Can You Have LASIK Twice?

IF your distance vision has began to become blurry, a second procedure may be possible. This is routinely done if the patients cornea is healthy and there is enough tissue left (we remove a very small amount of tissue every time we do LASIK). The surgeon may also choose to do a different type of refractive procedure for your enhancement. This will depend on the status of your cornea and technology available to the surgeon.

If your distance vision is still fine but your near has began to blur, this is not correctable with a second procedure. All patients with LASIK will inevitably loose their near clarity as the age beyond 40 years old. This is a natural aging process and LASIK will not help the near vision, only reading glasses. Your distance vision should remain stable as you age.

If your degree of refractive error is moderate and you are not too young, it's not realistic to worry about requiring a second procedure. I have performed over 30,000 Lasik procedures and very few of my patients have needed what we call a "touch up". Most experienced surgeons should be able to tell immediately from your degree of refractive error and a few other factors, if you are at risk of needing a second surgery down the road. In this case I usually recommended choosing contact lens implants. 
Needing a touch up shortly after your procedure is even more rare and most surgeons will cover the costs associated with such a procedure as long as its within a year or so. If you have had Lasik in the past and your distance vision is deteriorating I recommending consulting your surgeon although a second surgery should only be performed if required as it may raise your risk of a complication.

Of course it depends on your original treatment and what your eyes look like at the time of your second consultation. Rarely, patients require an enhancement (aka re-treatment) within the first year of surgery to achieve the desired 20/20 or better they sought out to get. But this question is typically directed at whether or not a treatment will be available 5/10/15+ years later. As long as there is enough cornea tissue available, the refraction is stable, and the cornea isn't too irregular, enhancements 10+ years later aren't a problem. There are some risks associated with doing so, but that's beyond the scope of this question. Also on your side is the fact that technology keeps advancing, and even today we can enhance far more patients than was previously capable.