Efficacy and Safety of the Preserflo® Microshunt as a Standalone Procedure Versus Its Combination with Phacoemulsification.

Background/

Objectives

Glaucoma is a leading cause of irreversible blindness, and lowering intraocular pressure (IOP) is the only proven strategy to slow disease progression. The Preserflo® Microshunt (PMS) is a minimally invasive subconjunctival drainage device used to treat uncontrolled glaucoma. Given that cataracts and glaucoma often coexist, this study aimed to compare the 12-month efficacy and safety of PMS implanted as a standalone procedure versus combined with phacoemulsification (PCE).

Methods

This single-center retrospective case-control study included 104 eyes (26 PMS + PCE; 78 standalone PMS) from patients treated between 2019 and 2023. Controls were matched 3:1 to cases on sex, age, glaucoma severity, baseline IOP, and number of prior glaucoma surgeries. Success at 12 months was defined as absolute (IOP ≤ 21 mmHg without medications) or qualified (IOP ≤ 21 mmHg with the same or fewer medications). Secondary outcomes included changes in IOP, medication burden, and safety profiles.

Results

At 12 months, absolute success was achieved in 23.1% of the PMS + PCE group versus 43.6% in the standalone PMS group (p = 0.13). However, the Kaplan-Meier survival probability of absolute success was significantly higher for standalone PMS (75.2% vs. 40.2%, p = 0.0028). Qualified success rates were comparable (53.9% vs. 70.5%, p = 0.30). Both groups showed similar reductions in mean IOP and medication counts. Although safety profiles were comparable, the mean time to first bleb revision (p = 0.031) and first needling (p = 0.015) was significantly shorter in the combined group.

Conclusions

Both standalone and combined PMS procedures are effective and safe in achieving sustained IOP reduction. Although standalone implantation appears to be associated with higher medication-free success rates, combined surgery remains a reasonable option for patients with coexisting cataract, despite a tendency toward earlier bleb fibrosis likely related to the inflammatory response induced by PCE.