[Reading Time : 5 min | Date : 23, February 2023 | Author : Omar Setty ]
A person with color vision deficiency can see colors differently than normal people do. In severe cases of these deficiencies, a person may be diagnosed with the color blind disease.
People who are facing mild color blindness may not be aware of the condition till they get tested. Those with severe forms however can’t distinguish differences between colors that appear obvious to other people.
We live in a color-coded world. Our global community increasingly relies on color to communicate. Yet 8% to 10% of all men and .5% of all women are color-blind. In a classroom of 20 children, at least one will likely have a problem discerning color.
There are a variety of color blind tests available to find out whether you are color vision deficient or not.
Three main types of color blindness are there :
complete color blindness
blue-yellow colorblind
Red-green colorblind.
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 colorblind. It consists of a series of Ishihara plates with numbers and/or forms of colored circles or dots.
They are of a different color than the background which is also a collection of circles 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.
Ishihara Test to detect Red Green Colorblind
The Ishihara test is one of the most common color-blind tests worldwide. Ishihara test mainly detects red-green colorblind.
The test consists of 38 Ishihara plates which are colored plates that contain dots of different sizes and colors. These dots are arranged in specific patterns to form numbers or figures that can be seen by people with normal color vision while those with color deficiency won’t be able to see all or parts of these colored plates.
Some of the Ishihara plates are visible only to those with color vision deficiency and there are invisible to those with normal color vision.
A typical Ishihara test has 36 colored plates but there are also tests with 10, 14 or 24 plates.
Types of colored plates in the Ishihara test
Demonstration plate: This is the first plate and is called the Demonstration plate. It typically has the number "12” but also can be the number “ 16”. This plate is seen by all individuals whether normal or color vision deficient. This plate is only for demonstration purposes and is usually not considered in making a score for screening purposes.
Transformation plates: People with normal color vision should see different figures from people with color vision defects.
Vanishing plates: Figures in these plates can be seen only by people with normal color vision.
Hidden digit plates: Figures in these plates can be seen only by people with color vision defects.
Diagnostic plates: Figures in these plates can be seen helping to detect the severity intended to determine the type of color vision defect protanopia (red deficiency) or deuteranopia (green deficiency) and the severity of it.
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 colorblind. It consists of a series of Ishihara plates with numbers and/or forms of colored circles or dots. They are of a different color than the background which is also a collection of circles 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 in industries where the 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.
Anomaloscope
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 have to be matched with a yellow light source.
The examinee looks through the eyepiece and sees a circle—the 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 the 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 differently compared to someone with normal color vision.
Neitz Test of Color Vision
The test for red/green color blindness, below, is called the Neitz Test of Color Vision. It is a revolutionary new approach to testing for color blindness, created by an RPB grantee.
It can be used with people of any age, including very young children. This online version of the test is meant only to indicate whether or not someone might have a color vision deficiency, based on two example items from the Neitz test.
Accurate testing must be done with the actual printed Neitz test, which is precisely calibrated. Only an eye care specialist trained in testing for color blindness can provide a thorough evaluation.
INSTRUCTIONS FOR TAKING THE SAMPLE TEST
This is a color vision test. There are two large gray circles. Below each large circle is an answer row indicating the possible shapes that you might see formed by colored dots.
You might see a circle, a triangle, a square, or a diamond. Try to find a colored shape in each of the two large gray circles. If you see more than one shape in a circle, choose the shape that has a color most different from gray as the correct answer.
You should try to find a shape for each of the two gray circles.
IMPLICATIONS OF COLOR BLINDNESS
Color vision deficiencies range from mild to severe. A full, accurately calibrated test can distinguish between different levels of severity.
MILD: Individuals identified as having mild color vision deficiencies will make a few mistakes on color vision tests.
Their color vision deficiency is unlikely to cause difficulties, even on color-related tasks.
Except for those jobs requiring perfect color vision, most career choices will be open to people with the mildest color vision deficiencies.
MODERATE: Those identified as having a moderate color vision deficiency will consistently make mistakes on color vision tests.
Their color discrimination is sufficiently impaired that it may cause difficulty at school or work when the task involves color, especially if time limits are imposed.
Careers requiring perfect color vision may present significant and possibly insurmountable difficulties for such individuals.
SEVERE: Even though they can differentiate some colors, individuals with severe color vision defects have great difficulty distinguishing many colors from each other.
Those with severe color vision deficiencies are expected to experience difficulty with schoolwork or other work that involves color-related tasks.
They also may not qualify for any job that has a color vision requirement