SMILE stands for SMall Incision Lenticule Extraction. The way the small incision and lenticule are created is the main part of the surgery. Femtosecond lasers have been around for about 15 years now. One day, someone said, “Hey, what if we used the femtosecond laser to do the whole vision correction procedure instead of just to create the flap?” SMILE was created as a result of that thought. It turns out, performing vision correction is possible from start to finish with just the laser that normally creates the LASIK flap.
How? It works by accomplishing the same act that LASIK does. If someone is myopic, then it’s possible to fix their myopia by flattening their cornea. LASIK does this by using an excimer laser to reshape the cornea. It reshapes the cornea with tiny pulses of invisible light which can remove thousandths of a millimeter of cornea very precisely at a time. It is like using the world’s tiniest paintbrush. Femtosecond laser is used to create a flap so the excimer laser can do its tiny paint-brushing work underneath and therefore leave the surface of the eye happy and undisturbed. In SMILE, the cornea is flattened for the same reason, but by a different method.
When a femtosecond laser creates a flap, it does so by placing a plane of microscopic air bubbles in between a couple of layers of corneal tissue. The cornea has layers kind of like an onion, so those bubbles just separate a layer from the one underneath along a natural plane. With SMILE, the same exact thing happens. Except this time, a second plane of microscopic bubbles is placed just above the first one. The layers of cornea in between those two planes of bubbles are now independent. A small sliver of cornea is now free floating (in a very tightly confined area) inside the cornea. That small sliver is called a lenticule (a.k.a. the “L” in SMILE). Now how to extract this lenticule? Well, there’s no better way than a SMall Incision right at the border of the lenticule. And so, it is removed just as the theoretical Kyle Smile first envisioned.
Removing a tiny sliver of cornea makes it flatter. SMILE works by tailoring the thickness of the sliver to the amount of myopia to be treated. It can treat enormous amounts of myopia, far beyond the safe range for LASIK. It’s because the only incision is small and the rest of the cornea around the removed, round lenticule is left intact. Since the corneal layers at the very front are the strongest ones, leaving all of them almost completely untouched means that a lot of cornea can be removed with minimal impact on its structural integrity.
There are some folks for whom SMILE is an option now available where no option was available until now. If you are exceptionally nearsighted and your eye is too small for an implantable contact lens (ICL), SMILE is worth researching further.
The doctors at Center for Advanced Eye Care will talk with you and evaluate the health of your eyes and let you know if SMILE will work for you.