....I have always had good night vision and can wander around at night with no lights, but my daytime vision is crap in the dark.
Martin. Not wanting to pick nits but your opening statement makes no sense to me for some reason....
OK, at night your eyes produce visual purple and also they switch to mainly rod operation than cone.
This takes a few minutes to work then you have full night vision. Until this happens you are using day vision.
Too much glare disables night vision, never had an issue with old style rear lights, just fog lights - they kill night vision.
I have always been happy to chuck on more front lighting to see where I am going if someone decides to kill my night vision.
In that case, as I said in the other thread, you are a danger to yourself, your passengers and anyone else unfortunate enough to meet you whilst you are driving in the dark and in control of a main beam control....

Park it, get a taxi or walk.

Sorry to be blunt, but I have had to deal with the residue of those who drive on the roads in the dark in a similar manner to that you describe, medically explained or otherwise.
