A recessive gene located on the X chromosome is the main culprit behind most color blindness, which is why men are much more likely to be colorblind than women. A woman could have one copy of the gene, but because she also has a copy of the gene for normal color vision, she has no problems seeing the full range of colors. She could still pass the color blindness gene on to her children, though.
Men only have one X chromosome to begin with, so they are either colorblind or not, and their daughters will be carriers of the color blindness gene as well. Overall, about eight percent of men are colorblind, but less than one percent of women are.
To understand color blindness, it helps to know how our color vision works. Our color vision comes from specialized cells in our retinas called cones. In normal color vision, there are cones that see short (blue), medium (green, and long (red) wavelengths, and they work together so that we can distinguish the colors in between. Old TVs and computer monitors worked in a similar way. If you look closely at their screens, you’ll notice pixels with red, green, and blue stripes.
Color blindness happens when one or more of the types of cones is missing or failing to do its job correctly. The most common type is red-green color blindness. Whether the green cones aren’t working (deuteranomaly) or the red cones (protanomaly), the outcome is essentially the same: a landscape with a lot of dull, yellowish-brown colors.
Less common is blue-yellow color blindness (tritanopia), which is what happens when the blue cones are the problem. This leaves you with in a teal, pink, and brown reality. Only five percent of colorblind people have tritanopia.
The rarest form of color blindness is monochromacy, or complete color blindness. Finally, that black-and-white movie idea is actually accurate. Seeing in grayscale isn’t where it ends for monochromats, though. Without functioning cones to give them sharp detail vision, their eyesight might be fuzzy in a way that glasses can’t fix, and bright light is often painful.
Not all color blindness happens the same way, even if the outcome looks the same. If you are dichromatic, it means your eyes are completely missing one of the three cone types, but if you are an anomalous trichromat, then some of your cones are simply responding to a wider range of light wavelengths than they should, overlapping with the others.
Anomalous trichromacy is more common than dichromacy, which is good news! When the overlap isn’t too great, it can be counteracted by wearing special glasses that block wavelengths of light that trigger both types of cones, opening up a whole new world of colors!
There are many resources available to help people living with color blindness. The first step is to determine how severe the color blindness is and what type it is. Schedule an appointment with us so that we can help you get what you need to make things easier!