Color blindness is difficult to treat at present. Color-blind people should not engage in art and other jobs dealing with colors, nor should they drive cars or trains because they can't tell the difference between traffic lights. After Dalton discovered the existence of color blindness in human beings, he wrote a paper entitled Abnormal Cases of Color Blindness, which was the first paper on human color blindness. Later, people called color blindness "Dalton's disease".