Abstract: Topical and systemic carbonic anhydrase inhibitors (CAIs) are widely used in the treatment of glaucoma for reducing intraocular pressure. This part of the review describes the characteristics of systemic CAIs, their side effects and the ways to overcome them, as well as contraindications. The use of CAIs during pregnancy is considered. Particular attention is paid to the antioxidant activity of CAIs and the promising development of hybrid forms based on the existing CAIs as a part of a multipurpose glaucoma treatment strategy.