Effect of latanoprost on diurnal variations of intraocular pressure in normal-tension glaucoma

OBJECTIVES: To study the effect of instillation of latanoprost on the diurnal variation in the intraocular pressure(IOP), blood pressure, and pulse rate in patients with normal-tension glaucoma(NTG). SUBJECTS AND METHODS: The diurnal variation in the IOP was determined in 23 eyes in 23 NTG patients after a washout period of 4 weeks or longer. The diurnal variation in IOP was then remeasured after latanoprost monotherapy of 8 weeks or longer. The IOP was measured by the Goldmann applanation tonometer at 10:00, 13:00, 16:00, 19:00, 22:00, 01:00, 03:00, 07:00, and 10:00 before and after treatment, and the IOP at each time point, mean diurnal IOP, maximum IOP, minimum IOP, and range of variation in IOP were compared before and after treatment. The blood pressure and pulse rate before and after treatment were also measured and compared. RESULTS: The IOP decreased significantly at all time points. The treatment caused significant decreases in the mean diurnal IOP, maximum IOP, minimum IOP, and range of variation in IOP. There were no differences in the blood pressure and pulse rate before and after treatment. CONCLUSIONS: Latanoprost significantly decreases the IOP throughout the day in NTG patients, and has no effects on the blood pressure and pulse rate. It is therefore useful in the treatment of NTG.