Have you ever had an argument with a friend about the color of a particular object? Just imagine that your favorite red jacket suddenly is, according to your crazy friend, a green one! Don't worry, take a deep breath.. probably he's just simply color blind... or maybe you are color blind? It's perfectly possible. It turns out that one out of every ten people on earth is color blind, and most of them do not even know it! How is that possible? It is actually quite simply: we cannot even imagine how people with eye disorders experience life. So today we will try to understand how a color blind person sees the world and to explain the causes of color blindness.