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.