Is Long Term Drift A Determining Factor In Primary Open Angle Glaucoma When Comparing Timolol To Latanoprost?

Objective: To compare the change over time of intra-ocular pressure (lOP) lowering effects of timolol maleate to latanoprost in 115 eyes. Methods: In a multi-center, retrospective analysis, 22.5 (45 eyes) patients with primary open-angle glaucoma (POAG) were treated with timolol and 35 (70 eyes) patients were treated with latanoprost. Patients with a baseline lOP of greater than 35mmHg or those with advanced glaucoma (cup to disc ratios of .9/.9 or greater and/or visual field loss within 10 degrees of fixation in one or more quadrants) were excluded. lOP measurements were obtained using Goldmann applanation tonometry. In each treatment group mean lOP readings were calculated. Distributions of slopes for lOP over time were compared between treatment groups. Results: Ofthe 115 eyes, 45 were treated with timolol and 70 were treated with latanoprost. The mean pre-treatment lOP was 20 +/- 4.85 for timolol and 22 +/-6.0, which decreased by 6 mmHg and 6 mmHg with timolol and latanoprost, respectively. Of 45 eyes treated with timolol 0/45 showed long-term drift, as defined by an increase in lOP of 5mmHg or more. In 70 eyes treated with latanoprost, long-term drift was demonstrated in 9/70 eyes. Conclusion: A diminished lOP lowering effect was not measured in patients using timolol compared to latanoprost over a 12-month period.