To compare the intraocular pressure (IOP)-lowering efficacy and safety of topical bimatoprost 0.03% with latanoprost 0.005%.

Multicenter, randomized, investigator-masked clinical trial.

After washout of glaucoma medications, ocular hypertension or glaucoma patients were randomly assigned to once-daily bimatoprost 0.03% (n = 133) or latanoprost 0.005% (n = 136) for 6 months. The primary outcome measure was mean change from baseline IOP (8 am, 12 pm, 4 pm). Secondary measures included mean IOP, ophthalmologic examination, adverse events, and the percentage of patients reaching specific target IOPs.

Mean change from baseline IOP was significantly greater for bimatoprost patients than for latanoprost patients at all measurements on each study visit; 1.5 mm Hg greater at 8 am (P < .001), 2.2 mm Hg greater at 12 pm (P < .001), and 1.2 mm Hg greater at 4 pm (P = .004) at month 6. At the end of the study, the percentage of patients achieving a ≥20% IOP decrease was 69% to 82% with bimatoprost and 50% to 62% with latanoprost (P ≤ .003). In addition, the distribution of patients achieving target pressures in each range (≤13 to ≤ 15 mm Hg, >15 to ≤ 18 mm Hg, and > 18 mm Hg) showed that bimatoprost produced lower target pressures compared with latanoprost at all times measured (P ≤ .026). Few patients were discontinued for adverse events (6 on bimatoprost; 5 on latanoprost). On ophthalmologic examination, conjunctival hyperemia (P < .001) and eyelash growth (P = .064) were more common in bimatoprost patients.

Bimatoprost is more effective than latanoprost in lowering IOP. Both drugs were well tolerated, with few discontinuations for adverse events.