Eye Diseases - Glaucoma

Glaucoma

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

Symptoms

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

Age: as people get older, the risk of glaucoma increases.
Race: African-Americans are about 3-4 times more likely to have glaucoma than Whites.
Family History: if a parent has glaucoma, his or her children have a 20% chance of having glaucoma. If a sibling has glaucoma, brothers and sisters have a 50% chance of having glaucoma.
Diabetes: people with diabetes have a 3 times higher risk of having glaucoma than people without diabetes.
Eye Injuries: injuries to the eye increase the risk of having glaucoma.
Corticosteroid Use: people who use corticosteroid drugs have a higher risk of having glaucoma.

Diagnosis

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.

Tonometer
Image from National Eye Institute
National Institutes of Health

Treatment

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.

Drugs that reduce the production of aqueous humor: beta-blockers, alpha-adrenergic agents, carbonic anhydrase inhibitors.
Drugs that increase the outflow of aqueous humor: prostaglandins, prostamides.
Surgery to improve the outflow of aqueous humor.
Implantation of a device to drain fluid in 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.