PURPOSE: The aim of the study was to evaluate the long-term 24-hour intraocular pressure (IOP) efficacy of travoprost monotherapy in primary open-angle glaucoma patients.PATIENTS AND METHODS: A total of 36 previously untreated primary open-angle glaucoma patients were enrolled in this 5-year study. Patients underwent an untreated 24-hour IOP evaluation. Subsequently all patients were assigned to topical therapy with travoprost 0.004% eye-drops preserved with benzalkonium chloride (Travatan, Alcon Laboratories Inc., Fort Worth, TX) administered once in the evening (8:00 PM) in both eyes. All patients were then scheduled for a 24-hour IOP assessment approximately 12 months after the baseline visit. This schedule of follow-up was maintained for the whole duration of the trial. The predetermined range of target IOP reduction selected in this cohort of patients ranged between 20% and 30%.RESULTS: A total of 34 patients completed all phases of the investigation. The mean survival time was 57.3±2.0 months and the cumulative survival rate was 0.82±0.6 at 60 months. Travoprost reduced the mean 24-hour IOP from 23.4±1.7 mm Hg at baseline to 16.8±2.4 mm Hg (28.4%), 16.8±2.5 mm Hg (28.1%), 16.8±2.4 mm Hg (28.5%), 16.7±2.5 mm Hg (28.6%), and 16.9±2.4 mm Hg (27.8%), respectively at the end of the first, second, third, fourth, and fifth year follow-up. No drug-related serious adverse events were registered during the study.CONCLUSIONS: The present study demonstrated the long-term 24-hour efficacy of travoprost for the treatment of primary open-angle glaucoma.