8% of men have colour blindness (daltonism). Are you sure you don´t?
Take this simple and free test and find out the answer. Ishihara´s test. Take a look at one sinlge picture and you get the answer.
M. Domhardt, E. Tunca, I. Zoller, P. Lotz, and L. Schmidt. 10. Berliner Werkstatt Mensch-Maschine-Systeme -- Grundlagen und Anwendungen der Mensch-Maschine-Interaktion (Berlin 2013), page 9-18. Berlin, (2013)