What is Glaucoma?

Glaucoma is an eye disease that affects the optic nerve. Your optic nerve carries the images you see to the brain. If not diagnosed and treated, glaucoma can cause a gradual loss of vision. It develops slowly and sometimes goes unnoticed for many years.


As may be seen with glaucoma

normal vision photo     vision with glaucoma photo

The most common form of optic nerve damage is open-angle glaucoma. Affecting three million Americans, this type of glaucoma happens when the eye's drainage canals become clogged over time.  The inner eye pressure (also called intraocular pressure or IOP) rises because the correct amount of fluid cannot drain from the eye.  The clogging problem occurs inside the drainage canals, like the clogging that can occur inside the pipe below the drain in a sink.  Most people have no symptoms and no early warning signs. It is often diagnosed during a regular eye examination.

drainage problem in the eye photo

About one-third of people diagnosed with glaucoma have low (normal) tension glaucoma in which the IOP is normal. It is diagnosed by detection of optic nerve damage and measurement of peripheral vision loss.  Several medical factors, including low blood pressure, contribute to it.

In angle-closure glaucoma, the fluid at the front of the eye cannot leave the eye. Eye pressure rises when the drainage canals are blocked by the iris. The iris and cornea are not as wide and open as they should be. The outer edge of the iris bunches up over the drainage canals and can cause marked eye pain if occurs rapidly. 

An infant whose eye defect slows the normal drainage of fluid has congenital glaucoma. The baby may have large eyes, cloudy eyes, tear excessively or be sensitive to light.

Secondary glaucoma can arise from advanced cataracts, eye surgery, eye injuries, certain eye tumors, eye inflammation, corticosteroid use, diabetes, or other systemic diseases. 

Any form of glaucoma should be addressed quickly by an eye care professional. While it is a serious and chronic condition, glaucoma can be successfully treated and managed if detected early.


The Vanderbilt Eye Institute offers the most advanced treatment options for all types of glaucoma. Staffed by fellowship-trained specialists, we offer many options to halt its progress, including special glaucoma eye drops and laser surgery and outpatient surgery.

A trabeculectomy is done as an outpatient surgery with a local anesthetic.  A small flap is made in the sclera (the white part of the eye). A filtration bleb, or reservoir is created under the conjunctiva, the thin, clear coating covering the sclera. The aqueous humor inside the eye can now drain through the flap and collect in the bleb, where it is then absorbed into the circulation around the eye.  This reduces the pressure inside the eye.

A Glaucoma Implant is a tiny plate with a tube attached, which is surgically implanted in the eye. It creates a new drain through which aqueous fluid can drain away and be reabsorbed into the circulation. This improved drainage system decreases the pressure in the eye and helps to prevent further pressure damage.


The Vanderbilt Eye Institute offers diagnosis and treatment for a wide range of conditions in an exceptional medical environment, with physician specialists treating all ocular problems. Full-time Ph.D. scientists work closely with physician researchers to conduct cutting-edge vision research directly related to patient care.

Whatever brings you to Vanderbilt Eye Institute, you will find a team of dedicated professionals working together to provide stellar, streamlined eye care.

Photographs courtesy National Eye Institute
Illustration copyright Jupiter Images