This study is a multicentre, randomised, open-label, parallel-group clinical trial to evaluate the efficacy and safety of a newly developed preservative-free (PF) brimonidine / timolol fixed-combination (BTFC) ophthalmic solutions as compared with preservative-containing (PC) BTFC ophthalmic solution in adult patients (aged ≥19 years) with open-angle glaucoma (OAG) and ocular hypertension (OHT). A total of the 106 patients were enrolled, with 53 patients each randomised to the two treatment groups and included in the analysis of the safety set (SS). Patients with an IOP below 35mmHg at 9am were enrolled following washout period. A total of 106 OAG and OHT patients were randomised to the PF group or PC group. All subjects were examined four and 12 weeks after first administration. At each follow-up visit, IOP was measured at 9am and 11am and the efficacy, safety and compliance were evaluated. Results: The mean IOP changes from baseline to 12 weeks at 11am were −3.45 ±2.53mmHg in the PF group and −3.65 ±2.76mmHg in the PC group (p<.0001 for both). The difference in mean IOP change between the two groups was 0.20 ±2.65mmHg, which was not significantly different. The proportion of patients with IOP reductions of ≥15% and ≥20% and IOP at all-time points in the PF group were not significantly different when compared with in the PC group. There were no specific differences between the two groups regarding the incidence of adverse events, with only one patient (one case) in the PF group developing corneal erosion. In the PC group, corneal abrasion and vitreous haemorrhage were reported in one patient (one case) each. The authors conclude that PF BTFC ophthalmic solution shows a similar efficacy and safety profile to that of PC BTFC.