Had to jump in here. I have PRK 11 years ago. Had 20/20 vision for 9 years. Then started noticing just a little decrease in vision I was a minus -1.00 in one eye and -1.5 in the other got an enhancment last year and have been fine ever since. So yes you may need an enhancement after many years that is why it is a good idea to get a doctor that gaurentees for life. If I had known then that I would need an enhancement after 10 years I still would have went for it, that's a pretty good deal to me. considering I was blind as a bat...
Also anyone with kids, my dd has eyes like mine terrible needed glasses in 3rd grade. I got her this wonderful thing called ortho-k(granted you need to find a good doctor to do this) they are hard contacts that she puts in when she goes to bed(overnight while she sleeps they flatten her cornea) in the morning she takes them out and can see 20/20 all day. It is the closest to lasik for kids that you can get. It is wonderful for kids in sports! It also keeps her prescription stable so she doesn't get such a strong precscription that she couldn't get lasik one day if she wanted. This is just the best thing we have ever done! All her friends have started with this also, no problems at all.
It is pricey, but so worth it.