The study aims to prospectively prove the equivalence of the test product and the reference solution in lowering intraocular pressure in patients with open angle glaucoma and ocular hypertension. For this purpose the patients are randomized into two sequences of study drug administration in a crossover study with an adequate wash-out period.

Inclusion Criteria:

• Male or female patients of any race aged 18 years or older
• A clinical diagnosis of open angle glaucoma, pseudoexfoliation or pigment dispersion glaucoma, or ocular hypertension in one or both eyes
• IOP controllable on one drug treatment in the study eye in way that assures clinical stability of vision and the optic nerve throughout the study
• Baseline IOP between 18 and 32 mmHg in the study eye (in eyes not included in the study IOP must have been controllable on no pharmacologic treatment or on the study medicine only)
• Best corrected visual acuity of 20/200 or better in the study eye(s)
• Ability of subject to understand character and individual consequences of clinical trial
• Signed and dated informed consent of the subject must be available before start of any specific trial procedures
• Women with childbearing potential have to practicing a medically accepted contraception during trial and a negative pregnancy test (serum or urine) should be existent before trial. Reliable contraception are systemic contraceptives (oral, implant, injection) and diaphragm or condoms with spermicidal. Women that are sterile by surgery or for more than two years postmenopausal can be participate in the trial.

Exclusion Criteria:

• Chronic or recurrent inflammatory eye disease

• Ocular trauma within the past six months

• Current ocular infection, i.e. conjunctivitis or keratitis

• Any abnormality preventing reliable applanation tonometry

• Intraocular surgery or laser treatment within the past three months

• Inability to discontinue contact lens wear during the study

• Use of any systemic medication that would affect IOP with less than a

  1-month stable dosing regimen before the screening visit

• Pregnancy and lactation

• History of hypersensitivity to the investigational medicinal product or to any drug with similar chemical structure or to any excipient present in the pharmaceutical form of the investigational medicinal product

• Participation in other clinical trials during the present clinical trial or within the last four weeks

• Medical or psychological condition that would not permit completion of the trial or signing of informed consent

• Subject is allergic to sulfonamides

• Severe renal dysfunction or hyperchloraemic acidosis