Daltonism is a vision disorder in which the eye is unable to perceive one or more primary colors. This disorder is caused by a defect in the X chromosome. However, this is not the only cause of the disease. Color perception may be impaired due to eye or nervous diseases, traumatic brain injury, severe flu, stroke, or heart attack. This pathology was named after the English chemist John Dalton, who also suffered from this disease, like his relatives, discovered and described the pathology in a book.