Colorblindness is an interesting concept to most people because we wonder what it must be like to not distinguish some colors—a function of vision that many people take for granted. Most people can live with colorblindness because it is present at birth. Many go years without realizing that they do not see a full array of colors.
The cause of color blindness usually involves faulty cones. Cones are cells in your eyes that distinguish the three wavelengths of light that we see. Light can be split into red, green, and blue for the spectrum visible to humans. Color blindness can happen because the cone cells are faulty in some way and do not show distinct colors. A person may see shades of yellow and blue, for example, but have problems distinguishing red and green. Many people believe that color blindness means seeing only in black and white, but that is far more rare than typical color blindness.
Color deficiency is much more common in men than women. Less than 1% of the female population has trouble seeing various colors, whereas somewhere between 8-12% of the male population is color blind.
Color blindness is usually an inherited genetic deficiency, but symptoms of color blindness may also occur due to stroke, old age, or due to a problem with pathways from the cones to the brain where the brain can determine colors.
Curious about your own color perception? Learn more about it here, and test your color vision!