A comparative study of timolol plus either brimonidine (0.2%) or dorzolamide (2%) or latanoprost (0.005%) dual therapy in suboptimal responders to timolol (0.5%) monotherapy among patients of open-angle glaucoma, ocular hypertension and normal-tension glaucoma

ABSTRACT

Background: Studies comparing the efficacy and tolerability of the three fixed combinations of timolol with its monotherapy are not readily available. In this background, the current prospective observational study was planned. Aim and Objective: To evaluate and compare the intraocular pressure (IOP) reduction, change in visual field, and cup-disc ratio in glaucoma patients receiving timolol monotherapy vis-a-vis timolol based dual therapies among timolol sub-optimal responders. Materials and Methods: After obtaining written informed consent and fulfilling the inclusion-exclusion criteria, fifty consecutive newly diagnosed cases of glaucoma or ocular hypertension with risk factors were recruited in the study. They received timolol eye drop up to 4th week. Participants not responding to timolol monotherapy optimally received either timolol plus brimonidine or timolol plus dorzolamide or timolol plus latanoprost for another 12 weeks. Participants responding optimally (at least 30% reduction of baseline) were continued with timolol monotherapy. Besides IOP changes, effects on visual field, visual acuity, cup disc ratio, safety, tolerability, and rate of persistency to therapy were studied. Results: Fifteen participants (30%) achieved target IOP reduction at 4 weeks of timolol monotherapy. All four treatment groups achieved significant IOP reduction (P < 0.001) from baseline to 16th week. Participants receiving timolol followed by timolol plus latanoprost had shown the highest IOP reduction at 16th week both from baseline and 4th week value (ANOVA test, P = 0.027, P = 0.000 respectively). No change in visual field or visual acuity or cup disc ratio was noticed. Adverse drug reactions observed were mild and mostly self limiting. Conclusion: Timolol and latanoprost combination might be a better choice in sub-optimal responders to timolol whereas it is wise to continue timolol monotherapy in optimally responders.