What are glaucoma tests?

Glaucoma tests

 Glaucoma tests are a group of tests that diagnose glaucoma, an eye disease that can cause vision loss and blindness. It occurs when fluid accumulates in the anterior part of the eye. This causes pressure in the eye to increase (eye pressure). Increased ocular pressure can cause damage to the optic nerve, which sends information from the eye to the brain. Damage to the optic nerve can cause severe vision problems.

There are several types of glaucoma. The main types are:
  • Open-angle glaucoma: Also called primary open-angle glaucoma. It is the most common type of glaucoma. It occurs when the eye fluid does not come out well through its drainage channels, accumulating like water in a blocked sink. This causes the eye pressure to increase. Open-angle glaucoma progresses slowly for months or years. At first, most people have no symptoms or changes in vision. Open-angle glaucoma usually affects both eyes at the same time
  • Closed-angle glaucoma: Also called angle closure glaucoma. It is not common in the United States. It usually affects one eye at a time. In this type of glaucoma, the drainage channels of the eyes are covered, as when placing a plug on a drain. Closed-angle glaucoma can be acute or chronic
  • Acute angle-closure glaucoma: Causes a rapid increase in eye pressure. It is a medical emergency. People with acute angle-closure glaucoma can lose their sight in a matter of             hours if they do not receive treatment immediately
  •  Chronic angle-closure glaucoma: Progress slowly. In many cases, it does not show                     symptoms until serious damage has occurred

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What are they used for?

Glaucoma tests are used to diagnose glaucoma. If glaucoma is diagnosed early, steps can be taken to prevent vision loss.

Why do I need glaucoma tests?

If you have open-angle glaucoma, you may not have any symptoms until the disease is severe. Therefore, if you have certain risk factors, it is important that you do tests. Your risk may be higher if you have a family history of glaucoma or if:
  • Is older than 60 years: Glaucoma is much more common in older people
  • Is of Hispanic descent and is older than 60 years: Hispanics in this age group have a higher risk of glaucoma than other older adults of European descent
  • African-American: Glaucoma is the leading cause of blindness in African-Americans
  • It's Asian: People of Asian descent have a higher risk of having angle-closure glaucoma
Closed-angle glaucoma can cause sudden and severe symptoms. If it is not treated as soon as possible, it can cause blindness. Symptoms include:
  • Sudden blurred vision
  • Intense eye pain
  • Redness of the eyes
  • Halos of colors around the lights
  • Nausea and vomiting
If you can see that symptoms please seek medical help as soon as possible


What happens during a glaucoma test?

Glaucoma is usually diagnosed with a group of tests called a complete eye exam. Usually, an ophthalmologist does these tests. An ophthalmologist is a doctor who specializes in eye health and the treatment and prevention of eye diseases.

A complete eye exam includes:
  • Tonometry: In tonometry, you sit in a chair next to a special microscope called a slit lamp. An ophthalmologist or other health professional put drops in your eyes to numb them. Then you rest your chin and forehead on the slit lamp and the health professional uses a device called a tonometer to measure the pressure in the eye. You feel a little puff of air, but it does not hurt
  • Pachymetry: As in tonometry, first drops are placed to numb the eye. Then the health professional uses a small device called a pachymeter that measures the thickness of the cornea. The cornea is the outer layer of the eye that covers the iris (the colored part of the eye) and the pupil. A thin cornea may increase the risk of glaucoma
  • Perimetry: Also known as a visual field test, it measures peripheral or lateral vision. During the perimetry, you are asked to look directly at a screen. A light or image appears on one side of the screen. Always looking forward, you notify the health professional every time you see this light or image
  • An eye exam with pupil dilation: In this test, the health professional puts drops in the eyes that widen (dilate) the pupils. Then use a device that has a light and a magnifying lens to see if there is damage to the optic nerve
  • Gonioscopy: In this test, the health professional puts drops in the eyes to numb them and dilate the pupils. Then place a special contact lens in the eye. The lens has a mirror that allows you to see the inside of the eye from different directions. You can show if the angle between the iris and the cornea is too wide (a possible sign of open-angle glaucoma) or too narrow (a possible sign of closed-angle glaucoma)

Should I do something to prepare for glaucoma tests?

While your pupils are dilated, you may have blurred vision and be more sensitive to light. These effects can last several hours and vary in severity. To protect the eyes from bright light, wear sunglasses for after the appointment. Also ask someone to accompany you when you go home, as you may not be able to see well enough to drive safely.


Do these tests have any risk?

Glaucoma tests do not have any risk. Some are a little uncomfortable. In addition, dilation can cause blurred vision for a short time.

What do the results mean?

Your ophthalmologist will analyze the results of all your tests to determine if you have glaucoma. If you determine that you have glaucoma, I may recommend one or more of the following treatments:
  • Medications to lower eye pressure or cause the eye to produce less fluid. Some medications are eye drops and other pills
  • Implantation of a drainage tube, another type of surgery. In this procedure, a flexible plastic tube is placed in the eye to drain excess fluid
  • Laser surgery to remove excess fluid from the eye. An ophthalmologist usually does the laser procedure in the office or in an outpatient surgery clinic. After laser surgery, you may need to continue taking glaucoma medications
If you have been diagnosed with glaucoma, the ophthalmologist will probably monitor your vision regularly.

Is there anything else you need to know about glaucoma tests?

Although glaucoma treatments do not cure the disease or restore lost vision, they can prevent further loss of vision. If diagnosed and treated early, most people with glaucoma do not suffer from significant vision loss.