Small incision lenticule extraction (SMILE) is believed to induce less biomechanical weakening of the cornea than LASIK because it requires a significantly smaller anterior stromal cut. Ideally, this should reduce the risk of postoperative ectasia, a rare, but serious complication associated with LASIK.
Khamar and colleagues chose to examine the corneal biomechanical properties of both the SMILE cap and the LASIK flap to determine whether SMILE results in less corneal weakening. Twenty-four patients underwent contralateral SMILE and LASIK. Researchers examined corneal strength before, during, and after the procedure.
Although both procedures weakened the cornea, the weakening was initially greater in the LASIK eyes. However, one week after the surgery, the researchers found a similar degree of corneal weakening in both the LASIK and the SMILE eyes. There was also no difference in corneal weakening one month after the procedure.
“Biomechanical differences between LASIK and SMILE eyes were similar after removal of tissue and ongoing wound healing,” write the authors.
Since this is a prospective study, further research will be necessary to determine if SMILE provides benefits over LASIK regarding corneal strength.
Full findings are published in the May 2019 issue of the Journal of Refractive Surgery.