Carbonic Anhydrase Inhibitors: Systemic Use
Carbonic anhydrase inhibitors (CAIs) can be useful in the treatment of all the glaucomas by virtue of their ability to reduce aqueous secretion and thus lower intraocular pressure (IOP) 1 regardless of the nature or extent of obstruction to outflow. Their mechanism of action appears to be the inhibition of CA isoenzymes that result in decreased bicarbonate ion secretion into the posterior chamber by the nonpigmented ciliary epithelium. 2 These enzymes are among the fastest known enzymes, and they catalyze the conversion of carbon dioxide and water into bicarbonate and hydrogen ions. Bicarbonate ions are actively secreted into the aqueous humor, resulting in a passive diffusion of water. Therefore, inhibition of bicarbonate formation decreases aqueous formation.
