Investigation of IOP and Tolerability of Bimatoprost 0.01% and Tafluprost Unit Dose Preservative Free 15 Microgram/ml

* A prospective, randomized, investigator-masked, crossover comparison; * Ocular hypertension or glaucoma (XFG or POAG) patients and who consent to participate will be enrolled in this study * Patients will be scheduled for a screening visit IOP assessment (IOP measurements at 08:30, 12:30 and 16:30 (±1 hour). * Patients who are on therapy at the screening visit and who consent to participate will undergo a washout period for 4 weeks (depending on therapy) before the baseline visit; * Patient can under the washout period be given brinzolamide (Azopt) if needed, Azopt should then be discontinued 5 days before baseline visit; * After the screening visit (and after wash-outperiod for treated patients) patients will be scheduled to undergo a baseline visit IOP assessment (IOP measurements at 08:30, 12:30 and 16:30 (± 1 hour with a minimum of 3 hours between readings) and will then be randomized for Period 1 to receive either BIMMD drops once in the evening (20:30) or TUDPF drops once in the evening (20:30) for 3 month * After 3 month, patients will be switched for Period 2, to the opposite treatment (e.g. switched to either BIMMD or TUDPF) to be dosed in the evening; * After another 3 months they will undergo the final evaluation of IOP levels and of tolerability; * Intermediate safety visits may be scheduled at the discretion of the investigator.