Relex / SMILE is performed for over ten years.

Surgical Technique

A flap (a small layer of the corneal tissue) is precut with a the femtoseconde laser.
The surgeon uses then a forceps to manually remove the flap.
The procedure is performed under topical anaesthesia (eye drops) and lasts 10 minutes per eye.


Post-operative evolution

The eyes are dry and watery for a few hours.

Vision recovers in one to three days (faster than with a surface technique but more slowly than with a LASIK or FemtoLASIK.


Advantages and disadvantages

The only real advantage of SMILE compared to LASIK or FemtoLASIK is the absence of displacement of the corneal cap or flap. A displacement of the cap after LASIK is very rare but, still, remains possible after a major ocular trauma at the edge of the cap.

The second advantage is lighter corneal hyposensibility and therefore less post-operative dry eyes but this advantage is relative: the difference only lasts for a few months compared to LASIK / FemtoLASIK.

Finally, some patients consider that SMILE helps maintain better corneal rigidity. Actually, this statement is purely theoretical and is not demonstrated in practice.

With regard to the disadvantages, let us quote :

  • Slower visual recovery
  • Surgical technique that is more traumatic for the cornea, more manual, less automated
  • Limitation of treatable defects (low to medium myopia)
  • The impossibility to perform personalized treatments (aberrometry, guided by topography or with irian recognition
  • Lower accuracy: the femtoseconde laser has an accuracy of +/- 5 microns while the excimer laser has an accuracy of +/- 0.25 microns
  • Some complications specific to the technique and difficult to correct: a tear of the flap
  • The impossibility to  retouch using the same technique. Any retouch aiming over or under correction should be performed with PRK with a high risk of abnormal healing.



SMILE is a particular technique that currently has meagre advantages and many disadvantages.