Laser eye surgery, encompassing procedures like LASIK, PRK, and SMILE, corrects vision errors such as nearsightedness, farsightedness, and astigmatism. This correction is achieved by precisely reshaping the cornea, the clear, dome-shaped front surface of the eye. The physical change made to the eye is permanent, but the living eye is subject to continuous, natural aging processes that can affect vision over time. Understanding this distinction between the lasting structural correction and subsequent visual changes is important.
The Permanent Change to the Cornea
Laser vision correction is permanent because the procedure targets the corneal stroma, the thick, middle layer of the cornea. This layer consists primarily of collagen fibers and does not regenerate or regrow once reshaped by the laser. Once the laser removes a microscopic amount of tissue, the new corneal shape is set permanently. This alteration changes how light is refracted onto the retina, eliminating the specific refractive error present at the time of surgery. Surgeons require a patient’s prescription to be stable before surgery, as success depends on the long-term stability of this corneal reshaping.
Natural Eye Aging That Affects Post-Surgical Vision
Vision changes that occur years or decades after successful laser surgery are due to the eye’s natural aging process, which the surgery cannot stop. These later vision declines are entirely unrelated to the permanent corneal correction performed earlier.
Presbyopia
One of the most common age-related changes is presbyopia, the gradual loss of near-focusing ability that typically begins around a person’s early to mid-40s. This condition is caused by the natural crystalline lens inside the eye losing its flexibility and hardening over time. Since laser eye surgery only corrects the curvature of the cornea, it does not affect the natural lens and cannot prevent presbyopia.
Cataracts
The second major age-related change is the formation of cataracts, the clouding of the eye’s natural lens. Cataracts are an inevitable consequence of aging and will develop in most people, regardless of whether they have had laser eye surgery. The development of a cataract is independent of the corneal change. When this occurs, cataract surgery can still be performed safely to remove the cloudy lens and replace it with an artificial intraocular lens, even in patients who previously had LASIK.
Understanding Minor Regression and Enhancement Surgery
While the corneal structure remains permanently altered, a small percentage of patients may experience a slight return of their refractive error, known as regression. This is a mild shift back toward the original prescription, not a complete reversion to the pre-surgical state. Regression is attributed to the eye’s natural healing process, where corneal surface tissue slightly thickens in the months following the procedure. For most patients, this slight change is minor and does not require additional treatment. If the regression is significant enough to affect daily life, an enhancement or “touch-up” may be recommended. This minor laser procedure fine-tunes the corneal shape, restoring the sharp vision initially achieved.