• Main objective is to compare the ability of Latanoprost 0.005% preservative-added ophthalmic solution versus Tafluprost 0.0015% preservative-free ophthalmic solution, both given once a day at the evening, in reducing 24-hour intraocular pressure (IOP) in patients with primary open angle glaucoma (POAG) and/or ocular hypertension (OHT) at first diagnosis. First efficacy variable will be the difference between mean nocturnal IOP values after three months of treatment: nocturnal IOP is defined as the mean value between 2AM and 6AM measurements.

• Secondary objectives will be the comparison between Latanoprost 0.005% and Tafluprost 0.0015% ophthalmic solution about:

  • Mean 24-hour IOP values after three months of treatment
  • IOP values at these time-points: 10AM (± 1 hour), 2PM (± 1 hour), 6PM (± 1 hour), 10PM (± 1 hour), 2AM (± 1 hour) and 6AM (± 1 hour) after three months of treatment

Inclusion Criteria:

• Male and female patients > 45 years
• Damage of the optic nerve and alterations of the visual field in case of POAG, no defects at the optic nerve and at the visual field in case of OHT
• Untreated IOP > 24 mm Hg but < 32 mm Hg in at least one eye at baseline (10AM) and central corneal thickness between 500 and 600 μm
• Negative pregnancy test (fertile women). Fertile women attending the study must express clear will to avoid pregnancy during all the study period and in the next three months
• Informed consent before starting the study

Exclusion Criteria:

• Secondary glaucoma (Sturge-Weber syndrome, Neurofibromatosis I, neovascular glaucoma, steroid glaucoma, etc)
• Anterior segment anomalies (cataract, irido-corneal disgenesy, congenital ectropion uvae, etc)
• Past ocular surgery, except cataract surgery in the previous 6 months
• Corneal abnormalities that can influence IOP measurements (corneal oedema)
• Positive pregnancy test or breast-feeding woman. No will to avoid pregnancy during all the study period and in the next three months