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Visual field test
Visual field test

Visual field
Definition:
The visual field is the total area where objects can be seen in the peripheral vision while the eye is focused on a central point.
Alternative Names:
Perimetry; Tangent screen exam; Automated perimetry exam; Goldmann visual field exam; Humphrey visual field exam
How the test is performed:

Confrontation visual field exam: A quick and basic evaluation of the visual field done by an examiner sitting directly in front of you. With one eye covered, you are asked to look at the examiner's eye and tell when you can see the examiners hand.

Tangent screen exam: You will be asked to sit about 3 feet from a screen with a target in the center. You will be asked to stare at the central target and let the examiner know when you can see an object brought into your peripheral vision. The extent of your peripheral vision is mapped.

Automated perimetry: You sit in front of a concave dome and state at a central target within the dome. A computer-driven program flashes small lights at different locations within the dome's surface, and you press a button when you see the small lights in your peripheral vision. Your responses are compared to age-matched controls to determine the presence of defects within the visual field.
How to prepare for the test:
Adults:
No special preparation is necessary for these tests.

Children:
The physical and psychological preparation you can provide for this or any test or procedure depends on your child's age, interests, previous experiences, and level of trust. For specific information regarding how you can prepare your child, see the following topics as they correspond to your child's age:

How the test will feel:
There is no discomfort with this test. Some visual field tests take a long time and may be tiring.
Why the test is performed:
The test will detect any loss of peripheral vision and provide a map of that loss which will be helpful in diagnosing the cause of the loss.
Normal Values:
The peripheral vision is normal in extent.
What abnormal results mean:
Abnormal results may indicate diseases or central nervous system such as tumors that damage or compress the parts of the brain that deal with vision. Other diseases that may affect the visual field of the eye include diabetes, tumors, hyperthyroidism (a condition where the thyroid produces an excess of hormones), hypertension, diseases of the pituitary gland, and multiple sclerosis.

Additional conditions under which the test may be performed:

What the risks are:
The test has no risks.
Special considerations:
The type of visual field testing to be done will be discussed with you by your doctor.
Review Date: 12/2/2001
Reviewed By: Edward B. Feinberg, M.D., M.P.H., Department of Ophthalmology, Boston University School of Medicine, Boston, MA. Review provided by VeriMed Healthcare Network.

The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. A licensed physician should be consulted for diagnosis and treatment of any and all medical conditions. Call 911 for all medical emergencies. Links to other sites are provided for information only -- they do not constitute endorsements of those other sites. Copyright 2002 A.D.A.M., Inc. Any duplication or distribution of the information contained herein is strictly prohibited.
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