Besides the non-measurable differences in color perception between individuals, there are indeed measurable variants of "normal" color vision, most of which are genetic. The most common variety is generally called "red-green color-blindness", and occurs in approximately 5% of the population, almost entirely male.
I know, 'cuz I are one!
The color vision test consisting of a "series of dots" that Rob mentions is the Ishihara color test and you can try a version of it on line ( here, for example
). The basis of the test is that a person with normal vision sees color differences more readily than contrast differences, and the "color-blind" (or, as I prefer to put it, "color-vision challenged", in proper PC-speak) person makes judgements first based on lightness-darkness differences, and only secondarily on color.
What does this mean for my photography? For the 40-plus years that I did B&W darkroom prints (and sent my Kodachromes to Mother K for processing), it didn't bother me (as long as I never tried toning a print more than was needed for archival processing). Once I went digital, and I could make my own color prints, I had a ball playing with color.
In color, I now make mostly two types of prints: landscapes and abstracts. I have found that in the landscapes I can't safely play with color (even light balance) without messing things up in ways that are visible to you "normal" guys. (Chris_T sees a slight magenta cast in the "blue" skies of some of my prints -- I can't see this.)
With the abstracts, I feel I can play all I want with color, as long as I make things look "interesting" to me. Saturation, color substitution, etc. all seem to be doable.
A lot of my work still ends up in black-and-white, and until I got Quad Tone RIP, I had a miserable time trying to get decent B&W prints from my Epson 2200. I do get together with a group of photographers every month or so, and I can rely on them to tell me when I'm going off the deep end.
Even with the (minor) roadblocks my defective eyes put in my way, photography is still a passion.
Curiously, my wife (with normal vision) sometimes misses color distinctions that I can see. I think that is simply because I spend so much time trying to see color differences.
By the way, I have played flute for over fifty years, and play regularly in a klezmer (Jewish folk music) band, although my hearing went bad in the high frquencies when I was a teenager. But that's a story for a different forum . . .