Glaucoma refers to a category of eye disorders often associated with a dangerous buildup of internal eye pressure (intraocular pressure or IOP), which can damage the eye's optic nerve that transmits visual information to the brain.

With untreated or uncontrolled glaucoma, you might eventually notice decreased ability to see at the edges of your vision (peripheral vision). Progressive eye damage could then lead to blindness.

Dr. Kung was instrumental in developing, and among the first to implant, the Glaucoma Mini-Express shunt in the United States. It is a little tube about the size of a grain of rice, which is inserted into the eye to relieve the intraocular pressure.

We also perform ECP (endocyclophotocoagulation), a laser procedure performed at the time of surgery to reduce the eye's ability to produce too much fluid, thereby lowering IOP.

Types of Glaucoma
The two major types of glaucoma are acute angle-closure glaucoma, with angle referring to the configuration of internal eye structures that drain fluids, and chronic or primary open-angle glaucoma (POAG). Other variations include congenital glaucoma, pigmentary glaucoma, and secondary glaucoma.

Primary open-angle glaucoma (POAG). Glaucoma gradually reduces your peripheral vision. But by the time you notice it, permanent damage has already occurred.

If your IOP remains high, the destruction can progress until tunnel vision develops, and you will be able to see only objects that are straight ahead.

Normal-tension glaucoma. Like POAG, normal-tension glaucoma (also termed normal-pressure glaucoma, low-tension glaucoma or low-pressure glaucoma) is an open-angle type of glaucoma that can cause visual field loss due to optic nerve damage. But in normal-tension glaucoma, the eye's IOP remains in the normal range.

Pain is unlikely and permanent damage to the eye's optic nerve may not be noticed until symptoms such as tunnel vision occur.

The cause of normal-tension glaucoma is not known. Researchers believe it is related to poor blood flow to the optic nerve. Normal-tension glaucoma is more common in those who are Japanese, are female and/or have a history of vascular disease.

Pigmentary glaucoma. This rare form of glaucoma is caused by pigment deposited from the iris that clogs the draining angles, preventing aqueous humor from leaving the eye. Over time, the inflammatory response to the blocked angle damages the drainage system.

You are unlikely to notice any symptoms with pigmentary glaucoma, though some pain and blurry vision may occur after exercise.

Angle-closure glaucoma. Angle-closure or narrow angle glaucoma produces sudden symptoms such as eye pain, headaches, halos around lights, dilated pupils, vision loss, red eyes, nausea and vomiting.

These signs may last for a few hours, then return again for another round. Each attack takes with it part of your field of vision.

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Treatments
Treatment can involve glaucoma surgery, lasers or medication, depending on the severity. Eye drops with medication aimed at lowering IOP usually are tried first to control glaucoma.

Glaucoma surgery procedures (whether laser or non-laser) are designed to accomplish one of two basic results: decrease the production of intraocular fluid or increase the outflow (drainage) of this same fluid. Occasionally, a procedure will accomplish both.

Currently the goal of glaucoma surgery and other glaucoma treatment is to reduce or stabilize intraocular pressure (IOP). When this goal is accomplished, damage to ocular structures -- especially the optic nerve -- may be prevented.

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