John C. Schwartz
Baylor University Medical Center, Dallas, Texas 77030
Glaucoma is a series of eye diseases characterized by increased intraocular pressure, optic nerve degeneration, and visual field defects [3, 4, 8]. It is one of the leading causes of blindness in the United States. The incidence of the disease increases with advancing age and ranges from 1 to 5% of adults over the age of 40. The disease is insidious in its origin and most patients are asymptomatic until late in the course of the illness. By the time the diagnosis of glaucoma is made, permanent visual loss often has already occurred.
The primary basis of glaucoma is an increase in intraocular pressure (greater than 20-24 Torr) leading to progressive deterioration of the optic nerve [3, 4,8]. The mechanism of the increased intraocular pressure is an obstruction to aqueous humor outflow: from the posterior chamber, from the anterior chamber through the trabecular meshwork on the way to the canal of Schlemm into the venous drainage system, or via drainage through uveal vessels and the sclera. While in theory an increase in aqueous humor production could lead to an increase in intraocular pressure, practically this rarely occurs. Initially the direct mechanical effect of the increased intraocular pressure on the optic nerve was thought to be the cause of the optic nerve damage. However, more recently
Diuretic Agents: Clinical Physiology and Pharmacology
Copyright © 1997 by Academic Press. All rights of reproduction in any form reserved.
the cause of the optic nerve deterioration has been felt to be pressure-mediated axonal degeneration of the optic nerve.
Was this article helpful?