While there are different ways a person can be considered colorblind, seeing in black and white is the result of only the rarest type, called monochromacy. It’s so rare that only one in every 33,000 is affected. For the majority of people with color blindness, monochromacy only affects specific colors. There are a few factors that determine which colors are affected and why, so let’s take a closer look.
The Basics of Color Vision
To know how color vision works, we must understand color blindness. Light hits the photoreceptors in our eyes, which come in two types: rods and cones. Cones detect differences in color, while the amount of light we see is distinguished by the Rods (important for things like night vision).
Three types of cones that absorb light from different parts of the visible spectrum are found in someone with normal color vision. Some process medium (green) wavelengths, some process short (blue) ones, some process long (red) ones, and some process medium (green) ones. Think about the old TV sets and how the tiny red, green, and blue phosphors combined to produce millions of colors.
Color Vision Genetics
When there is a mutation of the X chromosome is the cause of most color blindness. Men only have one chance to have the gene for normal color vision, while because it’s a recessive gene, women with two X chromosomes have two chances. This means the sons of a woman who isn’t colorblind herself but has a copy of the color blindness gene have a 50% chance of being colorblind. This is why only one in every 200 women is colorblind while one in about a dozen men is colorblind.
Different Types of Color Blindness
There are quite a few ways for color vision to go wrong, while there’s only one way for color vision to go right; this is called trichromacy. If a person has anomalous trichromacy, they have all the types of cones. However, some of them misfire, which results in limited color vision almost to the degree of someone with dichromacy (completely missing one type of cone).
The most common type of color blindness is Red-green, possibly because it happens whether it’s the green cones (deuteranomaly/deuteranopia) or the red cones (protanomaly/protanopia) that are absent or misfire. Either way, red-green color blindness results in a landscape of dull brownish-yellows. More men than women are affected by this type.
Blue-yellow color blindness is less common, with only 5% being affected (tritanomaly if the relevant cones are just misfiring or (tritanopia if they’re missing), which is split evenly between the sexes because they don’t come from the X chromosome. This results in a palette of teals, browns, and pinks (more so with tritanopia).
Monochromacy is the rarest of all. Monochromacy could happen because only one type of cone is working or no cones work, so there’s a problem with how the brain processes visual information from the retinas, or there’s no contrast to create color perception. This type of color blindness tends to be accompanied by severe light sensitivity, involuntary eye movements, and weak central vision.
Is Color Blindness Is Treatable?
In recent years, thanks to special glasses, some colorblind people have discovered a broader spectrum of color. However, they only help the types of color blindness where all cones are present, but some are misfiring, and even then, only when the overlap between two types of cones isn’t too significant.
The glasses work by blocking out wavelengths of light that have the most remarkable overlap between misfiring cones and the other cones. This increases contrast and helps train the cones to only respond to the correct wavelengths of light. Check out a few of the viral social media videos of people trying these glasses on for the first time. It’s quite remarkable!
Optic Gallery Screens for Color Blindness
It is possible for you to have a form of color blindness and not be aware of it. If you would like, we can screen you at your next eye exam to check how strong your color vision is. Compared to complete blindness, not being able to see all the colors might seem like a minor issue, but it does make some everyday tasks more challenging. Diagnosis is the first step towards overcoming these challenges!
The content on this blog is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of qualified health providers with questions you may have regarding medical conditions.