Additive intraocular pressure-lowering effect of dorzolamide 1%/timolol 0.5% fixed combination on prostaglandin monotherapy in patients with normal tension glaucoma

Abstract

Takanori Mizoguchi1, Mineo Ozaki2, Harumi Wakiyama1,3, Nobuchika Ogino11Mizoguchi Eye Clinic, Sasebo, 2Ozaki Eye Clinic and Dept of Opthalmology, Faculty of Medicine, University of Miyazaki, Miyazaki, 3The Japanese Red Cross Nagasaki Genbaku Hospital, Nagasaki, JapanPurpose: To evaluate the intraocular pressure (IOP)-lowering effect of adding dorzolamide 1.0%/timolol 0.5% fixed combination (DTFC) to prostaglandin analogs (PGAs) as monotherapy in patients with normal tension glaucoma.Methods: A prospective, clinical, case-controlled study of patients with normal tension glaucoma. Patients had been on a once-daily night dose of prostaglandins (PGs) as monotherapy and then received DTFC added to PGs for 8 weeks. The IOP was measured at 9 am, week 0 (baseline), week 4, and week 8.Results: The baseline IOP of 40 patients who had previously been treated by prostaglandin monotherapy was 15.6 ± 2.0 mmHg at baseline. The IOPs at 4 and 8 weeks after adding DTFC to PGs were 13.5 ± 2.1 mmHg and 13.7 ± 2.2 mmHg, respectively. Significant decrease of the IOP was observed at each time point of measurement as compared with the baseline IOP before adding DTFC (P = 0.01). The percent IOP reduction from the baseline IOP at week 4 and week 8 was 13.5% ± 12.3% and 11.7% ± 13.1%, respectively. The percentage of patients who achieved 10% or more IOP reduction from the baseline IOP at week 8 was 62.5%. The baseline IOP was significantly correlated with the percent IOP reduction at week 8 (P = 0.03, r = 0.34).Conclusion: DTFC therapy added to PGAs as glaucoma monotherapy is effective in patients with normal tension glaucoma.Keywords: IOP-lowering effect, prostaglandin, dorzolamide 1%/timolol 0.5% fixed combination, fixed combination, normal tension glaucoma