Aqueous Humor

Search Knowledgebase

Topic Contents

Aqueous Humor

Topic Overview

The shape of the front part of the eye is maintained by a fluid called aqueous humour.

  • Aqueous humour is made by the ciliary body. Strands from the ciliary body support the lens behind the coloured part of the eye (iris). See a picture of the iris and lens.
  • Aqueous humour flows into the front of the eye through the pupil.
  • Aqueous humour drains out of the eye through the trabecular meshwork. The trabecular meshwork is a spongy mass of tiny canals located in the drainage angle. The drainage angle is located between the iris and the clear covering of the eye (cornea), where the iris meets the white outer covering (sclera) of the eye.
  • Aqueous humour is returned into the bloodstream through a tiny channel (Schlemm's canal) located under the trabecular meshwork.

Aqueous humour is produced by and removed from the eye at a constant rate [about 1 tsp (5 mL) per day] to maintain a constant pressure in the front (anterior) chamber of the eye. While pressure in the eye varies throughout the day, the normal pressure within the eye is 10 mm Hg to 21 mm Hg.

Related Information

Credits

By Healthwise Staff
Primary Medical Reviewer Kathleen Romito, MD - Family Medicine
Primary Medical Reviewer Anne C. Poinier, MD - Internal Medicine
Specialist Medical Reviewer Christopher J. Rudnisky, MD, MPH, FRCSC - Ophthalmology
Last Revised August 2, 2010

This information does not replace the advice of a doctor. Healthwise, Incorporated disclaims any warranty or liability for your use of this information.