What is it?

Glaucoma refers to a group of disorders that all cause increased pressure within the eyeball. In a normal eye, a liquid called the aqueous humor is continuously produced and drained. In glaucoma, aqueous humor builds up and increases pressure within the eye. Such increased pressure can damage the optic nerve directly or restrict blood flow, thus damaging the optic nerve indirectly. This damage may lead to blind spots in the visual field. If left untreated, glaucoma can cause permanent blindness.

Circulation of Aqueous Humor

Image modified from National Eye Institute, National Institutes of Health


Glaucoma may cause:

  • Loss of peripheral vision
  • Sensitivity to light and glare
  • Problems with night vision
  • Blurred vision

Image modified from National Eye Institute, National Institutes of Health

Risk Factors


  • Tonometry: eyeball pressure is measured. Abnormally high eyeball pressure may suggest glaucoma.
  • Optic Nerve Examination: an eye doctor will examine the retina and check for damage.
  • Visual Field Examination: a patient's visual field (area in front) will be mapped to check for visual loss.

Image from National Eye Institute
National Institutes of Health


There is no cure for glaucoma and if the optic nerve is damaged, it cannot be fixed. The effects and progression of glaucoma can be controlled, however, by lowering the pressure within the eye.

Did you know?

  • Glaucoma affects 3-4 million people in the US and 50 million people worldwide.
  • Glaucoma is a leading cause of vision loss in the US.
  • Normal eye pressure ranges from 10-22 mm Hg.