What is the color deficiency for color-blind people?

[Zoie]

I have some questions about color-blind people. I have a friend who is color-blinded and I am curious about what is the really color can they see through their eyes. Is it offensive or disrespectful to ask them about it? Will we become color blinded later on in our life if something happens to you or if this is caused only when you are born with?

[New Hudson]

Actually, 98% color blind are called color deficiency, for short, CD. 92% of people with a CD are red/green deficient. They only have problems with shades of red and green, with them all looking like different shades of browns. The rest of the colors in their wolrd looks the same to them as it does to you. Almost all of them are born that way, except for some of them get it by hurting to eyes. Only about 2% of those with a CD are unable to see any colors and are truly color blind. Those people also have other serious visual problems and have very poor vision.

[Copalis Crossing]

One of my friend are color-blinded and he was not born that way but was caused by long-time playing computer games online. He has difficult to clarify red and green, in his eyes, those two colors are all looked brown. I think color blind is not a disease, and people have this problem are all the same with ordinary people, so it won't be a problem if you ask them about this. But avoid it if someone who cares about it.