Color Blindness Testing: What You Need to Know Testing for color blindness is a fairly simple process that your eye doctor can conduct in their office, usually with immediate results. Learn more about the different tests available. Color blindness, or color vision deficiency (CVD), is a fairly common condition that makes it difficult to distinguish between certain colors. An estimated 300 million people worldwide are affected by color blindness, specifically 1 in 12 men and 1 in 200 women. Color blindness is most commonly a genetic condition inherited at birth, but CVD can also result from disease, the use of certain medications, trauma4 to the eye or brain or aging. In the U.S., color blindness is a disability covered by the Americans with Disabilities Act (ADA) and requires employers to make reasonable accommodations for color-blind employees. Types of Color Blindness There are different types of color blindness that cause different difficulties in discerning between colors, including red-green, blue-yellow and monochromacy. Red-green color blindness 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. Protanopia 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 Blue-yellow color blindness is more rare, appearing in 1 in 10,000 people and affecting men and women equally. People with blue-yellow color blindness often develop the condition as a result of glaucoma, diabetic retinopathy, macular degeneration or optic nerve damage. People with blue-yellow color blindness struggle to distinguish between yellow and red, and blue and green. 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. Monochromacy 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 light3 and may wear dark glasses to protect their eyes. Color Blindness Symptoms 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 Testing for Color Blindness 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 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.