Small Incision Lenticule Extraction

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The Small Incision Lenticule Extraction ( SMILE ), or short-cut lenticule extraction, is a method of refractive surgery , i.e. an operation on the eye that is intended to replace glasses or contact lenses .

Basics

This method is a further development of the previously common ReLEx flex operation. The lenticle (a lenticular piece of tissue) is removed through a peripheral incision that leaves the front of the cornea of ​​the eye largely untouched. Theoretically, this procedure should protect most of the sensitive nerves of the cornea and minimize biomechanical irritation caused by major operations on the eye.

With ReLEx flex, as with LASIK, a flap is lifted off which allows the lenticule to be surgically removed. In contrast to this, with the SMILE method, only a small cut 2 to 4 mm long is produced for the manual removal of the previously separated lenticle.

Differences from conventional methods

The ReLEx method is minimally invasive compared to a LASIK procedure. The critical laser intervention is not performed on exposed tissue, but on the intact cornea, which minimizes the risk of variability caused by laser ablation . In addition, the ReLEx SMILE method has some theoretical advantages over the ReLEx flex method:

  • Less trauma to the cornea
  • Less loss of sensitivity by preserving the innervation
  • Greater postoperative biomechanical resilience due to the largely intact surface of the cornea

requirements

With the ReLEx method, myopic ametropia between −2 and −10 diopters and astigmatism up to 5 diopters can be corrected. If the ametropia is too low, the lenticule to be extracted would be too thin and could tear. Far-sightedness cannot be corrected with this method, as this would require the extraction of a concave lenticle.

Clinical results

Three months after the operation, the remaining ametropia averages between −0.25 ± 0.44 diopters. ReLEx SMILE is a very young method, which is why there are no long-term studies yet. In the first three months after the operation, however, similar to the results with the ReLEx flex method, there did not seem to be any notable changes in the corrected visual acuity (-0.15 diopters in the first month).

Complications

Most of the existing studies on ReLEx SMILE are too small to provide reliable information about the safety of the procedure. However, there is evidence that the safety of the method is comparable to the LASIK method, although the recovery time may be longer in some cases.

The most common complications are tears at the interface and slight signs of abrasion . Rare complications include difficulty removing the lenticle, reducing suction, decentralization, and perforation. However, complications that would arise from taking off a flap (pain, sensitivity disorders, etc.) are largely eliminated.

Individual evidence

  1. ↑ a b c Anders Ivarsen, Jesper Hjortdal: All-Femtosecond Laser Keratorefractive Surgery . In: Curr Ophthalmol Rep . tape 2 , 2014, p. 26-33 , doi : 10.1007 / s40135-013-0032-2 .
  2. ↑ W. Sekundo, K. Kunert, C. Russmann, A. Gillespie, W. bite, G. Stobrawa, M. stickers, M. Bischoff, M. Blum: First efficacy and safety study of femtosecond lenticule extraction for the correction of myopia: six-month results . In: Journal of Cataract and Refractive Surgery . tape 34 , no. 9 , 2008, p. 1513-1520 , doi : 10.1016 / j.jcrs.2008.05.033 .
  3. ↑ a b A. Vestergaard, AR Ivarsen, S. Asp, J. Ø. Hjortdal: Small-incision lenticule extraction for moderate to high myopia: predictability, safety, and patient satisfaction . In: Journal of Cataract and Refractive Surgery . tape 38 , no. 11 , 2012, p. 2003-2010 , doi : 10.1016 / j.jcrs.2012.07.021 .
  4. ↑ Alexandra Grass: A life without glasses. In: Wiener Zeitung. March 27, 2013, accessed August 16, 2014 .
  5. ↑ J. Ø. Hjortdal, AH Vestergaard, A. Ivarsen, S. Ragunathan, S. Asp: Predictors for the outcome of small-incision lenticule extraction for myopia . In: J Refract Surg . tape 28 , no. 12 , 2012, p. 865-871 , doi : 10.3928 / 1081597X-20121115-01 .
  6. ↑ Regina Albers: 125000 laser surgeries a year. In: Focus. November 25, 2013, accessed August 16, 2014 .
  7. ↑ Claudia Richter: With the laser into a life without glasses. diePresse, September 21, 2013, accessed on August 16, 2014 .
  8. ↑ KS Kunert, C. Russ, M. Blum, VLG Sluyterman: Vector analysis of myopic astigmatism corrected by femtosecond refractive lenticule extraction . In: Journal of Cataract and Refractive Surgery . tape 39 , no. 5 , 2013, p. 759-769 , doi : 10.1016 / j.jcrs.2012.11.033 .
  9. ^ Felix Heyder: New laser therapy against ametropia. derStandard, October 9, 2013, accessed August 16, 2014 .