Achieving low intraocular pressure in normal-tension glaucoma with the Preserflo MicroShunt: comparison with primary open-angle glaucoma and the XEN-45 Gel Stent.

BACKGROUND: Achieving low intraocular pressure (IOP) while minimizing surgical risk remains a central challenge in the management of normal-tension glaucoma (NTG). This study aimed to evaluate the efficacy and safety of the Preserflo MicroShunt (PMS) in NTG compared with primary open-angle glaucoma (POAG) and the XEN-45 Gel Stent. METHODS: In this retrospective dual-comparison study, the primary outcomes were 2-year complete success (≥ 30% reduction in IOP from baseline and ≤ 12 mmHg without medication) and hazard ratios (HRs) for surgical failure. Kaplan-Meier analyses and univariate Cox models were used to compare NTG PMS and POAG PMS patients (1:1 matched cohort; PMS analysis) and exploratory multivariable models for consecutive NTG PMS and NTG XEN-45 patients (NTG analysis). Secondary outcomes included bleb revision and complication rates. RESULTS: In the PMS analysis, 50 NTG patients were matched to 50 POAG patients. Two-year success rates were 69% and 45%, respectively (p = 0.0277). NTG diagnosis was associated with a lower risk of failure (HR 0.48, 95% CI 0.24-0.96) and fewer bleb revisions. In the NTG analysis, 45 PMS patients were compared with 23 XEN-45 patients. Two-year success rates were 71% and 17%, respectively (p < 0.0001). PMS implantation was associated with a lower risk of failure (HR 0.25, 95% CI 0.12-0.53) and fewer needling procedures. No sight-threatening complications occurred in any group. CONCLUSIONS: PMS implantation enabled a high rate of sustained low IOP control, with significantly higher success rates than in matched POAG patients and NTG XEN-45 patients, while requiring fewer postoperative interventions. These findings indicate that the PMS might achieve lower IOP thresholds in NTG than previously expected requiring evaluation in larger prospective studies.