W8.
There are so many variations of CVD, probably as many pilots. The most common are in the red/green, blue/green or Blue/violet regions of the spectrum. Monochrome vision is very, very rare.
My own 'Cvd' means that I can see discriminate and detect hues of blue and yellow at sensitivities far greater than most people. This means that I have trouble with Isihara (because the blues and yellows stand out more readily than the reds and greens), but none at all with the lantern test or signal lights.
As a result of my 'defect', I can see when there is too much blue or yellow pigment in 'white' paints where most people can't. I can also discriminate between white and yellow nautical markers at further distances and in low light than most people ( I was recently perplexed in a yacht race that the crew were heading towards a white mooring bouy when, to me, the yellow turn-point marker was about 30 degrees to the port).
There is some solid longstanding evidence that individuals with my "cvd" as less likely to be fooled by military camouflage. During ww2 we were selected for roles as snipers and artillery spotters as a result.
With the above in mind, the concept of "defect" is relative. 50,000 years ago, we were the guys who brought home the mammoth to feed the rest of the tribe, spotted the Sabre-Tooth Tiger before it spotted us. Hell, they probably would have made us the Chief
