LASIK vs SMILE: Which Laser Eye Surgery Is Right for You?

Research-informed explainer — last updated April 11, 2026

Both LASIK and SMILE can correct nearsightedness and give you sharp vision without glasses — but they do it differently, and those differences matter depending on your eyes, your lifestyle, and how much you value things like dry-eye risk and recovery speed. LASIK has a 30-year track record and can treat a wider range of prescriptions; SMILE is newer, flap-free, and better at preserving the structural integrity and nerve supply of the cornea. Neither is universally better. The right choice depends on your prescription, corneal thickness, tear-film health, and what your surgeon finds on your pre-op workup.

This explainer draws on peer-reviewed research from five ophthalmologists listed in the Convene directory: James Randleman, M.D., and William Dupps, MD, both at Cleveland Clinic, whose published work on corneal biomechanics and ectasia risk underpins how surgeons choose between these two procedures; Ayad Farjo, M.D., at Corewell Health in Michigan, whose research covers femtosecond LASIK flap technology; Sandeep Jain, M.D., at the University of Illinois, whose work on corneal nerves explains why SMILE tends to cause less dry eye; and Kerry Solomon, MD, at Carolina Eyecare Physicians, who has tracked how surgeon preferences and patient outcomes have evolved across the modern era of refractive surgery.

How each procedure works

LASIK — laser in situ keratomileusis — involves two steps. First, the surgeon creates a thin hinged flap in the outer cornea, either with a blade (microkeratome) or, more commonly today, with a femtosecond laser. The flap is folded back. An excimer laser then reshapes the corneal bed underneath by vaporizing precise amounts of tissue. The flap is replaced and bonds on its own within minutes. Ayad Farjo and colleagues reviewed the technology behind femtosecond flap creation in a 2012 paper in Ophthalmology, documenting how this approach improved flap consistency, reduced the rate of flap-related complications, and enabled broader candidacy compared to older microkeratome methods [8].

SMILE — small incision lenticule extraction — skips the flap entirely. A femtosecond laser creates a small, lens-shaped disc of corneal tissue (a lenticule) entirely within the stroma, plus a tiny arc incision of about 2 to 4 millimeters. The surgeon reaches in through that small opening and removes the lenticule, which flattens the cornea and corrects your vision. There is no flap, no folding, and no excimer laser step.

That structural difference — flap versus no flap — is at the heart of nearly every meaningful clinical distinction between the two procedures.

What research shows about corneal strength

The most cited biomechanical comparison of LASIK and SMILE comes from a 2013 mathematical model developed by researchers including James Randleman, published in the Journal of Refractive Surgery [1]. The model calculated the remaining tensile strength of the cornea after each procedure. Because SMILE leaves the strong anterior stromal lamellae intact and removes tissue only from the mid-stroma, the model predicted that SMILE produces considerably higher postoperative tensile strength than LASIK, even when correcting the same prescription.

A 2014 finite-element analysis by William Dupps and colleagues, published in the Journal of Cataract & Refractive Surgery, used computational modeling to confirm this mechanical picture [5]. In LASIK, the flap severs the anterior lamellae — the strongest corneal fibers — around the entire circumference of the treatment zone. That cut persists permanently. SMILE's small arc incision disrupts far fewer of those fibers, which is why the cornea retains more of its load-bearing capacity after the procedure.

For most patients with normal, healthy corneas and moderate prescriptions, this difference in residual strength may not be clinically relevant. Both procedures leave more than enough corneal tissue to maintain normal shape under the pressures the eye encounters in daily life. Where it matters most is at the margins: patients with thinner corneas, higher prescriptions, or other risk factors for post-refractive ectasia — a rare but serious complication where the cornea progressively bulges after surgery.

Ectasia risk: why candidacy screening is the most important step

Ectasia is the major safety concern in laser refractive surgery. It occurs when too much corneal tissue is removed and the weakened stroma cannot maintain the cornea's normal shape, leading to progressive thinning and distortion of vision that may eventually require a corneal transplant.

James Randleman published two landmark papers on ectasia risk that now form the backbone of pre-operative screening for both LASIK and SMILE candidates. A 2007 study in Ophthalmology developed the first comprehensive risk assessment framework, identifying the key preoperative variables that predict post-LASIK ectasia [2]. A 2008 paper in the American Journal of Ophthalmology validated a scoring system that lets surgeons assign a quantitative risk score before operating [3].

A 2014 study also co-authored by Randleman in the American Journal of Ophthalmology added another practical metric: the percent tissue altered (PTA), which divides the total tissue disrupted by flap and ablation by the total corneal thickness [4]. Eyes with a PTA above 40 percent showed substantially higher ectasia rates even when their preoperative topography looked normal. This finding changed how surgeons calculate safety margins for LASIK and pushed the field toward more conservative treatment thresholds.

For SMILE, the structural argument is that the preserved anterior lamellae provide a higher margin of safety at any given amount of tissue removal, which is why SMILE is often discussed as the better choice for patients near the boundary of safe LASIK candidacy. The caveat is that ectasia has also been reported after SMILE — it is not immune — and the same principle applies: the less tissue removed relative to total corneal thickness, the safer the outcome.

William Dupps, in a 2014 review on biomechanics of corneal ectasia in the Journal of Cataract & Refractive Surgery [7], summarized the evidence base for how both mechanical and cross-linking-based treatments are used to manage ectasia when it does occur. His earlier 2006 review on corneal biomechanics and wound healing in Experimental Eye Research [6] established the foundational framework that subsequent LASIK and SMILE biomechanical studies built on.

At a glance

Dry eye: the most common patient complaint

Dry eye after laser vision correction is the side effect patients ask about most. LASIK's flap creation severs the subbasal nerve plexus — the dense network of sensory nerve fibers that runs just beneath the epithelium and tells your brain to produce tears. After LASIK, the corneal sensitivity drops sharply and takes months to recover. For most patients this means a period of temporary dryness managed with artificial tears. For a minority, dryness is persistent and significantly impacts quality of life.

SMILE's small incision cuts far fewer of these nerves. A comprehensive 2014 review of corneal nerve anatomy and function published in Survey of Ophthalmology by Sandeep Jain and colleagues [10] documented how the subbasal plexus responds to injury and regenerates, providing the mechanistic rationale for why procedures that disrupt fewer fibers cause less dry eye. The clinical implication is direct: if you already have borderline dry eyes, or if tear-film health is important for your occupation — pilots, for example, or people who spend long hours on screens — the nerve-preservation advantage of SMILE is a meaningful consideration.

It is worth noting that this difference in nerve disruption is best understood as a difference in severity and duration of dry eye, not a guarantee that SMILE causes zero dryness. Some degree of tear-film disruption is common with any corneal surgery. Your surgeon should evaluate your tear film with a Schirmer test or meibomian gland assessment before recommending either procedure.

What LASIK can do that SMILE cannot

LASIK has one significant advantage: treatment range. LASIK corrects myopia (nearsightedness), hyperopia (farsightedness), and astigmatism. SMILE, at least in its currently FDA-approved form in the United States, is approved for myopia and myopic astigmatism only. If you are farsighted, LASIK or PRK remains your option for laser vision correction.

Wavefront-guided LASIK — which customizes the ablation pattern to your eye's unique higher-order optical aberrations — has a substantial evidence base. A 2008 assessment published in Ophthalmology by researchers including Ayad Farjo documented outcomes for wavefront-guided LASIK across a large study population, finding strong visual acuity outcomes with good control of higher-order aberrations [9]. Wavefront-guided SMILE is in development but not yet as widely available, which means some patients may achieve better quality-of-vision outcomes with wavefront-guided LASIK than with current SMILE platforms.

Retreatment is also more straightforward with LASIK. If your vision changes or the initial result undershoots the target, your surgeon can lift the original flap years later and apply additional laser treatment. SMILE retreatment is more complex because there is no flap to lift — a surface procedure (PRK) is typically required, which has a longer healing time.

Who is a better candidate for each

A good LASIK candidate generally has:

• Stable prescription for at least one to two years
• Adequate corneal thickness (typically 500 microns or more)
• Normal corneal topography with no signs of early keratoconus
• Ectasia risk score in the low range [2]
• No significant dry eye disease

SMILE may be a better fit when:

• You have borderline corneal thickness but still enough tissue for safe treatment
• You have a history of dry eye or a profession where dry eye is a serious concern
• Your prescription is in the myopic range (SMILE does not currently treat hyperopia)
• You participate in contact sports or activities where a flap displacement, however rare, would be a concern

Kerry Solomon and colleagues tracked how refractive surgeon preferences and patient outcomes evolved in surveys published in the Journal of Cataract & Refractive Surgery [11]. That longitudinal view captures how much the field has moved — from older microkeratome LASIK to all-femtosecond flap creation to the emergence of flapless procedures — and illustrates that surgeon volume and experience with a specific platform plays a meaningful role in outcomes.

Questions to ask your surgeon

• Based on my corneal topography and thickness, am I a safe candidate for LASIK, SMILE, or both?
• What is my ectasia risk score, and how does it affect which procedure you recommend?
• Do I have any dry eye disease, and if so, how should we manage it before considering surgery?
• Does your center perform wavefront-guided LASIK, and would that give me better quality vision than standard SMILE on your current platform?
• If my vision changes in five years and I need a touch-up, what retreatment options does each procedure leave open?
• How many SMILE procedures have you personally performed, and what are your outcomes?

The bottom line

LASIK and SMILE produce comparable visual acuity in properly selected patients. SMILE preserves more corneal structural strength and causes less disruption to corneal nerves — advantages that matter most for patients with thinner corneas, borderline ectasia risk, or existing dry eye disease. LASIK treats a broader prescription range including farsightedness, offers wavefront-guided customization with a longer evidence base, and allows simpler retreatment if needed. For most patients with moderate nearsightedness and healthy, thick corneas, either procedure is a safe, effective choice. The decision should be made with a surgeon experienced in both techniques who can evaluate your specific anatomy and risk profile.