SMILE Pro Laser Eye Surgery

Written and edited by the Smart Laser Eye Center Editorial Staff · Medically reviewed by Dr. Alim Huseynov, MD · Last updated: 10 September 2026

SMILE Pro is a flapless laser vision correction procedure. Instead of lifting a corneal flap and then reshaping the exposed stroma with an excimer laser, a femtosecond laser shapes a thin disc of tissue — the lenticule — inside the cornea, and the surgeon removes that disc through a single incision of a few millimetres. The front surface of the cornea is never opened across its full width.

The method belongs to the lenticule extraction family, known in the literature as SMILE (Small Incision Lenticule Extraction). “Pro” refers to the current generation of the platform, on which the lenticule scan is completed in roughly ten seconds and cyclotorsion and centration are tracked automatically. Those figures are manufacturer specifications, not the result of an independent comparative trial.

What SMILE Pro corrects, and what it does not

SMILE Pro is used for myopia and for myopic astigmatism. Hyperopic lenticule extraction is a separate development and is not part of the routine treatment range. Patients with hyperopia or mixed astigmatism are therefore assessed for LASIK, Q-LASIK or a lens-based route instead.

Because the correction is carried in a disc of tissue rather than in a surface ablation profile, the treatment is defined by the lenticule thickness rather than by an optical zone and a transition zone. The planning arithmetic changes accordingly, and so do the safety floors, as set out further down this page.

How SMILE Pro differs from flap-based laser eye surgery

There is no flap in SMILE Pro. There is a corneal cap: the layer of tissue that lies above the lenticule and stays continuous with the rest of the cornea except at the small incision. The distinction is not a matter of vocabulary. A flap is a lid that is lifted and laid back; a cap is never lifted at all.

Three practical consequences follow:

• The anterior lamellae stay intact. The strongest collagen lamellae of the cornea lie in its front third. A flap divides them across the whole flap diameter; a small incision divides them across a few millimetres.
• Fewer corneal nerves are divided. A systematic review and meta-analysis of twelve studies covering 1,076 eyes found no significant difference between SMILE and femtosecond LASIK in visual outcomes — uncorrected acuity, loss of best-corrected lines, spherical equivalent, or predictability within ±1.0 D — but did find a difference in dry eye in favour of SMILE, with a lower OSDI score at six months and significantly higher corneal sensation.

Shen Z et al. 2016 · PLoS One 11(7):e0158176 · doi:10.1371/journal.pone.0158176. The authors rate the overall quality of the evidence as low to very low by GRADE, so these findings are indicative rather than settled.

• There is no flap to displace later. Flap dislocation after direct trauma is rare but it is a recognised event, and it remains possible years after surgery. A cap removes that particular mechanism. It does not make the eye immune to injury.

The numbers behind a SMILE Pro decision

Lenticule procedures have their own safety floors. They are not the LASIK figures with a different label.

• Residual stromal bed: 280 µm. The stroma remaining beneath the lenticule bed.
• Residual corneal thickness: 400 µm. Pachymetry minus lenticule.
• Minimum pre-operative corneal thickness: 470 µm. A screening threshold before any planning is attempted.
• Cap thickness: 100, 110 or 120 µm. A separate menu from the flap thickness list used in the LASIK family, so that a flap value cannot silently become a cap value.

Percent tissue altered is calculated for SMILE Pro but it does not decide the case. The 40 % ceiling was derived from LASIK eyes and validated in LASIK eyes. In lenticule procedures the decision rests on the residual stromal bed and the residual corneal thickness, because those floors are specific to the procedure. Our reports state this explicitly rather than presenting a LASIK threshold as though it had been established here.

That caution is not theoretical. In a review of ectasia reported after SMILE, seven eyes of four patients developed ectasia at a mean percent tissue altered of 38 % — that is, below the LASIK ceiling — and most of those eyes had subclinical keratoconus that had been present before surgery. The authors treat subclinical keratoconus as an absolute contraindication and recommend that LASIK exclusion criteria continue to be applied to SMILE until criteria specific to the procedure have been validated.

Moshirfar M et al. 2017 · Clin Ophthalmol 11:1683–8 · doi:10.2147/OPTH.S147011

How RLES AI supports SMILE Pro planning

RLES AI® is refractive laser eye surgery planning software developed by our group. It applies the rule set above to the values printed on your own diagnostic reports and returns the options that pass every threshold, together with what each one costs in tissue. It is a decision support tool; the surgical decision remains with your surgeon.

For a SMILE Pro plan the software works through, among others:

• Keratoconus and ectasia screening before anything else. BAD-D, ART max and average, Kmax, ISV, IVA, posterior elevation, pachymetric progression, and CBI and TBI where a biomechanical measurement has been supplied. Given the ectasia reports above, a borderline screen carries more weight in a lenticule plan, not less.
• Contact lens warpage detection — separating a genuinely irregular cornea from one temporarily deformed by lens wear, so that a false keratoconus pattern does not exclude a suitable patient and a real one is not missed.
• The correct floors for the correct procedure. The software switches the cap menu, the residual stromal floor and the pre-operative thickness screen when the procedure changes, so that a LASIK value cannot carry over into a lenticule plan.
• Maximum treatable correction from the post-operative keratometry window: the cornea must remain no flatter than 36 D after treatment, and in a flat cornea this ceiling is often reached long before the tissue floors are.
• Comparison with the alternatives — if the numbers do not permit SMILE Pro, the report shows what remains: Q-LASIK, TransEpithelial PRK, or a phakic ICL when the correction should not be carried by the cornea at all.

Read more about RLES AI® and its clinical rule set →

Who is a candidate for SMILE Pro

SMILE Pro may be considered from 18 years of age, in myopia and myopic astigmatism, with a stable refraction, a normal topography and tomography, a pre-operative corneal thickness of at least 470 µm, and enough tissue to satisfy both floors with margin. Between 18 and 21 the decision belongs to the surgeon, and twelve months of documented stability is expected first.

It is not performed in keratoconus or suspected corneal ectasia, in active ocular infection or inflammation, in uncontrolled systemic or autoimmune disease, in pregnancy or breastfeeding, in severe untreated dry eye, or in a cornea that cannot supply the required residual stroma. Hyperopia and mixed astigmatism are outside the treatment range described here.

Recovery after SMILE Pro

• First hours. Watering, light sensitivity and a foreign-body sensation are usual and settle over the first evening.
• Day 1. Vision is functional for everyday tasks in most patients and the first examination is performed.
• First week. No eye rubbing, no water contact, drops exactly as prescribed.
• Weeks 2–4. Pools and the sea are avoided. Vision continues to sharpen.
• Months 1, 3 and 6. Scheduled examinations.

Visual recovery after lenticule extraction is often marginally slower in the first day or two than after a flap procedure, and then converges. Dry eye is generally less pronounced, which is the most consistently reported difference in the comparative literature cited above.

If a residual refractive error remains and treatment is warranted, it is addressed only after the refraction has been stable across at least two measurements taken six weeks or more apart, and it is not addressed by cutting a second plane. The route is a surface treatment over the existing cornea, or conversion of the cap where that is technically available.

Travelling to us for SMILE Pro

Patients travelling from another city or country can usually complete assessment and surgery within a short stay, provided the pre-operative measurements are valid on arrival: contact lenses out for long enough that the cornea has returned to its own shape, and any earlier reports sent in advance for review. The day-one examination is performed here; subsequent controls can be arranged locally and the reports shared back to us. Our patient concierge team arranges the practical side, and the patient journey page sets out each day.

Useful links

• All laser eye surgery methods
• Q-LASIK laser eye surgery
• LASIK laser eye surgery
• TransEpithelial PRK (No-Touch)
• Keratoconus and corneal cross-linking
• Our technology
• Free laser eye examination
• All frequently asked questions

Frequently asked questions about SMILE Pro laser eye surgery

References

1. Shen Z, Shi K, Yu Y, Yu X, Lin Y, Yao K. Small incision lenticule extraction (SMILE) versus femtosecond laser-assisted in situ keratomileusis (FS-LASIK) for myopia: a systematic review and meta-analysis. PLoS One. 2016;11(7):e0158176. doi:10.1371/journal.pone.0158176
2. Moshirfar M, Albarracin JC, Desautels JD, Birdsong OC, Linn SH, Hoopes PC Sr. Ectasia following small-incision lenticule extraction (SMILE): a review of the literature. Clin Ophthalmol. 2017;11:1683–8. doi:10.2147/OPTH.S147011
3. Santhiago MR, Smadja D, Gomes BF, et al. Association between the percent tissue altered and post-laser in situ keratomileusis ectasia in eyes with normal preoperative topography. Am J Ophthalmol. 2014;158(1):87–95. doi:10.1016/j.ajo.2014.04.002

Device figures given on this page are manufacturer specifications and are identified as such in the text. This page is patient information and does not replace an examination. Whether a procedure is suitable for a particular eye can only be established after a complete ophthalmological assessment, and the final clinical decision rests with your surgeon.

This page is general information only and is not a diagnosis or a treatment recommendation; suitability is determined by an eye examination.