Health Encyclopedia

Color vision test

Definition

A color vision test checks your ability to distinguish between different colors.

Alternative Names

Eye test - color; Vision test - color; Ishihara color vision test

How the test is performed

You will sit in a comfortable position, and your health care provider will explain the test to you. You will be shown several symbols made of colored dot patterns. These dot patterns are on a background of randomly mixed colors.

You will be asked to identify the symbols, if possible.

As you cover one eye, the tester will hold the test plates 14 inches from your face and ask you to quickly identify the symbol found in each color scheme.

How to prepare for the test

If your child is to have this test performed, it may be helpful to explain how the test will feel, and even practice or demonstrate on a doll. Your child will feel less anxious about the test if you explain what will happen and why..

If you or your child normally wears glasses, wear them during the test.

With small children, distinguishing a red bottle cap from caps of a different color may be the test.

How the test will feel

The test is similar to a vision test.

Why the test is performed

By using these plates, your health care provider can detect, classify, and estimate the degree of defect in your color vision.

In some circumstances, color vision testing is used to evaluate the function of the optic nerve. The optic nerve is the main nerve connecting the eye to the brain. Changes in color vision can often be the first sign of a vision problem.

Normal Values

Normally, you will be able to distinguish all symbols.

What abnormal results mean

This test can determine the following color vision problems:

Protanopia (difficulty distinguishing between blue/green and red/green)
Deuteranopia (difficulty distinguishing between red/purple and green/purple)
Tritanopia (difficulty distinguishing between yellow/green and blue/green)
Achromatopsia (complete color blindness, seeing only shades of gray)

What the risks are

There are no risks associated with this test.

Review Date:2/22/2007
Reviewed By:Manju Subramanian, MD, Assistant Professor in Ophthalmology, Vitreoretinal Disease and Surgery, Boston University Eye Associates, Boston, MA. Review provided by VeriMed Healthcare Network.

ADAM Quality A.D.A.M., Inc. is accredited by URAC, also known as the American Accreditation HealthCare Commission (www.urac.org). URAC's accreditation program is the first of its kind, requiring compliance with 53 standards of quality and accountability, verified by independent audit. A.D.A.M. is among the first to achieve this important distinction for online health information and services. Learn more about A.D.A.M.'s editorial process. A.D.A.M. is also a founding member of Hi-Ethics (www.hiethics.com) and subscribes to the principles of the Health on the Net Foundation (www.hon.ch).

The Agency for Health Care Administration (Agency) and this website do not claim the information on, or referred to by, this site is error free. This site may include links to websites of other government agencies or private groups. Our Agency and this website do not control such sites and are not responsible for their content. Reference to or links to any other group, product, service, or information does not mean our Agency or this website approves of that group, product, service, or information.

Additionally, while health information provided through this website may be a valuable resource for the public, it is not designed to offer medical advice. Talk with your doctor about medical care questions you may have.