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Biomechanical effects of small incision lenticule extraction (SMILE) and laser in situ keratomileusis (LASIK): finite element analysis

Session Details

Session Title: Corneal biomechanics

Session Date/Time: Tuesday 08/10/2013 | 08:00-10:30

Paper Time: 08:52

Venue: Elicium 1 (First Floor)

First Author: : C.Roberts USA

Co Author(s): :    A. Sinha Roy   W. Dupps, Jr.           

Abstract Details

Purpose:

The current study investigates the corneal biomechanical stresses of Laser-assisted in situ keratomileusis (LASIK) and Small incision lenticule extraction (SMILE) that is flapless.

Setting:

The Ohio State University, Columbus and Cleveland Clinic Cole Institute, Ohio, USA.

Methods:

A finite element anisotropic, collagen fiber-dependent model of myopic surgery using patient-specific corneal geometry was constructed for LASIK and SMILE, as well as an "idealized" model with unaltered material properties from the preoperative state, but with post-operative geometry including thickness. Surgical parameters, the magnitude of myopic correction, flap thickness in LASIK and depth of lenticule creation in SMILE were varied. Two sets of models, one with uniform and one with depth-dependent material properties were constructed.

Results:

Stress distribution in the post-SMILE simulations are similar to that of the idealized model. In contrast, LASIK consistently reduced the stress in the flap and increased the stress in the residual stromal bed compared to the idealized model. Further, increase in the thickness of the flap or depth of lenticule creation resulted in a greater amount of increase in the stress in residual stromal bed of the LASIK model compared to the SMILE model.

Conclusions:

SMILE may present less biomechanical risk to the residual bed of susceptible corneas than comparable corrections involving LASIK flaps, and corrections at deeper depths in the stroma may be possible in SMILE without increasing ectasia risk.

Financial Interest:

... receives consulting fees, retainer, or contract payments from a company producing, developing or supplying the product or procedure presented, ... travel has been funded, fully or partially, by a company producing, developing or supplying the product or procedure presented