Color Blindness Test and Vision Deficiency Guide

Color blindness, or color vision deficiency (CVD), is a common condition that makes it difficult to distinguish between certain colors. Around 300 million people worldwide are affected by color blindness, including approximately 1 in 12 men and 1 in 200 women.

Color blindness is usually inherited at birth, but it can also develop due to disease, certain medications, eye or brain injuries, or aging. In the United States, color blindness is recognized as a disability under the Americans with Disabilities Act (ADA), which requires reasonable workplace accommodations for affected individuals.

There are different types of color blind test that cause different difficulties in discerning between colors, including red-green, blue-yellow and monochromacy.

Red-green color blindness is the most common type of genetic color blindness and causes people with this type of CVD to confuse red, green, purple, blue, and orange. There are three types of red-green color blindness, including:

• Deuteranomaly: The most common type of red-green CVD, this type makes green and yellow appear more red. Blues and purples may also be confused. This type of color blindness is usually mild and does not typically interfere with everyday activities.
• Protanomaly: This CVD makes red, orange and yellow appear more green and less bright. This form of color blindness is also mild and doesn't interfere with daily activities.
• Potanopia and deuteranopia: These two types of CVD cause red and green to be indistinguishable. Protanopia causes red to appear black, and shades of orange and green to appear yellow. Deuteranopia causes green to appear as dark yellow, and red to appear yellow-brown.

Blue-yellow color blindness is a rare condition affecting 1 in 10,000 people. It causes difficulty distinguishing blue and green or yellow and red, often due to glaucoma, macular degeneration, or optic nerve damage. The two types of blue-yellow CVD are:

• Tritanomaly: In this type of color blindness, blue appears green, and there may be difficulty discerning between red, yellow, pink and orange.
• Tritanopia: People with this color blindness cannot tell the difference between blue and green, purple and red, and yellow and pink; colors may appear more muted.

Complete color blindness is rare, and patients with this type of CVD do not see color at all. Instead, they see shades of black, white and gray. People with monochromacy can be particularly sensitive to light and may wear dark glasses to protect their eyes.

CVD is often diagnosed early in children, as color blindness testing is usually included as part of a standard pediatric eye exam. If you have a history of color blindness in your family or exhibit any of the following symptoms, you can contact your eye doctor to perform simple tests to determine if you have color blindness:

• Difficulty discerning between colors
• Decreased attention span when coloring
• When asked, difficulty in selecting the correct colors in crayons, colored paper or other coloring materials
• Struggling to read or work with colored pages
• Headache or eye fatigue if working with a red and/or green background
• Sensitivity to bright light

Eye doctors normally test for color blindness during routine eye exams. You don't usually need to wait for results, as your doctor can tell if you have a form of CVD right away. If the results are unclear, there are other tests for color blindness that your doctor can do for more clarity.

In addition, there are online color blindness tests you can take at home if you suspect you may have a form of CVD. However, at-home test results should be confirmed by a qualified eye doctor, who will also be able to recommend an appropriate care plan.

Similarly, if you notice a change in your vision or color perception, inform your eye doctor and ask them to check for color blindness. Color blindness in children might first be noticed by a teacher or school nurse, but a full exam by your family's eye doctor should be conducted.

The following six tests are used as an initial screening for color vision deficiencies.

The Ishihara test is the most common type of color plate test for red-green color deficiency. Your eye doctor will ask you to look at a series of images made up of colored dots, with a number, pattern, or shape in the middle. Trouble discerning the shape, number or pattern could indicate a color deficiency.

This test is similar to the Ishihara test, but also screens for blue-yellow deficiencies in addition to red-green deficiencies.

This test uses a computer and is similar to the Ishihara test in that the patient is looking at a colored, spotted screen for a letter “C" to appear randomly. When the letter appears, the patient presses one of four keys.

The anomaloscope test measures color vision by asking patients to match the color and brightness of two circular halves using a knob. Difficulty matching them may indicate a color vision deficiency.

The Farnsworth-Munsell 100-hue test checks a person’s ability to identify subtle color differences by arranging colored pegs in order. Mistakes may indicate color vision deficiency and can affect color-related job requirements. 

The Farnsworth lantern test is used by the U.S. military to detect color blindness. Patients identify pairs of red, green, or yellow lights, helping determine mild or severe color vision deficiencies.

There is no cure for color blindness. However, newly developed technology offers people with mild to moderate CVD issues the potential to minimize and compensate for color deficiencies with glasses made with specially tinted lenses.

Color blind glasses are designed to help people with color vision deficiency identify colors more clearly. These glasses usually do not require a prescription and work similarly to sunglasses by filtering certain wavelengths of light. The average cost ranges from $200 to $250, while premium versions may cost over $450. Clip-on lenses are also available at lower prices.

Health insurance generally does not cover color blind glasses because they are not considered medically necessary, though some people may use FSA or HSA funds for purchase. The effectiveness of these glasses varies depending on factors such as the type and severity of color blindness, age, and lifestyle of the user.

Color blindness or color vision deficiency (CVD) is a common condition that affects the ability to distinguish certain colors. It is usually inherited but can also develop due to aging, injury, or certain health conditions.

Understanding the types, symptoms, and testing methods of color blindness helps with early detection and proper care. Regular eye exams and online color blindness tests can help people better understand their vision and seek guidance from eye care professionals.