Introduction: Reducing intraocular pressure (IOP), the only modifiable risk factor for open-angle glaucoma (OAG), is important for the preservation of vision and slowing of disease progression. Preservative-free tafluprost (0.0015%)/timolol (0.5%) fixed combination (PF Taf-T FC) is an approved combination therapy for OAG treatment. The VISIONARY study aimed to evaluate the effectiveness and tolerability of PF Taf-T FC in real-world clinical settings. Here, we present the results from the United Kingdom (UK) and Ireland., Methods: This observational, multicentre, European, prospective study recorded data during routine clinic appointments on the use of PF Taf-T FC for the treatment of OAG and ocular hypertension (OHT) in patients whose disease was insufficiently controlled on a prostaglandin analogue (PGA) or beta blocker monotherapy or who did not tolerate these medications. Mean change in IOP, symptom severity, changes in clinical signs, and tolerability were investigated over 6 months., Results: Eighty-two patients were recruited in the UK and Ireland. After 6 months of PF Taf-T FC treatment, mean IOP was significantly reduced from 22.0 to 16.2 mmHg in the UK group and from 18.6 to 14.1 mmHg in the Ireland group. In the UK (65 patients), 49 adverse events (AEs) were reported, of which 3 were serious. No AEs were reported in the Ireland group (17 patients). Overall, 91.9% of UK physicians reported PF Taf-T FC treatment to be the same or better than prior medication for improving clinical signs; 90.0% of UK patients reported PF Taf-T FC treatment to have good or very good tolerability., Conclusions: Treatment with PF Taf-T FC resulted in significant reductions in mean IOP over 6 months. Patients and physicians reported that treatment was well tolerated. These data demonstrate real-world efficacy of PF Taf-T FC for the treatment of OAG and OHT in routine clinical practice in the UK and Ireland., Trial Registration: European Union electronic Register of Post-Authorisation Studies (EU PAS) register number, EUPAS22204.