Does the intraocular pressure-lowering effect of prostaglandin analogues continue over the long term?

The purpose of the study is to assess the changes in the long-term effects of prostaglandin analogues (PGAs) on intraocular pressure (IOP) reduction in patients with primary open-angle glaucoma (POAG). Data of POAG patients treated with latanoprost (0.005 %), travoprost (0.004 %), or bimatoprost (0.03 %) as the first line treatment for 5 years or more were retrospectively evaluated. Baseline ophthalmic assessment values were recorded together with the IOP at the 6th month, 1st year, and then annually. The 79 patients included 33 (41.8 %) men and 46 (58.2 %) women. There were 34 (43.0 %) patients using latanoprost (0.005 %), 23 (29.1 %) patients using bimatoprost (0.03 %), and 22 (27.8 %) patients using travoprost (0.004 %). There was no difference between the groups in terms of age, gender, or baseline IOP levels. IOP levels at the 6th month were significantly lower than baseline IOP levels in all groups (p < 0.01, Friedman test). The IOP decrease was maintained after the 6th month in all three group with no statistically significant difference compared to the 6th month IOP value (p > 0.05, Friedman test) and no statistically significant difference between the groups during follow-up (Kruskal-Wallis test, p > 0.05). IOP reductions with PGAs were adequate and stable in the 5-year follow-up period with no decrease in effectiveness over time.