Refractive surgery is any eye procedure that reshapes the cornea or replaces the eye’s natural lens to correct vision problems like nearsightedness, farsightedness, astigmatism, and age-related reading difficulty. The goal is to change how light bends as it enters the eye so that it focuses precisely on the retina, reducing or eliminating the need for glasses or contacts. Over 95% of patients report satisfaction after the most common procedure, LASIK, and roughly 97% achieve driving-legal vision without correction.
How Refractive Surgery Corrects Vision
Your eye works like a camera. Light passes through the cornea (the clear front surface) and the lens behind it, which together bend light rays to meet at the retina in the back of the eye. When the cornea is too curved, too flat, or unevenly shaped, light lands in front of or behind the retina, producing blurry vision. Refractive surgery fixes this mismatch.
For nearsightedness, the surgeon removes a tiny disc of tissue from the center of the cornea to flatten it, so light that was focusing too early gets pushed back to the retina. For farsightedness, tissue is removed from the edges of the cornea instead, steepening the center so light converges sooner. For astigmatism, where the cornea curves more steeply in one direction than the other, microscopic cuts or laser pulses smooth out the irregularity so the surface bends light evenly.
Not all refractive surgery involves reshaping the cornea. Lens-based procedures work inside the eye, either adding an artificial lens in front of the natural one or replacing the natural lens entirely. Both approaches change the eye’s focusing power without touching the corneal surface.
Laser Procedures: LASIK, PRK, and SMILE
The three most widely performed laser procedures all use a laser to reshape corneal tissue, but they differ in how the surgeon accesses that tissue and how quickly you recover.
- LASIK. The surgeon creates a thin flap on the cornea’s surface, folds it back, then uses an excimer laser to reshape the exposed tissue before laying the flap back down. Most people return to work and driving the next day. The national average cost is about $2,250 per eye.
- PRK. Instead of creating a flap, the surgeon removes the cornea’s outermost layer entirely. The same excimer laser reshapes the tissue underneath. Because that outer layer has to regrow, vision stays blurry for up to three weeks, and full recovery takes longer. PRK is often less expensive than LASIK and can be a better fit for people with thinner corneas, since no flap is needed.
- SMILE. A femtosecond laser (different from the excimer used in LASIK and PRK) cuts a small disc of tissue inside the cornea. The surgeon then removes that disc through a tiny incision, only a few millimeters wide. Recovery typically takes about a week, falling between LASIK and PRK. SMILE also produces less post-surgical dry eye than LASIK because it disrupts fewer corneal nerves.
Lens-Based Procedures
When a prescription is too strong for safe laser correction, or the cornea is too thin or irregular, lens-based surgery offers an alternative. There are two main approaches.
An implantable collamer lens (ICL) is placed inside the eye in front of the natural lens, functioning like a permanent contact lens. The natural lens stays in place, which preserves the eye’s ability to shift focus at different distances in younger patients.
Refractive lens exchange (RLE) removes the natural lens entirely and replaces it with an artificial intraocular lens. During the procedure, the surgeon makes a small incision in the cornea, breaks up the natural lens with ultrasonic energy, and inserts a custom replacement. RLE is especially popular for adults over 40 who are developing presbyopia, the gradual loss of near-focus ability that makes reading glasses necessary. It’s also a strong option for people with very high prescriptions or corneal conditions that rule out laser surgery. Because the natural lens is removed, RLE also eliminates the possibility of cataracts later in life.
Correcting Age-Related Near Vision Loss
Presbyopia is one of the trickier problems for refractive surgery because it involves the lens losing flexibility rather than the cornea being the wrong shape. Surgeons use several strategies, none of which perfectly replicate the eye’s youthful ability to shift focus.
Monovision is the simplest approach. One eye is corrected for distance and the other for near vision. The brain learns to favor whichever eye has the sharper image for the task at hand. Success rates range from about 72% to 93%, and results tend to be best when the difference in correction between the two eyes is kept relatively small (under 1.50 diopters). Larger differences reduce depth perception and contrast sensitivity, making some people uncomfortable.
Multifocal intraocular lenses, used during RLE, attempt to provide clear vision at multiple distances by splitting incoming light into separate focal points. The tradeoff is a reduction in contrast sensitivity and potential glare or halos around lights at night. For most people these effects are tolerable, but in some cases the visual disturbances are bothersome enough that the lens needs to be exchanged.
Who Qualifies
Candidacy depends on several factors. Your prescription needs to have been stable for at least a year before surgery. Age matters: being under 30 is considered a risk factor for a rare complication called keratectasia, where the cornea progressively weakens and bulges after surgery. Most surgeons prefer candidates to be at least 18 to 21, though the risk continues to decrease with age.
Corneal thickness is a key measurement. Corneas thinner than 500 micrometers are considered a risk factor for LASIK, and the surgeon needs to leave enough residual tissue (at least 275 to 300 micrometers) after reshaping to maintain structural integrity. People with thin corneas may be steered toward PRK, SMILE, or a lens-based procedure instead. Other disqualifying factors can include certain autoimmune conditions, active eye infections, or unstable corneal shapes detected on topography scans.
Success Rates and Satisfaction
LASIK outcomes, the most studied of any refractive procedure, are consistently strong. A meta-analysis of FDA-approved LASIK devices found that 97% of patients achieved 20/40 vision or better without glasses (the legal threshold for driving in most states), and 62% reached 20/20. In a study of over 2,100 patients, overall satisfaction after primary LASIK surgery was 95.4%, with individual studies in the analysis ranging from 87% to 100%.
These numbers represent averages across a wide range of prescriptions. People with mild to moderate nearsightedness tend to have the highest rates of 20/20 outcomes, while those with very high prescriptions or significant astigmatism may end up with excellent functional vision that still falls slightly short of 20/20.
Risks and Side Effects
Dry eye is the most common side effect. Nearly all LASIK patients experience some degree of dryness immediately after surgery because the procedure cuts corneal nerves that regulate tear production. The reported prevalence of post-LASIK dry eye ranges from 36% to 75% in the early weeks. By three months, about one-third of patients who had normal tear function before surgery still report dry eye symptoms, though only about 4% describe them as severe. Between 8% and 48% of patients continue to experience dryness at six months.
SMILE causes less dry eye than LASIK because the smaller incision disrupts fewer nerves. PRK also affects the corneal nerves but through a different mechanism, with about 37% of patients reporting dry eye symptoms afterward.
Glare and halos around lights at night are another commonly reported concern, particularly in the first few months while the cornea heals. These visual disturbances tend to diminish over time for most people but can persist in a small percentage, especially those with large pupils or high prescriptions. More serious complications like infection, significant vision loss, or keratectasia are rare.
Recovery Timeline
How quickly you return to normal depends on the procedure. After LASIK, most people drive and work the next day, though vision may fluctuate for weeks. SMILE patients typically see well within a week. PRK has the longest initial recovery, with meaningful blur lasting up to three weeks and a slower return to driving and work.
Regardless of procedure, expect some blurry patches or shifting vision for several weeks to months as the cornea settles. Vision is generally stable and clear by about six months after surgery. During the healing period, you’ll use prescription eye drops and avoid rubbing your eyes. Physical activity restrictions vary by procedure but typically ease within a few weeks.