I am used to full magnify readers , and 3 stage ones that I can never really acclimate to unless it's something line this where I'm using a phone browser or reading a book so I wasn't expecting much but was hoping for better than what I'm used to by the lens being larger and round instead of rectangular . These did not disappoint .I find driving with them on is easy as the no magnify part is so large and there's a definite break between the areas . Some may find that "so 1980s " but my brain seems to prefer it over no lines.I have found reading while watching TV to be just as agreeable .When venturing outside on a cloudy morning I kinda saw what others said about not dark enough BUT then the sun came out and these things darkened right on up . Do they block 90% or more of the visible light like my M Frames ? No but about 75%-80% is more than adequate unless it's snowing . I do REALLY miss the polarizing of my M Frame lenses though .Since I don't need glasses all the time these will not be my fishing glasses but for overall use love at work these are so forget I'm wearing them comfortable I will no longer need to constantly move my dedicated readers up and down while on my forklift or pulling orders . Look down to see what I need to grab next , look ahead or up to go get it . They don't seem to be dirt and face grease magnets either , another plus.These will definitely not double add safety glasses but unless you need the extra protection they'll be ok. For that I have dedicated non magnified safety glasses I wear .Edit . I used these today specifically to see how much they darken , how long it takes , etc when the temperature is below freezing on a cloudless day and there is quite a dramatic increase in not only how dark but fast they darken and how much SLOWER they are too lighten up . So when I went from doing chores in the back yard to my truck I took a 10 minute trip in my truck and they were still semi dark when I arrived . I got out of the truck , they darkened almost instantly to VERY dark and then when I got back in and drove home they never got lighter than semi dark .Since these are readers only I'm gonna say that a very good thing as I can use them more when outside and know if I'm coming back in if it's really cold out I'm not going to be able to use them for far away for away BUT they still worked fine for magnified viewing.