Both LASIK and SMILE are proven laser eye surgery procedures that can correct short-sightedness and astigmatism with excellent results. Many patients researching their options encounter both terms and find it difficult to understand the practical differences. While both use laser technology and produce comparable visual outcomes, they work in fundamentally different ways, and those differences matter for the right patients.
How LASIK Works
LASIK creates a thin hinged flap in the outer corneal layer using a femtosecond laser. The flap is lifted, an excimer laser reshapes the underlying corneal tissue to correct the refractive error, and the flap is repositioned without sutures. Most patients notice dramatically improved vision within 24 to 48 hours, with discomfort typically resolving within hours of the procedure.
LASIK (Laser In Situ Keratomileusis) is the most widely performed laser eye surgery procedure in the world. A femtosecond laser creates a thin, hinged flap in the outer layer of the cornea. This flap is gently lifted, and an excimer laser precisely reshapes the underlying corneal tissue to correct the refractive error. The flap is then carefully repositioned, where it adheres naturally without sutures. LASIK offers a very rapid recovery; most patients notice dramatically improved vision within 24 to 48 hours of surgery, and discomfort typically resolves within a few hours of the procedure.
How SMILE Works
SMILE (Small Incision Lenticule Extraction) is a flapless laser procedure in which a femtosecond laser creates a precisely shaped disc of corneal tissue (a lenticule) within the intact cornea. The lenticule is extracted through a tiny 2 to 3 millimetre incision. No flap is created at any point, and the corneal surface remains largely intact throughout. SMILE is currently approved for the correction of myopia and myopic astigmatism.
SMILE (Small Incision Lenticule Extraction) is a newer, entirely flapless laser procedure. A femtosecond laser creates a precisely shaped disc of corneal tissue (a lenticule) within the intact cornea, and this lenticule is then extracted through a tiny incision of approximately 2 to 3 millimetres. No flap is created at any point in the procedure, and the corneal surface remains largely intact throughout. SMILE is currently approved for the correction of myopia (short-sightedness) and myopic astigmatism.
Key Differences
The most clinically important difference between LASIK and SMILE is the absence of a flap in SMILE, eliminating any risk of flap displacement from eye trauma, making SMILE preferable for contact sports or occupations with eye injury risk. SMILE also severs fewer corneal nerves, which may mean less post-operative dry eye. LASIK can correct myopia, hyperopia, and astigmatism; SMILE is currently approved for myopia and myopic astigmatism only.
The absence of a flap is the most important practical distinction between LASIK and SMILE. Because no flap is created in SMILE, there is no risk of flap-related complications, including flap displacement from a direct blow to the eye. This makes SMILE an attractive option for patients who participate in contact sports, martial arts, or occupations where eye trauma is possible, such as military or police service.
Dry eye is another meaningful difference. LASIK severs more corneal nerves during flap creation, which can temporarily worsen dry eye symptoms in the weeks and months following surgery. SMILE disrupts fewer corneal nerves due to the smaller incision, and may be associated with less post-operative dry eye, though this difference diminishes over time as nerve regeneration occurs.
In terms of prescription range, LASIK can correct myopia, hyperopia, and astigmatism, whereas SMILE is currently approved only for myopia and myopic astigmatism. For patients who are long-sighted, LASIK or PRK remains the laser treatment of choice. Recovery speed is broadly similar between both procedures, though LASIK may offer a slightly faster visual improvement in the first day or two.
Who Suits Each Procedure?
LASIK suits most suitable patients with myopia, hyperopia, or astigmatism who have no particular reason to prefer a flapless approach. SMILE tends to be favoured for patients with moderate to high myopia who are concerned about flap-related risks or post-operative dry eye, or who engage in contact sports. PRK is preferred for patients with thin corneas or those for whom a surface approach is clinically indicated.
LASIK remains an excellent first-line option for most suitable patients with myopia, hyperopia, or astigmatism who do not have a particular reason to prefer a flapless approach. SMILE tends to be favoured for patients with moderate to high myopia who are concerned about flap-related risks or post-operative dry eye, or who are engaged in contact sports. For patients with thin corneas or mild dry eye where surface treatment is preferred, PRK (surface laser without a flap) is also an established and highly effective option.
The Importance of a Pre-Operative Assessment
No reputable refractive surgeon will confirm suitability or recommend a specific procedure without a thorough pre-operative assessment. At Northern Eye Consultants, Dr Ross MacIntyre performs comprehensive assessments including corneal topography and tomography, pachymetry, dry eye evaluation, wavefront aberrometry, and a full dilated eye examination. The procedure recommended is based on your individual measurements and lifestyle; there is no single right answer. A referral from your GP or optometrist is required to attend for an assessment.
No reputable refractive surgeon will confirm your suitability or recommend a specific procedure without a thorough pre-operative assessment. At Northern Eye Consultants, Dr Ross MacIntyre performs comprehensive assessments that include corneal topography and tomography, pachymetry, dry eye evaluation, wavefront aberrometry, and a full dilated eye examination. Based on these results, he will provide a clear recommendation tailored to your anatomy and visual goals. There is no single right answer; the best procedure is the one matched to your individual measurements and lifestyle. A referral from your GP or optometrist is required to attend for an assessment.