Laser vision correction works by precisely removing and reshaping the tissue of the cornea. At higher levels of correction more tissue needs to be removed. This leaves the cornea thinner and potentially weaker. Laser vision correction for higher prescriptions are also sometimes less accurate and have a higher chance of regression and need for second treatment. Quality of vision after higher attempted corrections can also be poorer because of induced optical aberrations, resulting in problems with night vision, haloes, and reduced contrast sensitivity.
If you do have a higher prescription (greater than +5.0 to +6.0 dioptres of long sight or -10.0 dioptres of short sight) you should ask your surgeon what alternatives to laser eye surgery may be available.
If the clinic you visit is only able to offer laser eye surgery, they are very likely to push the boundaries of treatment and be less likely talk about alternatives. Arguments by these clinics that they possess superior technology that allow them to push the limits of treatment are questionable. A surgeon that offers more that just laser eye surgery will be able to discuss the various excellent options available for your eyes. These will vary dependent on age, glasses prescription and your individual eye anatomy. There are now a number of excellent alternatives to laser eye surgery and you should make an informed decision about the best treatment for you.