Last month I noticed that the IOF intend to try and adjust their mapping standard for colour-deficient orienteers (as noted here), so I contacted Ales Hejna of the IOF Map Commission and asked him how to volunteer, and it turned out that I'm the first one to do so.
Yes, I'm colour-blind (deficient), and always have been. I've been failing those tests with the coloured dots regularly since I was 17, and I tried again just in case, but I still have Deuteranomaly, which means red-green problems.
How does this affect my orienteering? Usually I have problems discriminating between light green (30%) and yellow (50%) on maps, especially when they are mixed up. To a lesser extent, there can be a problem also with darker green (60%) and full yellow (100%). And when the printed colours are non-standard, it can get worse – I remember a race a long time ago, where I was attacking a control in an open area and couldn't understand all the bushes in my way. Luckily I managed to find it, and when comparing routes at the end and complaining about the map someone pointed out to me that the green was actually marked and I hadn't seen it.
The best test I could find was here, though it's in French. There's also one here. You can test yourselves and contact Ales if you are colour-blind as well.
The yellow patches on the left are a problem for me. Those on the right a bit less. There is also a difference between the screen and the printed map.