I have worn Trifocal lenses for over 15 years now and had no problem with the regular Bifocal lenses I started with that were NOT progressive.
I began with progressive and after a month or so, took them back and told the guy I cannot see what I am looking for, unless my head is aimed just at what I was looking for, very poor peripheral view in my opinion when looking through that middle very narrow hourglass shape the way lenses are cut. If I put down my hammer in the basement, I would be walking around for 20 minutes until I finally was focused with my head aimed straight at the hammer, then I would be able to see it. When looking for things, with that very narrow field of view in the middle of that hourglass makes for them being useless in my book!
I must wear Trifocal lenses all the time. In doing so, I have gotten extremely used to the lines (two lines instead of one). When I am shooting, scope or open sights, doesn't matter, I use the largest top portion, typically looking down low, just above the upper line for the clearest image.
Most people cannot focus on the rear and front sights and also on a target that is fifty yards out. One must compensate and determine which is best for him. I find that focusing on the front sight works best for me, with the target bullseye a bit blurred and the rear sight a bit blurred. Of course, with a scope, my trifocals use the upper one, and the scope is highly-focused. There is no way I could hunt without any glasses on as I cannot see at any distance at all! I would have a hard time seeing the ammo I am loading, a hard time telling if the gun is loaded without opening the bolt nearly all the way, would not see any animals, people, objects, etc!
I always wear lightweight titanium frame glasses that have a very small bow around the ear that does not bother any earmuffs I have ever used.