For AF/Navy/Marine, all the flying requirements are basically the same. Army's weird. But for the sane services, your vision needs to be correctable to 20/20 and within a certain range, which I'm not exactly sure... your eyes can't be too bad. On top of general vision, there's color-aptitude and depth-perception tests as well, which a surprising number of people have trouble with. If you go through one of the service academies and you're interested in flying, typically they'll hook you up with laser surgery if your eyes can take it -- and most can.
In terms of prior flying ability, you don't need any whatsoever. The program is designed to take you from a zero to a Zemke. I had no prior experience, and now I can fly cloverleaf maneuvers in close formation. The advantage you'll have is that you'll do much better in the screening programs, like IFS and whatever the Navy does, and you might even learn faster in UPT as well.
actually explains all the medical quals, so, give it a look if you're interested in that.