For patients with high myopia, small incision lenticule extraction (SMILE) may be a better choice than femtosecond-LASIK (FS-LASIK), a study in the Journal of Cataract & Refractive Surgery reports.

Chinese researchers enrolled 60 patients who had a maximum myopic meridian greater than 10D. SMILE was performed on 30 patients and FS-LASIK was used to correct the other 30.

The researchers examined patients before and six months after surgery to compare refractive outcomes, corneal curve, contrast sensitivity, ocular aberrometry and corneal biomechanical responses.

At six-months post-op, the investigators reported the average uncorrected visual acuity what better in the SMILE group compared with the LASIK group, –0.01 ± 0.06 and –0.05 ± 0.10, respectively. Corrected visual acuity was  –0.07 ± 0.07 and –0.08 ± 0.08, respectively. Additionally, postoperative sphere equivalent was –0.20 ± 0.25D for SMILE and –0.03 ± 0.20D in the LASIK group. The study found the change of spherical equivalent was –0.01 ± 0.26 and –0.13 ± 0.30 after one week, respectively.

 The researchers noted the posterior corneal curvature was unchanged after both procedures, but corneal thickness was reduced by 137.40 ± 15.01μm in SMILE and 155.06 ± 17.43μm in LASIK eyes.

The investigators also reported the peak distance (the distance between the highest points of the non-deformed corneal parts) differed between the groups (1.06±1.44mm vs. –0.26±1.16mm). The researchers observed smaller changes in higher order aberrations and spherical aberrations in SMILE compared with LASIK.

SMILE offered superior safety and objective visual quality, comparable stability and efficacy, and a little inferior predictability, the researchers said.

Yang X, Liu Q, Liu F, et al. A prospective comparison of outcome between SMILE and femtosecond LASIK in eyes having refractive error greater than -10-diopters. J Cataract Refract Surg. August 22, 2019. [Epub ahead of print].