I am Red/Green colourblind. I have known this since I was about 11 years old - and I found out because I was asked to look at a distinctive set of coloured cards designed by the Japanese opthalmologist Shinobu Ishihara (1879 – 1963).
I was told at the time that the Red/Green colourblindness that I had would mean that I would never be a pilot. They were right, I'm not.
It is quite tricky finding out about Ishihara - there is a biographical book on him published in 1984 but it is in Japanese and it doesn't look like there is an English translation. Eric Kindel has a good piece HERE.