LASIK (Laser-Assisted In Situ Keratomileusis) is a highly successful procedure that has provided excellent vision correction for millions of people. While the vast majority of patients achieve their vision goals, a small percentage find their results are less than perfect. For these patients, understanding the precise nature of the issue is the first step toward finding a successful solution. Suboptimal outcomes, though uncommon, can almost always be addressed through further treatment or a change in corrective strategy.
Defining Suboptimal LASIK Outcomes
When a patient reports that their LASIK procedure “didn’t work,” the issue typically falls into one of three categories. The most common problem is a residual refractive error, meaning the correction was either slightly under-corrected or over-corrected. This leaves the patient with a small amount of residual nearsightedness, farsightedness, or astigmatism, resulting in blurry vision.
Another issue is visual regression, where the initial excellent result gradually deteriorates over time. This happens when the eye’s natural healing response causes the cornea to subtly return toward its original shape. Regression is more common in patients who had a high degree of refractive error corrected during the primary surgery.
The third category involves persistent visual disturbances, which are qualitative complaints about the clarity of vision. These include experiencing halos or starbursts around lights, particularly at night, or a reduction in contrast sensitivity. Furthermore, prolonged or severe dry eye syndrome that does not resolve following surgery can cause fluctuating and blurred vision.
Factors Contributing to Poor Results
Suboptimal results often stem from a combination of biological and procedural factors unique to each patient. A significant biological factor is the individual healing response of the cornea. In some people, the corneal tissue reacts strongly to the laser treatment, leading to regression of the correction over time.
Pre-existing eye conditions, such as severe or undiagnosed dry eye, can be exacerbated by the procedure, leading to chronic discomfort and unstable vision. Procedural factors also play a role, including the amount of corneal tissue available for the initial treatment. Patients with thin corneas, especially those with high prescriptions, may not have enough tissue left to safely achieve a full correction. Equipment calibration or slight misalignment during laser ablation can also contribute to a less precise outcome. Complications related to the corneal flap, such as microscopic wrinkles or incomplete adhesion, can distort the corneal surface.
Addressing Residual Refractive Error
For the majority of patients with residual refractive error, the most direct solution is a LASIK enhancement or “touch-up.” This secondary surgery fine-tunes the initial result, correcting the remaining small prescription. Eligibility requires a period of stable vision, typically three to six months after the primary procedure. The surgeon must confirm that enough corneal tissue remains to safely perform a second laser ablation. A specific amount of tissue, called the residual stromal bed, must be preserved to maintain the structural integrity of the cornea and prevent ectasia.
The enhancement procedure is often quicker than the original surgery. The surgeon typically uses a specialized instrument to gently lift the original corneal flap, which never fully adheres, and then applies the excimer laser for a brief second treatment. Alternatively, if the original flap is difficult to access or the risk of flap complications is high, a surface ablation technique like Photorefractive Keratectomy (PRK) may be performed on the corneal surface.
Surgical and Non-Surgical Alternatives
For patients who are not candidates for a LASIK enhancement, often due to thin corneas or severe dry eye, several other options are available. Photorefractive Keratectomy (PRK) is a common alternative, as it does not require a corneal flap and may be safer for eyes with limited remaining corneal thickness. The PRK procedure involves removing the surface layer of the cornea, the epithelium, before the laser reshapes the underlying tissue.
Implantation of a Phakic Intraocular Lens (ICL) is another option for correcting significant residual refractive error. This procedure involves surgically placing a custom-made lens inside the eye, typically behind the iris, without altering the cornea further. ICLs are effective for correcting higher degrees of myopia and astigmatism not fully resolved by the initial LASIK procedure.
If surgical re-treatment is not desired or feasible, non-surgical correction remains a reliable pathway. New custom-fitted eyeglasses or contact lenses can be prescribed to address the residual error. The post-LASIK cornea is a different shape, but modern contact lens technology, including specialty rigid gas permeable (RGP) lenses, can provide excellent, sharp vision.