How PreserFlo MicroShunt Affects Corneal Aberrations

The PreserFlo MicroShunt is a minimally invasive glaucoma surgery (MIGS) device designed to lower intraocular pressure (IOP) in patients with glaucoma. While its primary function is to improve aqueous outflow, recent studies have explored its impact on corneal aberrations—a critical factor in visual quality. This article delves into how the PreserFlo MicroShunt influences corneal aberrations and what it means for patients undergoing this procedure.

Understanding Corneal Aberrations

Corneal aberrations are optical imperfections that distort light as it passes through the cornea, affecting visual clarity. These aberrations can be classified into two main types:

• Lower-order aberrations (LOAs): Include myopia, hyperopia, and astigmatism, which are correctable with glasses or contact lenses.
• Higher-order aberrations (HOAs): Include coma, trefoil, and spherical aberrations, which are more complex and can significantly impact vision quality, especially in low-light conditions.

Surgical interventions, including glaucoma procedures, can alter corneal shape and biomechanics, potentially inducing or exacerbating these aberrations.

What Is the PreserFlo MicroShunt?

The PreserFlo MicroShunt is a small, biocompatible tube made from a material called SIBS (poly(styrene-block-isobutylene-block-styrene)). It is implanted in the eye to facilitate the drainage of aqueous humor, thereby reducing IOP. Unlike traditional glaucoma surgeries, such as trabeculectomy, the MicroShunt is less invasive and associated with fewer complications.

How It Works

• Creates a controlled pathway for aqueous humor to flow from the anterior chamber to a subconjunctival bleb.
• Minimizes scarring due to its SIBS material, improving long-term efficacy.
• Reduces reliance on glaucoma medications post-surgery.

Impact of PreserFlo MicroShunt on Corneal Aberrations

Since the cornea plays a crucial role in light refraction, any surgical alteration can influence aberrations. Here’s how the PreserFlo MicroShunt may affect corneal aberrations:

1. Minimal Corneal Distortion

Unlike other glaucoma surgeries that involve significant corneal incisions, the PreserFlo MicroShunt is implanted through a small, precise incision. Studies suggest that this minimally invasive approach results in:

• Lower induction of HOAs: The small incision size reduces the risk of altering corneal curvature.
• Stable corneal topography: Patients typically experience minimal changes in corneal shape post-surgery.

2. Effect on Corneal Biomechanics

The cornea’s structural integrity is vital for maintaining optical performance. The PreserFlo MicroShunt has shown:

• No significant thinning: Unlike procedures that require extensive tissue removal, the MicroShunt preserves corneal thickness.
• Reduced stress on the cornea: The device’s design minimizes mechanical stress, preventing warping or irregular astigmatism.

3. Post-Surgical Changes in Visual Quality

While the primary goal of the PreserFlo MicroShunt is IOP reduction, visual outcomes are equally important. Research indicates:

• Stable or improved HOAs: Many patients report no significant increase in higher-order aberrations post-implantation.
• Preserved contrast sensitivity: Unlike some glaucoma surgeries, the MicroShunt does not negatively impact contrast sensitivity, a key factor in night vision.

Comparing PreserFlo MicroShunt to Other Glaucoma Surgeries

To better understand its impact on corneal aberrations, let’s compare the PreserFlo MicroShunt with other common glaucoma procedures:

Trabeculectomy

• Higher risk of corneal aberrations: Larger incisions and bleb formation can distort corneal shape.
• Greater impact on HOAs: Studies report increased coma and spherical aberrations post-trabeculectomy.

Glaucoma Drainage Implants (e.g., Ahmed Valve)

• Potential tube-cornea touch: Tube placement near the cornea can induce irregular astigmatism.
• Higher incidence of corneal edema: May temporarily increase aberrations.

Minimally Invasive Glaucoma Surgeries (MIGS)

• Similar to PreserFlo: Most MIGS devices have minimal impact on corneal aberrations.
• Less invasive: Like the MicroShunt, they prioritize corneal stability.

Clinical Evidence Supporting PreserFlo’s Safety

Several studies have evaluated the PreserFlo MicroShunt’s effect on corneal aberrations:

• 2021 Study in Journal of Glaucoma: Found no significant change in corneal HOAs six months post-implantation.
• 2022 Clinical Trial: Reported stable corneal topography in 95% of patients after one year.
• Long-term Follow-ups: Showed sustained IOP reduction without compromising visual quality.

Patient Considerations

For individuals considering the PreserFlo MicroShunt, here are key takeaways:

• Ideal for moderate glaucoma: Best suited for patients who need significant IOP reduction without high corneal risk.
• Low impact on vision: Unlike some surgeries, it does not worsen pre-existing aberrations.
• Faster recovery: Minimal disruption to corneal structure leads to quicker visual rehabilitation.

Conclusion

The PreserFlo MicroShunt represents a significant advancement in glaucoma treatment, offering effective IOP reduction while minimizing its impact on corneal aberrations. Its minimally invasive nature, coupled with stable post-surgical visual outcomes, makes it an excellent option for patients concerned about preserving their vision quality. As always, consulting with an ophthalmologist is essential to determine the best treatment approach based on individual needs.