Glaucoma Medications Mechanism of Action

Glaucoma is a group of diseases affecting the optic nerve and involving loss of retinal ganglion cells. Glaucoma results in optic neuropathy. Elevated intraocular pressure (i.e., eye pressure) is a significant risk factor for developing glaucoma; however, there is no set threshold for intraocular pressure that causes glaucoma. One person may develop nerve damage at a relatively low pressure, while another person may have high eye pressures for years and yet never develop damage. Untreated glaucoma leads to permanent damage of the optic nerve and resultant visual field loss, which can progress to blindness.

Glaucoma is the second leading cause of blindness in the United States and is the leading cause of blindess in African-Americans. Approximately 2.3 million people in the United States have glaucoma with 66.8 million worldwide.

Glaucoma is treated with medications and with surgery. We are currently working on a book directed for patients and non-ophthalmologists. Please return to read the book as chapters are published.

The table below lists the general classes of glaucoma medications and their mechanism of action.

Medication Class	Aqueous Production	Trabecular Outflow	Uveoscleral Outflow
cholinergic agonists	no affect	increase	decrease
nonselective adrenergic agonists	slight Decrease	increase	minor increase
α2-adrenergic agonists	decrease	no affect	minor increase with brimonidine (Alphagan®)
β-adrenergic antagonists	decrease	no affect	no affect
carbonic anydrase inhibitors	decrease	no affect	no affect
prostaglandin analogues	no affect	no affect	increase

Reference

Alward, Wallace L.M. Glaucoma The Requisites in Ophthalmology. Mosby. 2000.