Corneal biomechanical changes of SMILE versus LASIK

Patients with myopia of greater than -6.00 dioptres (D) who underwent femtosecond laser-assisted LASIK, experienced a more significant decrease in corneal hysteresis, corneal resistance factor, and p1 and p2 areas than patients who underwent small incision lenticule extraction (SMILE).

Researchers in China studied 187 eyes that were treated with SMILE and 79 eyes that were treated with LASIK. The eyes were also grouped by degree of myopia: -68.00 D or less, or greater than -6.00 D. In all patients, corneal hysteresis, corneal resistance factor, and 37 waveform parameters were compared preoperatively, and at 1 week and 1 and 3 months postoperatively.

Using an Ocular Response Analyzer (Reichert Ophthalmic Instruments) the researchers noted in both the SMILE patients and the LASIK patients a significant decrease of corneal hysteresis, corneal resistance factor, p1 area, and p2 area. The differences in these parameters between the two procedures were not significant in patients who had myopia of -6.00 D or less. However, in patients with myopia greater than -6.00 D, all of the parameters decreased significantly more in the eyes that underwent LASIK than in those that underwent SMILE.

The findings were reported in the Journal of Refractive Surgery.