LASIK (Laser-Assisted In Situ Keratomileusis) is a surgical procedure that uses an excimer laser to precisely reshape the cornea, correcting common refractive errors like nearsightedness, farsightedness, and astigmatism. Millions of people have successfully reduced or eliminated their dependence on glasses or contact lenses. The central question is whether the results are permanent or if another procedure will be needed. The answer involves understanding the permanent nature of the corneal change versus the natural aging process of the eye.
How Stable is the LASIK Correction
The physical change made to the cornea during LASIK is permanent and does not revert over time. This permanence stems from the laser removing microscopic amounts of tissue from the corneal stroma, the middle layer of the cornea. Since this tissue does not regenerate, the altered curvature of the cornea is fixed for life.
The majority of patients enjoy stable vision for many years following LASIK surgery. In a small percentage of cases, however, a minor shift in vision, known as regression, can occur. Regression is a slight return of the original refractive error, often due to the eye’s natural healing response or biomechanical changes in the cornea’s shape. This minor change is minimal and does not compromise the overall success of the initial correction.
Understanding Vision Changes After LASIK
While the LASIK correction is permanent, the eye continues to age, which is the primary reason vision may change years later. The most common cause of declining vision after successful LASIK is presbyopia, or age-related farsightedness. Presbyopia typically begins around age 40 and results from the natural stiffening of the eye’s internal lens, making it difficult to focus on close objects.
Since LASIK only reshapes the cornea and not the internal lens, it does not prevent the onset of presbyopia. Patients who had excellent distance vision after LASIK may still require reading glasses later in life. Another unrelated age-related change is the development of cataracts, which is the clouding of the eye’s natural lens.
Cataracts are an inevitable part of the aging process, affecting the lens behind the cornea and having no connection to the LASIK procedure itself. If a cataract develops, it requires separate treatment, usually cataract surgery, to restore clear vision. These natural, internal aging processes should be differentiated from a failure of the initial LASIK correction.
When a Second Procedure is Necessary
If a patient’s vision does not achieve desired clarity after the initial healing period, or if minor regression occurs years later, a second procedure known as an “enhancement” may be recommended. Enhancements fine-tune the result by addressing any residual refractive error. This is a minor adjustment to the corneal shape, not a complete re-do of the surgery.
For an enhancement to be safely performed, the patient must meet specific criteria, primarily having sufficient residual corneal tissue thickness. Since LASIK removes tissue, a minimum amount of un-ablated stromal tissue must remain to maintain the cornea’s structural integrity. The patient’s prescription must also be stable, meaning no significant changes for at least six to twelve months.
The timing for an enhancement varies. If due to an initial under-correction, it is usually performed after three to six months when vision has fully stabilized. If the need arises years later due to minor drift or regression, the surgeon typically re-lifts the existing corneal flap to apply the laser correction. While enhancements are highly successful, only a small percentage of patients (less than 5% over a lifetime) require one.