Recently I've had the unfortunate privilege of trying out like five sets of different contacts in a desperate attempt to find the 'right' pair. As a result I've experienced a variety of visual acuities ranging from 1.0 (20/20) all the way up to a monstrous 1.5 (20/13). The funny thing is that each visual acuity made me feel a certain "way" and thought it kinda affected my behavior in a subtle way. I'll explain below:
1.0 (20/20)
Considered "standard vision" in the US and England, I like to think of it as "relaxed vision", because it lets you focus on near objects with minimal eye accommodation while still giving you decent distance vision. That being said though, after you've experienced 1.2 or 1.5 you'll probably think 1.0 is a bit near-sighted, which scientifically it is (the human eye supposedly has a maximum natural healthy acuity of about 1.2 ). I think for people who like to read lots of books or use the computer a lot, 1.0 is probably the best compromise between relaxed near vision and decent distance vision. It's the perfect eyesight for brainy people, no doubt. But I think compared to a 1.2 person you might get caught in a few situations where you can't read a distant blackboard or sign... or you'd have to squint.
1.2 (20/16)
Considered "standard vision" in Japan and Taiwan. I like to think of it as "clear vision" - you can see distant objects very well but long hours in front of the computer will probably cause eyestrain. That being said I think most jobs these days involve long hours at the desk, so 1.2 vision can actually be quite tiring. In fact having 1.2 vision is enough to discourage me from using the computer or studying for long periods of time, as it causes a fair bit of eye strain. But for looking at beautiful scenery outside or admiring a gorgeous sunny sky, 1.2 is quite a lot better than 1.0. I think it's the right eyesight for people like salesmen or tour guides, who usually spend most of their time outside looking at mid to far range objects. Most eye doctors in Japan target this visual acuity when they prescribe eyeglasses or contacts.
1.5 (20/13)
"Ultra-clear-vision". If you have 1.5 eyesight and you go outside it's like everything's in super-sharp focus. Not only that but oddly enough contrast ratios seem to go up... so when you look at something like Christmas lights, it looks really beautiful because it's almost as if the lights are shining brighter. You can also see the texture on objects with utmost clarity, like if you were looking at a field of grass, you could make out each individual blade of grass very easily. But the downside to 1.5 vision is that looking at anything close than 8 feet becomes really tiring, to the point where it encourages me to look at something farther away. The funny thing is that even close objects have this ultra-contrast ultra-sharpness quality to them. Still I would never want 1.5 vision because the amount of visual information coming in at any given time is just OVERWHELMING. That and it's impossible to use a computer at regular distances... it's just too much eyestrain. I can see why hunters, golfers and sports athletes want this kind of visual acuity, it really makes a difference. You can really see "the whites of their eyes" so to speak.
One interesting thing I read about eyesight is that some people who often do computer work want to have a bit of near-sightedness to minimize eyestrain, so they stubbornly ask for undercorrection. However one Japanese eye doctor said that below the age of 38 it's a very bad idea to go around with less than 0.9 eyesight because your eye will rapidly lose its ability to accommodate, and presbyopia ("old-man vision") will set in quicker than normal.
