Vision for Air Force Pilots

I have always been confused about the vision requirement to be an AF pilot. So I read Near vision: uncorrected 20/40, but corrected to 20/20

So if you are 20/40, how do you correct to 20/20? By glasses? Are they saying if you are 20/40 and wear glasses you are okay? So why not 20/60 by glasses. I would assume it doesnt mean corrected by Laser surgery because from what I read you can be far worse than 20/40 and have the Laser surgery