ABSTRACT
PURPOSE: To determine whether a patient who is non-responder to latanoprost after one month of use should continue using latanoprost or switch to either bimatoprost or travoprost. PATIENTS AND METHODS: Prospective randomized clinical trial. We recruited new patients who were felt to require intraocular pressure reduction. Patients who had≤20% intraocular pressure reduction after one month of latanoprost treatment were randomly assigned to another month of treatment with latanoprost or a switch to bimatoprost or travoprost for an additional month. RESULTS: Overall, 83 non-responders to latanoprost after one month of treatment were included in the study. Before latanoprost treatment, the mean intraocular pressure was 23.7±4.7mmHg. At randomization on latanoprost, mean intraocular pressure was 21.5±4.5mmHg. One month after the switch of medication, the mean reduction in intraocular pressure was not significantly different between the groups (P=0.148) and was -0.9mmHg, -2.10mmHg and -2.5mmHg, for latanoprost, bimatoprost and travoprost respectively. One month after randomization, 32 (38.5%) of the patients had become responders, with IOP reduction>20%. Of those patients, 9 (31%) were using latanoprost, 13 (41.9%) bimatoprost and 10 (43.5%) travoprost. The number of new responders was similar between the three groups (P=0.584). CONCLUSION: There is no added benefit of switching latanoprost to another topical prostaglandin for patients who are initially non-responders. Regression towards the mean and the Hawthorne effect are probably important factors explaining the additional IOP reduction obtained after randomization and explain the result of most switch studies.
