Which of the following conditions does the Ishihara test detect?

I am red green colour blind and I found it interesting that as well as not being able to see numbers that others see I also found numbers that people with "normal" colour vision don't see.

cones in our eyes help us see colours, without them we would be colour blind!

Player #28825483, It is the same for early pattern balding being a gene from the Mother's side of her family. My father was noticeably balding at age 18, as were my sons.

Someone told me this is mandatory for airplane personnel because he failed the test.