Corneal aberrations and visual performance after flap creation of LASIK with a femtosecond laser and a mechanical microkeratome

Authors:Zhang Jing,  Zheng Yan,  Liu Qian,  Zhou Yuehua
DOI: 10.3760/cma.j.issn.2095-0160.2016.06.011
Published 2016-06-10
Cite as Chin J Exp Ophthalmol, 2016,34(6): 527-533.

Abstract

Background

Laser in situ keratomileusis (LASIK) for myopia and/or myopic astigmatism still is one of primary surgeries.Femtosecond laser (FS)-LASIK offers several advantages over microkeratomes for flap creation including better safety, reproducibility, and predictability.However, the visual performance after FS-LASIK is of high clinical concern.

Objective

This study was to compare the visual performance between Intralase FS60 femtosecond laser flap and mechanical microkeratome Moria M2 flap in LASIK.

Methods

A prospective non-randomized controlled study was performed.Two hundred and four myopic eyes of 102 patients were enrolled in this study and divided into two groups according to patients’ opinion, with matched demography between the two groups.LASIK with FS60 femtosecond laser flap was performed on 100 eyes of 50 myopia and/or myopic astigmatism in the FS group, and Moria M2 flap LASIK was performed on 104 eyes of 52 patients in the microkeratomes group.Zernike coefficients and the root-mean-square (RMS) of higher order aberrations were measured by Wavescan wavefront aberrometer before and 3, 6 and 12 months after surgery, and the contrast sensitivity (CS) in different spatial frequencies under the scotopia and scotopia+ glare background was detected using Optec 6500 visual function instrument before and 3, 6, 12 months after surgery.This study protocol was approved by Ethic Committee of Beijing Tongren Hospital, and written informed consent was obtained from each patient prior to surgery.

Results

The uncorrected visual acuity (UCVA) levels after surgery reached or was superior to the preoperative best corrected visual acuity (BCVA) in 95.1%, 94.2% and 93.9% patients in the FS group and in 94.2%, 93.8% and 93.2% patients in the microkeratomes group 3, 6, 12 months after surgery, respectively.The mean spherical equivalent (SE) was (-6.37±2.06)D, (-0.26±0.45)D and (-0.45±0.51)D in the FS group, (-6.25±2.43)D, (-0.44±0.64)D and (-0.35±0.59)D in the microkeratomes group before surgery and 3, 12 months after surgery, respectively.There were no significant differences in the SE in various time points between the two groups (u=1.194, 1.429; both at P>0.05). The root means square high order (RMSh) and RMS3-6 in the FS group were significantly lower than those in the microkeratomes group 3, 6 and 12 months after surgery (all at P<0.05). Under the background of scotopia or scotopia+ glare, the LogCS values under different spatial frequencies were significantly higher in the FS group than those in the microkeratomes group 3 and 6 months after surgery (all at P<0.05). In 12 months after surgery, no significant difference was found in the LogCS under the 1.5 c/d in the background of scotopia between FS group and microkeratomes group (P>0.05), and the LogCS values under the 12.0 c/d and 18.0 c/d in the background of scotopia or scotopia+ glare in the FS group were better than those in the microkeratomes group (all at P<0.05).

Conclusions

Femtosecond laser assistant LASIK has better visual performance and lower higher-order aberrations than microkeratomes assistant LASIK.

Key words:

Keratomileusis, laser in situ; Lasers, excimer; Myopia/surgery; Surgical flaps; Aberration; Contrast sensitivity; Femtosecond laser; Comparative study

Contributor Information

Zhang Jing
Beijing Tongren Eye Center, Beijing Key Laboratory of Ophthalmology and Visual Science, Beijing Tongren Hospital, Capital Medical University, Beijing 100730, China
Zheng Yan
Liu Qian
Zhou Yuehua
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Updated: October 8, 2019 — 8:47 am