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Intraocular pressure and glaucoma

Intraocular pressure (IOP) is the pressure caused by the fluid inside the eye that helps maintain the shape of the eye. The level of pressure inside the eyes depends on:

  • How much fluid is produced inside the eye.
  • Whether fluid can travel normally through the eye.
  • How well the fluid is removed from the eye.

The pressure within the eyes varies during the day. Normally, the pressure inside the eye ranges from 10 millimeters of mercury (mm Hg) to 21 mm Hg.

  • Intraocular pressure can vary from person to person.
  • Not all people with open-angle glaucoma (OAG) have increased pressure inside the eye. As many as 15% to 40% of cases of OAG may occur without increased pressure inside the eye.1

Citations

  1. American Academy of Ophthalmology (2003). Primary Open-Angle Glaucoma, Limited Revision (Preferred Practice Pattern). San Francisco: American Academy of Ophthalmology.

Author Robin Parks, MS
Editor Kathe Gallagher, MSW
Associate Editor Michele Cronen
Associate Editor Pat Truman
Primary Medical Reviewer Adam Husney, MD
- Family Medicine
Primary Medical Reviewer Kathleen Romito, MD
- Family Medicine
Specialist Medical Reviewer Carol L. Karp, MD
- Ophthalmology
Last Updated July 7, 2006

WebMD Medical Reference from Healthwise

Last Updated: July 07, 2006
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