Comparison of Dry Eye and Corneal Sensitivity between Small Incision Lenticule Extraction and Femtosecond LASIK for Myopia

Abstract

PurposeTo investigate the changes in dry eye symptoms and clinical signs and corneal sensitivity after small incision lenticule extraction (SMILE) and femtosecond LASIK (femto-LASIK).DesignProspective, non-randomized comparative study.MethodsThe study included a total of 71 eyes of 71 patients; the SMILE group comprised 38 eyes of 38 patients, and the femto-LASIK group comprised 33 eyes of 33 patients. Ocular Surface Disease Index (OSDI), Tear film breakup time (TBUT), the Schirmer test without anesthesia (S1T), corneal fluorescein staining, and central corneal sensation were evaluated before surgery and at 1 week, 1 month, 3 months, and 6 months after surgery.ResultsOSDI scores in both groups were increased immediately and returned to preoperative level at 1 month after surgeries. The TBUT values in both groups were reduced after surgeries relative to their preoperative scores. Patients in SMILE group were less likely to have corneal staining compared with those in the femto-LASIK group ([odds ratio] OR = 0.50, 95% [confidence interval] CI 0.28 to 0.93, P = 0.03). Central corneal sensitivity was decreased at all postoperative time points in both groups. However, the central corneal sensation scores in the SMILE group were greater than that in the femto-LASIK group at all of the postoperative time points (all P<0.05).ConclusionsSMILE surgeries resulted in a short-term increase in dry eye symptoms, tear film instability, and loss of corneal sensitivity. Furthermore, SMILE surgeries have superiority over femto-LASIK in lower risk of postoperative corneal staining and less reduction of corneal sensation.

Comparison of Visual and Refractive Outcomes Following Femtosecond Laser-Assisted LASIK With SMILE in Patients With Myopia or Myopic Astigmatism

“…20,21 Li et al found that patients in the SMILE group had less corneal staining and greater central corneal sensitivity scores than patients in the FS-LASIK group. 22 Our study demonstrated a significantly lower incidence of dry eyes in the SMILE group compared with the LASIK group. During LASIK, sub-basal and superficial stromal nerve bundles get cut during flap creation.…”

Small-incision lenticule extraction

“…86 Available studies indicate a lower propensity for corneal fluorescein staining and fewer subjective symptoms of dry eye with small-incision lenticule extraction than with LASIK. [87][88][89] OTHER BENEFITS AND/OR LIMITATIONS Other potentially beneficial features of small-incision lenticule extraction compared with LASIK include a significantly shortened procedural time due to use of a single laser platform instead of the 2-platform procedure and exclusion of the refractive unpredictability of excimer laser-based techniques due to variance in corneal hydration. 90 Eyes treated with small-incision lenticule extraction exhibit significantly fewer total HOAs than those treated with LASIK; in particular, the spherical aberration subset is significantly lower.…”

Dry Eye after Small Incision Lenticule Extraction (SMILE) versus Femtosecond Laser-Assisted in Situ Keratomileusis (FS-LASIK) for Myopia: A Meta-Analysis

“…Recent studies have compared dry eye after SMILE and FS-LASIK [6,12,14–17]. Some studies supported the position that SMILE reduced the incidence of dry eye disease when compared with FS-LASIK [6,14,15,17], but others reported no differences in dry eye parameters between these two groups [12,16].…”

“…Some studies supported the position that SMILE reduced the incidence of dry eye disease when compared with FS-LASIK [6,14,15,17], but others reported no differences in dry eye parameters between these two groups [12,16]. One meta-analysis cited dry eye as a primary outcome when comparing SMILE and FS-LASIK [5].…”