Local therapy for glaucoma is known to induce a conjunctival inflammation. Because of this, trabeculectomy is more likely to fail. The investigators exchange the local therapy by systemic therapy using acetazolamide and measure the eye pressure using local therapy and systemic therapy using acetazolamide. The investigators suspect an elevated eye pressure using acetazolamide compared to local therapy. In summary acetazolamide could be a better choice in reference to conjunctival inflammation, but a worse choice in reference to controlling eye pressure.

Inclusion Criteria:

• Patients with uncontrolled intraocular eye pressure
• Patients with planed trabeculectomy in 3 to 4 weeks

Exclusion Criteria:

• Patients not meeting the inclusion criteria
• Patients with known intolerance to acetazolamide

All patients of the university hospital with a planed trabeculectomy in 3 to 4 weeks.