In most cases, LASIK is a one-off procedure that lasts many years or decades. No secondary LASIK is required in such cases.
Occasionally, some pre-existing spectacle power may reoccur, and this is called regression. If significant regression occurs, an 'enhancement' procedure can be considered whereby the LASIK flap is lifted, and then laser treatment is applied to remove the residual spectacle power.
The main question regarding suitability for 'enhancements' has to do with how thick the cornea is after the first LASIK. If the cornea is already at the limit of the acceptable remaining thickness (what some people call 'too thin'), then your doctor will advise against any further laser treatment. In this case, glasses or sometimes contact lenses remain options to achieve clear vision.
If you are above 40 years of age at the time and myopic regression is present (ie there is some remaining shortsightedness/myopia), some people may elect to leave things as they are, because the little bit of myopia helps them to read.
These are some of the important considerations-mainly for the issue of regression. There may be other scenarios, and the best thing to do if you have any specific concerns would be to consult a doctor who performs refractive surgery for further discussions.
