Can People Really See In Black and White?
Author: Andrea Corral
We have all heard of the 2015 viral internet sensation “the dress” dilemma, a thought provoking photograph that turned friends against each other. Viewers disagreed over whether this dress was colored blue and black, or white and gold. But what if I told you this is a dilemma some individuals face on a daily basis. While some of us can distinctly see the red flowers, some people see green instead. Can they see pink? Can people see in black and white?
Before we dive in deeper, let's find out how this mutation happens.
What is Color Blindness ?
The retina in your eye is responsible for detecting color. The retina consists of two photoreceptor cells known as rods and cones. Cones sense colour while the rods detect light and darkness. Colored cone cells are classified into three different types: red, green and blue. Data from these cone cells is used by the brain to assess our color vision. Colorblindness is a genetically inherited trait that occurs when color cone cells are absent or do not function correctly. Color blindness is not the inability to see any color. In reality, the vast majority of colorblind people (99 percent) can see color, but the number of colors they can see, or their color perception, is more restricted.
Individuals who are colorblind, have a hard time distinguishing shades of colors. For instance, a colorblind person will have more trouble picking out crayons, and only choose 6 out of the 24, as they cannot differentiate between certain colors. There are distinct types of colorblindness, that dictate the range and shades of colors one can recognize and fail to see.
Types of Colorblindness
Each cone cell is made up of a specific photopigment named opsin, that is most sensitive to particular wavelengths of light, the opsin pigments in cone cells lead to different types of colorblindness.
Red-green colorblindness, is the most common type of colorblindness, where one can not differentiate between red and green. Cone cells consisting of opsin that are made from the OPN1LW gene are called long wavelength sensitive , or L cones for short. Compared to those with ospin made from the OPN1MW gene, are identified as middle wavelength sensitive, or M cones. The absence of these L or M cones, through genetic mutations, cause red-green colorblindness.
There are sublevels of red-green colorblindness:
Deuteranomaly occurs when the M-cones in the eye are present but not functioning, leading to the color green looking more red.
Protanomaly happens when L-cones in the eye are present but are defective. This caused red pigments to look more green.
Protanopia is when the L-cones located in the eye are completely absent. This prevents you from seeing red light. (Figure 2).
Deuteranopia occurs when the M-cones are not present in the retina, preventing one from perceiving green light.
Blue-Yellow colorblindness, also known as tritan defects, is the less common type of colorblindness. About 1 in 10,000 people are affected by it. This condition affects one's ability to distinct the colors blue and green, yellow and red, and dark blue and black.
There are two types of blue-yellow colorblindness:
Tritanomaly is when there is a sensitivity to their blue S cone cells (cone cells consisting of opsin that are made from the OPN1SW gene are called short wavelength sensitive or S cells) causing confusion between the colors blue from green and red from yellow.
Tritanopia is a result of no blue S cone cell sensitivity, making it difficult to tell the difference between blue and green, purple and red, and yellow and pink. Colors also become less vibrant. (Figure 3).
Finally, the most uncommon and quite severe color deficiency is Blue Cone Monochromacy also known as complete color blindness. People with monochromacy cannot see any shade of color, they see in only black and white, as well as have underlying severe vision problems such as photophobia (increased light sensitivity), involuntary eye movements (nystagmus) and nearsightedness (myopia). Blue cone monochromacy affects 1 in 100,000 people globally, and has a higher diagnosis rate in males than females.
Living with color blindness can be challenging, and can interfere with your daily life but it's not impossible. There is no “cure” for colorblindness, because it is a genetically inherited trait. Although there are ways to adjust to it by changing some daily routines. Such as: color labeling your clothes, alternating lighting, using gadgets, memorizing daily activities. Scientists have even developed EnChroma glasses that can help bring back partial color acuity for color blind people. There are ways we can make it easier on our colorblind friends. Steering clear of the red-green color scheme for activities, instead try to go for easily distinguishable combos such as blue and red. Increasing awareness can help make a more color blind friendly environment.
Etudo, M. (2021, January 6). What Do Color-Blind People See? verywellhealth.com. https://www.verywellhealth.com/what-do-color-blind-people-see-5092522
Mayo Clinic. (2019, December 28). Color Blindness. https://www.mayoclinic.org/diseases-conditions/poor-color-vision/diagnosis-treatment/drc-20354991
National Eye Institute. (2019, June 26). Types Of Colorblindness. National Eye Institute. https://www.nei.nih.gov/learn-about-eye-health/eye-conditions-and-diseases/color-blindness/types-color-blindness