Femto LASIK or SMILE?

Femto LASIK and SMILE (KLEx) are the two laser techniques most often chosen today. Femto LASIK creates a flap on the cornea, lifts it for treatment, then repositions it afterwards; SMILE works through a much smaller incision, removing tissue from inside the cornea with no flap. This can affect dry eye risk and how the eye feels in the first few days. Which technique suits you depends on your corneal structure and refractive error, and SMILE is only used for myopia and astigmatism. The final decision is made at your examination; both are quick, outpatient procedures.

In Femto LASIK, a femtosecond laser creates a thin flap on the cornea's surface, lifted so the laser can treat the inner layer, then repositioned at the end. The computer-controlled laser cuts the flap to a pre-planned thickness, and it settles back into place without stitches. Femto LASIK can be considered for myopia, hyperopia and astigmatism alike. The eye should not be knocked or rubbed in the early period, and protective eyewear is recommended for the first few days.

In SMILE, a femtosecond laser shapes a lens-like piece of tissue (a lenticule) inside the cornea, removed through a small incision just a few millimetres wide, with no flap created. Because the incision is so small, most of the corneal surface stays largely untouched. Clinically, SMILE is used only for myopia and astigmatism, and is not an option for hyperopia. Protective eyewear is still recommended afterwards; for some patients, the small incision is an advantage when returning to daily activities.

In Femto LASIK a wide flap is opened and closed again, whereas SMILE uses a much smaller incision with no flap; because fewer corneal nerves are cut, this can affect dry eye symptoms for some patients. The difference also determines which method suits which refractive error — for hyperopia, the choice narrows to Femto LASIK. Protective drops are prescribed after both procedures, and avoiding any knock to the eye early on is advised for both; SMILE's smaller incision can ease this somewhat. Mild sensitivity around lights at night can occur with either method in the first few weeks and usually fades. The incision or flap size is roughly 9 mm for Femto LASIK and around 3 mm for SMILE; the diagram below shows this difference.

The table below summarises six key differences between Femto LASIK and SMILE. The method marked under each criterion generally comes to the fore there; the final decision still depends on the refractive error, corneal structure and dry eye history. No tick means one method is absolutely superior — it only reflects a general tendency.

Femto LASIK may be preferred for patients with hyperopia, or those for whom a flap-based method suits. Since SMILE is not an option for hyperopia, assessment proceeds directly through Femto LASIK. It may also suit patients with sufficient corneal thickness for a flap-based method, including those with previous dry eye who cannot have SMILE because of hyperopia. The first check-up after Femto LASIK is usually the next day, confirming the flap sits correctly.

SMILE can be considered for patients with myopia and/or astigmatism who, due to a tendency towards dry eye, prefer a less invasive option, and for those who want a smaller incision and take part in contact sports. SMILE is not an option for hyperopia. For myopic or astigmatic patients whose work or social life makes a quick return to visual comfort important, SMILE can stand out for this reason too. The first check-up after SMILE is also usually the next day; the small incision tends to simplify follow-up.

Op. Dr. Anıl Kaya, an eye surgeon (ophthalmologist), decides which method suits by assessing the refractive error, corneal thickness, dry eye history and the patient's expectations together. Refractive error type is the first deciding factor: hyperopia rules out SMILE, while myopia or astigmatism means corneal structure and dry eye history are weighed together. The patient is then told the date of the first check-up and what to watch for during recovery — protective eyewear, prescribed drops, and avoiding any knock to the eye. Hyperopia sends the decision straight to Femto LASIK; myopia or astigmatism brings corneal thickness, dry eye history and sporting or occupational needs into the assessment.

To clarify which method might suit you, review the decision-support information on which laser method is right for you, then arrange a laser suitability examination. Your refractive error type is the first step; that, together with the myopia, hyperopia and astigmatism pages and an examination, gives a clearer picture. This page only summarises general tendencies — which method suits you becomes clear from the measurements at your examination. Both methods aim for a lasting solution, reducing dependence on glasses or contact lenses; the difference lies in which refractive error each treats and the incision size.

To clarify which method may suit you, request an appointment through the contact page and then arrange a laser suitability examination. Sharing your current glasses prescription and previous eye examination records at your appointment speeds up the initial assessment. You can get in touch via the phone number or form on the contact page.