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Glaucoma: Open-Angle

What is open-angle glaucoma?

Open-angle glaucoma is the more common type of glaucoma in the US. Glaucoma is an eye disease in which the optic nerve is damaged, usually by high pressure inside the eye. Eye pressure can get too high if there is a problem with the way fluid drains from your eye. Damage to the optic nerve can cause a loss of vision. People whose eye pressure is normal may also develop damage to the optic nerve.

Fluid produced in the eye normally flows out of the eye. When fluid flows out too slowly, eye pressure builds up. In open-angle glaucoma, the pressure increases slowly even though the drainage channel for the fluid is open. Without treatment, the eye pressure can damage the optic nerve and cause vision loss or blindness.

How does it occur?

Normally, the fluid in the front of the eye (called the aqueous humor) flows from where it is formed (the ciliary body) to the front of the eye. The fluid drains from the angle (where the iris and cornea come together). The tissue that drains fluid from the angle is called the trabecular meshwork. This fluid nourishes your eye and helps to keep its shape.

Open-angle glaucoma:

  • occurs most often after age 55 but sometimes happens in children
  • tends to run in families
  • is more common among black people than white people

One type of open-angle glaucoma is caused by injury to the eye. It may show up months or years after the injury. This type of glaucoma may not respond to some common glaucoma medicines, and surgery may be needed.

Occasionally, nerve damage happens without high pressure in the eye. In some cases of open angle glaucoma, it is not known what causes the fluid to drain out too slowly. Using your eyes for close work or in poor light does not increase your chances of having glaucoma.

Open-angle glaucoma gets worse gradually if not treated. Usually it affects both eyes but sometimes it can affect one eye more than the other. You may not notice early vision loss caused by glaucoma. Blind spots happen first in side vision. Later, central vision may be affected. Vision loss is permanent because the damaged nerve cells cannot return to normal. However, treatment can prevent more damage and loss of vision.

What are the symptoms?

Open-angle glaucoma often causes no symptoms in the early stages. In later stages, you will begin to notice a loss of vision. Side vision is usually affected first.

How is it diagnosed?

Diagnosis is usually made during a routine eye exam.

  • Your eye care provider can measure the pressure inside your eye with a quick and painless test.
  • Your provider checks the inside of your eye to see if there are changes in the optic nerve or the angle.
  • Your provider checks your side vision, usually with a special machine. This allows your side vision to be carefully compared over time.

How is it treated?

The goal of treatment is to prevent more damage to the optic nerve by reducing pressure in the eye. This may be done with eyedrops, pills, laser, or other surgery. Some of these treatments reduce the amount of fluid your eyes make. Other treatments make fluid drain from the eye faster.

For open-angle glaucoma, eyedrops may be the only treatment you need. Your eye care provider may want to check your eyes often to see if the medicine is working. The medicine may cause eye irritation, a rash, heart problems, or other side effects. Call your provider if you have any side effects. Be sure to let all your healthcare providers know what eyedrops you are using.

Laser treatments are common and often can lower pressure in the eyes. However, the procedure may need to be repeated.

You may need a surgical procedure called a trabeculectomy or another type of surgery called a tube shunt. In these procedures the eye surgeon creates a new pathway to drain fluid from the eye. These treatments are also called filtering surgery.

How can I help prevent open-angle glaucoma?

Open-angle glaucoma cannot be prevented. However, blindness can be prevented if you get treatment before pressure in the eye severely damages the optic nerve.

You may be able to help prevent open-angle glaucoma from becoming severe if you:

  • Have regular, complete eye exams, according to your provider's recommendation.
  • Learn about your family history. Open-angle glaucoma often runs in families. Let your family members know if you have been diagnosed with glaucoma so that they can be checked.
  • Use your eyedrops as directed. If it is hard for you to use them correctly, let your provider know. Other treatments may work better for you.
  • See your eye care provider right away if you notice any changes in your vision.
Reviewed for medical accuracy by faculty at the Wilmer Eye Institute at Johns Hopkins. Web site: http://www.hopkinsmedicine.org/wilmer/
Developed by RelayHealth.
Published by RelayHealth.
Last modified: 2011-07-20
Last reviewed: 2010-10-18
This content is reviewed periodically and is subject to change as new health information becomes available. The information is intended to inform and educate and is not a replacement for medical evaluation, advice, diagnosis or treatment by a healthcare professional.
© 2011 RelayHealth and/or its affiliates. All rights reserved.
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