How the Build Up of Aqueous Humor Can Damage the Optic Nerve
Medical illustration showing how the build up of aqueous humor can influence eye pressure

Illustration by Bob Morreale, provided courtesy of the American Health Assistance Foundation.


Most, but not all, forms of glaucoma are characterized by high intraocular pressure. Intraocular pressure is maintained at normal levels when some of the fluid produced by the eye is allowed to flow out. The fluid (aqueous humor) is produced by the ciliary body where it flows into the anterior chamber and then out through a spongy tissue at the front of the eye called the trabecular meshwork into a drainage canal. In open-angle glaucoma, fluid cannot flow effectively through the trabecular meshwork, and this causes an increase in intraocular pressure causing damage to the optic nerve and leading to vision loss.

Reviewed on 2/14/2008

 

 

Glossary of Terms

Aqueous Humor - watery fluid that nourishes the interior of the front of the eye.

Ciliary body - part of the eye that produces the aqueous humor.

Choroid - layer of the eye containing blood vessels that nourish the retina.

Cornea - the outer, transparent structure that covers the iris, pupil, and anterior chamber.

Fovea Centralis - the small depression near the center of the macula where vision is most acute.

Iris - the colored ring of tissue behind the cornea that regulates the amount of light entering the eye by adjusting the size of the pupil.

Lens - the transparent structure suspended behind the iris that helps to focus light on the retina.

Optic Nerve - the bundle of nerve fibers that carry visual messages from the retina to the brain.

Sclera - the tough outer coat that protects the entire eyeball.

Trabecular Meshwork - aqueous humor flows out of the eye through this spongy tissue located near the cornea.

Vitreous Humor - a clear gel which occupies the posterior compartment of the eye, located between the lens and the retina.

 

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