I'm assuming since I only get to peer through one half of the lens at a time, the larger the lens the better. I've been comparing my cheater lens to my prescription reading glasses. Although the cheater lens works very well, it seems as though my prescription reading glasses allow for an ever so slightly clearer view of the weld puddle. I have a pair of bifocals already, but being that the lenses are so rectangularly small in order to be stylish, I find myself peering through a very narrow section at the bottom of the lens; too narrow of a section for welding because if I move my head up or down the slightest amount, I'm no longer in focus of the weld puddle. Would giant eyeglass frames with giant lenses be the way to go for bifocals?