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Digital Supplement | Sponsored by Carl Zeiss Meditec

Plenty of Reasons to SMILE

The story of this procedure is really only just beginning.

In 2006, Walter Sekundo, MD, PhD, and I presented, for the first time worldwide at the American Academy of Ophthalmology meeting in Las Vegas, our vision of a refractive surgery procedure that could be performed intrastromally using a femtosecond laser and without ablating the cornea.1 The responses to our presentation ranged from polite interest to skepticism and even ridicule. “It will never work,” seemed to be the general consensus.

Nearly 14 years later and after more than 2 million Small Incision Lenticule Extractions with SMILE performed with the VisuMax femtosecond laser (Carl Zeiss Meditec), it is clear that the critics were wrong. Not only does the procedure work—and work very well—but it continues to gain market share as more surgeons discover the benefits of minimally invasive, flap-free refractive surgery for their patients.


We published our first results with the refractive lenticule extraction procedure for the treatment of myopia and myopic astigmatism in 2008.2 Taking advantage of the properties of the VisuMax femtosecond laser, during the procedure, a lenticule was manually removed after lifting a corneal flap. Evolving from that early success was the refined option of SMILE. In SMILE, the lenticule interface can be separated through one or two small incisions, thereby eliminating the need for a flap.

The ability to avoid the need for a corneal flap, and therefore eliminate all of its associated complications, is one of SMILE’s biggest selling points and one of the reasons the procedure has become so popular. Patients like the idea of minimally invasive intrastromal surgery that can correct their refractive errors and give them excellent quality and quantity of vision.

As the procedure became more popular, the data has accumulated, attesting to the safety and efficacy of SMILE for myopia.3-6 Our own group recently reported the 10-year results of the first cohort of patients treated by VisuMax, and the results are excellent.7 In that study, 56 eyes of 30 patients treated in the initial 2006–2007 study were evaluated after 1 decade. Between baseline and 6 months postoperative, no significant changes were found in terms of visual acuity. The mean spherical equivalent at 6 months postoperative was -0.35 ±0.66 D, which was close to target refraction. Further, 16 eyes (29%) gained 1 to 2 Snellen lines. There was no loss of 2 or more lines in the long-term, and regression over the decade since the procedure was minimal.

This long-term study confirmed my own clinical impression that SMILE is effective, stable, and safe for the treatment of myopia and myopic astigmatism.


As clinicians continue to become more familiar and confident with the technology, SMILE is opening new frontiers into hyperopia, presbyopia, and keratoconus treatments. Some of these exciting developments, and the possibilities they hold to improve the quality of life of our patients, are presented in the pages of this supplement.

SMILE has come a long way since the early results were first presented in Las Vegas in 2006—it is now an established procedure in the ophthalmological mainstream, and it is gratifying to see so many symposia and scientific sessions at the major meetings devoted exclusively to Small Incision Lenticule Extraction. Thanks to the hundreds of clinicians and researchers who have embraced this technology, it is clear that the SMILE story is really only just beginning.

Explore more and get in contact!

1. Blum M. Clinical case studies with the femtosecond system of Carl Zeiss Meditec. Paper presented at: the American Academy of Ophthalmology Annual Meeting; November 12, 2006; Las Vegas.

2. Sekundo W, Kunert K, Russmann C, et al. First efficacy and safety study of femtosecond lenticule extraction for the correction of myopia: six-month results. J Cataract Refract Surg. 2008;34(9):1513-1520. Erratum in: J Cataract Refract Surg. 2008;34(11):1819. 3. Blum M, Täubig K, Gruhn C, Sekundo W, Kunert KS. Five-year results of Small Incision Lenticule Extraction (ReLEx SMILE). Br J Ophthalmol. 2016;100(9):1192-1195.

4. Blum M, Flach A, Kunert KS, Sekundo W. Five-year results of refractive lenticule extraction. J Cataract Refract Surg. 2014;40(9):1425-1429.

5. Sánchez-González JM, Alonso-Aliste F. Visual and refractive outcomes of 100 small incision lenticule extractions (SMILE) in moderate and high myopia: a 24-month follow-up study. Graefes Arch Clin Exp Ophthalmol. 2019;257(7):1561-1567.

6. Agca A, Tülü B, Yasa D, Yıldırım Y, Yıldız BK, Demirok A. Long-term (5 years) follow-up of small-incision lenticule extraction in mild-to-moderate myopia. J Cataract Refract Surg. 2019;45(4):421-426.

7. Blum M. et al: 10-year results of SMILE, under review.

Marcus Blum, MD
  • Chairman of Ophthalmology, Helios Klinikum Erfurt, Erfurt, Germany
  • marcus.blum@helios-gesundheit.de
  • Financial disclosure: Scientific advisory board (Carl Zeiss Meditec)