LASIK, or Laser-Assisted In Situ Keratomileusis, is a popular refractive surgery designed to correct common vision errors like nearsightedness, farsightedness, and astigmatism. The procedure permanently reshapes the cornea, the transparent front dome of the eye, to improve how light focuses onto the retina. While the corneal reshaping is permanent, a patient’s overall vision can still change over time due to natural biological processes. These changes may eventually lead to the need for a follow-up procedure known as an enhancement.
Longevity of the Initial Correction
The physical change made to the cornea during the initial LASIK procedure is permanent and long-lasting. Studies indicate that well over 90% of individuals still do not require distance prescription lenses five years after their surgery. The initial period immediately following the procedure is when the eye settles into its final corrected state, a process that typically takes between six and twelve months.
A slight return of the original refractive error, known as regression, is the most common reason for needing an enhancement shortly after the initial surgery. Regression is a biological healing response where the corneal tissue, specifically the epithelial layer, slightly remodels itself over the reshaped area. This healing can partially counteract the laser correction, resulting in a minor loss of sharpness.
The rate at which patients require an enhancement procedure remains low, but it is not zero. Clinical data suggests that within the first decade following LASIK, approximately 5% to 10% of patients may opt for a touch-up to maintain their achieved vision level. The need for this early enhancement is more likely for individuals who had a very high pre-operative prescription, as these eyes require a greater amount of corneal tissue removal and may exhibit a more pronounced healing response.
Regression that occurs in the first year is generally attributed to this healing response or an initial slight under-correction. After the first year, the rate of needing an enhancement drops significantly, often averaging around 1% per year thereafter.
Reasons Vision Might Change After Surgery
While early vision changes are often due to a minor healing response, changes that occur many years after a successful LASIK procedure are usually a consequence of the eye’s natural aging process. These later changes are not a sign that the original surgery has failed, but rather that the eye is developing conditions that LASIK was never intended to prevent.
A common age-related condition is presbyopia, which typically begins to affect people around the age of 40. Presbyopia involves the gradual hardening of the eye’s natural lens, which reduces its flexibility and its ability to focus on near objects. Since LASIK only reshapes the cornea, it does not stop the lens from aging, meaning reading glasses will become necessary for most LASIK patients in middle age.
Another inevitable age-related condition is the formation of cataracts, which involves the clouding of the eye’s lens. This condition can develop years or decades after LASIK and will cause distance vision to become blurred and hazy. Addressing cataracts requires lens replacement surgery, which is a different type of procedure entirely and is not considered a LASIK enhancement.
For a smaller group of patients, the underlying refractive error, such as myopia, may continue to progress even after the age when vision is typically stable. This progression causes the eyeball to slightly lengthen over time, which shifts the focal point away from the retina and can result in vision loss. These patients may eventually require a second procedure to correct the new prescription that has developed over the intervening years.
The Enhancement Procedure
If a patient’s vision falls below an acceptable level, an enhancement procedure is an option to restore clear vision. Doctors typically recommend waiting until the patient’s prescription has remained stable for several months before performing the retreatment. This waiting period ensures that any minor post-operative healing or regression has fully stabilized, allowing the surgeon to target the final, settled prescription.
The procedure for an enhancement is very similar to the initial LASIK surgery, but it is often quicker. In cases where the original procedure created a corneal flap, the surgeon can gently lift this existing flap to access the underlying tissue for the new laser treatment. This avoids the need to create a new flap, often resulting in a faster recovery than the initial surgery.
If the initial surgery was performed using a surface ablation technique like PRK, or if the cornea is deemed too thin to safely re-lift the original flap, a new surface treatment may be performed instead. Eligibility for a second procedure depends primarily on the amount of residual corneal tissue thickness remaining after the first treatment. Comprehensive screening tests are necessary to confirm that enough tissue remains to ensure the eye’s long-term structural integrity.
Many reputable clinics include a policy where an enhancement is offered free of charge or at a significantly reduced rate if it is required within the first year. This policy covers early regression or residual refractive error. However, any subsequent procedures needed years later due to age-related changes, such as the progression of presbyopia or late myopia, are typically considered separate treatments and are charged at the standard rate.