LASIK (Laser-Assisted In Situ Keratomileusis) is a procedure that corrects common refractive errors like nearsightedness, farsightedness, and astigmatism. It uses an excimer laser to precisely reshape the cornea, the clear, dome-shaped tissue at the front of the eye. While the physical change made by the surgery is permanent, a person’s overall vision can still be altered by the natural aging process over a lifetime.
The Permanence of the LASIK Correction
The correction achieved by LASIK is structurally permanent due to the nature of the corneal tissue. During surgery, the excimer laser removes microscopic amounts of tissue from the middle layer of the cornea, called the stroma, creating a new, fixed curvature. This stromal tissue does not regenerate or revert to its original shape after being ablated.
This structural change provides long-term stability for distance vision correction. In a small number of patients, a slight shift toward the original prescription, known as regression, may occur. This minor refractive change is due to the eye’s natural healing response and usually stabilizes within the first six months to a year after the procedure. Significant regression is uncommon, particularly when patients are screened for corneal stability and a stable prescription before surgery.
Natural Changes That Affect Long-Term Vision
Vision changes occurring years or decades after successful LASIK are due to the eye’s natural aging process, which the surgery does not prevent. The most common change is presbyopia, the gradual loss of near vision that affects nearly everyone, typically beginning around age 40. Presbyopia occurs because the eye’s natural lens, located behind the cornea, loses its flexibility and ability to change shape to focus on close objects.
Since LASIK only reshapes the cornea and does not affect the natural lens, it provides no protection against presbyopia. Even a person who achieves perfect distance vision after LASIK will eventually require reading glasses or other correction for up-close tasks as the lens stiffens.
Another age-related condition is the formation of cataracts, which involves the clouding of the natural lens. Cataracts are an inevitable part of the aging process and develop independently of any prior LASIK surgery. The LASIK procedure modifies the cornea, while cataracts form in the lens, meaning they are physically separate concerns.
Options for Maintaining Clear Vision Post-Surgery
For the small percentage of patients who experience regression of their distance vision, a follow-up procedure known as an enhancement may be performed. This touch-up is done only after the eye has fully healed and the vision has stabilized, usually three to six months after the initial surgery. An enhancement is performed by gently lifting the original corneal flap and applying additional laser energy to fine-tune the result.
When presbyopia begins to affect near vision, several options exist for the post-LASIK patient. The simplest solution is using non-prescription reading glasses, which compensate for the stiffening of the natural lens. Alternatively, some patients may opt for a monovision correction, where one eye is targeted for distance vision and the other is slightly under-corrected for clear near vision.
If cataracts develop later in life, cataract surgery remains a safe and effective treatment. This procedure involves removing the cloudy natural lens and replacing it with an artificial intraocular lens (IOL). Because LASIK permanently altered the shape of the cornea, the surgeon uses specialized measurements to accurately calculate the IOL power, but the prior surgery does not prevent the procedure.