Abstract

The objective of this study was to compare the effect on intraocular pressure (IOP) of latanoprost 0.005% once daily with timolol 0.5% twice daily in patients with open angle glaucoma or ocular hypertension. The study was designed as a single-centre, randomised, double-masked parallel-group comparison of latanoprost with timolol after 12 weeks of treatment. 60 patients with open angle glaucoma or ocular hypertension with IOP of at least 22 mm Hg were included. Administration of previous ocular hypotensive medication necessitated a wash-out period of 5 to 21 days before the start of the study treatment. The patients were randomised to treatment with latanoprost 0.005% once daily or timolol 0.5% twice daily. Mean diurnal IOP was measured at baseline and after 6 and 12 weeks of treatment. After 6 weeks of treatment, the diurnal IOP reduction (mean± standard error of the mean [SEM]) in the latanoprost group was 12.1±1.1 mm Hg (41%;p<0.001; analysis of covariance [ANCOVA]) and 8.7 ± 1.1 mm Hg (30%; p < 0.001; ANCOVA) in the timolol group. The difference of 3.4 ± 1.6 mm Hg was statistically significant in favour of latanoprost (p = 0.034; ANCOVA). A 30% reduction or more in mean diurnal IOP was achieved by 71 % of patients in the latanoprost group and by 34% of patients in the timolol group. After 12 weeks of treatment, the diurnal IOP reduction (mean± SEM) in the latanoprost group was 11.1±1.2 mm Hg (39%; p < 0.001; ANCOVA) and 9.1 ± 1.1 mm Hg (32%; p < 0.001; ANCOVA) in the timolol group. Most side effects observed were mild and transient and no serious adverse events were reported. Latanoprost 0.005% administered once daily in the evening was at least as effective as timolol 0.5% twice daily in reducing the mean diurnal IOP after 6 and 12 weeks of treatment. Both medications were well tolerated during the study period.