Précis: The Preserflo MicroShunt effectively lowered intraocular pressure in primary high and normal pressure open angle glaucoma. Purpose: To evaluate the efficacy and safety of the Preserflo MicroShunt in patients with primary open angle glaucoma (POAG) and the 2 variants high (HPG) and normal pressure glaucoma (NPG) after 1 year. Methods: Single-center prospective interventional case series consecutively including eyes of White/European patients with POAG, who received the Preserflo MicroShunt as a primary and standalone glaucoma intervention. Primary outcome measures: change in mean 24-hour IOP (mdIOP, mean of 6 measurements), peak IOP, IOP fluctuations, antiglaucoma medications, and success rates. Secondary outcome measures include visual acuity, visual fields, complications, surgical interventions, and adverse events. Results: Forty-two eyes of 42 patients with POAG, 29 in the HPG and 13 in the NPG group, were analyzed after 1-year follow-ups. Median [Q25, Q75] medicated mdIOP (mm Hg) dropped by 30% from 16.5 [13.7-27.3] to 12.8 [10.2-14.5] in the HPG and by 40% from 14.3 [13.3-16.0] to 9.5 [8.3-11.1] in the NPG group, with a median postoperative medication use of 0 [0-0] in both groups. At 1 year, 92.5% of eyes were medication-free versus 0% preoperatively. The reduction of mdIOP (P=1.0), peak IOP (P=0.932), IOP fluctuations (P=0.142), and the rate of interventions (P=0.298) were not statistically significantly different between the HPG and NPG group. None of the patients experienced severe adverse events or loss of vision. Conclusions: Effective and safe intraocular pressure lowering was observed 1 year following MicroShunt implantation for primary HPG and NPG in White patients of European descent.