PreserFlo MicroShunt: Definition, Uses, and Clinical Overview

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PreserFlo MicroShunt Introduction (What it is)

PreserFlo MicroShunt is a small implanted glaucoma drainage device designed to lower eye pressure.
It creates a controlled pathway for fluid inside the eye to exit to the outer surface tissues.
It is most commonly used in the surgical management of glaucoma, especially when drops alone are not enough.
It is implanted by an ophthalmologist in an operating-room setting.

Why PreserFlo MicroShunt used (Purpose / benefits)

The main purpose of PreserFlo MicroShunt is to reduce intraocular pressure (IOP)—the pressure inside the eye. Elevated IOP is a major risk factor for glaucoma, a group of diseases that can damage the optic nerve (the cable that carries vision signals from the eye to the brain). Lowering IOP is currently the most established way to slow glaucoma progression in many patients, although responses vary by clinician and case.

Many people with glaucoma start with medicated eye drops and sometimes laser treatment. When these approaches do not achieve a target IOP, are not tolerated, or are difficult to maintain long term, surgical options may be considered. PreserFlo MicroShunt is one option intended to provide a more consistent pressure-lowering effect than medications alone for selected patients.

Potential benefits that clinicians may consider include:

  • Pressure lowering through a physical drainage pathway rather than relying solely on daily medication use.
  • Reduction in medication burden for some patients (the degree of reduction varies).
  • A bleb-forming approach (a small reservoir under the conjunctiva), similar in concept to trabeculectomy, but using a standardized implant to create the channel.
  • A design intended to provide controlled outflow of aqueous humor (the clear fluid inside the front of the eye).

Importantly, outcomes depend on glaucoma type, disease stage, prior surgeries, healing response (scarring), and follow-up care. No single glaucoma procedure is ideal for every eye.

Indications (When ophthalmologists or optometrists use it)

PreserFlo MicroShunt is typically considered in scenarios such as:

  • Primary open-angle glaucoma when IOP remains above goal despite medications and/or laser
  • Pseudoexfoliative glaucoma or other open-angle variants where additional pressure lowering is needed (selection varies)
  • Cases where clinicians aim to achieve lower target IOPs than some less invasive procedures usually provide
  • Patients who have difficulty adhering to drop schedules or cannot tolerate medication side effects (dryness, irritation, systemic effects)
  • Eyes in which a surgeon is considering filtering surgery (bleb-based surgery) rather than angle-based micro-stents
  • Selected cases as a standalone glaucoma surgery or sometimes combined with cataract surgery (practice patterns vary by surgeon and case)

Optometrists frequently play a role in detection, co-management, and follow-up support, while implantation is performed by ophthalmic surgeons.

Contraindications / when it’s NOT ideal

PreserFlo MicroShunt may be less suitable, or require extra caution, in situations such as:

  • Angle-closure glaucoma that is not appropriately opened/treated (because the anatomy and mechanism differ)
  • Active eye infection or significant ocular surface inflammation (timing and approach may be adjusted)
  • Conjunctival scarring or compromised conjunctiva in the intended surgical area (from prior surgery, injury, or inflammation), which can affect bleb formation
  • Eyes with a high scarring tendency where bleb-based surgery is less likely to remain functional (risk varies by patient and history)
  • Some forms of uveitic glaucoma (inflammatory glaucoma) where inflammation control is a major determinant of success; suitability varies by clinician and case
  • Certain cases of neovascular glaucoma (abnormal new blood vessels and severe disease), where other surgical approaches may be preferred
  • Situations where a different surgical target is needed (for example, when a tube shunt to a plate device is favored based on anatomy or prior failure)

Only a clinician evaluating the full eye exam, imaging, and history can determine whether the device is appropriate for a specific patient.

How it works (Mechanism / physiology)

Mechanism of action (high level)

PreserFlo MicroShunt lowers IOP by providing a pathway for aqueous humor to leave the anterior chamber (the fluid-filled space between the cornea and iris) and drain into the subconjunctival space (beneath the conjunctiva, the thin clear tissue covering the white of the eye). This drainage forms a small fluid reservoir called a filtering bleb.

In simple terms: the device helps the eye’s internal fluid exit through a controlled channel, reducing pressure.

Relevant anatomy

Key structures involved include:

  • Anterior chamber: where aqueous humor circulates
  • Sclera: the white, supportive outer wall of the eye; surgical tunnels/pockets are created in or through it depending on technique
  • Conjunctiva and Tenon’s capsule: the outer tissue layers where the bleb forms; their healing response strongly influences long-term function
  • Trabecular meshwork: the eye’s natural drainage tissue (often the site of resistance in open-angle glaucoma); the MicroShunt bypasses the need for this pathway by draining externally

Onset, duration, and reversibility

  • Onset: Pressure reduction may occur soon after surgery, but the final stabilized IOP often depends on healing and bleb maturation over time.
  • Duration: The intended effect is long term, but durability varies, largely due to tissue healing and scarring around the bleb.
  • Reversibility: PreserFlo MicroShunt is an implanted device and is not “reversible” in the way a medication is. However, glaucoma surgeries can sometimes be revised, and devices can sometimes be removed or replaced if clinically necessary. The specific options depend on the eye’s condition and surgical findings.

PreserFlo MicroShunt Procedure overview (How it’s applied)

PreserFlo MicroShunt is not a medication or a diagnostic test; it is a surgical implant. Techniques differ by surgeon, but a general workflow often looks like this:

  1. Evaluation / exam – Comprehensive glaucoma assessment: IOP readings, optic nerve evaluation, visual field testing, and imaging (such as OCT) are commonly used. – Review of prior treatments (drops, laser, prior surgeries) and overall eye health (cornea, lens/cataract, conjunctiva).

  2. Preparation – Pre-operative planning includes selecting the surgical site and evaluating conjunctival health. – Anesthesia is typically local/regional with sedation, or another approach depending on patient and facility. – Surgeons may use medications during surgery to reduce scarring; the choice and dose vary by clinician and case.

  3. Intervention – The surgeon creates a pathway from the anterior chamber to the subconjunctival space and positions the PreserFlo MicroShunt to maintain that channel. – The goal is to establish controlled outflow and allow a functioning bleb to form under the conjunctiva.

  4. Immediate checks – The eye is examined for appropriate implant position, fluid flow, and overall stability. – IOP is measured post-operatively as part of routine monitoring.

  5. Follow-up – Multiple post-operative visits are typical to monitor IOP, bleb appearance, healing, and inflammation. – Additional treatments (for example, adjustments in drops or office-based bleb management) may be used when needed; the approach varies by clinician and case.

This overview is intentionally general; surgical steps and aftercare protocols differ between practices and individual eyes.

Types / variations

PreserFlo MicroShunt refers to a specific glaucoma implant, but “variations” commonly come from how and when it is used, rather than multiple models for different prescriptions like eyeglasses.

Common real-world variations include:

  • Standalone PreserFlo MicroShunt implantation

  • Performed as a dedicated glaucoma procedure when pressure lowering is the main goal.

  • Combined surgery (selected cases)

  • In some practices, a microshunt procedure may be combined with cataract surgery when both cataract and glaucoma require treatment. Whether this is appropriate depends on anatomy, glaucoma severity, and surgeon preference.

  • Differences in surgical technique

  • The exact approach to tissue handling, implant placement, and wound closure can differ.

  • Use of anti-scarring medication during surgery and post-operative management strategies can also vary by clinician and case.

  • Positioning and bleb management approach

  • Surgeons may choose different quadrants of the eye based on conjunctival health, prior surgery, and exposure risk.

For context, PreserFlo MicroShunt also sits within a broader category of glaucoma procedures sometimes discussed as MIGS (minimally invasive glaucoma surgery), although classifications and definitions can vary. Some MIGS are angle-based (working through the eye’s natural drainage angle), while PreserFlo MicroShunt is subconjunctival/bleb-based.

Pros and cons

Pros:

  • Can provide meaningful IOP reduction in appropriately selected glaucoma cases
  • May reduce reliance on daily eye drops for some patients (degree varies)
  • Uses a standardized implant to create an outflow pathway
  • Designed for controlled aqueous outflow into the subconjunctival space
  • Can be considered when drops and/or laser are insufficient or poorly tolerated
  • Often fits into a stepwise treatment plan between medications/laser and more extensive procedures (placement in the pathway varies by clinician and case)

Cons:

  • It is surgery, with inherent surgical risks and the need for follow-up monitoring
  • Long-term success can be limited by scarring of the conjunctiva/Tenon’s tissues (a common challenge in bleb-based surgery)
  • May still require additional medications or procedures if IOP is not at goal
  • Bleb-related issues can occur (for example, discomfort, changes in appearance, or need for management), and require monitoring
  • IOP can be too high or too low in the early period in some eyes, requiring clinician-directed management
  • Not suitable for every glaucoma type or ocular anatomy; selection is individualized

Aftercare & longevity

Aftercare for PreserFlo MicroShunt is largely about supporting healthy healing while monitoring IOP and the bleb. The details (drop schedules, visit frequency, activity restrictions) are clinician-specific and should be individualized; what follows is a general overview of factors that often influence outcomes.

What can affect longevity and results

  • Healing response and scarring

  • Scar tissue can reduce bleb function over time. Some patients form scar tissue more aggressively than others due to genetics, inflammation, or prior surgery.

  • Severity and type of glaucoma

  • Eyes requiring very low target pressures may need closer monitoring and sometimes additional interventions.

  • Ocular surface health

  • Dry eye, blepharitis, or chronic irritation can affect comfort and tolerance of post-operative medications and exams.

  • Prior eye surgeries

  • Previous conjunctival surgery can make bleb formation more challenging and may influence site selection.

  • Adherence to follow-up

  • Post-operative visits allow clinicians to detect early issues such as inflammation, pressure fluctuations, or bleb changes.

  • Comorbidities

  • Conditions such as uveitis (inflammation), diabetes, or vascular disease can influence healing and risk profiles, depending on the individual.

Practical expectations (non-prescriptive)

Many patients have a period of frequent follow-up soon after surgery, followed by longer intervals once the eye stabilizes. Some eyes maintain benefit for extended periods, while others need medication adjustments, bleb management, or additional glaucoma procedures over time. Because glaucoma is chronic, long-term monitoring typically continues even when IOP is improved.

Alternatives / comparisons

PreserFlo MicroShunt is one option among several glaucoma management strategies. A balanced comparison usually focuses on the target pressure needed, risk tolerance, anatomy, prior treatment history, and ability to maintain therapy.

Observation and monitoring

  • Appropriate for glaucoma suspects or very early disease in selected cases.
  • Does not lower IOP by itself; relies on careful surveillance and starting treatment when indicated.

Medicated eye drops

  • Common first-line therapy and often effective.
  • Limitations can include side effects, cost, supply issues, and adherence challenges.
  • Drops may still be used after surgery depending on pressure targets and response.

Laser treatment (commonly SLT)

  • Selective laser trabeculoplasty (SLT) is often used in open-angle glaucoma to improve natural outflow through the trabecular meshwork.
  • Typically less invasive than surgery, but pressure lowering may be insufficient for advanced targets, and effect can diminish over time.

Angle-based MIGS (stents, canal procedures)

  • Generally aimed at improving outflow through the eye’s natural drainage pathways.
  • Often combined with cataract surgery.
  • May be favored when moderate IOP reduction is sufficient, but may not achieve very low pressures in some eyes compared with bleb-forming approaches (varies by device and case).

Trabeculectomy (traditional filtering surgery)

  • A long-established bleb-forming procedure that can achieve low IOP targets in selected eyes.
  • It can be effective but may involve intensive post-operative management, and complication profiles differ.
  • PreserFlo MicroShunt is sometimes discussed as an alternative bleb-based option using an implant rather than creating a scleral flap, but direct comparisons depend on study design and patient selection.

Tube shunt surgery (e.g., plate-based devices)

  • Often used in more complex cases, such as eyes with prior failed filtering surgery or significant scarring.
  • Uses a tube that drains to a plate reservoir, usually placed farther back under the conjunctiva.
  • May be preferred in certain higher-risk or previously operated eyes, depending on surgeon judgment.

No approach is universally “better”; suitability depends on individual anatomy, disease goals, and clinician assessment.

PreserFlo MicroShunt Common questions (FAQ)

Q: Is PreserFlo MicroShunt the same as a stent?
It is an implanted glaucoma drainage device, and people sometimes use “stent” as a general term. PreserFlo MicroShunt is typically described as a microshunt that drains aqueous humor to a subconjunctival bleb, which differs from many angle-based glaucoma stents. The mechanism and tissue location are important distinctions.

Q: What does it feel like after it’s implanted—can you feel the device?
Many patients do not feel the implant itself once healing is complete. Early on, the eye may feel irritated or scratchy from surface healing and sutures, which can vary. Sensations should be assessed by a clinician because discomfort can have multiple causes.

Q: Does the procedure hurt?
During surgery, anesthesia is used to reduce pain. After surgery, some soreness, foreign-body sensation, and light sensitivity can occur, especially in the first days to weeks. Pain experience varies by individual and by healing response.

Q: How long does PreserFlo MicroShunt last?
It is intended as a long-term implant, but long-term pressure control depends heavily on tissue healing and scarring around the bleb. Some eyes maintain good function for an extended time, while others require additional medications, bleb management, or further glaucoma procedures. Longevity varies by clinician and case.

Q: Is PreserFlo MicroShunt considered “minimally invasive”?
Definitions of MIGS vary. Compared with traditional trabeculectomy or tube shunt surgery, some clinicians view microshunts as a less extensive approach, but it is still incisional surgery and is bleb-forming, which requires ongoing monitoring. Classification can differ by region, training, and guidelines.

Q: Will I still need glaucoma drops afterward?
Some patients can reduce the number of drops, while others still need one or more medications to reach their target IOP. Needing drops after surgery does not automatically mean the procedure failed; it may reflect how low the target pressure is and how the eye heals. Management plans vary by clinician and case.

Q: What is recovery like—when can I drive or return to screens/work?
Vision can be blurry initially, and follow-up visits are typically frequent early on. Driving and return to work depend on visual clarity, comfort, and clinician guidance, and may differ if cataract surgery was also performed. Screen use is often possible as comfort allows, but dryness and strain can be more noticeable during healing.

Q: Are there risks or complications?
All surgeries carry risk. With bleb-forming glaucoma procedures, potential issues can include infection risk at the bleb, scarring that reduces effectiveness, pressure that is too low or too high, inflammation, bleeding, or need for additional procedures. The likelihood and severity vary by eye and by surgical context.

Q: How much does PreserFlo MicroShunt cost?
Costs vary widely by country, facility, surgeon fees, insurance coverage, and whether other procedures (like cataract surgery) are performed at the same time. Out-of-pocket costs can also differ depending on deductibles and coverage policies. A clinic’s billing team is usually best positioned to explain expected expenses.

Q: Does PreserFlo MicroShunt cure glaucoma?
Glaucoma is generally a chronic condition. PreserFlo MicroShunt is used to help lower IOP, which can reduce risk of progression, but it does not restore lost optic nerve tissue. Ongoing monitoring remains important even when pressure improves.

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