The laser makes a very subtle change in the surface, or with LASIK or IntraLASIK, under the surface layer of the cornea. The “repair cells” of the cornea sense this change and try to recreate the original state. This is primarily true for surface (PRK) surgeries, because surface repair cells are more active.
After IntraLASIK interventions, this activity is low. That is why PRK surgeries require a 12-month checkup period, in which the activity of repair cells is decreased by eye drops, whereas IntraLASIK requires a much shorter checkup period. That is also why IntraLASIK is recommended for refractive errors above 4 diopters, because in order to maintain the outcome of the surgery, a low repair cell activity is essential.
In both cases though, after the recovery period, repair cells accept the change and begin to guard this new cornea shape against external effects, which is now responsible for the clear vision. After this period, vision clarity does not change and the achieved outcome lasts a lifetime.
We would like to point out that no laser vision correction procedure will prevent the aging of the eye, so even lasertreated patients will need to use reading glasses as they age. Distance vision, however, will remain clear after the recovery period.