Mechanism of Action
Carbonic anhydrase inhibitors (CAIs) decrease aqueous humor production by inhibiting the activity of ciliary epithelial carbonic anhydrase. Systemic CAI therapy may further decrease aqueous humor formation because of the resultant renal metabolic acidosis, which may reduce the activity of the Na+,K+-ATPase in the ciliary epithelium. The enzyme carbonic anhydrase is present in many tissues, including corneal endothelium, iris, retinal pigment epithelium, red blood cells, epithelial cells lining the choroid plexus of the brain, and kidney. More than 90% of the ciliary epithelial enzyme activity must be inhibited to decrease aqueous production and lower IOP.
Excerpted from BCSC 2020-2021 series: Section 10 - Glaucoma. For more information and to purchase the entire series, please visit https://www.aao.org/bcsc.