Color Blind Tests
A person with color vision deficiency perceives colors differently than normal people do. In severe cases of deficiencies, a person might be diagnosed as color blind. People with mild color blindness may not be aware of the condition unless tested. Those with severe forms however can’t distinguish differences between colors that appear obvious to other people.
There are 3 main types of color blindness: complete color blindness, blue-yellow color blindness and Red-green color blindness
What are Color Blind Tests?
There are a variety of color blind tests available. Some may even be found online for self-evaluation. The most common is the Ishihara Color Test.
The Ishihara test is a color perception test for red-green color deficiencies. It consists of a series of Ishihara plates with numbers and/or forms of colored circles or dots. They are of different color than the background that is also a collection of circle or dots in different colors and sizes.
Those with normal color vision can see the numbers or forms, but those with red-green color blindness may have difficulty or might not see the numbers or forms at all.
Other Color Blind Tests
Farnsworth Lantern Test
FALANT or The Farnsworth Lantern Test is commonly used by the military, marines and aviation industry to identify whether a person is suitable to work on industries where accurate reading of light colors is required for safety purposes. It screens red-green color deficiencies.
The test consists of a pair of vertical lights with combinations of either yellow-white, green or red. The examinee is asked to identify the given 2 colors, with 9 pairs used during the test.
The Anomaloscope is an instrument that tests red-green color deficiencies. It’s a simple color match test that uses 2 different light sources—red and green light sources that has to be matched with a yellow light source.
The examinee looks through the eyepiece and sees a circle—lower half is a combination of green and red lights, and the upper half is a yellow light. The examinee is asked to match the brightness and colors of the lights. With the anomaloscope it is possible to detect the different types of red-green color deficiencies.
Quantitative Color Blind Tests or Arrangement Tests
The arrangement tests consist of colored plates or discs that need to be arranged in specific color orders. The most popular one is the Farnsworth D-15 arrangement test. It includes 15 colored plates to be arranged in a correct order. Other well known arrangement tests are Lanthony desaturated D-15 test, and Farnsworth-Munsell 100 hue test.
The Lanthony desaturated D-15 test is a more sensitive test than the Farnsworth D-15. It is similar to the Farnsworth D-15 but the plates or discs are less saturated. It can detect more subtle color deficiencies.
The Farnsworth-Munsell 100 hue test uses 100 different plates grouped in rows that have the same colors but different hues. They are arranged in order of hue.
People with color blindness will not be able to distinguish colors in certain lines and will arrange the colors in a different way compared to someone with normal color vision.