Small incision lenticule extraction (SMILE) vs LASIK: an ex vivo biomechanical evaluation of low and high Myopic corrections

Session Details

Session Title: Refractive
Session Date/Time: Sunday 28/02/2016 | 08:30-11:00
Paper Time: 10:00
Venue: Skalkotas
First Author: : G.Asimellis GREECE
Co Author(s): :    A. Kanellopoulos              

Abstract Details

Purpose:

To evaluate corneal biomechanical changes associated with low and high myopic correction performed with Small Incision Lenticule Extraction (SMILE, employing the Visumax laser, Carl Zeiss Meditec, Jena Germany) compared to Femtosecond-laser assisted LASIK (FS200 & EX500 lasers, Alcon Surgical, Ft. Worth, TX).

Setting:

LaserVision.gr Clinical and Research Eye Institute, Athens, Greece

Methods:

30 human donor corneas subjected to myopic SMILE or LASIK. The corneas were randomly allocated to four groups (n=5 each), subjected to: group-A -3.00 diopters (D) SMILE, group-B -8.00D SMILE, group-C -3.00D LASIK, group-D -8.00D LASIK. Additionally, two control groups were formed, one for each procedure: group-E SMILE and group-F LASIK. The corneas in these control groups were subjected to the corresponding femtosecond-laser lamellar cuts but not to tissue removal. Biomechanical evaluation of tensile strength was conducted by biaxial force application. Primary outcome measures were stress at 10% and 15% strain, and Young’s modulus at 10% and 15% strain.

Results:

In SMILE, the average relative difference Δ of the four metrics evaluated was -35.6% between the -3.00D correction and control and -50.2% between the -8.00D correction and control. In LASIK, average Δ was -21.2% between the -3.00D correction and control, and -50.4% between the -8.00D correction and control. When comparing same myopic correction, SMILE compared to LASIK appears to result in more biomechanical reduction for the -3.00D corrections by -25.9%, while a non-statistically significant difference was noted in the -8.00D corrections.

Conclusions:

Biomechanical tensile strength is reduced with increasing amount of myopia corrected in both procedures. SMILE and LASIK appear to result in similar corneal tensile strength reduction for higher myopic corrections ex-vivo, however LASIK appears to result in less strength reduction in smaller myopic corrections.

Financial Disclosure:

One or more of the authors travel has been funded, fully or partially, by a company producing, developing or supplying the product or procedure presented