PreserFlo MicroShunt Complications Lead to Corneal Damage and Surgical Revision

The PreserFlo MicroShunt has been widely adopted as a minimally invasive surgical option for glaucoma patients, offering an alternative to traditional trabeculectomy. While the device has shown promise in reducing intraocular pressure (IOP), emerging reports highlight complications such as corneal damage and the need for surgical revision. This article explores these adverse outcomes, their underlying causes, and potential solutions for patients and surgeons.

Understanding the PreserFlo MicroShunt

The PreserFlo MicroShunt is a small, biocompatible tube designed to divert aqueous humor from the anterior chamber to a subconjunctival space, lowering IOP. Made from a soft, flexible material called SIBS (poly(styrene-block-isobutylene-block-styrene)), it aims to minimize scarring and improve long-term outcomes compared to traditional methods.

How It Works

• Inserted under a partial-thickness scleral flap
• Creates a controlled drainage pathway
• Reduces reliance on postoperative medications

Despite its benefits, complications have been observed, particularly concerning corneal damage and subsequent surgical interventions.

Reported Complications: Corneal Damage

Several studies and case reports have documented instances where the PreserFlo MicroShunt led to corneal complications, including:

• Corneal endothelial cell loss – Progressive thinning of the corneal endothelium
• Corneal decompensation – Swelling and loss of transparency
• Tube-cornea touch – Direct contact between the shunt and cornea, causing abrasion

Why Does Corneal Damage Occur?

The primary mechanisms behind these complications include:

• Improper shunt positioning – If placed too close to the cornea, mechanical irritation occurs.
• Excessive flow – High aqueous outflow may disrupt corneal endothelial function.
• Inflammation – Postoperative inflammation can accelerate endothelial cell loss.

Surgical Revision: When Is It Necessary?

In cases where corneal damage becomes severe, surgical revision may be required. Common scenarios include:

• Tube repositioning – Adjusting the shunt to prevent corneal contact.
• Shunt removal – Complete extraction if damage is irreversible.
• Corneal transplantation – In extreme cases, a corneal graft may be necessary.

Preventing Complications

Surgeons can take several precautions to minimize risks:

• Accurate placement – Ensuring the shunt is positioned away from the cornea.
• Flow regulation – Using antimetabolites like mitomycin C to control scarring without excessive drainage.
• Close monitoring – Regular follow-ups to detect early signs of corneal damage.

Patient Outcomes and Long-Term Implications

While many patients experience successful IOP reduction with the PreserFlo MicroShunt, those who develop corneal complications face additional challenges:

• Reduced visual acuity – Corneal edema or scarring can impair vision.
• Multiple surgeries – Revision procedures increase recovery time and risks.
• Psychological impact – Prolonged treatment can affect quality of life.

Alternative Treatment Options

For patients at high risk of corneal complications, alternative glaucoma treatments may be considered:

• Minimally invasive glaucoma surgery (MIGS) – Devices like iStent or Hydrus.
• Selective laser trabeculoplasty (SLT) – Non-invasive IOP reduction.
• Traditional trabeculectomy – Despite higher scarring risk, it avoids corneal contact.

Conclusion

The PreserFlo MicroShunt remains a valuable tool in glaucoma management, but awareness of its potential complications—particularly corneal damage—is crucial. Surgeons must prioritize precise placement and postoperative monitoring to mitigate risks. For patients experiencing adverse effects, timely surgical revision can help preserve vision and improve outcomes. As research continues, refining surgical techniques and patient selection will be key to maximizing the benefits of this innovative device.