Measurement of aqueous humor flow.

Aqueous humor flow, one of the primary determinants of intraocular pressure, has been measured non-invasively in the human eye since the early 1950s. Other than sleep, which decreases flow rate to approximately half of what it is during alert wakefulness, few conditions affect flow rate. Three classes of medication can suppress flow and have been used therapeutically, beta-adrenergic antagonists, alpha(2)-adrenergic agonists, and carbonic anhydrase inhibitors. Studies of the production and circulation of aqueous humor have provided a basis for understanding the fundamental dynamics of the eye as well as understanding treatments for glaucoma.