Glaucoma is a disease that damages your eye’s optic nerve. It usually happens when fluid builds up in the front part of your eye. That extra fluid increases the pressure in your eye, damaging the optic nerve. Glaucoma is a leading cause of blindness for people over 60 years old. But blindness from glaucoma can often be prevented with early treatment.

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Types of Glaucoma

There are two major types of glaucoma.

Primary open-angle glacuoma This is the most common type of glaucoma. It happens gradually, where the eye does not drain fluid as well as it should (like a clogged drain). As a result, eye pressure builds and starts to damage the optic nerve. This type of glaucoma is painless and causes no vision changes at first. 

Angle-Closure glaucoma (also called "closed-angle glaucome" or "narrow-angle glaucoma") This type happens when someone’s iris is very close to the drainage angle in their eye. The iris can end up blocking the drainage angle. When the drainage angle gets completely blocked, eye pressure rises very quickly. This is called an acute attack. Angle-closure glaucoma can cause blindness if not treated right away.

Who is at Risk of Glaucoma? 

People who:

  • are over age 40
  • have family members with glaucoma
  • are of African or Hispanic heritage
  • have high eye pressure
  • are farsighted or nearsighted
  • have had an eye injury
  • have corneas that are thin in the center
  • have thinning of the optic nerve
  • have diabetes, migraines, poor blood circulation or other health problems affecting the whole body

Causes of Glaucoma 

Your eye constantly makes aqueous humor. As new aqueous flows into your eye, the same amount should drain out. The fluid drains out through an area called the drainage angle. This process keeps pressure in the eye (called intraocular pressure or IOP) stable. But if the drainage angle is not working properly, fluid builds up. Pressure inside the eye rises, damaging the optic nerve.

The optic nerve is made of more than a million tiny nerve fibers. It is like an electric cable made up of many small wires. As these nerve fibers die, you will develop blind spots in your vision. You may not notice these blind spots until most of your optic nerve fibers have died. If all of the fibers die, you will become blind.

Glaucoma Treatment

Glaucoma damage is permanent—it cannot be reversed. But medicine and surgery help to stop further damage. To treat glaucoma, your ophthalmologist may use one or more of the following treatments.


Glaucoma is usually controlled with eyedrop medicine. Used every day, these eye drops lower eye pressure. Some do this by reducing the amount of aqueous fluid the eye makes. Others reduce pressure by helping fluid flow better through the drainage angle. Glaucoma medications can help you keep your vision, but they may also produce side effects. Some drugs can cause problems when taken with other medications. It is important to give your doctor a list of every medicine you take regularly.

Be sure to talk with your ophthalmologist if you think you may have side effects from glaucoma medicine.

Never change or stop taking your glaucoma medications without talking to your ophthalmologist. 

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