There is such a thing as blue-green colour blindness, though it's a little more unusual (I as understand it). My father is one of those lucky people. His fath

There is such a thing as blue-green colour blindness, though it's a little more unusual (I as understand it). My father is one of those lucky people. His father was completely colour blind. My father can see the two colours just fine, but if they're adjacent to each other and about the same kind of tone, they start to blur into grey. One particular example I remember growing up. He hated the board game "Game of Life" because there's all these greens (ground) and blues (rivers, lakes, ocean etc) right next to each other all over the board. It was not a pleasant experience to be looking at it.