Corrective eye surgery reshapes the cornea or implants a lens to reduce or eliminate the need for glasses and contact lenses. The most common version is LASIK, but several other procedures exist, each suited to different eyes and prescriptions. Overall satisfaction rates for laser vision correction run between 82% and 98%, with about 95% of patients reporting they achieved their main goal for surgery.
What These Surgeries Actually Fix
Your eye focuses light by bending it through the cornea, the clear front layer, and then through the lens behind it. When the cornea’s curvature doesn’t match the length of your eyeball, light lands in the wrong spot on the retina. That mismatch is what causes nearsightedness, farsightedness, and astigmatism. Corrective eye surgery fixes the problem at its source: either reshaping the cornea so light bends correctly, or placing an artificial lens inside the eye to redirect light onto the retina.
LASIK: The Most Common Option
LASIK accounts for the vast majority of vision correction procedures performed worldwide. The surgeon uses a femtosecond laser to create a thin, hinged flap in the outer layers of the cornea, then folds that flap back to expose the tissue underneath. A second laser, called an excimer laser, precisely removes microscopic amounts of corneal tissue to reshape its curvature. The flap is then laid back in place, where it adheres naturally without stitches.
The procedure itself takes only minutes per eye. Most people notice dramatically improved vision within hours, and the majority return to normal activities within a day or two. In a meta-analysis of FDA-approved LASIK devices, 97% of patients achieved vision of 20/40 or better (the legal threshold for driving without glasses), and 62% reached 20/20.
Modern LASIK platforms offer different mapping technologies that improve precision. Wavefront-optimized treatments aim to prevent new visual distortions from being introduced during surgery. Topography-guided treatments go further by mapping the cornea’s surface irregularities and creating a fully customized reshaping plan. Studies comparing the two found that topography-guided LASIK produced better contrast sensitivity, fewer visual aberrations like halos or glare, and used less corneal tissue in the process.
PRK: A Surface-Level Alternative
Photorefractive keratectomy, or PRK, uses the same excimer laser as LASIK but skips the flap entirely. Instead, the surgeon removes the outermost layer of the cornea (the epithelium) before applying the laser directly to the surface. That epithelial layer grows back on its own within several days, during which you wear a bandage contact lens to protect the eye.
PRK is often the better choice if you have thin corneas, since cutting a flap deeper into already-thin tissue raises the risk of complications. It’s also preferred for people with chronic dry eyes, because creating a LASIK flap can disrupt the corneal nerves involved in moisture production. Athletes or anyone at risk of physical eye contact may also benefit, since there’s no flap that could shift from impact later on.
The tradeoff is recovery time. While the corneal surface closes over by day four or five, full visual stabilization takes longer than LASIK, sometimes several weeks. Discomfort in the first few days is also more noticeable.
SMILE: No Flap, No Surface Removal
Small incision lenticule extraction (SMILE) takes a different approach altogether. Rather than creating a flap or removing the surface layer, a femtosecond laser carves a tiny disc-shaped piece of tissue (called a lenticule) inside the cornea. The surgeon then extracts this lenticule through a small incision, typically 2 to 4 millimeters wide. Removing that internal disc changes the cornea’s shape and corrects vision.
SMILE was FDA-approved in 2016 for nearsightedness between -1 and -8 diopters, with later approvals expanding its range to cover astigmatism up to 3 diopters (and up to 6 diopters on certain platforms). It performs comparably to LASIK in terms of safety and effectiveness for those prescriptions. Because the corneal surface stays mostly intact, SMILE preserves more corneal nerve function and structural strength than LASIK, which can mean less post-surgical dryness and a more stable cornea long-term.
Lens-Based Procedures for Higher Prescriptions
Laser procedures work by removing corneal tissue, so there’s a natural limit to how much correction they can provide. For people with very high prescriptions or corneas too thin for laser reshaping, implantable lenses offer an alternative.
An implantable collamer lens (ICL) is placed inside the eye, behind the iris and in front of the natural lens. It works like a permanent contact lens that you never have to remove or maintain. Your natural lens stays in place, preserving your ability to focus at different distances. ICLs are particularly effective for high myopia: in comparative studies, ICL patients achieved better visual sharpness and more stable prescriptions over six months than patients who had their natural lens replaced.
Refractive lens exchange (RLE) removes the natural lens entirely and replaces it with an artificial one, essentially the same procedure as cataract surgery performed before a cataract develops. RLE is more common in patients over 40 whose natural lens is already losing flexibility, since removing it also eliminates the eventual need for cataract surgery. The downside is that removing the natural lens permanently changes the eye’s focusing system, and multifocal artificial lenses don’t always replicate the full range of natural vision.
Risks and Side Effects
Dry eye is the most frequently reported issue after corneal laser surgery. In a large population study of people who had undergone refractive surgery, about 24% had been diagnosed with dry eye disease, and 33% reported dry eye symptoms. For most, this improves over several months as corneal nerves regenerate, but some people experience persistent dryness that requires ongoing use of artificial tears.
Visual side effects like halos, glare, and starbursts around lights at night are common in the early weeks after surgery and usually fade as the eyes heal. People with naturally large pupils are more prone to these symptoms, particularly in dim lighting.
Serious complications are rare. Corneal ectasia, a progressive weakening and bulging of the cornea, is the most feared outcome, but a large retrospective study found it occurred in only 0.033% of LASIK patients over eight years. Conditions like cataracts, glaucoma, and retinal problems requiring surgery after refractive procedures were each found in fewer than 0.5% of patients.
Who Qualifies and Who Doesn’t
The FDA identifies several factors that can disqualify someone from laser vision correction. Your prescription needs to have been stable for at least a year. If your glasses or contacts changed recently, your cornea may still be shifting, and surgery on a moving target leads to unpredictable results.
Corneal thickness matters significantly. Every laser procedure removes tissue, and starting with a cornea that’s too thin raises the risk of structural damage. This is measured during a pre-surgical evaluation and is one reason PRK or SMILE may be recommended over LASIK, since they preserve more corneal tissue.
Pupil size also plays a role. People with large pupils, especially in dark conditions, are more likely to experience glare and halos after surgery because the treated zone on the cornea may not fully cover the dilated pupil. Younger patients and those on certain medications tend to have larger pupils.
Beyond these physical measurements, certain health conditions can affect candidacy. Autoimmune disorders that impair healing, uncontrolled diabetes, and active eye infections or diseases all typically rule out surgery until they’re resolved or managed. Pregnancy and nursing can temporarily change your prescription, so most surgeons ask you to wait.
Choosing Between Procedures
The right surgery depends on your prescription, corneal anatomy, age, and lifestyle. LASIK offers the fastest recovery and is suitable for the broadest range of common prescriptions. PRK trades slower healing for a safer profile in thin corneas and dry eyes. SMILE offers a middle ground with a minimally invasive approach but currently treats only nearsightedness and astigmatism. ICLs fill the gap for prescriptions too high for laser correction, and RLE makes the most sense for patients approaching cataract age who want to address both vision correction and lens aging in one step.
A thorough pre-operative evaluation, including corneal mapping, thickness measurements, and pupil assessment in dark conditions, determines which options are actually on the table for your specific eyes. Many people walk in assuming they want LASIK and learn that a different procedure is a better fit.