Rolle T, et al. – This study is conducted to compare Ocular Surface Disease (OSD) signs and symptoms of Tafluprost 0.0015% versus preservative free (PF) Timolol 0.1% eyedrops in ocular hypertensive (OH) and in primary open–angle glaucoma (POAG) patients. Compared to PF Timolol 0.1%, Tafluprost 0.0015% demonstrated similar safety concerning tear function and corneal status and a similar tolerability profile. Both therapy groups demonstrate some alterations in corneal microstructure but no side effects on tear function except for an increased tear instability in PF Timolol 0.1% group. Ophtalmologists ought to know that even PF formulations may lead to a mild ocular surface impairment.