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Song Y, Deng S, Lyv X, Xu Y, Zhang F, Guo N. Corneal subbasal nerve plexus reinnervation and stromal cell morphology with different cap thicknesses in small incision lenticule extraction. EYE AND VISION (LONDON, ENGLAND) 2024; 11:15. [PMID: 38584290 PMCID: PMC11000360 DOI: 10.1186/s40662-024-00381-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/25/2023] [Accepted: 03/10/2024] [Indexed: 04/09/2024]
Abstract
PURPOSE The corneal cap thickness is a vital parameter designed in small incision lenticule extraction (SMILE). The purpose was to investigate the changes in corneal subbasal nerve plexus (SNP) and stromal cells with different cap thicknesses and evaluate the optimized design for the surgery. METHODS In this prospective, comparative, non-randomized study, a total of 108 eyes of 54 patients who underwent SMILE were allocated into three groups with different corneal cap thicknesses (110 μm, 120 μm or 130 μm group). The SNP and stromal cell morphological changes obtained from in vivo corneal confocal microscopy (IVCCM) along with their refractive outcomes were collected at 1 week, 1 month, 3 months and 6 months postoperatively. One-way analysis of variance (ANOVA) was used to compare the parameters among the three groups. RESULTS The SNPs in the three groups all decreased after surgery and revealed a gradual increasing trend during the 6-month follow-up. The values of the quantitative nerve metrics were significantly lower in the 110 μm group than in the 120 μm and 130 μm groups, especially at 1 week postoperatively. No difference was detected between the 120 μm and 130 μm groups at any time point. Both Langerhans cells and keratocytes were activated after surgery, and the activation was alleviated during the follow-up. CONCLUSIONS The SMILE surgeries with 110 μm, 120 μm or 130 μm cap thickness design achieved good efficacy, safety, accuracy and stability for moderate to high myopic correction while the thicker corneal cap was more beneficial for corneal nerve regeneration.
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Affiliation(s)
- Yanzheng Song
- Beijing Ophthalmology and Visual Sciences Key Lab, Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing, 100730, China
| | - Shijing Deng
- Beijing Ophthalmology and Visual Sciences Key Lab, Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing, 100730, China
| | - Xiaotong Lyv
- Beijing Ophthalmology and Visual Sciences Key Lab, Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing, 100730, China
| | - Yushan Xu
- Beijing Ophthalmology and Visual Sciences Key Lab, Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing, 100730, China
| | - Fengju Zhang
- Beijing Ophthalmology and Visual Sciences Key Lab, Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing, 100730, China.
| | - Ning Guo
- Beijing Ophthalmology and Visual Sciences Key Lab, Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing, 100730, China.
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Lv X, Zhang F, Song Y, Zhai C, Guo N, Lai L, Xu Y. Corneal biomechanical characteristics following small incision lenticule extraction for myopia and astigmatism with 3 different cap thicknesses. BMC Ophthalmol 2023; 23:42. [PMID: 36717828 PMCID: PMC9885585 DOI: 10.1186/s12886-023-02786-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2022] [Accepted: 01/16/2023] [Indexed: 01/31/2023] Open
Abstract
BACKGROUND The design of cap thickness for small incision lenticule extraction (SMILE) plays a role in post-laser vision correction (post-LVC) corneal biomechanics. This study aimed to compare the corneal biomechanical characteristics following SMILE with different cap thicknesses of 110 μm, 120 μm, and 130 μm for myopia and myopic astigmatism correction. METHODS Seventy-five patients (146 eyes) who underwent SMILE with designed cap thickness of 110 μm, 120 μm, and 130 μm were recruited at the Eye Center of Beijing Tongren Hospital between August 2020 and November 2021. Visual acuity, refraction, and corneal biomechanical parameters were measured preoperatively, 1 week and 1, 3, 6 months postoperatively. One-way analysis of variances (ANOVA) with Bonferroni correction or Kruskal-Wallis test was performed to compare the parameters among different groups. Repeated-measures analysis of variance with Bonferroni correction or Friedman test was applied for comparing the parameters within different follow-up times. RESULTS Uncorrected distance visual acuity of 110-μm group was better only at 1-week and 1-month postoperatively (P = 0.012, 0.037). There were no significant differences in spherical equivalent, nor in Corvis biomechanical index-laser vision correction (CBI-LVC). All the parameters reached stability at 3-month postoperatively. Integrated radius (IR) and deformation amplitude ratio 2 mm (DA ratio 2 mm) in 120-μm and 130-μm groups were higher than 110-μm group at 1-month postoperatively (P = 0.019, 0.002). So was Ambrósio relational thickness (ARTh) at 6-month postoperatively (P = 0.011). Stiffness parameter at applanation A1 (SP-A1), stress-strain index (SSI), biomechanically corrected intraocular pressure (bIOP) and central corneal thickness (CCT) were highest in 130-μm group, followed by 120-μm group, then 110-μm group at 3-month (P<0.001, P = 0.030, P = 0.027, P = 0.008) and 6-month (P<0.001, P = 0.002, P = 0.0023, P = 0.001) postoperatively. CONCLUSIONS The corneal stiffness following SMILE was greatest with 130-μm cap, followed by 120-μm cap, then 110-μm cap. 130-μm cap might have advantages in terms of corneal biomechanics and retreatment option. The SMILE-designed protocol should be customized in practice.
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Affiliation(s)
- Xiaotong Lv
- grid.414373.60000 0004 1758 1243Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing Ophthalmology & Visual Sciences Key Lab, No 1, Dongjiaominxiang Street, Dongcheng District, Beijing, 100730 China
| | - Fengju Zhang
- grid.414373.60000 0004 1758 1243Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing Ophthalmology & Visual Sciences Key Lab, No 1, Dongjiaominxiang Street, Dongcheng District, Beijing, 100730 China
| | - Yanzheng Song
- grid.414373.60000 0004 1758 1243Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing Ophthalmology & Visual Sciences Key Lab, No 1, Dongjiaominxiang Street, Dongcheng District, Beijing, 100730 China
| | - Changbin Zhai
- grid.414373.60000 0004 1758 1243Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing Ophthalmology & Visual Sciences Key Lab, No 1, Dongjiaominxiang Street, Dongcheng District, Beijing, 100730 China
| | - Ning Guo
- grid.414373.60000 0004 1758 1243Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing Ophthalmology & Visual Sciences Key Lab, No 1, Dongjiaominxiang Street, Dongcheng District, Beijing, 100730 China
| | - Lingbo Lai
- grid.414373.60000 0004 1758 1243Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing Ophthalmology & Visual Sciences Key Lab, No 1, Dongjiaominxiang Street, Dongcheng District, Beijing, 100730 China
| | - Yushan Xu
- grid.414373.60000 0004 1758 1243Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing Ophthalmology & Visual Sciences Key Lab, No 1, Dongjiaominxiang Street, Dongcheng District, Beijing, 100730 China
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贾 园, 贺 瑞, 李 晓, 宋 耀, 魏 俊, 秦 宏, 杨 昕, 陈 维. [Effects of SMILE with different residual stromal thicknesses on corneal biomechanical properties of rabbits in vivo]. SHENG WU YI XUE GONG CHENG XUE ZA ZHI = JOURNAL OF BIOMEDICAL ENGINEERING = SHENGWU YIXUE GONGCHENGXUE ZAZHI 2022; 39:679-684. [PMID: 36008331 PMCID: PMC10957367 DOI: 10.7507/1001-5515.202203069] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 03/23/2022] [Revised: 04/26/2022] [Indexed: 06/15/2023]
Abstract
Femtosecond laser small incision lenticule extraction (SMILE) with different residual stromal thicknesses (RST) is set to investigate its effect on corneal biomechanical properties of rabbits in vivo. In this study, 24 healthy adult Japanese rabbits were randomly divided into group A and B. The RST of group A was set 30% of the corneal central thickness (CCT), and the RST of group B was 50% of the CCT. The thickness of the corneal cap in both groups was set one third of CCT. Corneal visualization Scheimpflug technology (Corvis ST) and Pentacam three-dimensional anterior segment analyzer were used to determine corneal biomechanical and morphological parameters before surgery, and 1 week, 1 month and 3 months after surgery. Pearson correlation analysis was used to analyze factors affecting corneal biomechanical parameters after SMILE. The results showed that the corneal stiffness of group A was significantly higher than that of group B at 1 week and 1 month after surgery, and most biomechanical parameters returned to preoperative levels at 3 months postoperatively. The results of correlation analysis showed that postoperative CCT and RST were the main factors affecting corneal biomechanical parameters after SMILE. There was no significant difference in corneal posterior surface height (PE) between 3 months after surgery and before surgery in both two groups. It indicates that although the ability to resist deformation of cornea decreases in SMILE with thicker corneal cap and less RST, there is no tendency to keratoconus, which may be related to the preservation of more anterior stromal layer.
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Affiliation(s)
- 园 贾
- 太原理工大学 生物医学工程学院(太原 030024)College of Biomedical Engineering, Taiyuan University of Technology, Taiyuan 030024, P. R. China
| | - 瑞 贺
- 太原理工大学 生物医学工程学院(太原 030024)College of Biomedical Engineering, Taiyuan University of Technology, Taiyuan 030024, P. R. China
| | - 晓娜 李
- 太原理工大学 生物医学工程学院(太原 030024)College of Biomedical Engineering, Taiyuan University of Technology, Taiyuan 030024, P. R. China
| | - 耀文 宋
- 太原理工大学 生物医学工程学院(太原 030024)College of Biomedical Engineering, Taiyuan University of Technology, Taiyuan 030024, P. R. China
| | - 俊超 魏
- 太原理工大学 生物医学工程学院(太原 030024)College of Biomedical Engineering, Taiyuan University of Technology, Taiyuan 030024, P. R. China
| | - 宏伟 秦
- 太原理工大学 生物医学工程学院(太原 030024)College of Biomedical Engineering, Taiyuan University of Technology, Taiyuan 030024, P. R. China
| | - 昕 杨
- 太原理工大学 生物医学工程学院(太原 030024)College of Biomedical Engineering, Taiyuan University of Technology, Taiyuan 030024, P. R. China
| | - 维毅 陈
- 太原理工大学 生物医学工程学院(太原 030024)College of Biomedical Engineering, Taiyuan University of Technology, Taiyuan 030024, P. R. China
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Long-Term Clinical Outcomes of Small-Incision Femtosecond Laser-Assisted Intracorneal Concave Lenticule Implantation in Patients with Keratoconus. J Ophthalmol 2022; 2022:9774448. [PMID: 35340275 PMCID: PMC8942691 DOI: 10.1155/2022/9774448] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Accepted: 02/25/2022] [Indexed: 11/17/2022] Open
Abstract
Purpose The purpose of this study was to evaluate the long-term prognosis of small-incision femtosecond laser-assisted intracorneal concave lenticule implantation (SFII) in correction of human keratoconus. Methods This was a prospective study for 11 patients who received SFII after being diagnosed as progressive keratoconus based on the Amsler–Krumeich classification system. Clinical assessment was performed for all the patients prior to and postsurgically at different time points for 5 years. These included uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), biomechanically corrected intraocular pressure (bIOP), corneal topography, anterior segment optical coherence tomography (AS-OCT), confocal microscopy, and biomechanical assessment with Corvis ST. Results Comparison of preoperative and 60-month postoperative UDVA and CDVA (P60months=0.081 and 0.001, respectively), all eyes showed an improvement in CDVA. Corneal topography showed no significant changes in corneal anterior K1, K2, posterior K1, K2, posterior elevation, or corneal densitometry compared with preoperative levels (P > 0.05). Corvis ST showed that central corneal thickness (CCT) and stiffness at applanation 1 (SP-A1) were significantly greater 1 week postsurgically when compared to the baseline (P < 0.05) and remained stable thereafter. The lenticule under the AS-OCT remained transparent throughout the entire postsurgical period. Under confocal microscopy, corneal edema and an increase in cell activation and reflectivity were observed at the lenticule-stromal interface within 1 week postoperatively. These reactions gradually subsided with time within 6 months. Conclusion SFII is an effective procedure to prevent the progression of keratoconus due to its minimal invasiveness and capability of maintaining a steady biometry of the cornea.
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Lang M, Cao KW, Liu T, Zhu Y, Ye J. Five-year results of refractive outcomes and vision-related quality of life after SMILE for the correction of high myopia. Int J Ophthalmol 2021; 14:1365-1370. [PMID: 34540612 DOI: 10.18240/ijo.2021.09.11] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2021] [Accepted: 05/11/2021] [Indexed: 11/23/2022] Open
Abstract
AIM To evaluate the long-term visual, refractive outcomes and vision-related quality of life after small incision lenticule extraction (SMILE) for the correction of high myopia. METHODS Thirty patients (60 eyes) with high myopia who underwent SMILE more than 5y were selected as the SMILE group. Another 30 high myopia patients (60 eyes) who had worn corrective spectacles for more than 5y were selected as the control group. In SMILE group, the postoperative follow-up time were 3, 6mo, 1 and 5y. Uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), spherical equivalent (SE), and ocular axial length (AL) were analyzed. The Chinese version of the National Eye Institute Visual Function Questionnaire-25 (CHI-NEI-VFQ-25) was used to evaluate the vision-related quality of life in the SMILE group and the control group. RESULTS In SMILE group, the mean preoperative SE was -7.29±0.87 D (range -6.00 to -9.125 D). At 5-year follow up, the efficacy index and safety index of SMILE were 1.09±0.18 and 1.19±0.12, respectively. Five years postoperatively, 44 eyes (73%) obtained a visual acuity of 20/20 or better. There were no eyes with CDVA loss of one or more Snellen lines. Forty-nine eyes (82%) and 57 eyes (95%) were within ±0.50 and ±1.00 D of attempted correction at 5-year follow-up, respectively. Forty-eight eyes (80%) had astigmatism <0.50 D at 5-year follow-up. The postoperative mean SE values at 3, 6mo, 1, and 5y were 0.11±0.44, 0.07±0.45, -0.02±0.41, and -0.15±0.46 D, respectively. No significant change was observed in the ocular AL from before operation to 5y postoperatively (26.08±0.96 mm vs 26.01±0.94 mm, P=0.068). Compared to the control group, the SMILE group showed a significantly higher total score on the CHI-NEI-VFQ-25 (90.14 vs 81.43, P<0.001). CONCLUSION In the present study, in a long-term follow-up we demonstrate that correcting high myopia with SMILE is safe, effective, and predictable. Vision-related quality of life after SMILE is better in the SMILE group than in the control group who wore corrective spectacles.
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Affiliation(s)
- Min Lang
- Department of Ophthalmology, Daping Hospital, Army Medical University, Chongqing 400042, China
| | - Kai-Wei Cao
- Department of Ophthalmology, Daping Hospital, Army Medical University, Chongqing 400042, China
| | - Ting Liu
- Department of Ophthalmology, Daping Hospital, Army Medical University, Chongqing 400042, China
| | - Ying Zhu
- Department of Ophthalmology, Daping Hospital, Army Medical University, Chongqing 400042, China
| | - Jian Ye
- Department of Ophthalmology, Daping Hospital, Army Medical University, Chongqing 400042, China
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Jun I, Kang DSY, Roberts CJ, Lee H, Jean SK, Kim EK, Seo KY, Kim TI. Comparison of Clinical and Biomechanical Outcomes of Small Incision Lenticule Extraction With 120- and 140-µm Cap Thickness. Transl Vis Sci Technol 2021; 10:15. [PMID: 34259803 PMCID: PMC8288062 DOI: 10.1167/tvst.10.8.15] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose The purpose of this study was to compare the clinical outcomes and corneal biomechanical changes between 120-µm and 140-µm cap thickness after small incision lenticule extraction (SMILE). Methods This prospective study included 150 eyes (150 patients: 91 eyes in the 120-µm group, and 59 eyes in the 140-µm group) who underwent SMILE. Enhanced correction nomograms were applied for patients according to cap thickness. Clinical outcomes, including visual acuity, refraction, and corneal wavefront aberrations, were compared between the two groups. Corneal biomechanics were evaluated using the Corvis ST (Oculus, Wetzlar, Germany). Results The mean uncorrected-distance visual acuity, safety and efficacy indices, and refractive predictability were comparable in the 120-µm and 140-µm groups after SMILE. The postoperative total corneal root mean square higher-order aberrations (HOAs) and spherical aberrations was 0.48 ± 0.31 and 0.26 ± 0.10 in the 120-µm group, and 0.53 ± 0.16 and 0.34 ± 0.13 in the 140-µm group, which showed significant differences between the two groups (P = 0.027, and <0.001, respectively). Although corneal stiffness decreased after SMILE in both groups, the changes in the deformation amplitude ratio were significantly higher in the 140-µm group than in the 120-µm group (P = 0.022). Conclusions SMILE with 120-µm and 140-µm cap thickness provided excellent predictable outcomes according to our enhanced correction nomogram. The amount of tissue removal required to achieve the same amount of refractive correction was greater in the thicker cap group. The induction of corneal HOAs and weakening of corneal biomechanics were less pronounced in the thin-cap group, which may be associated with the thinner cap, lesser lenticule thickness, or thicker residual stromal bed. Translational Relevance Although SMILE with different cap thickness was effective, thicker lenticule thickness in the thick-cap group may be associated with induction of HOAs, and corneal stiffness changes.
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Affiliation(s)
- Ikhyun Jun
- The Institute of Vision Research, Department of Ophthalmology, Yonsei University College of Medicine, Seoul, Republic of Korea.,Corneal Dystrophy Research Institute, Department of Ophthalmology, Yonsei University College of Medicine, Seoul, Republic of Korea
| | | | - Cynthia J Roberts
- Department of Ophthalmology & Visual Sciences and Department of Biomedical Engineering, The Ohio State University, Columbus, OH, USA
| | - Hun Lee
- Department of Ophthalmology, University of Ulsan College of Medicine, Seoul, Republic of Korea
| | | | - Eung Kweon Kim
- Corneal Dystrophy Research Institute, Department of Ophthalmology, Yonsei University College of Medicine, Seoul, Republic of Korea.,Saevit Eye Hospital, Goyang-Si, Gyeonggi-Do, Republic of Korea
| | - Kyoung Yul Seo
- The Institute of Vision Research, Department of Ophthalmology, Yonsei University College of Medicine, Seoul, Republic of Korea
| | - Tae-Im Kim
- The Institute of Vision Research, Department of Ophthalmology, Yonsei University College of Medicine, Seoul, Republic of Korea.,Corneal Dystrophy Research Institute, Department of Ophthalmology, Yonsei University College of Medicine, Seoul, Republic of Korea
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Li M, Yang D, Zhao Y, Yang W, Shang J, Zhou X, Yao P, Yang D, Lin X, Zhou X. Impact of ablation ratio on 5-year postoperative posterior corneal stability after refractive surgery: SMILE and FS-LASIK. EYE AND VISION 2020; 7:53. [PMID: 33292814 PMCID: PMC7654178 DOI: 10.1186/s40662-020-00218-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/03/2020] [Accepted: 10/20/2020] [Indexed: 11/10/2022]
Abstract
BACKGROUND To investigate the impact of the ablation ratio on 5-year postoperative posterior corneal stability in myopic eyes after small incision lenticule extraction (SMILE) and femtosecond laser-assisted in situ keratomileusis (FS-LASIK) surgery. METHODS A prospective, nonrandomized, cohort study: 80 eyes of 43 patients underwent SMILE surgery and 63 eyes of 32 patients underwent FS-LASIK surgery at the EYE & ENT Hospital, Fudan University. Ablation ratio was defined as lenticule thickness (SMILE cases) or ablation depth (FS-LASIK cases) divided by central corneal thickness (CCT). Posterior corneal elevation changes were recorded as posterior central elevation (PCE), posterior corneal surface at thinnest point (PTE) and posterior corneal mean elevation (PME). Patients were followed up at 6-month and 5-year interval to investigate the impact of the ablation ratio on posterior corneal elevation after SMILE and FS-LASIK surgery. RESULTS PCE dropped at the 6-month follow-up for both SMILE (decreased by -1.11 ± 2.93 μm, P < 0.05) and FS-LASIK groups (decreased by -0.46 ± 3.72 μm, P < 0.05). PTE also dropped in SMILE (reduced by -2.04 ± 3.02 μm, P < 0.05) and FS-LASIK group (reduced by -1.28 ± 4.21 μm, P < 0.05) at the 6-month follow-up. Stable PCE (elevation change: SMILE -0.28 ± 4.03 μm; FS-LASIK 0.79 ± 4.13 μm, P > 0.05) and PTE (elevation change: SMILE -0.08 ± 4.28 μm; FS-LASIK 1.42 ± 3.85 μm, P > 0.05) for both groups were recorded at the 5-year follow-up compared to the 6-month visit. Ablation ratio was strongly correlated with 5-year postoperative PCE (β = 2.68 ± 1.05, P < 0.01) and PTE (β = 2.35 ± 1.17, P < 0.05). Cut-off value for 5-year postoperative raised PCE and PTE was 27.3 and 27.1%, respectively. CONCLUSIONS Ablation ratio was strongly correlated with postoperative posterior corneal elevation in a 5-year follow-up in both SMILE and FS-LASIK groups. PCE and PTE underwent slight backward displacement 6-month postoperatively and remain stable at the 5-year follow-up. Threshold of the ablation ratio for resisting forward displacement of posterior corneal surface was 27.3 and 27.1% for SMILE and FS-LASIK groups, respectively.
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Affiliation(s)
- Meiyan Li
- Department of Ophthalmology, EYE & ENT Hospital, Fudan University, Shanghai, China.,NHC Key Laboratory of Myopia (Fudan University), Shanghai, China.,Shanghai Research Center of Ophthalmology and Optometry, Shanghai, China
| | - Danjuan Yang
- Department of Ophthalmology, EYE & ENT Hospital, Fudan University, Shanghai, China.,NHC Key Laboratory of Myopia (Fudan University), Shanghai, China.,Shanghai Research Center of Ophthalmology and Optometry, Shanghai, China
| | - Yu Zhao
- Department of Ophthalmology, EYE & ENT Hospital, Fudan University, Shanghai, China.,NHC Key Laboratory of Myopia (Fudan University), Shanghai, China.,Shanghai Research Center of Ophthalmology and Optometry, Shanghai, China
| | - Weiming Yang
- Department of Ophthalmology and Optometry, Children's Hospital of Fudan University, Shanghai, China
| | - Jianmin Shang
- Department of Ophthalmology, EYE & ENT Hospital, Fudan University, Shanghai, China.,NHC Key Laboratory of Myopia (Fudan University), Shanghai, China.,Shanghai Research Center of Ophthalmology and Optometry, Shanghai, China
| | - Xueyi Zhou
- Department of Ophthalmology, EYE & ENT Hospital, Fudan University, Shanghai, China.,NHC Key Laboratory of Myopia (Fudan University), Shanghai, China.,Shanghai Research Center of Ophthalmology and Optometry, Shanghai, China
| | - Peijun Yao
- Department of Ophthalmology, EYE & ENT Hospital, Fudan University, Shanghai, China.,NHC Key Laboratory of Myopia (Fudan University), Shanghai, China.,Shanghai Research Center of Ophthalmology and Optometry, Shanghai, China
| | - Dong Yang
- Department of Ophthalmology, EYE & ENT Hospital, Fudan University, Shanghai, China.,NHC Key Laboratory of Myopia (Fudan University), Shanghai, China.,Shanghai Research Center of Ophthalmology and Optometry, Shanghai, China
| | - Xue Lin
- Department of Ophthalmology, Dalian Municipal Women and Children's Medical Center, Dalian, China.
| | - Xingtao Zhou
- Department of Ophthalmology, EYE & ENT Hospital, Fudan University, Shanghai, China. .,NHC Key Laboratory of Myopia (Fudan University), Shanghai, China. .,Shanghai Research Center of Ophthalmology and Optometry, Shanghai, China. .,Department of Ophthalmology and Optometry, Children's Hospital of Fudan University, Shanghai, China.
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Lee H, Kang DSY, Reinstein DZ, Roberts CJ, Ambrósio R, Archer TJ, Jean SK, Kim EK, Seo KY, Jun I, Kim TI. Adjustment of Spherical Equivalent Correction According to Cap Thickness for Myopic Small Incision Lenticule Extraction. J Refract Surg 2019; 35:153-160. [PMID: 30855092 DOI: 10.3928/1081597x-20190205-01] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2018] [Accepted: 02/05/2019] [Indexed: 11/20/2022]
Abstract
PURPOSE To evaluate the amount of spherical equivalent correction for three different cap thicknesses (120, 130, and 140 µm) during myopic small incision lenticule extraction (SMILE) and determine the association between the amount of spherical equivalent correction and several variables in each cap thickness group. METHODS In this retrospective, comparative, observational case series study, the authors compared refractive errors, keratometric values, laser setting (sphere correction, cylinder correction, spherical equivalent correction, optical zone, and cap diameter), and spherical aberration measured preoperatively and at 3 months postoperatively between three different cap thickness groups: 120 µm (n = 554), 130 µm (n = 377), and 140 µm (n = 90). Multiple linear regression analyses were used to determine the associations between the amount of spherical equivalent correction and several variables, including age, preoperative spherical equivalent, optical zone diameter, central corneal thickness, preoperative mean keratometric values, and preoperative corneal asphericity. RESULTS According to cap thickness, attempted correction is adjusted to achieve the same refractive outcomes for different cap thicknesses. There were significant differences in the amount of sphere correction and spherical equivalent correction, as well as lenticule thickness, among subgroups. Changes in keratometric values, corneal asphericity, and spherical aberration were also significantly different among subgroups (all P < .001). Changes in keratometric values, corneal asphericity, and spherical aberration significantly increased as cap thickness increased. Preoperative spherical equivalent mainly influenced the amount of spherical equivalent correction in each group. CONCLUSIONS Dioptric adjustment of spherical equivalent correction according to cap thickness is essential to obtain similar refractive outcomes in myopic SMILE procedures. [J Refract Surg. 2019;35(3):153-160.].
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Comparison of the posterior corneal elevation and biomechanics after SMILE and LASEK for myopia: a short- and long-term observation. Graefes Arch Clin Exp Ophthalmol 2019; 257:601-606. [DOI: 10.1007/s00417-018-04227-5] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2018] [Revised: 12/18/2018] [Accepted: 12/19/2018] [Indexed: 10/27/2022] Open
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Contralateral Eye Comparison Between 2 Cap Thicknesses in Small Incision Lenticule Extraction: 110 Versus 130 μm. Cornea 2018; 38:617-623. [DOI: 10.1097/ico.0000000000001835] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Chiche A, Trinh L, Baudouin C, Denoyer A. [SMILE (Small Incision Lenticule Extraction) among the corneal refractive surgeries in 2018 (French translation of the article)]. J Fr Ophtalmol 2018; 41:650-658. [PMID: 30170707 DOI: 10.1016/j.jfo.2018.03.006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2018] [Revised: 03/05/2018] [Accepted: 03/13/2018] [Indexed: 11/24/2022]
Abstract
Refractive surgery is a field in constant evolution. In recent years, a new procedure has appeared under the name SMILE (Small Incision Lenticule Extraction). This technique, carried out solely with a femtosecond laser, should make it possible to better preserve corneal innervation and biomechanics. After a detailed review of the technique itself, we then focus on the scientific evidence for the safety and efficacy of SMILE and its current indications. Advantages of SMILE will be discussed in comparison to disadvantages of the conventional techniques, particularly concerning dry eye and the risk of corneal ectasia with LASIK. Lastly, the current limitations of SMILE (indications, retreatment) are discussed, and future applications are considered regarding improvements in the technique.
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Affiliation(s)
- A Chiche
- Service d'ophtalmologie 3, centre hospitalier national d'ophtalmologie des Quinze-Vingts, université de Versailles-Saint-Quentin-en-Yvelines, 28, rue de Charenton, 75012 Paris, France
| | - L Trinh
- Service d'ophtalmologie 3, centre hospitalier national d'ophtalmologie des Quinze-Vingts, université de Versailles-Saint-Quentin-en-Yvelines, 28, rue de Charenton, 75012 Paris, France; Espace Nouvelle Vision, 6, rue de la Grande Chaumière, 75006 Paris, France
| | - C Baudouin
- Service d'ophtalmologie 3, centre hospitalier national d'ophtalmologie des Quinze-Vingts, université de Versailles-Saint-Quentin-en-Yvelines, 28, rue de Charenton, 75012 Paris, France; Inserm U968, université UPMC Paris VI, UMR S 968, CNRS, UMR 7210, 75012 Paris, France
| | - A Denoyer
- Inserm U968, université UPMC Paris VI, UMR S 968, CNRS, UMR 7210, 75012 Paris, France; Hôpital Robert-Debré, CHU de Reims, rue du Général Koenig, 51100 Reims, France; URCA, université de Reims-Champagne-Ardenne, Reims, France.
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Corneal Cap Thickness and Its Effect on Visual Acuity and Corneal Biomechanics in Eyes Undergoing Small Incision Lenticule Extraction. J Ophthalmol 2018; 2018:6040873. [PMID: 30050690 PMCID: PMC6046116 DOI: 10.1155/2018/6040873] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2017] [Revised: 05/11/2018] [Accepted: 05/22/2018] [Indexed: 11/17/2022] Open
Abstract
Purpose To evaluate the effect of corneal cap thickness on visual acuity and corneal biomechanics in small incision lenticule extraction (SMILE) for the treatment of myopia. Methods Forty eyes of 20 patients undergoing SMILE for the treatment of myopia were enrolled in this prospective controlled study. The patients with 510 μm–560 μm central corneal thickness (CCT) and a refractive spherical equivalent of −3.00 D to −8.00 D were included. It was designed randomly to undergo SMILE with a 110 μm cap thickness in one eye and 150 μm cap thickness in the other. Ophthalmic examinations included best-corrected and uncorrected visual acuity (UCVA); refractive status, contrast sensitivity, and objective visual quality were evaluated at 2 h, 4 h, and 24 h postoperatively; while at 3 months after the procedure, corrected intraocular pressure (IOP), higher order aberrations (HOAs), and morphologic modifications of corneal architecture of both eyes were assessed. Results Compared with the 150 μm group, the incidence of OBL was significantly higher in the 110 μm cap thickness group (P=0.004), and UCVA, Strehl ratio (SR), objective scatter index (OSI), modulation transfer function (MTF) cutoff frequency, and photopic and scotopic contrast sensitivity at medium spatial frequency were all significantly better in 110 μm group at 2 h and 24 h postoperatively (P < 0.05). Corneal spherical aberration and corrected IOP by Corvis ST were significantly higher in the 110 μm group at 3 months postoperatively (P < 0.05). No statistically significant differences were found in manifest refraction, UCVA, SR, OSI, MTF cutoff, and mesopic and photopic contrast sensitivity at low frequency, photopic contrast sensitivity at high frequency, endothelial density, corneal coma, and total HOAs at 3 months after the procedure. No visual decline was found in the patients in this study. Conclusions Both 110 μm and 150 μm cap thickness in SMILE were safe and effective for treatment of myopia. A 110 μm cap thickness demonstrated better visual outcomes during early and late postoperative periods with higher corneal spherical aberration and corrected IOP at 3 months postoperatively. This trial is registered with ChiCTR-IOR-17013369.
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Chiche A, Trinh L, Baudouin C, Denoyer A. SMILE (Small Incision Lenticule Extraction) among the corneal refractive surgeries in 2018. J Fr Ophtalmol 2018; 41:e245-e252. [PMID: 29914764 DOI: 10.1016/j.jfo.2018.05.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2018] [Revised: 04/27/2018] [Accepted: 05/15/2018] [Indexed: 11/27/2022]
Abstract
Refractive surgery is a field in constant evolution. In recent years, a new procedure has appeared under the name SMILE (SMall Incision Lenticule Extraction). This technique, carried out solely with a femtosecond laser, should make it possible to better preserve corneal innervation and biomechanics. After a detailed review of the technique itself, we then focus on the scientific evidence for the safety and efficacy of SMILE and its current indications. Advantages of SMILE will be discussed in comparison to the conventional techniques, particularly concerning dry eye and the risk of corneal ectasia related to LASIK. Lastly, the current limitations of SMILE (indications, retreatment) are discussed, and future applications are considered regarding new improvements in the technique.
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Affiliation(s)
- A Chiche
- Ophthalmology Service 3, Quinze-Vingts National Ophthalmology Hospital, University of Versailles Saint-Quentin-en-Yvelines, 78000 Versailles, France
| | - L Trinh
- Ophthalmology Service 3, Quinze-Vingts National Ophthalmology Hospital, University of Versailles Saint-Quentin-en-Yvelines, 78000 Versailles, France; Espace Nouvelle Vision, 75012 Paris, France
| | - C Baudouin
- Ophthalmology Service 3, Quinze-Vingts National Ophthalmology Hospital, University of Versailles Saint-Quentin-en-Yvelines, 78000 Versailles, France; INSERM, U968, 75012 Paris, France; UMR S 968, Institut de la Vision, University UPMC Paris VI, 75012 Paris, France; CNRS, UMR 7210, 75012 Paris, France
| | - A Denoyer
- INSERM, U968, 75012 Paris, France; UMR S 968, Institut de la Vision, University UPMC Paris VI, 75012 Paris, France; CNRS, UMR 7210, 75012 Paris, France; University Hospital Robert-Debré, rue du Général-Koenig, 51100 Reims, France; URCA, University of Reims Champagne-Ardenne, 51100 Reims, France.
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Evaluation of Human Corneal Lenticule Quality After SMILE With Different Cap Thicknesses Using Scanning Electron Microscopy. Cornea 2018; 37:59-65. [PMID: 29053560 DOI: 10.1097/ico.0000000000001404] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
PURPOSE To evaluate the surface characteristics of lenticules created by small-incision lenticule extraction (SMILE) with different cap thicknesses. METHODS This prospective study included 20 consecutive patients who underwent bilateral SMILE. Surface regularity of the extracted corneal lenticule was analyzed using scanning electron microscopy (SEM) combined with 2 methods: qualitative and quantitative regularity. Qualitative regularity of SEM images was graded by masked observers using an established scoring system. Quantitative regularity of SEM images was assessed by counting the total number and areas of tissue bridges using Image-Pro Plus software. Four different cap thickness of 120, 130, 140, and 150 μm were compared. Refractive outcomes of patients were measured at baseline and 1 month after surgery. RESULTS As 10 specimens were not analyzable, only 30 eyes were included. Postoperatively, all eyes had postoperative uncorrected distance visual acuity of 20/20 or better; 43% had an unchanged corrected distance visual acuity; 43% gained 1 line; 10% lost 1 line. Ultrastructurally, surface irregularity was primarily caused by tissue bridges. The average surface regularity score obtained was 10.87 ± 2.40 for 120 μm, 10.78 ± 2.60 for 130 μm, 8.76 ± 2.16 for 140 μm, and 8.70 ± 2.66 for 150 μm (P < 0.001). The total number and areas of tissue bridges of 120 to 130 μm were significantly less than 140 to 150 μm (P < 0.05). Surface regularity decreased as cap thickness increased (P < 0.05). CONCLUSIONS There is smoother appearance of the lenticular surface as seen through SEM when a thin cap is created compared with a thick cap qualitatively and quantitatively.
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Femtosecond Laser-Assisted Small Incision Endokeratophakia Using a Xenogeneic Lenticule in Rhesus Monkeys. Cornea 2018; 37:354-361. [PMID: 29408829 DOI: 10.1097/ico.0000000000001470] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
PURPOSE To evaluate the feasibility and safety of xenogeneic endokeratophakia in rhesus monkeys and to explore the effects of a concave lenticule on refractive power. METHODS Three adult New Zealand white rabbits and 6 healthy rhesus monkeys were used. The xenogenic concave grafts were created from the rabbits using a modified small incision lenticule extraction technique; after being cryopreserved in glycerol for 1 week, the grafts were implanted into the monkey recipient corneas. Spherical equivalent (SE), central corneal thickness, and keratometry curvature were assessed preoperatively, 1 week, 1, 4 and 6 months postoperatively. The quality of the xenogenic graft was also assessed by slit-lamp microscopy, in vivo confocal microscopy, and optical coherence tomography with anterior segment imaging. RESULTS The graft appeared to be swollen a day after the operation but reduced considerably after a week. A trend of a lower refractive power (hyperopic shift) was demonstrated in relation to the SE after concave graft implantation. The mean SE increased from -0.60 ± 1.31 (median -0.69, interquartile range -1.00 to 0.50) preoperatively to 0.75 ± 1.27 (median 1.38, interquartile range -0.25 to 1.63) at 1 month postoperatively (P = 0.01). Central corneal thickness was significantly thicker each time after surgery compared with that recorded preoperatively (P < 0.01). The anterior and posterior interface between the graft and stroma was visible during the study. Corneal nerve regeneration was evident at 6 months postoperatively. The xenogeneic concave graft was stable and transparent at follow-up. Severe adverse events or evidence of a rejection response were not observed. CONCLUSIONS Femtosecond laser-assisted small incision endokeratophakia using a xenogeneic corneal lenticule seems to be feasible and safe, which may provide a new method for myopia correction and keratoconus treatment.
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Fu D, Wang L, Zhou XT, Yu ZQ. Cap morphology after small-incision lenticule extraction and its effects on intraocular scattering. Int J Ophthalmol 2018; 11:456-461. [PMID: 29600180 DOI: 10.18240/ijo.2018.03.16] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2017] [Accepted: 10/14/2017] [Indexed: 11/23/2022] Open
Abstract
AIM To investigate cap morphology after small-incision lenticule extraction (SMILE) and its effects on intraocular scattering. METHODS Sixty-five eyes of 33 patients undergoing SMILE were enrolled. In addition to regular evaluation, Fourier-domain optical coherence tomography was used to investigate cap thickness at 1d, 1wk, 1 and 3mo postoperatively. The optical quality including modulation transfer function cutoff frequency, Strehl ratio, Optical Quality Analysis System (OQAS) values, and objective scattering index (OSI), were evaluated using OQAS™. RESULTS Cap thickness decreased from 1d to 1wk (P<0.001), but remained higher than intended thickness of 120 µm after 3mo (P<0.001). Cap thickness in central area was thinner than that of in the paracentral and peripheral areas (P<0.0001). Total number of microdistortions decreased from 1d to 3mo (P<0.0001). Pearson analysis revealed a weak correlation between OSI and standard deviation of cap thickness at 1d and 1mo, as well as between range of cap thickness and OSI at 1mo. No correlation was found between microdistortion and OSI, but a negative correlation existed between microdistortion and range at 1d and 1moafter surgery. CONCLUSION The corneal cap tends to be more accurate and regular with time lapse. Better cap morphology tends to contribute less intraocular scattering in the eyes undergoing SMILE.
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Affiliation(s)
- Dan Fu
- Eye and ENT Hospital of Fudan University, Shanghai 200031, China
| | - Lin Wang
- Eye and ENT Hospital of Fudan University, Shanghai 200031, China
| | - Xing-Tao Zhou
- Eye and ENT Hospital of Fudan University, Shanghai 200031, China.,Myopia Key Laboratory of the Health Ministry, Shanghai 200031, China
| | - Zhi-Qiang Yu
- Eye and ENT Hospital of Fudan University, Shanghai 200031, China.,Myopia Key Laboratory of the Health Ministry, Shanghai 200031, China
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Effect of Cap-Lenticule Diameter Difference on the Visual Outcome and Higher-Order Aberrations in SMILE: 0.4 mm versus 1.0 mm. J Ophthalmol 2017; 2017:8259546. [PMID: 29270316 PMCID: PMC5705886 DOI: 10.1155/2017/8259546] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2017] [Revised: 09/29/2017] [Accepted: 10/12/2017] [Indexed: 11/17/2022] Open
Abstract
Purpose To evaluate the effect of cap-lenticule diameter difference (CLDD) on the visual outcome and higher-order aberrations (HOAs) of small-incision lenticule extraction (SMILE). Methods A total of 132 patients who had bilateral SMILE for myopia or myopic astigmatism were included. The CLDD was 0.4 mm in 54 patients (group 1) and 1.0 mm in 78 patients (group 2). The refractive parameters, uncorrected (UDVA) and corrected distance visual acuity (CDVA), and HOAs were determined preoperatively and during six months follow-up. Results Group 1 had better CDVA (in logMAR) compared to group 2 at day 1 (−0.07 ± 0.07 versus 0.04 ± 0.07, resp.; p < 0.001) and week 1 (−0.07 ± 0.07 versus –0.04 ± 0.07, resp.; p = 0.001). The visual acuity improved more in group 1 than in group 2. The UDVA (in logMAR) was 0.07 ± 0.07 and 0.29 ± 0.09 at day 1 (p < 0.001) and −0.08 ± 0.07 and −0.06 ± 0.06 at six months (p = 0.038) in group 1 and group 2, respectively. Group 1 was associated with significantly less induction of HOAs (0.24 ± 0.08 μm and 0.32 ± 0.26 μm, resp.; p = 0.002). Conclusions In SMILE, 0.4 mm CLDD is associated with better visual outcome and less induction of HOAs than 1.0 mm. Narrow CLDD should be considered in SMILE to increase the visual acuity particularly in the early postoperative period.
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