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

Zhang, Hui; Wang, Yan; Li, Hua

doi:10.1155/2017/4921090

Cited by 18 publications

(15 citation statements)

References 23 publications

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“…The DA and AA accounted for the majority of the total aberrations, hence the TLOA and TWA also decreased after the operation. As to the higher order aberrations, the increasing trend was similar to the previous studies [ 12 , 38 , 39 ]. Due to the surgery incision and the postoperative wound healing, the asymmetry of eye plane such as irregularity, inclination and decentration might occur, which could be reflected by CAs [ 24 ].…”

Section: Discussionsupporting

confidence: 89%

Comparison of the optical quality after SMILE and FS-LASIK for high myopia by OQAS and iTrace analyzer: a one-year retrospective study

et al. 2021

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Background To compare the correction effect and optical quality after small-incision lenticule extraction (SMILE) and femtosecond laser assisted laser in situ keratomileusis (FS-LASIK) for high myopia. Methods 51 high myopia eyes after SMILE and 49 high myopia eyes after FS-LASIK were enrolled and divided into two groups retrospectively. The OQAS and iTrace analyzer were used for optical quality inspection. Between the two groups the spherical equivalent (SE), astigmatism, uncorrected distant visual acuity (UDVA), strehl ratio (SR), modulation transfer function cutoff frequency (MTF cutoff), objective scatter index (OSI) and wavefront aberrations were analyzed and compared before surgery and at 1, 6 and 12 months after surgery. Results After the operation: (1) SE and astigmatism declined and UDVA increased significantly in both groups, and UDVA was better after SMILE than FS-LASIK. (2) SR and MTF cutoff reduced and OSI increased significantly after SMILE and FS-LASIK. SR and MTF cutoff were significantly higher after SMILE than FS-LASIK. OSI was significantly lower after SMILE than FS-LASIK. (3) The total wavefront aberration, total low-order wavefront aberration, defocus and astigmatism aberration as well as trefoil aberration reduced significantly in both groups. The total high-order wavefront aberration increased significantly after FS-LASIK. The spherical and coma aberration increased significantly in both groups. The total high-order wavefront aberration and coma aberration at 1 month were higher after FS-LASIK than SMILE. Conclusion The optical quality descended after SMILE and FS-LASIK. SMILE was superior to FS-LASIK at the correction effect and optical quality for high myopia. The combination of OQAS and iTrace analyzer is a valuable complementary measurement in evaluating the optical quality after the refractive surgery. Trial registration This is a retrospective study. This research was approved by the ethics committee of Xiangya Hospital and the IRB approval number is 201612074.

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Section: Discussionsupporting

confidence: 89%

Comparison of the optical quality after SMILE and FS-LASIK for high myopia by OQAS and iTrace analyzer: a one-year retrospective study

et al. 2021

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“…Previous studies have found that the morphological changes of the anterior corneal surface after SMILE and FS-LASIK are different [ 9 ], and the introduction of HOAs into SMILE after surgery is lower than that into FS-LASIK. Zhang et al [ 10 ] showed that Trans-PRK changes the corneal curvature to a greater extent and the visual quality ( Q -value, aberrations) to a lesser extent than FS-LASIK.…”

Section: Introductionmentioning

confidence: 99%

Corneal Asphericity and Higher-Order Aberrations after FS-LASIK and Trans-PRK for Myopia

Wang

et al. 2021

Journal of Ophthalmology

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Objective. To compare the corneal asphericity and higher-order aberrations (HOAs) of femtosecond laser-assisted in situ keratomileusis (FS-LASIK) with Smart Pulse Technology (SPT) assisted transepithelial photorefractive keratectomy (Trans-PRK) for myopia and myopic astigmatism correction. Methods. This prospective study analyzed 88 eyes of 44 patients treated with FS-LASIK and 64 eyes of 32 patients treated with Trans-PRK. All eyes had low to moderate myopia with or without astigmatism (spherical equivalent (SE) <−6.00 diopters). The uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), SE, asphericity (Q value) of the anterior corneal surface, index of surface variance (ISV), corneal higher-order aberrations (HOAs), vertical coma (Z3−1), horizontal coma (Z31), and spherical aberration (Z40) over a 6 mm diameter central corneal zone diameter were evaluated preoperatively and 1, 3, and 6 months postoperatively. Results. At 6 months, the UDVA and SE were −0.14 ± 0.06 and 0.33 ± 0.33D in FS-LASIK and −0.15 ± 0.06 and 0.35 ± 0.37D in Trans-PRK. There was no difference between the two groups in the postoperative UDVA and SE ( P > 0.05 ). After FS-LASIK and Trans-PRK, the Q values in the 6, 7, 8, and 9 mm zones and ISV of the anterior corneal surface significantly increased ( P < 0.001 ). At 1, 3, and 6 months after surgery, corneal HOA, Z3-1, Z31, and Z40 in both groups were significantly increased compared with those before surgery, with statistically significant differences ( P < 0.001 ). At 1, 3, and 6 months after surgery, the Z3−1 of the Trans-PRK group was significantly lower than that of the FS-LASIK group ( P < 0.001 ). ΔHOA and ΔZ40 were dramatically correlated with the ΔQ value for both FS-LASIK and Trans-PRK procedures. The ΔQ was significantly correlated with the preoperative SE, AD, and AD/CCT after both two procedures (all P < 0.001 ). Conclusions. Both FS-LASIK and Trans-PRK caused the anterior corneal surface to become flatter, and the morphology of the corneal surface was irregular. Corneal HOAs were significantly increased after the two procedures. Trans-PRK using SPT introduced less corneal vertical coma than FS-LASIK. Corneal asphericity changes contributed to the corneal aberrations changes following FS-LASIK and Trans-PRK.

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“…However, postoperative increase in coma was smaller in SMILE than LASEK and was similar to that of femtosecond (FS)-LASIK [22,24]. Studies reported that early wound healing response of SMILE is less reactive than that of FS-LASIK [25] and that the corneal epithelial remodeling after SMILE exhib- ited lesser shift toward oblateness than that after FS-LASIK [24]. Such advantages may compensate for the effect of decentration of SMILE compared with that of FS-LASIK.…”

Section: Discussionmentioning

confidence: 78%

“…Other studies have reported that single incisions in the SMILE procedure may cause an imbalanced corneal healing response and induce optical changes, which could increase coma postoperatively [23]. However, postoperative increase in coma was smaller in SMILE than LASEK and was similar to that of femtosecond (FS)-LASIK [22,24]. Studies reported that early wound healing response of SMILE is less reactive than that of FS-LASIK [25] and that the corneal epithelial remodeling after SMILE exhib- ited lesser shift toward oblateness than that after FS-LASIK [24].…”

Section: Discussionmentioning

confidence: 96%

Clinical Outcomes of Small Incision Lenticule Extraction in Myopia: Study of Vector Parameters and Corneal Aberrations

Kwak

Jun

Kim

et al. 2020

Korean J Ophthalmol

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Since Jose Barraquer invented keratomileusis for correction of high myopia in 1949, researchers have combined keratomileusis with excimer laser surface ablation to develop one of the most commonly used laser corneal refractive surgery techniques, laser in situ keratomileusis (LASIK) [1]. Creation of a corneal flap allows early visual recovery, less discomfort, and reduced stromal inflamma-Purpose: To investigate clinical outcomes of small incision lenticule extraction (SMILE) including vector parameters and corneal aberrations in myopic patients. Methods: This retrospective, observational case series included 57 eyes (29 patients) that received treatment for myopia using SMILE. Visual acuity measurement, manifest refraction, slit-lamp examination, autokeratometry, corneal topography, and evaluation of corneal wavefront aberration were performed preoperatively and at 1 and 3 months after surgery. We analyzed the safety, efficacy, vector parameters, and corneal aberrations at 3 months after surgery. Results: Preoperatively, mean manifest refraction spherical equivalent refraction was -4.94 ± 1.94 D (range, -8.25 to 0 diopters [D]), and the cylinder was -1.14 ± 0.82 D (range, -3 to 0 D). Mean manifest refraction spherical equivalent improved to -0.10 ± 0.23 D at 3 months postoperatively, when uncorrected distance visual acuity was 20 / 20 or better in 55 (96%) eyes. The linear regression model of target induced astigmatism vector versus surgically induced astigmatism vector exhibited slopes and coefficients (R 2 ) of 0.9618 and 0.9748, respectively (y = 0.9618x + 0.0006, R 2 = 0.9748). While total corneal root mean square higher order aberrations, coma and trefoil showed statistically significant increase, spherical aberration did not show statistically significant change after SMILE. Conclusions: SMILE has proven to be effective and safe for correcting myopia and astigmatism. We showed that SMILE did not induce spherical aberrations. A small increase in postoperative corneal higher order aberration may be associated with increase in coma and trefoil.

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

Cited by 18 publications

References 23 publications

Comparison of the optical quality after SMILE and FS-LASIK for high myopia by OQAS and iTrace analyzer: a one-year retrospective study

Comparison of the optical quality after SMILE and FS-LASIK for high myopia by OQAS and iTrace analyzer: a one-year retrospective study

Corneal Asphericity and Higher-Order Aberrations after FS-LASIK and Trans-PRK for Myopia

Clinical Outcomes of Small Incision Lenticule Extraction in Myopia: Study of Vector Parameters and Corneal Aberrations

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