Learn How Color Vision Works and the Different Types of Color Blindness
According to the nonprofit Color Blind Awareness, 1 in 12 men and 1 in 200 women has some type of color blindness. Complete color blindness, or monochromacy, is the rarest form, affecting only one person in 30,000. In addition, this vision issue affects only specific colors for most people, and many factors determine which ones. Read on to learn what types of color blindness there are.
How Color Vision Works
Understanding why some people are color blind first helps to know how color vision works. There are two types of photoreceptors in our retinas: rods and cones. Rods distinguish between the amount of light we see, and cones detect color differences. People with full-color vision have three different types of cones, each one absorbing light from various parts of the visible spectrum. Cones absorb:
- Long wavelengths (reds)
- Medium wavelengths (greens)
- Short wavelengths (blues)
Cones send electric signals to the optic nerve. Most people have more long-wavelength cones than short-wavelength ones. More than 60% of the cones in the retina absorb red light wavelengths, while only 2% react to blue light wavelengths.
What is Color Blindness?
Color blindness is when you cannot see colors in the usual way. It occurs when one or more color cones in your retinas are absent, don’t work, or detect a different color. Severe color blindness happens when all three types of cones are missing.
A mutation in the X chromosome is the most common cause of color blindness. Because women have two X chromosomes, they are less likely to have color blindness. However, diseases that damage the optic nerve or retina can cause color blindness, as well.
Different Types of Color Blindness
There are a few ways in which color vision can go wrong. Red and green color blindness is most common. It occurs if either red or green cones are absent or misfire. Someone with this type of color blindness sees in dull browns and yellows. Only 5% of people have blue and yellow color blindness. One form of it, tritanomaly, makes it difficult to differentiate between blue and green and between red and yellow. Tritanomaly occurs when cones misfire.
Another type of blue and yellow color blindness is tritanopia. It makes it impossible to tell between blue and green, purple and red, and yellow and pink. Tritanopia also makes all colors look less bright, and it occurs when cones are missing. Monochromacy, the rarest form of color blindness, can occur if no cones work or if only one type works. If the brain has trouble processing visual information from the retina, it can also result in monochromacy.
Testing & Treating Color Blindness
Some forms of color blindness are treatable. The ones in which all cones are present but do not work or misfire can improve with special glasses. These glasses block out wavelengths that overlap between malfunctioning cones and those that work correctly. They train misfiring cones to only respond to the correct light wavelengths.
If you suspect you may have some form of color blindness, turn to your optometrist. With a simple test, you will know if you have trouble seeing specific colors and what treatments may be available.
At Looking Glass Optical, we offer eye exams that will alert you if you suffer from color blindness or are at risk of any other vision issues. From providing solutions to common eye problems to vision therapy, we are here to help. So give us a call today or schedule your appointment online.