The Efficacy and Safety of Preservative-containing and Preservative-free Brimonidine-Timolol Fixed Combination in Normal Tension Glaucoma

Purpose: To analyze the efficacy and safety of preservative-containing and preservative-free 0.2% brimonidine tartrate and 0.5% timolol maleate fixed combination drug in normal tension glaucoma.Methods: Fifty-one patients (84 eyes) who were diagnosed with normal tension glaucoma and with preservative-containing or preservative-free brimonidine-timolol fixed combinations alone were analyzed retrospectively from January 2017 to February 2020. Intraocular pressure (IOP) was measured four times a day (9 a.m., 11 a.m., 2 p.m., and 4 p.m.) before and at 6 months after applying eye drops. We analyzed and compared the effect of lowering IOP and the occurrence of intra or extra-ocular adverse effects.Results: A significant mean IOP reduction was shown in both groups: -1.95 ± 2.50 mmHg (-12.26 ± 15.87%) in the preservative-containing group and -1.60 ± 2.06 mmHg (-10.54 ± 13.94%) in the preservative-free group at 6 months after eyedrop instillation. The IOP was lowest in both groups at 11 a.m. There were no significant differences between the two groups in lowering IOP. Serious adverse effects causing discontinuation of the eye drops were not observed.Conclusions: Both preservative-containing and preservative-free brimonidine-timolol fixed combinations are effective in lowering IOP in normal tension glaucoma patients and are considered to be effective as eye drops without serious adverse effects.