LASIK reshapes the clear front surface of your eye (the cornea) so that light focuses precisely on the retina at the back, correcting blurry vision. The entire procedure takes less than 30 minutes for both eyes, the actual laser runs for only seconds per eye, and most people can drive within 24 hours.
Why Vision Gets Blurry in the First Place
Your cornea and the lens behind it work together to bend incoming light so it converges on the retina, where images are formed. When the eyeball is slightly too long, light focuses in front of the retina and distant objects look blurry (nearsightedness). When the eyeball is too short, light hasn’t focused yet by the time it hits the retina, making close objects harder to see (farsightedness). In astigmatism, the cornea curves unevenly, scattering light in multiple directions at once.
Glasses and contacts compensate by bending light before it enters the eye. LASIK skips the middleman and permanently changes the cornea’s curvature so it does the job on its own.
Step 1: Creating the Corneal Flap
The surgeon begins by placing numbing drops in your eye. A device holds your eyelids open, and gentle suction steadies the eye. Then a specialized laser fires pulses lasting just a femtosecond (one quadrillionth of a second) at a near-infrared wavelength. These pulses are focused at a precise depth inside the cornea, typically around 100 to 110 microns below the surface, roughly the thickness of a sheet of paper.
Each pulse creates a tiny microscopic bubble of water and carbon dioxide within the corneal tissue. Thousands of these bubbles are placed side by side in a programmed pattern until they merge into a single flat plane, essentially separating one thin layer from the tissue beneath it. The laser then extends the cut to the surface along the edges, leaving a small hinge on one side. The surgeon lifts this flap, about the size of a contact lens, to expose the deeper corneal tissue underneath.
Older LASIK techniques used a mechanical blade to cut this flap. Most modern practices now use the femtosecond laser because it allows more precise control over flap thickness and position.
Step 2: Reshaping With the Excimer Laser
With the flap lifted, a second laser takes over. This is the excimer laser, which emits ultraviolet light at a wavelength of 193 nanometers. Each photon carries enough energy to directly break the molecular bonds holding corneal tissue together. The broken molecular fragments are ejected from the surface almost instantly. This process removes tissue without generating meaningful heat, so surrounding cells aren’t burned or damaged.
Because the ultraviolet light is absorbed almost entirely at the surface, each pulse removes an extraordinarily thin, precise layer. The laser sculpts the cornea according to a treatment plan calculated from your prescription. For nearsightedness, it flattens the central cornea so light bends less steeply. For farsightedness, it steepens the curvature. For astigmatism, it smooths out the uneven areas so the cornea curves symmetrically. The actual laser firing time is typically under a minute per eye.
Step 3: Replacing the Flap
Once reshaping is complete, the surgeon folds the corneal flap back into its original position. No stitches are needed. The flap adheres naturally within minutes and begins healing on its own. You’ll rest briefly in the office, and your surgeon will check the flap’s position before sending you home with protective eye shields.
Wavefront-Guided vs. Standard Treatment
Traditional LASIK corrects your basic prescription: the same sphere and cylinder numbers on your glasses. Wavefront-guided LASIK goes further by mapping subtle optical imperfections unique to your eye, called higher-order aberrations. These are irregularities that a standard prescription doesn’t capture but that can cause glare, halos, and reduced contrast, especially at night.
A wavefront-optimized approach uses your eye’s measurements to preserve the cornea’s natural shape during treatment, reducing the chance of introducing new aberrations. A fully wavefront-guided approach creates a completely individualized ablation pattern based on a detailed map of how light travels through your specific eye. Both approaches have been shown to reduce postoperative complaints like starbursts and halos compared to conventional treatment, with some evidence suggesting the fully guided version performs better for people with significant astigmatism.
What Recovery Looks Like
Vision improves noticeably within hours, though it may be hazy or fluctuating at first. Most people are cleared to drive the day after surgery and meet the legal vision standard at that point. You can shower and wash your hair after 24 hours, and flying is fine within a day or two.
By one week, most patients return to moderate exercise like jogging or light weightlifting and can wear eye makeup again. Your vision will continue to sharpen and stabilize over the following weeks. Complete healing, including final stabilization of your prescription, typically takes three to six months. During this period, mild fluctuations in clarity are normal and not a sign that something went wrong.
How Effective LASIK Is
A meta-analysis of FDA-approved LASIK devices found that 97% of patients achieved 20/40 vision or better without glasses, the threshold for legally driving in most states. About 62% reached 20/20. More recent individual studies have reported even higher numbers, with 99% of eyes hitting 20/40 or better. Results depend on your starting prescription: people with moderate nearsightedness tend to land closest to perfect vision, while those with very high prescriptions or significant astigmatism may still need thin glasses for certain tasks.
Common Side Effects
Dry eye is the most frequent side effect, affecting anywhere from 20% to over 50% of patients in the weeks and months following surgery. The flap creation process temporarily disrupts corneal nerves that signal your eye to produce tears. For most people, dryness improves gradually over three to six months as those nerves regenerate. Artificial tears are a staple of early recovery, and some patients need them occasionally for longer.
Halos and starbursts around lights at night are also common in the early recovery period, particularly in dim conditions when your pupil dilates. These visual disturbances tend to diminish as healing progresses, though a small percentage of patients notice them long-term. Wavefront-guided treatments have helped reduce the frequency of these symptoms compared to earlier generations of the procedure.
Serious complications like infection, significant vision loss, or flap problems are rare. The combination of a bladeless flap and computer-guided reshaping has made the procedure considerably more predictable than it was in its earlier years.