo achieves a marginally lower mean IOP and is preferred in moderate-to-advanced primary open-angle glaucoma; XEN is preferred in milder disease, in patients who decline a peritomy, and when combined with phacoemulsification.

Is PreserFlo MicroShunt safe? What are the main risks?

The PreserFlo has an excellent safety profile in experienced UK hands. The most important risks are early hypotony (7 to 10 per cent, usually self-limiting), bleb failure requiring needling (15 to 25 per cent in year 1, included in the 90-day package), bleb encapsulation (5 to 8 per cent), bleb-related infection or blebitis (0.3 to 0.8 per cent per year cumulative), implant exposure or extrusion (0.5 to 1.5 per cent over 3 years), choroidal effusion (3 to 5 per cent, usually self-resolving) and rare suprachoroidal haemorrhage (0.1 to 0.4 per cent). Cataract progression in phakic eyes is 15 to 25 per cent at 2 years, lower than after trabeculectomy.

Will my private medical insurance cover PreserFlo MicroShunt?

Yes — Bupa, AXA Health, Aviva, Vitality and WPA cover the PreserFlo for primary open-angle and selected secondary open-angle glaucomas with pre-authorisation. The CCSD procedure code is typically C66.5 (insertion of glaucoma drainage device) with the appropriate diagnostic code. Pre-authorisation requires documented disease progression on maximally tolerated medical therapy, prior SLT and a consultant clinical justification letter. The clinic team will prepare the pre-authorisation package on your behalf and confirm cover in writing before booking.

Can PreserFlo MicroShunt be combined with cataract surgery?

Yes — combined phaco-PreserFlo is a routine option in eyes with both cataract and progressing glaucoma. Emerging data (Marolo et al., 2024) suggest equivalent year-1 IOP outcomes when staged or combined, though the combined cases have a slightly higher needling rate (likely due to higher post-operative inflammation). Most surgeons stage the cataract first when the glaucoma is mild and the cataract is visually significant, and combine when both are advanced.

When can I drive after PreserFlo MicroShunt surgery?

Most patients return to driving at 1 to 2 weeks after surgery, once the operated eye is comfortable and the surgeon confirms that the unoperated fellow eye meets the DVLA visual standard (6/12 corrected and intact binocular visual field). Patients with only one functional eye or with significant visual field loss should not drive until specifically cleared by the consultant and may need formal binocular Esterman visual field testing.

How long does the PreserFlo operation take?

The MicroShunt operation itself takes 25 to 40 minutes of theatre time once the sub-Tenon or peribulbar block has set. Total admission time is approximately 3 to 4 hours including pre-operative checklist, theatre, recovery and discharge. The block itself takes 5 to 10 minutes and is performed in the anaesthetic room under topical anaesthetic plus a single needle pass to deliver the local anaesthetic posteriorly.

Can I have PreserFlo if I have already had glaucoma surgery in the past?

Possibly, but with caveats. If the previous surgery was in a different quadrant (most commonly superior trabeculectomy) and the planned PreserFlo quadrant has healthy conjunctiva, the operation can usually proceed. If the planned quadrant has any prior bleb, conjunctival scarring, or significant cautery from prior surgery, the chance of MicroShunt success is reduced and a tube shunt (Baerveldt or Ahmed) is often the better operation. Pre-operative assessment includes a careful slit-lamp survey of the conjunctiva in all four quadrants.

Will I still need glaucoma drops after PreserFlo?

In 55 to 65 per cent of eyes, all glaucoma drops are stopped at week 4 to 6 after PreserFlo and the patient remains drop-free at year 2. In the remainder, 1 drop (most often a prostaglandin analogue) is sufficient to reach target IOP. A small minority (5 to 10 per cent) require 2 drops or a repeat surgical intervention. The clinical goal is the lowest drop burden compatible with the individual target IOP, which depends on the severity of optic nerve damage and visual field loss.

When should I consider PreserFlo MicroShunt instead of MIGS?

Choose bleb-forming surgery (PreserFlo or trabeculectomy) when the target IOP is mid-teens or lower, when there is moderate or advanced optic nerve and visual field damage, when MIGS would be expected to fall short, or when the patient is on maximum medical and laser therapy and the disease is documented to be progressing. MIGS (iStent inject W, Hydrus, OMNI, Kahook) are the right choice in mild-to-moderate open-angle glaucoma combined with cataract where a modest 20 to 30 per cent IOP reduction will achieve target. The choice is rarely subtle: where MIGS will do, MIGS is preferred; where MIGS will not do, MicroShunt or trabeculectomy is required. See our editorial briefing on glaucoma treatment options: drops vs SLT vs MIGS vs surgery UK for a full head-to-head walk-through.

Methodology and sources

This UK 2026 patient pricing and pathway guide was prepared by the Eye Surgery Clinic editorial team and reviewed by a UK GMC-registered consultant ophthalmologist with glaucoma subspecialty interest. Pricing reflects a CQC-registered UK glaucoma surgical sample audited against published 2024 to 2026 self-pay tariffs from the major UK glaucoma providers. Clinical statements are anchored on:

• Baker ND, Barnebey HS, Moster MR, et al. Ab-externo MicroShunt versus trabeculectomy in primary open-angle glaucoma: one-year results from a 2-year randomized multicenter study. Ophthalmology 2021; 128(12): 1710–1721.
• Baker ND, Barnebey HS, Moster MR, et al. PRESERFLO MicroShunt versus trabeculectomy: 2-year results. Ophthalmology 2022; 129(6): 615–625.
• Beckers HJM, Aptel F, Webers CAB, et al. Safety and effectiveness of the PRESERFLO MicroShunt in primary open-angle glaucoma: 3-year European multicenter study. Ophthalmology Glaucoma 2022; 5(2): 195–209.
• Pillunat KR, Herber R, Pillunat LE. PRESERFLO MicroShunt 2-year outcomes — German multicentre real-world cohort. Acta Ophthalmologica 2023; 101(4): 432–441.
• Schlenker MB, Durr GM, Michaelov E, Ahmed IIK. PreserFlo MicroShunt in pseudoexfoliation and pigmentary glaucoma: surgical outcomes. Journal of Glaucoma 2023; 32(7): 567–575.
• Marolo P, Reibaldi M, Borrelli E, et al. Combined phacoemulsification with PreserFlo MicroShunt versus PreserFlo alone in primary open-angle glaucoma: 12-month outcomes. Graefe's Archive Clinical Experimental Ophthalmology 2024; 262(8): 2615–2625.
• Gazzard G, Konstantakopoulou E, Garway-Heath D, et al. Selective laser trabeculoplasty versus eye drops for first-line treatment of ocular hypertension and glaucoma (LiGHT). Lancet 2019; 393(10180): 1505–1516.
• NICE Interventional Procedures Guidance IPG622: PRESERFLO MicroShunt insertion for primary open-angle glaucoma (2018, updated).
• Royal College of Ophthalmologists Glaucoma Commissioning Guidance (latest edition).
• American Academy of Ophthalmology Primary Open-Angle Glaucoma Preferred Practice Pattern 2024.
• UK and Eire Glaucoma Society (UKEGS) registry and audit reports 2024 and 2025.
• Care Quality Commission (CQC) inspection reports for major UK glaucoma surgical units (Moorfields Eye Hospital, Royal Free Hospital, Western Eye Hospital, Cromwell Hospital, Optegra Eye Hospital).
• General Medical Council (GMC) Good Medical Practice and consent guidance.

This page is editorial and educational. It is not personalised medical advice. PreserFlo MicroShunt suitability can only be confirmed by an in-person glaucoma consultation with gonioscopy, OCT-RNFL, visual field and lens-status assessment.

Book your UK PreserFlo MicroShunt consultation

Speak directly to a UK GMC-registered consultant ophthalmologist with glaucoma subspecialty interest. Same-week consultation slots are usually available. OCT-RNFL, 24-2 and 10-2 visual field, gonioscopy, pachymetry and lens-status assessment are included in the consultation. Confidential, no-obligation review of whether PreserFlo MicroShunt, trabeculectomy, XEN gel stent, MIGS (iStent inject W, Hydrus, OMNI) or repeat SLT is the right option for your eye.

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