Color blindness, which is sometimes called color deficiency, is a condition in which a person can’t see colors normally. In many cases, the patient can’t tell certain colors apart. Many such patients, for example, can’t distinguish between green and red.The problem lies in the retina, which contains two kinds of cells for detecting light. Rods detect darkness and light and help a person see in limited light. Cones enable people to perceive colors, and there are three types. Cones enable people to see either red, green, or blue. They send signals to the brain that then determines what colors the person sees.A patient who is color-blind may have cones that are not working properly. For example, they may be detecting a different color than normal. The color-blind patient may also be missing some cones. In the most severe cases, they may have no cones at all and see everything in shades of gray. Fortunately, this type of color blindness is rare. At the other end, people with mild color blindness can perceive colors more or less normally in well-lit areas but have trouble in dim light.
Color blindness generally affects both eyes, and it typically does not get worse or better. Most people are born color-blind, but there are conditions that can cause a patient to become color-blind. As some of these conditions are serious, anybody who notices a decline in their ability to see color should talk to their ophthalmologist.
