With the noticeable increase in traffic in my area over the past several years my night vision is definitely being effected by the onslaught of more numerous oncoming headlights.
Previously when I saw an occasional car/truck coming my eyes would have time to adjust back to the "darkness" as I continued to ride/drive. But with repeated exposures in much shorter duration to headlights now my eyes don't have as much time to fully adjust. I have really great night vision too . . ..
In the shadows or darkness those reflective eyes of the critters are Nature's way of saying "Hey . . . ". Also any kind of movement is suspect. A lot of the time deer are just grazing by the side of the road but when they are on the run they just keep right on going. Same thing with coyotes/coywolves . . . they will just run right out in front of you.
Road debris is another story. It could be anything. Generally if you are riding along with the "high beam" on you have a pretty good chance of spotting something well enough in advance if you are traveling at a reasonable speed, speed limit. Pot holes are a hole different thing (no pun intended).
Bottom line is ATGATT (or most of it) and ride to conditions relevant to the speed limits.
I find that tailgaters are a nuisance and it's best to just turn off onto a different road or find some place to slow or pull over to let them go by. Their headlights reflecting in your mirrors significantly reduce your night vision capability.
