Aim To compare 24 h intraocular pressure (IOP) control obtained with preservative free (PF) tafluprost 0.0015% versus branded preservative containing latanoprost 0.005% administered as first choice monotherapy in patients with primary open angle glaucoma (POAG) or ocular hypertension (OHT).

Methods This prospective, observer-masked, crossover study included consecutive newly diagnosed patients with POAG or OHT, and baseline IOP between 24 and 33 mm Hg. Qualifying patients underwent baseline untreated 24 h IOP monitoring in habitual positions, with Goldmann tonometry at times 10:00, 14:00, 18:00 and 22:00, and Perkins supine tonometry at times 02:00 and 06:00. They were then randomised to either latanoprost or tafluprost, administered in the evening, for 3 months and then switched to the opposite therapy for another 3 months. 24 h monitoring was repeated at the end of each treatment period.

Results 38 patients completed the study. Mean untreated 24 h IOP (24.9 mm Hg) was significantly reduced with both prostaglandins (p<0.001). Tafluprost demonstrated similar mean 24 h efficacy compared with latanoprost (17.8 vs 17.7 mm Hg; p=0.417). Latanoprost demonstrated significantly better 24 h trough IOP (15.9 vs 16.3 mm Hg; p=0.041) whereas tafluprost provided significantly lower 24 h IOP fluctuation (3.2 vs 3.8 mm Hg; p=0.008). No significant difference existed between the two prostaglandins for any adverse event.

Conclusions PF tafluprost achieved similar 24 h IOP reduction to branded latanoprost. The current study highlights the importance of complete assessment of efficacy over 24 h.

Clinical trials registration NCT01162603.