Is SMILE Something Really Worth Smiling About?

January 31, 2017

SMILE or Small Incision Lenticular Extraction is a procedure that entails using a femtosecond laser to create a lenticule of a defined thickness that can be removed through a small incision made in the cornea. It is sometimes hailed as the third generation of laser vision correction technology (After PRK and LASIK). The reasoning behind considering this technology stems from the fact that SMILE allows surgeons to be able to remove the desired amount of tissue to correct vision without having to either create a surface ablation in PRK or a flap-like in LASIK. This technology was recently approved in the United States and Canada.

In August of 2015, I had the pleasure of personally flying to Jena, Germany to further investigate this technology from the manufacturer and from various surgeons in Germany. I had spent a great deal of time researching this technology in anticipation that it may get approved in North America in the near future. After consulting with the manufacturer and surgeons using this technology, I was left with several conclusions:

1. SMILE works only for patients who are nearsighted and have astigmatism. There is no effective way to use SMILE for hyperopia.
2. SMILE technology as currently practiced cannot address astigmatism fully as it cannot account for any cyclotorsion that may arise during the time of surgery. In contrast, excimer laser systems have sophisticated tracking software that can ensure pristine alignment during the ablation is achieved to maximize the success of vision correction
3. SMILE technology cannot address high order aberrations that are now considered an important issue to address in any laser vision correction. To put things in perspective, when LASIK and PRK were first introduced there were no effective ways to address high-order aberrations at the time either.
4. For patients with less than 3 diopters, experienced SMILE surgeons indicated to me that there will be challenges to performing manual removal of the lenticules as they can be thin and more fragile. As such, most SMILE surgeons recommend performing SMILE initially on patients with 3 diopters or more of nearsightedness.
5. There have already been reports of ectasia developing after SMILE in the literature which, contrary to popular belief, was felt to be less likely to develop with this technology compared to LASIK. Ectasia is a rare complication that can occur after laser surgery which was deemed less likely to develop with SMILE vs LASIK. We now know that this is not necessarily true.
6. Patients who get SMILE according to experienced SMILE surgeons typically find their vision recovering after 1 week. This is in keeping with what newer treatments using advanced PRK technology are like. There remains no other technology like LASIK in giving patients the fastest recovery after laser treatment which is usually within a day.
7. If patients require enhancements after SMILE for whatever reason, the only way they can have that is to resort to using PRK which voids the overall point of having SMILE in the first place.

The final question I asked SMILE surgeons was simple: Would you recommend SMILE if I was a mild myope? I was surprised by some SMILE surgeons recommending PRK to me over SMILE because they felt there was more predictability in outcomes!

In summary, I am excited by the fact that we have potentially a new technology for correcting vision as I do truly believe we have to continue refining and developing new ways to correct vision. But I felt that SMILE is currently at its first generation of laser correction with many issues that still need to be refined similar to when PRK and LASIK were first introduced. Currently, we are in the sixth generation of excimer technology and we continue to further perfect our vision outcomes with more refinement in excimer lasers. I do believe that SMILE will one day become a strong contender for correcting vision. My personal opinion is that it’s not as effective as what excimer technology can offer our patients and for that reason, we decided to hold off for now in bringing this technology.

Video: Schwind laser’s capability to deliver an incredibly smooth laser surface is demonstrated in this animated video. This allows for more precision in treating high-order aberrations as well.
At Clarity Laser Vision, we strive to bring the most advanced, and more importantly, proven technology to correct vision. I hope one day SMILE will prove its merit the same way PRK and LASIK did. When it does, I will be sure to introduce it to my patients to ensure we continue our mandate of bringing the best technology.