Technology keeps on advancing and in medical sciences it keeps on making a difference to lives of millions of people across the globe. This is even truer for us, Lasik surgeons, who continue to get access to better laser vision correction procedures.
Let’s for a minute go back and see how the Laser vision correction started and how it has evolved.


PRK is first generation Laser Vision correction to get rid of spectacles. Photorefractive Keratectomy (PRK) also known as Epi-Lasik or surface Lasik where top layer of cornea is mechanically removed and then excimer laser is applied to the cornea to re-shape it and correct patient’s eye power. Due to surface ablation, the post procedure recovery period was painful and there some initial problems noted related to delayed and inferior healing.


Advent of First generation LASIK: The next advancement which became hugely popular was LASIK. Lasik laser vision correction is a great procedure in which tissue is precisely ablated (burned/ vaporized) using excimer laser to reshape the cornea and thus remove the spectacle power. However Lasik entails making a flap with a mechanical blade called microkeratome. So to further improve and advance the procedure, Femtolasik was developed.

Femto Lasik:

Second generation- Femtosecond laser (also called Femto Lasik): In FemtoLasik compared to Lasik, corneal flap is created with the help of another cutting laser called Femtosecond laser. The introduction of Femtosecond laser increased the precision and accuracy of flap making as compared to the micorkeratome blade. Hence Femto-Lasik was also called bladeless LASIK. Femto-Lasik thus allowed the laser vision correction surgery to become even more safer by adding extra precision. But the problem of a large 20mm cut for making a flap remained whether with the blade or with Femto second laser.

Relex Smile:

Third generation Lasik – Relex Smile Lasik: What if we have a procedure where we can do away with flap as well and make it more precise, accurate, and safe compared to the previous laser vision correction procedures? Wouldn’t that be wonderful and make the procedure so much better. I think this is where ReLEx SMILE also called SMILE Laser Surgery comes into picture.

What is Smile Lasik laser surgery?

Smile Lasik surgery, also the short form of “Small Incision Lenticule Extraction” is an all laser based flapless surgery which is possible only with the Visumax femtosecond laser platform from Carl Zeiss. In the current times no other laser machine allows this procedure to be performed. With Smile Lasik laser surgery the disadvantages of earlier procedures have disappeared and the advantages have remained!

How is Relex Smile Lasik different from Femto Lasik/ Custom Lasik?

In Femto LASIK, patient is first positioned under the Femto Lasik machine. The femtosecond laser helps in creating the flap. The flap creation with Femto second laser machine, depending on the laser machine, entails the cup touching the eye and an increase in pressure on the eye surface. It is also a quick process. Overall the flap creation with femto second laser is far more precise and accurate compared to blade based flap creation. But the fact of the matter is that flap creation is still done. Once the flap is created, patient bed moves to the Excimer laser machine. Excimer laser precisely burns the corneal tissue and reshapes the cornea. Flap is then repositioned and it again becomes a part of the cornea. So first a flap is created and then Excimer laser ablation is done.

In SMILE Lasik laser vision correction, with the help of femto second laser generated from a platform called Visumax from Carl Zeiss, a tissue lenticule is prepared inside the intact cornea, thickness of which is dependent on patient’s eye power. The advanced cup of the machine calibrates itself to the patient’s corneal curvature. A gentle touch of the cup and a mild pressure are felt during the procedure. The laser precisely creates the tissue disc inside the cornea. This entire treatment takes place in a closed environment unlike a flap based procedure. This ‘lenticule’ is then removed through a small key-hole 2mm opening made by the laser in the periphery of the cornea. All this is done without creating a flap and hence it is a flapless and a bladeless procedure. In nutshell, instead of a 20mm cut for a flap creation, there is a small 2mm cut for removing the cornea.

Surgical Advantages of SMILE Lasik laser over Femto Lasik laser

The major advantage of ReLEx smile is that there is a precise tissue disc creation in a closed environment and there is no flap cutting involved. Unlike excimer–laser-based procedures like LASIK or Femto Lasik, ReLEx smile uses a solid-state laser, and is not affected by environmental humidity. The VisuMax is a silent, soft, and gentle laser. It does not produce any burning smell, there is no vision blackout during the procedure. Additionally during the laser procedure due to the shape of the cup and its calibration to patient’s cornea, patient’s cornea is not forced into a non-physiological planar shape. Therefore artifacts are avoided during the laser procedure. Also there is no need to unnecessarily increase intraocular pressure to very high levels.

Advantages of Smile Surgery:

  1. Induction of spherical aberration is minimized. Therefore ReLEx smile patients are more likely to achieve better quality of vision, which is especially true for those with high myopia. Additionally ReLEx SMILE may be more accurate than LASIK, especially for higher degrees of myopia.
  2. Biomechanical stability of cornea is better retained after ReLEx Smile than procedures like Lasik or Femto Lasik where flap is created.
  3. As there is no flap there is minimal postoperative discomfort.
  4. When flap is created during femto Lasik nerves are cut and this causes dry eye. In cases of ReLEx SMILE there is no increased dry eye as no flap is created.
  5. With no risk of flap displacement, ReLEx smile is the best procedure for those who are involved in contact sports and combative professions like army, air force etc where they may be chances of trauma.
  6. ReLEx SMILE is also faster to perform than Femto LASIK as the patient bed stays under one laser machine only.
  7. ReLEx SMILE Laser vision correction treatment takes place in a closed environment, without outside contact. Unaffected by outside temperature, humidity, draft, etc. This increases the precision of the whole procedure as well.

In the evolution of refractive laser techniques, we surgeons have always longed for a time when closed intra corneal surgery would come to the front, avoiding the need to disturb the corneal surface and creating a flap. SMILE Lasik laser vision correction is a step in the right direction which has made the eye power reduction procedure safer and more effective.