Laser-Assisted In Situ Keratomileusis, commonly known as LASIK, is a refractive eye surgery designed to correct common vision problems. This procedure works by permanently reshaping the cornea, the clear, dome-shaped front surface of the eye, to improve how light is focused onto the retina. LASIK is primarily used to treat refractive errors such as nearsightedness (myopia), farsightedness (hyperopia), and astigmatism. The goal of the surgery is to reduce or eliminate a person’s dependence on glasses or contact lenses for daily visual tasks.
How the Procedure Works
The LASIK procedure is an outpatient surgery that typically takes less than 30 minutes for both eyes, with the actual laser time lasting only seconds to a minute per eye. The process begins with the administration of numbing eye drops to ensure patient comfort. A specialized instrument is then used to create a thin, hinged flap on the outermost layer of the cornea. This flap is carefully lifted and folded back to expose the underlying corneal tissue, called the stroma.
The patient is instructed to focus on a target light while an excimer laser, which is pre-programmed with the patient’s specific prescription measurements, is activated. This laser precisely removes microscopic amounts of stromal tissue to reshape the cornea’s curvature, correcting the refractive error. For example, in cases of myopia, the laser works to flatten the cornea, while for hyperopia, it steepens the curvature. Once the laser sculpting is complete, the corneal flap is gently repositioned back over the treated area, where it adheres and begins to heal naturally without the need for stitches.
Key Advantages
Patients experience improved vision quickly, often noticing significant clarity within hours of the procedure. The high effectiveness of the surgery is demonstrated by statistics showing that over 96% of patients achieve 20/40 vision or better, with a majority attaining 20/20 vision. This outcome allows many individuals to discontinue the use of corrective lenses entirely for most activities.
The recovery period following LASIK is notably short. Most patients are able to return to work and resume driving the day after the procedure, experiencing minimal downtime. The long-term cost savings can be substantial, as the one-time expense of the surgery replaces the recurring cost of purchasing and maintaining prescription glasses, contact lenses, and lens care solutions over many years. LASIK also boasts a high patient satisfaction rate, often exceeding 96%.
Potential Risks and Side Effects
LASIK carries a risk of potential complications and side effects, the most common of which is dry eye syndrome. This occurs because the creation of the corneal flap temporarily disrupts the delicate nerves responsible for signaling the eye to produce tears, leading to decreased tear production and discomfort. While this dryness typically resolves within a few months, it can persist longer for some individuals, requiring ongoing management with lubricating drops.
Temporary visual disturbances are also common in the initial healing period, including the perception of glare, halos, or starbursts around lights, particularly when driving at night. These symptoms usually diminish as the eye heals. More serious, though rare, complications can arise, such as undercorrection or overcorrection, which result in a residual refractive error requiring further treatment or corrective lenses.
Rarer complications include issues related to the corneal flap, such as displacement or the abnormal growth of epithelial cells underneath the flap, known as epithelial ingrowth. The most severe, sight-threatening complication is corneal ectasia, where the cornea weakens and bulges forward due to excessive tissue removal. This condition can lead to significant vision loss and may necessitate a corneal transplant. The overall rate of serious, sight-threatening complications is reported to be less than 1% of procedures.
Determining Suitability
A comprehensive screening process is necessary to determine if a person is a good candidate for LASIK. A fundamental requirement is that the patient must be at least 18 years old, and ideally 21, with a stable vision prescription that has not changed significantly for at least one year. This stability ensures that the correction provided by the laser will be long-lasting.
Corneal thickness is a physical factor, as the cornea must be thick enough to allow for both the creation of the flap and the subsequent laser reshaping without compromising the eye’s structural integrity. Certain existing medical conditions are considered contraindications, including uncontrolled autoimmune disorders like lupus or rheumatoid arthritis, which can impair the body’s natural healing process. Additionally, conditions such as severe dry eye, advanced glaucoma, or keratoconus—a progressive thinning of the cornea—are disqualifiers. Women who are pregnant or breastfeeding are also advised to postpone the surgery, as hormonal fluctuations can cause temporary changes to the eye’s shape and prescription.