Library · Physiology
Aqueous humor
Make it clearer
Aqueous humor is the clear fluid that fills the front of the eye, the part that lies in front of the lens, the eye's internal focusing element. It does not just sit still in there: it is made around the clock by the epithelium of the ciliary body, a structure that encircles the lens behind the iris.
This fluid has a delivery job. The cornea, the clear window at the front, and the lens have no blood vessels. Aqueous humor brings them nutrients and oxygen.
Then it leaves. It passes through the pupil into the anterior chamber, the space between the cornea and the iris, and exits at the angle of the eye through the trabecular meshwork, a kind of strainer, and the canal of Schlemm, which returns it to the veins.
Think of a sink with the faucet and the drain open at the same rate. What is secreted and what is reabsorbed balance out, and that balance is what regulates the pressure of the fluid inside the eye, which is called intraocular pressure.
In brief
Aqueous humor is the clear fluid the ciliary body epithelium secretes nonstop, filling the chambers at the front of the eye.
It feeds the cornea and the lens, which have no blood vessels, then exits through the pupil into the anterior chamber and drains through the trabecular meshwork and canal of Schlemm.
The balance between what is secreted and what is reabsorbed regulates the pressure of the fluid inside the eye.
A sink with the faucet and the drain open at the same rate.
Sources (2)
- National Center for Biotechnology Information, StatPearls PublishingPhysiology, Aqueous Humor Circulation, StatPearlsPublished
- National Center for Biotechnology Information, StatPearls PublishingAnatomy, Head and Neck, Eye, StatPearlsPublished
This page explains the topic in general terms; it does not tell anyone what treatment to follow.
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