I have red-green-brown color blindness. I’ve been fooling around with a red dot reflex sight in a pellet gun recently. No problem seeing the dot.
I also have astigmatism. Even lens corrected, this does distort the dot. Looks like a little off-centered starburst.
As for traffic lights, only issue I have is that at night green looks like a white light, so hard to tell difference between a green traffic light and a street light. Yellow and red stand out though, which is more important.
I also find that at times, pulling into a toll booth, perhaps dependent on sunlight, I have a hard time distinguishing between open booths and closed booths based on what I guess must be green or red lights. Fall back position, in such a case, is to ask the wife, if she’s with me, or follow another car.
Where it is a real problem though, is at night on the sea or in an airplane. Don’t want me in charge in those cases! The captain or the pilot needs to see the colors of lights in order to understand where he is and where other craft are in relation to him.