Eye Fatigue.....

Something about progressive lenses that I found out the hard way, cheap progressive lenses only have a very narrow field of view. 
One that does not work well with looking through a scope, for me at least what I discovered is that half my pupil would be looking through the magnifying section with the other half outside of the section.

Be carful about good prices on glasses they are cheap for a reason. What I discovered is it’s best to get a single vision glasses for shooting, I will not go against @idoc about tented lenses but I have found a light yellow tint does help both my day and night vision