Introduction: To evaluate the efficacy and safety of PreserFlo® MicroShunt in primary open angle glaucoma (POAG) eyes after a single failed trabeculectomy.

Methods: Retrospective review of POAG eyes with a failed trabeculectomy that underwent PreserFlo® MicroShunt implantation from March 2019 to November 2019, in two Italian glaucoma centers. Pre- and postoperative data were collected and compared.

Results: A total of 31 surgeries in 31 patients were reviewed. Mean preoperative IOP and mean preoperative number of medications were 24.12 ± 3.14 mmHg and 3.29 ± 0.64, respectively, and decreased to 12.56 ± 2.64 mmHg and 0.46 ± 0.77 at the 12-month postoperative follow-up visit (p < 0.01). The most frequent adverse events were transient hypotony (6 eyes, 19.3%) and choroidal effusion (3 eyes, 9.6%). In all cases spontaneous resolution was observed, with no intervention.

Conclusion: In POAG eyes with a single failed trabeculectomy, the PreserFlo® MicroShunt was safe and effective in reducing the IOP after a 12-month follow-up. The PreserFlo® MicroShunt may represent a viable choice as a second surgery.