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Fact sheet Fact sheet

The aqueous humour


Aqueous humour

What is ‘humour’?

Humour (or humor, depending on where you live) is a traditional Latin word. It is used to describe some bodily secretions that are considered to affect a person’s health.

What are the chambers of the eye?

Your eye is divided into 3 chambers – the anterior chamber, the posterior chamber and the vitreous chamber. The vitreous chamber is the large chamber at the back of your eye, the anterior chamber is the space between your cornea and iris, while the posterior chamber is the space between your iris and the lens of your eye.

Both the anterior and posterior chambers are filled with aqueous humour.

What is the aqueous humour?

The aqueous humour is a thin, transparent fluid similar to plasma. It’s made up of 99.9% water ­­– the other 0.1% consists of sugars, vitamins, proteins and other nutrients. This fluid nourishes the cornea and the lens, and gives the eye its shape.

What does the aqueous humour do?

The aqueous humour plays an essential role in the health of your eye. As well as nourishing the cornea and the lens by supplying nutrition such as amino acids and glucose, the aqueous humour will:

  • Maintain intraocular pressure
  • Transport vitamin C in the front segment to act as an antioxidant agent
  • Provide inflation for expansion of the cornea. This increases protection against dust, wind, pollen grains and a number of pathogens.

How it works

Without becoming too technical, the aqueous humour is continuously produced by the ciliary body (located in the anterior chamber near the lens of the eye). To work as it should, the production must be balanced by drainage at an equal rate.

Even small variations in the production or outflow of the aqueous humour are significant, because they will have a large influence on your intraocular pressure.

When the intraocular pressure is increased, it can lead to glaucoma, a major cause of vision loss.


The aqueous humour fills the anterior and posterior chambers of the eye. It is one of the fundamental components in ensuring that the optical physics and health of your eye are properly maintained. Continuous production of aqueous humour is critical to the eye’s shape and size, and the quality of image it produces.

The information on this page is general in nature. All medical and surgical procedures have potential benefits and risks. Consult your ophthalmologist for specific medical advice.

Date last reviewed: 2020-08-10 | Date for next review: 2022-08-10

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