Glaucoma is a disease caused by increased intraocular pressure (IOP) resulting either from an overproduction of fluid or from a malfunction of the eye's drainage structures. Left untreated, an elevated IOP causes irreversible damage to the optic nerve and retinal fibers, which leads to progressive and permanent vision loss. Early detection and treatment can slow or halt the progression of the disease.

Essentially, glaucoma occurs when the delicate balance between the production and drainage of aqueous is thrown off-balance. Common types of glaucoma are open angle and acute angle closure.

Open angle glaucoma results from aqueous fluid building up within the anterior chamber, causing IOP to become elevated. Left untreated, this may result in permanent damage of the optic nerve and retina.

Acute angle closure occurs in only about 10% of the glaucoma population. It is the result of an abnormality of the structures in the front of the eye, collectively called the angle. In most of these cases, the angle space between the iris and cornea is more narrow than normal, leaving a smaller channel for the aqueous to pass through. If the flow of aqueous becomes completely blocked, IOP rises sharply, causing a sudden angle closure attack.

Two less common forms of glaucoma are secondary glaucoma, which results from another disease or problem in the eye and congenital glaucoma, a rare type that is seen in infants and requires surgery.

The danger of glaucoma lies in its lack of symptoms. Generally, it takes a routine eye exam to detect the disease. However, acute angle closure may cause a sudden decrease in vision, extreme eye pain, headache, nausea or vomiting, or acute glare and light sensitivity.

Most patients with glaucoma require only medication to control the eye pressure. Sometimes more than one medication will be prescribed. Surgery is indicated when medical treatment fails to lower the pressure satisfactorily. The purpose of surgery is to allow fluid to drain from the eye more efficiently so IOP is not elevated.