Comparison of the Effects of Latanoprost versus Carteolol on the Diurnal Variation in the Intraocular Pressure in Patients with Normal Tension Glaucoma

Abstract

Abstract: : Purpose:To compare the ocular hypotensive effects of latanoprost given once a day against 2% carteolol given twice a day on the 24 hr diurnal variation in the intraocular pressure in patients with normal tension glaucoma (NTG). Methods:Patients with NTG initially underwent a pre-treatment measurement of the 24-hour diurnal variation in the intraocular pressure (measured eight times every three hours starting at 15:00 in the sitting position using the Goldmann applanation tonometer) and were then randomly assigned to the group treated with latanoprost once a day at 08:00 (latanoprost group) or the group treated with 2% carteolol twice a day at 08:00 and 20:00 (carteolol group). After three months or more of the monotherapy, the 24-hour diurnal variation in the intraocular pressure was again measured. The mean diurnal intraocular pressure (the mean of the intraocular pressure at all time points) and the intraocular pressure at each time point were compared in 20 eyes in 20 subjects in the latanoprost group versus 18 eyes in 18 subjects in the carteolol group. Results:The mean diurnal intraocular pressures (mmHg) in the latanoprost group were 15.2 ± 2.2 prior to treatment and 13.6 ± 1.5 after treatment (p < 0.001), while in the carteolol group the pressures were 15.4 ± 1.8 prior to treatment and 14.8 ± 1.7 after treatment (p = 0.11). The drug administration led to a significant decrease in the mean diurnal intraocular pressure in the latanoprost group, and the post-treatment mean diurnal intraocular pressure in the latanoprost group was significantly lower than in the carteolol group (p = 0.030).The intraocular pressures after treatment in the latanoprost group were significantly lower when measured at 06:00, 09:00, 12:00, 15:00, 18:00, and 21:00 (p < 0.028) and showed a trend towards a decrease at 03:00 and 24:00 (p < 0.078). The carteolol group showed a significant decrease at 12:00 and 18:00 (p < 0.011). The post-treatment intraocular pressures in the latanoprost group were significantly lower than in the carteolol group at 03:00, 06:00, 12:00, and 24:00 (p < 0.039). Conclusions:In patients with NTG, the ocular hypotensive effect was the greatest in the afternoon with carteolol but persists throughout the day with latanoprost. Latanoprost was more effective than carteolol in decreasing the intraocular pressure at late night/early morning and in the morning.

Keywords: intraocular pressure