Corneal Spherical Aberration and Corneal Asphericity after Small Incision Lenticule Extraction and Femtosecond Laser-Assisted LASIK.

Hui Zhang,Yan Wang,Hua Li

doi:10.1155/2017/4921090

Abstract

Purpose To investigate corneal spherical aberration and corneal asphericity after small incision lenticule extraction (SMILE) and femtosecond laser-assisted laser in situ keratomileusis (FS-LASIK). Methods This study enrolled 70 patients having SMILE and 64 subjects receiving FS-LASIK. The preoperative spherical equivalent (SE) was −5.83 ± 1.23 diopters (D) and −6.20 ± 1.52 D, respectively. The uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), SE, corneal spherical aberration, and asphericity over the 6.0 mm cornea were evaluated preoperatively and postoperatively. Results At 6 months, the UDVA, CDVA, and SE were −0.12 ± 0.11, −0.05 ± 0.05, and −0.16 ± 0.19 D in SMILE and −0.10 ± 0.06, −0.03 ± 0.06, and −0.08 ± 0.25 D in FS-LASIK. There was no difference between groups in the postoperative UDVA, CDVA, or SE (P > 0.05). SMILE showed lower inductions of spherical aberration along the anterior surface and the total cornea and less increases in corneal asphericity of the anterior surface postoperatively than FS-LASIK (P < 0.01). There were significant correlations between the changes in spherical aberration and corneal asphericity (P < 0.001). Conclusions SMILE and FS-LASIK exhibited excellent visual results and refractive outcomes. SMILE induced less increase in corneal spherical aberration and better preserved the corneal asphericity of the anterior corneal surface than FS-LASIK. Corneal asphericity changes contributed to the corneal spherical aberration changes following SMILE and FS-LASIK.

Highlights

For the past few years, small incision lenticule extraction (SMILE) has become an increasingly popular corneal refractive surgery worldwide, with being approved by FDA of the United States recently
Our results showed that eyes achieved promising and similar visual and refractive outcomes in terms of uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), and spherical equivalent (SE) with treatment of SMILE and FS-LASIK
We found that the amount of changes in spherical aberration was smaller after SMILE than after FS-LASIK for the anterior surface and the total cornea, but not for the posterior corneal surface

Summary

Introduction

For the past few years, small incision lenticule extraction (SMILE) has become an increasingly popular corneal refractive surgery worldwide, with being approved by FDA of the United States recently. In terms of safety, stability, predictability, and efficacy [1,2,3], were reported, an increase in the corneal spherical aberration was still found in patients undergoing SMILE procedure [4, 5]. The visual performance of the eye probably could be affected, because strong correlation between starburst and glare with spherical aberration was showed in previous study [6]. The increase in the corneal spherical aberration after SMILE was reported to be less than that after femtosecond laser-assisted laser in situ keratomileusis (FS-LASIK) [4, 5, 7]. Corneal spherical aberration and corneal asphericity are proportionally related [8, 9]. The study was conducted to compare the change patterns of corneal spherical aberration and corneal asphericity between SMILE and FS-LASIK and investigate how much changes of corneal asphericity could account for the variation of corneal spherical aberration after SMILE and FS-LASIK procedures

Methods

Results

Conclusion