Comparison of additional intraocular pressure-lowering effects of latanoprost vs brimonidine in primary open-angle glaucoma patients with intraocular pressure uncontrolled by timolol dorzolamide-combination

Purpose To compare the additive intraocular pressure (IOP)-lowering effects of latanoprost 0.005% and brimonidine 0.2% in primary open-angle glaucoma (POAG) patients uncontrolled on fixed combination of timolol 0.5% and dorzolamide 2% (TDC) alone. Methods In all, 80 eyes of 80 POAG patients with IOP inadequately controlled by TDC were randomly assigned to receive either latanoprost 0.005% or brimonidine 0.2%. IOP measurements were recorded at 1000 ( peak effect) and 1600 ( trough effect) on day 0 ( baseline) and at 1 and 3 months. At each stage and time point, the mean IOP reductions from baseline were evaluated for both groups, and success rates ( minimum 15% reduction) were determined. Results At baseline, the mean peak/trough IOPs with TDC were 20.2/21.6 and 19.9/ 21.4 mmHg in latanoprost and brimonidine groups, respectively. Latanoprost + TDC reduced the mean peak/trough IOP by 4.4/3.4 and 5.2/3.5 mmHg at 1 and 3 months. The corresponding values for brimonidine + TDC were 3.9/2.9 and 4.6/2.9 mmHg. Each of these results represented a significant reduction from baseline ( P<0.001 for all); however, the groups' peak/trough reductions from baseline did not differ at any time point (P>0.05 for all). With the latanoprost + TDC combination, the peak/trough success rates at 1 and 3 months were 76.3%/ 42.1% and 77.1%/ 40%. The corresponding values with the brimonidine + TDC combination were 71.8%/ 41% and 77.7%/ 41.7%. There were no significant differences in the groups' success rates at any time point (P>0.05 for all). Conclusion Addition of latanoprost 0.005% or brimonidine 0.2% to TDC reduces peak/trough IOPs significantly and the effects of these combinations are comparable.