A review of clinical outcomes following SMILE for the treatment of astigmatism

ABSTRACT

Introduction

Lenticule extraction refractive procedures have emerged as a capable alternative to excimer laser-based correction procedures, with many associated advantages. At the same time, this technique lacks automated centration and cyclotorsion control, resulting in several concerns regarding its capability to correct moderate or high levels of astigmatism, potentially resulting in higher residual refraction postoperatively compared to excimer laser based refractive corrections.

Areas covered

Using PubMed with keywords ‘SMILE’ and ‘astigmatism,’ the objective of this paper is to review the reported outcomes of lenticule extraction refractive procedures for the correction of myopic astigmatism, and compare them to the excimer laser-based corneal refractive surgery techniques. The inclusion criterion was strict relevance and adequacy to the clinical questions under research, and availability of the abstract in English language.

Expert opinion/commentary

From scientific literature reviewed in this article, lenticule extraction procedures were found to produce satisfactory visual outcomes in terms of safety, efficacy, and predictability. The technique is also predictable and effective for astigmatic corrections, but could present with undercorrections especially for higher refractive corrections. Manual cyclotorsion error compensation and triple marking centration methods are capable additions to the technique in improving outcomes for high-astigmatism corrections, compared to conventional subjective patient fixation.

KEYWORDS:

• Lenticule extraction refractive correction
• femto-LASIk
• myopic astigmatism corrections
• cyclotorsion
• decentration
• higher order aberrations
• cornea biomechanics

Article highlights box

• Lenticule extraction procedures have arguably a steep learning curve compared to conventional flap-based corneal ablative procedures, with Lenticule dissection and extraction being the most difficult step, which could lead to a multitude of complications.

• Lenticule extraction procedures produce satisfactory visual outcomes in terms of safety, efficacy, and predictability.

• The technique is predictable and effective for astigmatic corrections, but presents with undercorrections especially for higher refractive corrections.

• Manual cyclotorsion error compensation and triple marking centration methods are capable additions to the technique in improving the outcomes for high-astigmatism corrections, compared to the conventional subjective patient fixation.

• Astigmatic correction has shown not to be significantly affected by the location of opening incisions or dissection method.

• With increasing surgeon experience and ongoing technical efforts, a standard optimized technique is expected to evolve that may be performed in all types of cases with optimal outcomes and minimal adverse effects.

Financial disclosure

This work has been conducted without external financial support.

Samuel Arba-Mosquera and Shwetabh Verma are employee of SCHWIND eye-tech-solutions GmbH.

Declaration of interest

No potential conflict of interest was reported by the authors.