Three-year clinical outcomes of PRESERFLO MicroShunt implantation in eyes with previous failed trabeculectomy.

OBJECTIVE: To describe the 3-year clinical outcomes of PRESERFLO MicroShunt (PMS) implantation in eyes with uncontrolled glaucoma and previous failed trabeculectomy. DESIGN: A retrospective, single-centre observational cohort study. PARTICIPANTS: Seventy-four eyes with glaucoma that had at least 1 failed trabeculectomy and no other previous surgeries for glaucoma. METHODS: All consecutive eyes undergoing PMS implantation after failed trabeculectomy were included. Clinical data were collected at baseline and scheduled postoperative visits. Primary outcome measures were intraocular pressure (IOP), number of glaucoma medications, and surgical success, defined as an IOP reduction ≥20% (criterion 1) or ≥30% (criterion 2) from baseline, with postoperative IOP <18 mm Hg and no need for additional glaucoma filtering surgery. Complete success was defined as achieving target IOP without medications and qualified success as achieving target IOP with medications. RESULTS: The median follow-up was 36 months. Mean baseline IOP was 23.0 ± 5.7 mm Hg on 3.0 ± 0.7 medications. At 3 years, mean IOP decreased to 12.1 ± 3.5 mm Hg (-46.1%; mean reduction -10.6 mm Hg; 95% CI, -12.1 to -8.3; P < 0.001) with 0.8 ± 1.3 medications; 51.4% of eyes were medication-free. Using criterion 1, overall success was 68.6% (51.5% complete); using criterion 2, overall success was 62.9% (51.5% complete). No eye required additional glaucoma-filtering surgery. Complications occurred in 44.6% of eyes, most of which were mild and self-resolving; 5.9% required surgical intervention. CONCLUSIONS: PMS implantation resulted in sustained IOP reduction, reduced medication burden, and an acceptable safety profile over 3 years in eyes with previous failed trabeculectomy. Further prospective studies with longer follow-up are warranted.