Is it possible to have better than 20/20 vision with LASIK?
Yes, it is.
This is not so much a matter of how far you "push" the LASIK, though, it is about how well your eye has the potential to see. 20/20 is average good visual acuity, not perfect vision. Most young people can actually see better than that, if only with contacts or glasses: every day I see people with 20/16, 20/12.5, even 20/10 vision. With an excellent tear film, clear natural lens, and healthy macula, this is not so rare. As we age past 40, however, the eyes lose their young, high performance characteristics and become subject to a gradual, slow decline in what is called "Best-Corrected Visual Acuity."
It is the eye's capacity for a particular level of visual acuity, not the LASIK itself, that is the rate-limiting step.
Written by J. Trevor Woodhams, M.D. - Chief of Surgery, Woodhams Eye Clinic