Color vision deficiency (CVD), commonly called color blindness, is a condition that alters a person’s ability to see or distinguish between colors. Contrary to a widespread misunderstanding, it does not mean seeing the world in only black and white. Most individuals with CVD perceive color, but they see a more limited range of shades compared to those with normal vision. The condition exists on a spectrum, from mild difficulties that might go unnoticed to a complete inability to perceive any color. It stems from how specialized nerve cells in the eye’s retina, known as cones, process light.
How Different Types of Color Blindness Affect Vision
Our ability to perceive color originates from three types of cone cells in the retina, each sensitive to red, green, or blue light. When one or more of these cone types are absent or don’t function correctly, color vision is affected. The most common form is red-green color blindness, which results from a malfunction in the red-sensitive (L) cones or green-sensitive (M) cones. For someone with deuteranomaly, the most frequent type, green colors appear more reddish. With protanomaly, reds appear more green and less bright.
A less common form of the condition is blue-yellow color blindness, or tritanomaly. This type makes it difficult to differentiate between blue and green, as well as between yellow and shades of pink or red. Blues may appear faded or less vibrant.
The rarest form of color vision deficiency is monochromacy, often called total color blindness. People with this condition, known as achromatopsia, lack all three types of working cone cells and see the world only in shades of black, white, and gray. This condition is often accompanied by other vision issues, such as poor visual acuity.
Everyday Life with Color Vision Deficiency
The altered perception of color introduces unique challenges into many aspects of daily life that people with normal vision might not consider. Activities like choosing an outfit can be difficult, as coordinating clothes without being able to reliably distinguish between colors like red, green, and brown can be a daily hurdle.
In the kitchen, determining if food is safe and appealing to eat presents another set of problems. A person with red-green color blindness may not be able to tell if a piece of meat is cooked to the desired level or still raw. Assessing the ripeness of fruits and vegetables, like telling a ripe yellow banana from an unripe green one, can be a challenge. Even prepared foods can cause mix-ups, such as confusing chocolate sauce with ketchup.
Beyond personal tasks, color-coded information in professional and educational settings can be a barrier. Reading charts, graphs, or maps that use color to distinguish data can be difficult or impossible, potentially affecting performance at school or work. Navigating the world also requires interpretation of color signals, most notably traffic lights, where individuals must often rely on the position of the light rather than its color to know when to stop and go.
Tools and Technology for Color Blindness
Fortunately, a variety of tools and technologies are available to assist individuals with color vision deficiency. One of the most well-known aids is specialty lenses, such as those made by EnChroma. These glasses use optical filters that separate overlapping wavelengths of light, which can enhance the contrast between confusing colors like red and green for many users. While they do not cure color blindness, they can significantly improve color discrimination in about four out of five cases of red-green CVD.
Mobile applications have also become a powerful resource, turning a smartphone into a real-time color identifier. Apps like Color Blind Pal or Seeing AI use the phone’s camera to detect a color and then display or speak its name, helping with tasks from shopping to choosing clothes.
Accessibility is increasingly being built directly into the technology we use every day. Many operating systems, websites, and video games now include color-blind modes. These features adjust the on-screen color palettes, often shifting colors to higher-contrast combinations that are easier to distinguish. By using different patterns, labels, and textures in addition to color, designers can make information accessible to everyone.