There are several different types of colorblindness. Here is some good information from the National Eye Institute about colorblindness in general and the different types of colorblindness. According to Kolandaisamy, Subaramaniam, and Heng (2019) about 8% of males and 0.5% of females are colorblind. Less commonly, individuals may struggle discerning blue and green, and yellow and red. The most common form manifests as difficulty distinguishing red and green, as depicted in the following image retrieved from Designing for Colorblindness.
What types of problems confront biology students who cannot distinguish colors? The problems abound in a biology class. Go through your course materials, especially the plethora of figures and illustrations you use in lecture and the microscopy media and stains used in lab. How many require the ability to distinguish red and green, blue and green, yellow and red? Imagine a student with colorblindness trying to determine what people chose as the color of their favorite fruit from this graph, the data for which I totally made up.
What can you do to help students with colorblindness in your biology classes? Well, the most important thing is to be aware of the difficulty, and consider it in your course design and as you teach. Make sure the room lighting is bright. Bright light helps in distinguishing colors. Write out color names rather than using colored chalk or markers. Add emphasis with bold, textures, or different shapes rather than color. Don’t use red or green text, paper, etc. Make sure your visuals make sense when viewed in black and white. Explain visuals in terms other than color. Instead of using differently-colored lines to distinguish variables in a graph, use solid lines, sequential dashes and dots, etc.
Of utmost importance is to identify those students who are colorblind and talk with them routinely to ensure the accommodations are supporting their needs. I’ve had students who are colorblind in my microbiology class which requires students to perform many biochemical tests and stains for which correct interpretation is routinely based on color. When it’s time to interpret each test, we find distinctions among the possible results that enable students to correctly interpret the media or stain. For example, they may not see the same colors as other students when examining a Gram stain, but we discuss what they do see when looking at the control organisms. Students have always been able to figure out some difference between the appearance of the Gram-positive and Gram-negative cells so that they can correctly distinguish one from the other. If they cannot, using Bismark brown instead of safranin in the Gram stain may help (Laboratory Techniques in Microbiology n.d.).
Biology is the most visual of the sciences, and normally incorporates a vast array of color in both lecture and lab. You don’t have to make your course a monochrome of grey; those who can distinguish colors appreciate them. Just be aware that some of your students may not be able to distinguish by color. Penn State has good information on making visuals for students with colorblindness. Somersault1824 is another good resource.
Kolandaisamy, R., Subaramaniam, K., & Heng, L. K. (2019). ICYou – A colour identification application for colour blind. Global Business & Management Research, Special Issue, 11(1), 526-537.
Laboratory Techniques in Microbiology. Gram stain. http://mikrobiotek.blogspot.com/2008/06/gram-stain.html