Color Blindness

Color Blindness

What Colors Do You See? Imagine looking at a box of crayons and seeing only shades of gray, blue, and yellow. That's what they look like to many people who are color-blind. Most people who are color- blind can still see some colors. They just can't see as many colors as other people.

Where Do Colors Come From? White light has every color of the rainbow hidden inside it. Each color is a different wavelength. Things appear to be different colors because they absorb and reflect different wavelengths of light. A strawberry looks red because it reflects red wavelengths while absorbing most others.

How Color Vision Works People see colors because our eyes respond differently to different wavelengths of light. When light enters one of your eyes, it gets focused on the retina. The retina is a thin layer of tissue at the back of the eyeball. The light triggers rod cells and cone cells. These cells send signals to the brain, which uses the signals to make images.

Rods and Cones Rod cells are the most sensitive cells in your retina. They let you see in very low light. However, they can't tell different colors apart. Cone cells handle color vision. There are three types of cone cells. One type absorbs blue light, one green light, and one red light. Combining these three main colors allows us to see thousands of colors. When one or more types of cone cells aren't working, though, color blindness results.

Different Types of Color Blindness Red-Green Color Blindness People with red-green color blindness have trouble telling red and green apart. This is the most common type of color vision problem. It affects about one out of every twelve men and one out of every two hundred women. People with red-green color blindness usually have something wrong with their green cone cells. As a result, green and yellow objects appear reddish in color. Sometimes red-green color blindness is caused by a missing or damaged red cone cell. In this case, red, orange, and yellow objects appear green or black.