Purpose: To evaluate 24-hour intraocular pressure (IOP) and blood pressure (BP) with bimatoprost or latanoprost in patients with normal-tension glaucoma.
Design: Prospective, randomized, crossover, active-controlled, observer-masked study.
Methods: After a 6 week medicine-free period, we randomized patients to either latanoprost or bimatoprost for 8 weeks and then to the opposite medicine for 8 weeks. At baseline, and at the end of each treatment period, we evaluated IOP and BP at 08:00 and then every 2 hours over the 24-hour day. Diastolic ocular perfusion pressure (DOPP) was calculated from the above parameters.
Results: Forty completed patients had a 24-hour untreated baseline IOP of 15.5±2.3 mm Hg, and a DOPP of 59.2±6.1 mm Hg. Both treatments lowered IOP at each time point (P<0.006), and over the 24-hour curve (P<0.001, both medicines 13.1 mm Hg, 16% decrease). No difference existed between treatments in absolute IOP, at each time point, and over the 24-hour curve (P ≥0.26). Additionally, no differences were found between treated 24-hour systolic (P≥0.29) and diastolic BP (P≥0.12). The mean 24-hour DOPP for latanoprost was increased from baseline (3%, P=0.031) but not for bimatoprost (2%, P = 0.21). However, no difference in DOPP existed between treatments at any time point or over the 24 hour curve (P≥0.17). No difference was observed between treatments for any adverse event (P>0.05).
Conclusions: In patients with normal-tension glaucoma both bimatoprost and latanoprost reduce the 24-hour intraocular pressure from untreated baseline to a similar extent. Latanoprost is associated with slightly improved ocular diastolic perfusion pressure over 24 hours.