LASIK, an acronym for Laser-Assisted In Situ Keratomileusis, is a type of refractive surgery that aims to reduce or eliminate the need for glasses or contact lenses by permanently changing the shape of the cornea. The procedure targets refractive errors such as myopia (nearsightedness), hyperopia (farsightedness), and astigmatism, where the eye does not bend light properly onto the retina. Successfully performed LASIK allows the eye to focus light rays more accurately, improving visual acuity. The decision to undergo this procedure involves balancing the potential for clearer vision with the medical criteria and possible side effects.
Understanding the LASIK Procedure
The LASIK procedure is an outpatient surgery that typically takes less than 30 minutes to treat both eyes, with the actual laser time lasting under a minute for each. It begins with the application of numbing eye drops, followed by the creation of a thin, hinged flap on the cornea’s outermost layer. This flap may be cut using a mechanical oscillating blade called a microkeratome or, more commonly in modern practice, a computer-guided femtosecond laser.
Once the flap is created, the surgeon lifts and folds it back to expose the underlying corneal tissue, known as the stroma. An excimer laser, which uses ultraviolet light, is then used to vaporize microscopic amounts of stromal tissue, reshaping the cornea according to the patient’s specific prescription. For nearsightedness, the laser flattens the cornea, while for farsightedness, it steepens the center. After the reshaping is complete, the surgeon repositions the corneal flap, which adheres naturally without the need for stitches.
Determining Suitability for Surgery
Not everyone is a candidate for LASIK, and a pre-surgical screening is required to ensure the procedure’s safety and effectiveness. A primary requirement is a stable vision prescription for at least 12 months, as undergoing surgery while the refractive error is still changing can compromise the long-term result. Patients must be at least 18 years old to ensure their eyes have reached full maturity.
Corneal thickness is another factor, as sufficient tissue is necessary for the flap creation and subsequent reshaping. If the cornea is too thin, an alternative procedure like PRK may be recommended. Certain pre-existing conditions can disqualify a person, including advanced glaucoma, severe dry eye syndrome, and uncontrolled autoimmune disorders such as rheumatoid arthritis or lupus, as these can impair the body’s ability to heal. Pregnant or nursing women are advised to wait due to hormonal fluctuations that can affect vision stability and healing.
The Advantages of Vision Correction
The most immediate benefit of LASIK is the rapid improvement in vision, often within 24 hours of the procedure. Most patients report significantly enhanced visual acuity, with more than 90% achieving 20/20 vision or better and over 99% achieving 20/40 or better.
Achieving independence from glasses and contact lenses provides substantial convenience in daily life, especially for those who participate in sports or water activities. This freedom eliminates the daily hassle of cleaning, inserting, or losing corrective aids. Although the upfront cost of the surgery is considerable, LASIK can be cost-effective over a lifetime compared to the continuous expense of purchasing new frames, lenses, and contact supplies. The quick recovery time, with many patients returning to normal activities within a day or two, minimizes disruption to work and routine.
Potential Risks and Side Effects
Like any surgical procedure, LASIK carries potential risks and side effects. Dry eye syndrome is the most common complaint after surgery, affecting about half of patients in the first week. This condition occurs because the procedure alters nerves in the cornea, temporarily reducing tear production, though symptoms typically resolve within weeks to months as the eye heals.
Nighttime visual disturbances are also frequent, including the perception of halos, glare, and starbursts around light sources. These symptoms usually diminish as the cornea heals over the first few months. Less common but more serious risks include flap complications, such as displacement or irregular healing, and the possibility of regression, where the original refractive error returns over time. There is also a risk of developing corneal ectasia, a progressive thinning and bulging of the cornea, or a slight chance of significant vision loss.