This study examines efficacy and tolerability of 3 different Latanoprost 0.005% eyedrops preparations, commercially available in Italy, in subjects affected by primary open angle glaucoma.

Prospective, randomized, single blinded study of the duration of 3 months, involving subjects affected by POAG or OH under therapy with different Latanoprost drugs (Galaxia, Iopize or Latanoprost Rathiopharm).

A total of 120 patients affected by POAG or OH newly diagnosed or already under topical therapy. will be recruited.

After a recruitment visit to assest eligibility of each subject, a "run-in" therapy composed of timolol 0,5% 2 drops per day will be prescribed for 4 weeks.

Then a baseline visit will be performed to evaluate IOP values and adverse effects in each subject. All subjects elegible for a therapy with a single dose of Latanoprost will be randomized into 3 arms.

After 4 weeks of therapy a second visit will be made to assest IOP changes and safety. Therapy will be continued for another 4 weeks, and after that, a final visit will be made.

Inclusion Criteria:

• Age ranged between 18 and 80
• Untreated IOP ranged between 21 and 30 mmHg
• IOP already treated with a single drug (monotherapy) ranged between 10 and 28 mmHg

Exclusion Criteria:

• History of adverse events or any controindication to drugs administred during sperimentation, i. e. Latanoprost and Timolol.
• Narrow or closed iridocorneal angle.
• History of acute angle-closure glaucoma.
• Previous laser trabeculoplasty within 3 months before screening.
• Severe visual field defects within 10° from fixation in at least one eye (at least 2 points with a p<0,5 in a pattern deviation map obtained from a reliable 24-2 Sita Standard SAP).
• History of refractive surgery or any keratoplasty procedure, corneal opacities or diseases that make not suitable applanation tonometry.
• Use of contact lenses.
• BCVA less than 20/200.
• Ocular inflammation/infection occurring within three months before screening.
• History of bradicardia, systemic hypotension, bundle branch or any atrio-ventricular block
• Asthma
• Women of childbearing potential who were not using adequate contraceptive methods or who were pregnant or nursing