BACKGROUND: Prostaglandin analogs reduce intraocular pressure (IOP) in patients with open-angle glaucoma or ocular hypertension; however, these medications may affect the ocular surface and elicit ocular discomfort when preserved with benzalkonium chloride (BAK). METHODS: This was an open-label, single-arm study conducted in Latin America from February 2012 to May 2013. Patients with open-angle glaucoma or ocular hypertension who were intolerant of latanoprost 0.005 % were transitioned to receive once-daily BAK-free travoprost 0.004 % containing polyquaternium-1 (Travatan® preserved with POLYQUAD® [PQ], Alcon Laboratories, Inc; Fort Worth, TX) for 12 weeks. Mean change in IOP from baseline (primary efficacy endpoint) and the percentage of patients who achieved a target IOP of ≤18 mmHg were evaluated at all on-therapy visits. Ocular hyperemia, patient preference, and self-projected adherence were assessed at week 12. Adverse events (AEs) were monitored throughout the study. RESULTS: All enrolled patients were included in the analysis (n = 191); the majority of patients (90.6 %, n = 173/191) completed the study. Mean (SD) patient age was 67.5 (11.3) years, and mean baseline IOP was 14.8 mmHg. Mean IOP was reduced by 0.94 mmHg at week 6 and by 1.09 mmHg at week 12 (P < 0.001 for both). A greater percentage of patients achieved a target IOP of ≤18 mmHg at week 6 (93.1 %; n = 163/175) and week 12 (93.3 %; n = 166/178) compared with baseline (89.5 %; n = 171/191). There was a 10.5 % increase in the percentage of patients with "none/trace" amounts of hyperemia. Most patients preferred the study medication (81.5 %; n = 141/173) and were confident that they would adhere to their preferred medication (90.8 %; n = 157/173). No serious AEs were reported, and eye irritation (3.7 %; n = 7/191) was the most common treatment-related AE. CONCLUSIONS: Transitioning from BAK-containing latanoprost 0.005 % to BAK-free travoprost 0.004 % preserved with PQ reduced IOP in patients with open-angle glaucoma or ocular hypertension who were intolerant of latanoprost. BAK-free travoprost 0.004 % is a viable alternative for patients who require switching their IOP-lowering medications because of tolerability issues. TRIAL REGISTRATION: ClinicalTrials.gov identifier, NCT01510145.