i wear contacts, but i have two pairs of glasses i wear shooting. i have a pair that are bifocal (which i did not notice when i bought), and a par that are refular lenses. personally, i see no difference between the two when shooting, although when i am reloading, the bifocals do make it more difficult for me to see depth. probably because i don't require bifocals, but to each his own. my step brother swears that the bifocals make it easier for him to reload, and he doesnt require corrective lenses, so go figure?