Glaucoma is a serious eye condition that often goes unnoticed until considerable vision loss occurs. The symptoms of the condition are usually so subtle in the earlier stages that you likely won’t know you have it.
With the help of an effective tool called a visual field test, glaucoma can be caught early, preventing substantial damage. Keep reading to learn more about what happens during a glaucoma visual field test.
What is Glaucoma?
Glaucoma is a group of eye diseases that damage the optic nerve, typically caused by fluid buildup in the front of the eye. In a healthy eye, fluid (aqueous humor) flows in and out steadily through the drainage angle, maintaining stable eye pressure.
However, if too much fluid is produced or drainage is blocked, pressure can increase and damage the optic nerve, which carries visual information to the brain. This damage is irreversible and can cause permanent vision loss.
Since glaucoma often has no early warning signs, regular eye exams with visual field tests are crucial for early detection and treatment.
Regular visual field tests can help your eye doctor catch and treat glaucoma early, slowing or preventing further vision loss.
What is a Glaucoma Visual Field Test?
A glaucoma visual field test is an essential evaluation that helps diagnose and monitor glaucoma. Your visual field is the entire area you can see when your eyes are focused on a central point, straight ahead.
A visual field test measures:
- How well you can see above, below, and on the sides when looking straight ahead
- How clear your vision is in various parts of your visual field without moving your eyes
The test is used to identify blind spots or areas of vision loss and where they are located. Specific patterns of visual field loss can point to glaucoma.
Often, glaucoma affects your peripheral vision first. However, you may lose your side vision without realizing it, so assessing this area of your vision is crucial.
A visual field test can detect changes in your vision early on before glaucoma causes extensive damage.
What Happens During a Visual Field Test?
A visual field test is a non-invasive and painless procedure. A glaucoma visual field test can be performed in different ways. The most common types are:
Automated Static Perimetry Test
An automatic static perimetry provides more detailed information for your eye doctor. It begins with you staring at the center of a bowl-shaped machine called a perimeter with one eye while your chin rests on a plate.
Your other eye will be covered.
An automatic static perimetry is called a static test because lights don’t move across the screen inside the machine. Instead, they blink with varying amounts of brightness at various locations.
This enables the machine to detect the dimmest light each eye can see at different locations. The eye being tested may have your lens prescription in front of it to ensure your vision is as clear as possible.
Your optometrist or ophthalmologist will then ask you to stare at a fixed target straight ahead and press a button any time you see a light blink in your peripheral vision. The machine will record what lights and which levels of dimness you can and can’t see.
Using this data, it will create a detailed map of your entire visual field, showing any blind spots.
Confrontation Visual Field Test
During this test, your eye doctor will sit facing you. They’ll ask you to stare at an object directly in front of you with one eye covered.
They may hold up their fingers or an object in different areas of your peripheral visual field. They’ll then ask you to identify what you can see while looking at a target straight ahead.
Have you had your annual eye exam yet? If not, schedule your appointment at Simone Eye Center in Warren or Macomb Township, MI, today to protect your eye and vision health.
