Comparison of 24-hour Intraocular Pressure Control Between Timolol 0.5%, Brimonidine 0.2% and Latanoprost 0.005% in Patients with Primary Open Angle Glaucoma
Vol. 4 Issue 1 : 2016


Purpose: To compare the 24-hour intraocular pressure (IOP) control between timolol 0.5, brimonidine 0.2% %, and latanoprost 0.005% in patients with primary open angle glaucoma (POAG).
Patients and Methods : In this open label, crossover, self-controlled clinical trial, 24 patients with POAG on monotherapy who attended Ophthalmology Clinic, Hospital Universiti Kebangsaan Malaysia from December, 2001 to December, 2002 were treated with timolol 0.5%, brimonidine 0.2% and latanoprost 0.005% for 6 weeks consecutively. All patients underwent IOP measurements for three 24-hour diurnal tonometric curves after each 6 weeks period of treatment. The patients were admitted to the hospital, and IOP measurements were performed by one investigator. Measurements were taken at 8 am, 10 am, 2 pm, 6 pm, 10 pm, 2 am and 6 am with Goldmann applanation tonometer. Statistical analysis were done to test the significance between the mean IOP of the 3 groups.
Results : Mean 24-hour IOP for timolol, brimonidine and latanoprost group was 16.3 + 3.1 mm Hg, 15.2 + 2.8 mm Hg and 13.6 + 2.8 mm Hg respectively, and there was statistical significant difference in the mean IOPs between latanoprost and timolol treatment group (p=0.002). The mean IOP fluctuation (between the peak and trough) differences for timolol, brimonidine and latanoprost treatment group was 5.96 + 2.12 mm Hg, 5.42 + 2.57 mm Hg and 4.63 + 1.44 mm Hg respectively, and statistical significance (p=0.03) was only observed when timolol was compared with latanoprost treatment group. The peak IOP for timolol occurs at 2 pm, brimonidine at 2 am and latanoprost at 6 pm. The trough IOP for timolol occurs at 8 am, brimonidine at 10 pm and latanoprost at 10 pm.
Conclusions: All three medications have a smooth diurnal intraocular pressure. However, latanoprost treatment group has the lowest mean 24-hour intraocular pressure (13.6 + 2.81 mm Hg) with a smaller IOP fluctuation (4.6 + 1.4 mm Hg). The diurnal IOP curves observed in this study were different from the physiological curve indicating the drug therapy alters the diurnal curve and peak IOP occurs after office hours.