Despite its prevalence, color blindness often goes undiagnosed until it starts interfering with daily functions. Colorblindness tests have become essential tools in diagnosing this condition. Learn about the various types of testing available, their accuracy, and how they aid in diagnosing color perception problems.
Diagnosing Color Blindness with Colorblind Tests
Diagnosing color blindness involves a series of examinations conducted by an eye doctor.
The most common color blindness assessments are the Ishihara test, anomaloscope examination, and hue test.
1. Ishihara Colorblindness Test
The Ishihara test is the most widely used test for red-green color blindness (Daltonism).
The evaluation consists of plates with colored dots in various patterns. Numbers (for adults) or shapes (for kids) are embedded within these patterns. The colorblindness test determines which numbers/shapes a person can distinguish.
The first plate shown to the patient is a control plate. Everyone should be able to read the plate, regardless of their color vision status.
For the next few plates, people with red-green color blindness may see different numbers or no numbers at all, compared to those with regular color perception!
Some of the Ishihara colorblindness test samples are transformation plates. They show one number to individuals with standard color vision and another number to those with red-green color blindness.
There are also vanishing plates. Vanishing plates show a number to people with color vision which those with red-green color blindness cannot see.
Another "trick" of the Ishihara test is the hidden digit plates. These plates reveal a number only to the red-green colorblind. Those with normal color vision cannot see a clear number.
By the end of this colorblindness test, the examiner can tell the patient's red and green color-distinguishing capabilities. So the eye doctor can give or dismiss a Daltonism diagnosis.
For other types of color blindness, the patient may need to undergo additional testing.
2. Farnsworth-Munsell 100 Hue Test
The Farnsworth-Munsell 100 Hue Test is another method to evaluate color vision deficiencies. But unlike other methods, it is useful for diagnosing subtle and more complex forms of color blindness.
This colorblindness test involves arranging multiple color caps/forms in order of hue. It helps assess a person's ability to discern slight variations in color hues.
The test includes four trays, containing a series of small colored caps, each with a slightly different hue.
The patient starts to arrange the caps in a sequence, which represents a gradual transition of color hues.
At the end of the Farnsworth-Munsell 100 Hue Test, the examiner compares the sequence to the correct order.
Errors in arranging the caps indicate the presence, severity, and type of color vision deficiency. Specific patterns of mistakes correlate with different types of color blindness.
The test provides a detailed assessment of hue discrimination. It identifies deficiencies other colorblind tests might not detect.
3. Anomaloscope Colorblind Test
An anomaloscope is a device used to diagnose the common red-green color blindness. The test measures how well a person can match different colors. It determines the type and severity of color vision deficiency.
The anomaloscope examination is quick, effective, and non-painful.
At the beginning of the colorblind test, the patient looks into an eyepiece. There they see two separate fields of light.
One field displays a fixed yellow light, while the other field allows the patient to adjust the mixture of red and green lights until it matches the yellow field.
The patient uses controls to change the intensity and ratio of the red and green lights to achieve a perceived match with the fixed yellow light.
The way a patient adjusts the colors and the accuracy of their matches indicate the presence and type of color blindness.
For example, individuals with protanopia or deuteranopia will have different matching patterns compared to those with normal color vision.
The results help determine the type and severity of the color blindness.
In summary...
Colorblindness tests not only help in diagnosing color blindness but also assist in tailoring coping strategies for those affected. If you suspect that you or someone you know is colorblind, try the abovementioned colorblind tests online and if the results suggest abnormal color perception, schedule an eye doctor's appointment.
There are many coping strategies for the colorblind to make life a bit easier.
Checked by Atanas Bogoev, MD.