What Is a Visual Field
field is the entire area (field of vision) that can be seen when the eyes are
focused on a single point. In addition to what can be seen straight ahead, the
visual field includes what can be seen above, below, and to either side of the
point the eyes are focused on. Vision is typically the sharpest in the middle
of the visual field.
field test is often given as part of an eye exam. Visual field testing helps
your doctor to determine where your side vision (peripheral vision) begins and
ends and how well you can see objects in your peripheral vision.
field can be tested in a few different ways, including the confrontational
visual field exam, tangent screen test, and automated perimetry exam (described
below). Your doctor may perform one or a combination of these tests to examine
your visual field.
results of these tests, your doctor will be able to determine if you are having
trouble seeing in certain areas of your visual field, as well as possible
causes for these difficulties.
What Happens During the
Confrontational Visual Field Exam?
confrontational visual field exam is a basic exam performed by your eye doctor.
They will sit or stand 3 to 4 feet in front of you. You will be instructed to
cover one of your eyes using an occluder, which looks like a large spoon.
will instruct you to stare straight ahead as they move their hand in and out of
your visual field. You will indicate when you are able to see the doctor’s
hand. This test will then be repeated on the other eye.
confrontational visual field exam only tests the outside of the visual field
and is not as accurate as some of the other visual field tests. However, this
test can help your doctor decide if further visual field testing is needed.
What Happens During a
Tangent Screen Exam?
screen exam (Goldmann field exam) can be conducted in your eye doctor’s office.
You will be seated about 3 feet away from a computer screen. This screen will
have a target in the center for you to focus on throughout the test.
will generate images on different areas of the screen. Without moving your
eyes, you will tell your doctor when you are able to see objects in your side
vision. Your doctor will be able to use the information collected to form a map
of your visual field. This will help them determine if there are certain areas
in your visual field that you are not able to see. The location of these areas
can help your doctor diagnose the cause of the visual field problems.
What Happens During an
Automated Perimetry Test?
automated perimetry test uses a computer program to test an individual’s visual
field. You will sit and look into a dome-shaped instrument. Your doctor will
instruct you to look at an object in the middle of the dome throughout the
be small flashes of light on the dome. When you see these flashes of light, you
will press a button. The computer program will provide your doctor with a map
of your visual field. Your doctor can then use this information to help
diagnose problems or order more vision tests.
What Are the Causes of
Visual Field Problems?
problems have a number of causes, including disorders that don’t originate in
the eye, but in the central nervous system or the part of the brain that deals
may use information from the visual field tests to diagnose:
nervous system disorders
may order further eye tests to diagnose a problem. If an eye problem is not
indicated as the cause of vision problems, your doctor may send you for a
physical examination and blood tests.