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Fan Y, Hong Y, Bao H, Huang Y, Zhang P, Zhu D, Jiang Q, Zuo Y, Swain M, Elsheikh A, Chen S, Zheng X. Biomechanical and histological changes associated with riboflavin ultraviolet-A-induced CXL with different irradiances in young human corneal stroma. Comput Biol Med 2024; 178:108607. [PMID: 38897147 DOI: 10.1016/j.compbiomed.2024.108607] [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: 01/10/2024] [Revised: 05/08/2024] [Accepted: 05/11/2024] [Indexed: 06/21/2024]
Abstract
Keratoconus (KC) is a degenerative condition affecting the cornea, characterized by progressive thinning and bulging, which can ultimately result in serious visual impairment. The onset and progression of KC are closely tied to the gradual weakening of the cornea's biomechanical properties. KC progression can be prevented with corneal cross-linking (CXL), but this treatment has shortcomings, and evaluating its tissue stiffening effect is important for determining its efficacy. In this field, the shortage of human corneas has made it necessary for most previous studies to rely on animal corneas, which have different microstructure and may be affected differently from human corneas. In this research, we have used the lenticules obtained through small incision lenticule extraction (SMILE) surgeries as a source of human tissue to assess CXL. And to further improve the results' reliability, we used inflation testing, personalized finite element modeling, numerical optimization and histology microstructure analysis. These methods enabled determining the biomechanical and histological effects of CXL protocols involving different irradiation intensities of 3, 9, 18, and 30 mW/cm2, all delivering the same total energy dose of 5.4 J/cm2. The results showed that the CXL effect did not vary significantly with protocols using 3-18 mW/cm2 irradiance, but there was a significant efficacy drop with 30 mW/cm2 irradiance. This study validated the updated algorithm and provided guidance for corneal lenticule reuse and the effects of different CXL protocols on the biomechanical properties of the human corneal stroma.
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Affiliation(s)
- YiWen Fan
- State Key Laboratory of Ophthalmology, Optometry and Visual Science, Eye Hospital, Wenzhou Medical University, Wenzhou, 325027, China; National Engineering Research Center of Ophthalmology and Optometry, Eye Hospital, Wenzhou Medical University, Wenzhou, 325027, China; National Clinical Research Center for Ocular Diseases, Eye Hospital, Wenzhou Medical University, Wenzhou, 325027, China
| | - YuXin Hong
- State Key Laboratory of Ophthalmology, Optometry and Visual Science, Eye Hospital, Wenzhou Medical University, Wenzhou, 325027, China; National Engineering Research Center of Ophthalmology and Optometry, Eye Hospital, Wenzhou Medical University, Wenzhou, 325027, China; National Clinical Research Center for Ocular Diseases, Eye Hospital, Wenzhou Medical University, Wenzhou, 325027, China
| | - Han Bao
- State Key Laboratory of Ophthalmology, Optometry and Visual Science, Eye Hospital, Wenzhou Medical University, Wenzhou, 325027, China; National Engineering Research Center of Ophthalmology and Optometry, Eye Hospital, Wenzhou Medical University, Wenzhou, 325027, China; National Clinical Research Center for Ocular Diseases, Eye Hospital, Wenzhou Medical University, Wenzhou, 325027, China
| | - YunYun Huang
- State Key Laboratory of Ophthalmology, Optometry and Visual Science, Eye Hospital, Wenzhou Medical University, Wenzhou, 325027, China; National Engineering Research Center of Ophthalmology and Optometry, Eye Hospital, Wenzhou Medical University, Wenzhou, 325027, China; National Clinical Research Center for Ocular Diseases, Eye Hospital, Wenzhou Medical University, Wenzhou, 325027, China
| | - Pei Zhang
- State Key Laboratory of Ophthalmology, Optometry and Visual Science, Eye Hospital, Wenzhou Medical University, Wenzhou, 325027, China; Key Laboratory of Coastal Environment and Resources Research of Zhejiang Province, School of Engineering, Westlake University, Hangzhou, 310000, China
| | - DeXi Zhu
- State Key Laboratory of Ophthalmology, Optometry and Visual Science, Eye Hospital, Wenzhou Medical University, Wenzhou, 325027, China; National Engineering Research Center of Ophthalmology and Optometry, Eye Hospital, Wenzhou Medical University, Wenzhou, 325027, China; National Clinical Research Center for Ocular Diseases, Eye Hospital, Wenzhou Medical University, Wenzhou, 325027, China
| | - QiuRuo Jiang
- State Key Laboratory of Ophthalmology, Optometry and Visual Science, Eye Hospital, Wenzhou Medical University, Wenzhou, 325027, China; National Engineering Research Center of Ophthalmology and Optometry, Eye Hospital, Wenzhou Medical University, Wenzhou, 325027, China; National Clinical Research Center for Ocular Diseases, Eye Hospital, Wenzhou Medical University, Wenzhou, 325027, China
| | - Yi Zuo
- State Key Laboratory of Ophthalmology, Optometry and Visual Science, Eye Hospital, Wenzhou Medical University, Wenzhou, 325027, China; National Engineering Research Center of Ophthalmology and Optometry, Eye Hospital, Wenzhou Medical University, Wenzhou, 325027, China; National Clinical Research Center for Ocular Diseases, Eye Hospital, Wenzhou Medical University, Wenzhou, 325027, China
| | - Michael Swain
- AMME, Biomechanics Engineering, The University of Sydney, Sydney, Australia
| | - Ahmed Elsheikh
- School of Engineering, University of Liverpool, Liverpool, L69 3GH, UK
| | - ShiHao Chen
- State Key Laboratory of Ophthalmology, Optometry and Visual Science, Eye Hospital, Wenzhou Medical University, Wenzhou, 325027, China; National Engineering Research Center of Ophthalmology and Optometry, Eye Hospital, Wenzhou Medical University, Wenzhou, 325027, China; National Clinical Research Center for Ocular Diseases, Eye Hospital, Wenzhou Medical University, Wenzhou, 325027, China.
| | - XiaoBo Zheng
- State Key Laboratory of Ophthalmology, Optometry and Visual Science, Eye Hospital, Wenzhou Medical University, Wenzhou, 325027, China; National Engineering Research Center of Ophthalmology and Optometry, Eye Hospital, Wenzhou Medical University, Wenzhou, 325027, China; National Clinical Research Center for Ocular Diseases, Eye Hospital, Wenzhou Medical University, Wenzhou, 325027, China.
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Yang D, Chen Z, Zhao W, Zhao J, Zhou X, Wang J. Characterization the corneal transparency profile in SMILE-treated myopic patients with densitometry: A 7-year cohort study. Indian J Ophthalmol 2024; 72:S429-S434. [PMID: 38317330 DOI: 10.4103/ijo.ijo_1787_23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2023] [Accepted: 11/03/2023] [Indexed: 02/07/2024] Open
Abstract
PURPOSE To investigate 7-year changes in corneal densitometry (CD) and its influencing factors following small incision lenticule extraction (SMILE) for moderate to high myopia. METHODS A total of 32 patients (52 eyes) with a mean spherical equivalent (SE) refraction of -6.30 ± 1.30 D who underwent SMILE were recruited for this prospective study. Pre- and postoperative CD and corneal aberrations were measured by an oculus Pentacam system, and patients were followed up to 7 years. The CD evolution over time and its influencing factors were explored. RESULTS No complications were observed after SMILE. There was a significant time effect on postoperative CD ( P < 0.05). The CD values at the 0-to-2 and 2-to-6 mm of the anterior layer increased at the first day ( P < 0.05) and declined to baselines at 1 year postoperatively; after that, CD values at any zone and any corneal layer presented a decreasing trend over time (all P < 0.05). Multivariate analysis showed that postoperative CD was positively correlated with age and optical zone (OZ), whereas negatively correlated with SE, corrected distance visual acuity (CDVA), and corneal aberrations (higher-order aberrations, Coma0 and Coma90) (all P < 0.05). Generalized estimating equation revealed that age, SE, CDVA, OZ, and Coma0 were the main factors influencing postoperative CD values (all P < 0.05). CONCLUSION CD manifested a long-term decreasing trend in moderate to high myopia treated with SMILE. Its main influencing factors are age, SE, CDVA, OZ, and Coma0.
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Affiliation(s)
- Dongmei Yang
- Eye Institute and Department of Ophthalmology, Fudan University, Shanghai, China
- NHC Key Laboratory of Myopia (Fudan University), Key Laboratory of Myopia, Chinese Academy of Medical Sciences, Shanghai, China
- Shanghai Research Center of Ophthalmology and Optometry, Shanghai, China
- Second People's Hospital of Yunnan Province, Affiliated Hospital of Yunnan University, Kunming, China
| | - Zhuoyi Chen
- Eye Institute and Department of Ophthalmology, Fudan University, Shanghai, China
- NHC Key Laboratory of Myopia (Fudan University), Key Laboratory of Myopia, Chinese Academy of Medical Sciences, Shanghai, China
- Shanghai Research Center of Ophthalmology and Optometry, Shanghai, China
| | - Wuxiao Zhao
- Eye Institute and Department of Ophthalmology, Fudan University, Shanghai, China
- NHC Key Laboratory of Myopia (Fudan University), Key Laboratory of Myopia, Chinese Academy of Medical Sciences, Shanghai, China
- Shanghai Research Center of Ophthalmology and Optometry, Shanghai, China
- Center for Optometry and Visual Science, The People's Hospital of Guangxi Zhuang Autonomous Region, Guangxi Academy of Medical Sciences, Nanning, China
| | - Jing Zhao
- Eye Institute and Department of Ophthalmology, Fudan University, Shanghai, China
- NHC Key Laboratory of Myopia (Fudan University), Key Laboratory of Myopia, Chinese Academy of Medical Sciences, Shanghai, China
- Shanghai Research Center of Ophthalmology and Optometry, Shanghai, China
| | - Xingtao Zhou
- Eye Institute and Department of Ophthalmology, Fudan University, Shanghai, China
- NHC Key Laboratory of Myopia (Fudan University), Key Laboratory of Myopia, Chinese Academy of Medical Sciences, Shanghai, China
- Shanghai Research Center of Ophthalmology and Optometry, Shanghai, China
| | - Jifang Wang
- Eye Institute and Department of Ophthalmology, Fudan University, Shanghai, China
- Department of Nursing, Eye and ENT Hospital, Fudan University, Shanghai, China
- NHC Key Laboratory of Myopia (Fudan University), Key Laboratory of Myopia, Chinese Academy of Medical Sciences, Shanghai, China
- Shanghai Research Center of Ophthalmology and Optometry, Shanghai, China
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Li J, Dai Y, Mu Z, Wang Z, Meng J, Meng T, Wang J. Choice of refractive surgery types for myopia assisted by machine learning based on doctors' surgical selection data. BMC Med Inform Decis Mak 2024; 24:41. [PMID: 38331788 PMCID: PMC10854042 DOI: 10.1186/s12911-024-02451-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2023] [Accepted: 02/02/2024] [Indexed: 02/10/2024] Open
Abstract
In recent years, corneal refractive surgery has been widely used in clinics as an effective means to restore vision and improve the quality of life. When choosing myopia-refractive surgery, it is necessary to comprehensively consider the differences in equipment and technology as well as the specificity of individual patients, which heavily depend on the experience of ophthalmologists. In our study, we took advantage of machine learning to learn about the experience of ophthalmologists in decision-making and assist them in the choice of corneal refractive surgery in a new case. Our study was based on the clinical data of 7,081 patients who underwent corneal refractive surgery between 2000 and 2017 at the Department of Ophthalmology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences. Due to the long data period, there were data losses and errors in this dataset. First, we cleaned the data and deleted the samples of key data loss. Then, patients were divided into three groups according to the type of surgery, after which we used SMOTE technology to eliminate imbalance between groups. Six statistical machine learning models, including NBM, RF, AdaBoost, XGBoost, BP neural network, and DBN were selected, and a ten-fold cross-validation and grid search were used to determine the optimal hyperparameters for better performance. When tested on the dataset, the multi-class RF model showed the best performance, with agreement with ophthalmologist decisions as high as 0.8775 and Macro F1 as high as 0.8019. Furthermore, the results of the feature importance analysis based on the SHAP technique were consistent with an ophthalmologist's practical experience. Our research will assist ophthalmologists in choosing appropriate types of refractive surgery and will have beneficial clinical effects.
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Affiliation(s)
- Jiajing Li
- School of Artificial Intelligence, China University of Mining and Technology (Beijing), Beijing, China.
- Wangganzhicha Information Technology Inc., Nanjing, Jiangsu Province, China.
| | - Yuanyuan Dai
- School of Artificial Intelligence, China University of Mining and Technology (Beijing), Beijing, China
| | - Zhicheng Mu
- School of Artificial Intelligence, China University of Mining and Technology (Beijing), Beijing, China
| | - Zhonghai Wang
- Department of Ophthalmology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Beijing, China
- Key Laboratory of Ocular Fundus Diseases, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China
| | - Juan Meng
- Community Health Service Center of Douhudi Town, Gongan County, Jingzhou, Hubei Province, China
| | - Tao Meng
- Wangganzhicha Information Technology Inc., Nanjing, Jiangsu Province, China
| | - Jimin Wang
- Department of Information Management, Peking University, Beijing, China
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Yang YZ, Li FF, Wu SQ, Dai Q, Bao FJ, Cheng D, Zhu J, Ye YF. Comparison of myopic astigmatic correction after cross-assisted SMILE, FS-LASIK, and transPRK. J Cataract Refract Surg 2023; 49:1242-1248. [PMID: 37616187 PMCID: PMC10664787 DOI: 10.1097/j.jcrs.0000000000001294] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2023] [Revised: 08/16/2023] [Accepted: 08/19/2023] [Indexed: 08/26/2023]
Abstract
PURPOSE To compare astigmatic correction among cross-assisted small-incision lenticule extraction (SMILE), femtosecond laser-assisted in situ keratomileusis (FS-LASIK), and transepithelial photorefractive keratectomy (transPRK). SETTING The Eye Hospital of Wenzhou Medical University, Zhejiang, China. DESIGN Prospective comparison study. METHODS 154 right eyes of 154 patients with astigmatism of -1.00 to -2.75 diopters (D) were included in this study. 64 eyes, 42 eyes, and 48 eyes were receiving SMILE, FS-LASIK, and transPRK, respectively. The SMILE group used cross-axial alignment for head positioning for astigmatism correction. In the FS-LASIK and transPRK groups, static and dynamic cyclotorsion control were used. Changes in ocular parameters and vector analysis were assessed at 6 months postoperatively. RESULTS The safety and efficacy indices were comparable among the 3 groups at 6 months postoperatively. Residual astigmatism was smallest in the SMILE group (-0.23 ± 0.25 D) compared with that in FS-LASIK (-0.40 ± 0.28 D, P = .009) and transPRK groups (-0.42 ± 0.32 D, P = .001). 53 (82.8%), 36 (85.7%), and 37 (77.1%) eyes achieved an angle of error within ±5 degrees, respectively ( P = .55). Notably, vector analysis showed that the difference vector, the magnitude of the error, and its absolute value were significantly smaller in the SMILE group than those in the other groups ( P < .05). In addition, the higher-order aberrations, especially coma, were significantly induced postoperatively in each group ( P < .001). CONCLUSIONS Residual astigmatism magnitude was smallest by cross-assisted SMILE, followed by FS-LASIK and transPRK, and the astigmatism axial correction was comparable among groups.
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Affiliation(s)
- Yi-Zeng Yang
- From the National Clinical Research Center for Ocular Diseases, Eye Hospital, Wenzhou Medical University, Wenzhou, China
| | - Fen-Fen Li
- From the National Clinical Research Center for Ocular Diseases, Eye Hospital, Wenzhou Medical University, Wenzhou, China
| | - Shuang-Qing Wu
- From the National Clinical Research Center for Ocular Diseases, Eye Hospital, Wenzhou Medical University, Wenzhou, China
| | - Qi Dai
- From the National Clinical Research Center for Ocular Diseases, Eye Hospital, Wenzhou Medical University, Wenzhou, China
| | - Fang-Jun Bao
- From the National Clinical Research Center for Ocular Diseases, Eye Hospital, Wenzhou Medical University, Wenzhou, China
| | - Dan Cheng
- From the National Clinical Research Center for Ocular Diseases, Eye Hospital, Wenzhou Medical University, Wenzhou, China
| | - Jun Zhu
- From the National Clinical Research Center for Ocular Diseases, Eye Hospital, Wenzhou Medical University, Wenzhou, China
| | - Yu-Feng Ye
- From the National Clinical Research Center for Ocular Diseases, Eye Hospital, Wenzhou Medical University, Wenzhou, China
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Cao H, Jhanji V, Wang Y. Relationship between postoperative residual refractive error and preoperative corneal stiffness in small-incision lenticule extraction. J Cataract Refract Surg 2023; 49:942-948. [PMID: 37379041 DOI: 10.1097/j.jcrs.0000000000001250] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2022] [Accepted: 06/21/2023] [Indexed: 06/29/2023]
Abstract
PURPOSE To explore the relationship between postoperative residual refractive error and preoperative corneal stiffness after small-incision lenticule extraction (SMILE). SETTING Hospital clinic. DESIGN Retrospective cohort study. METHODS Corneal stiffness was evaluated using the stress-strain index (SSI). Associations between postoperative spherical equivalent (SE) and corneal stiffness were determined using longitudinal regression analysis after adjustment for sex, age, preoperative SE, and other variables. The cohort was divided into halves to compare risk ratios for residual refraction in corneas with different SSI values. Low SSI values were defined as having less-stiff corneas and others as having stiffer corneas. RESULTS 287 patients (287 eyes) were included. Greater undercorrection was found in less-stiff corneas across all follow-up timepoints (less-stiff corneas: 1 day: -0.36 ± 0.45 diopters [D], 1 month: -0.22 ± 0.36 D, and 3 months: -0.13 ± 0.15 D; stiffer corneas: -0.22 ± 0.37 D, -0.14 ± 0.35 D, and -0.05 ± 0.11 D, respectively). Postoperative refraction exhibited a mean 0.05 D undercorrection for every 0.1-unit decrease in the SSI after adjustment for variables. The SSI accounted for nearly 10% of the variance in refractive outcomes. Less-stiff corneas increased the risk ratio of postoperative absolute SE >0 D and ≥0.25 D by 2.242 (95% CI, 1.334-3.768) and 3.023 (95% CI, 1.466-6.233), respectively, compared with stiffer corneas. CONCLUSIONS Postoperative residual refractive error was associated with preoperative corneal stiffness. Patients with less-stiff corneas had a 2- to 3-fold increased risk of residual refractive error after SMILE. Preoperative analysis of corneal stiffness can help modify nomogram algorithms of surgery and improve the predictability of refractive outcomes.
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Affiliation(s)
- Huazheng Cao
- From the School of Medicine, Nankai University, Tianjin, China (Cao); Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania (Jhanji); Tianjin Eye Hospital, Tianjin Key Lab of Ophthalmology and Visual Science, Tianjin Eye Institute, Nankai University Affiliated Eye Hospital, Tianjin, China (Wang); Nankai Eye Institute, Nankai University, Tianjin, China (Wang)
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Yang F, Dong Y, Bai C, Alzogool M, Wang Y. Bibliometric and visualized analysis of myopic corneal refractive surgery research: from 1979 to 2022. Front Med (Lausanne) 2023; 10:1141438. [PMID: 37575980 PMCID: PMC10416457 DOI: 10.3389/fmed.2023.1141438] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2023] [Accepted: 07/14/2023] [Indexed: 08/15/2023] Open
Abstract
Background Myopic corneal refractive surgery is one of the most prevalent ophthalmic procedures for correcting ametropia. This study aimed to perform a bibliometric analysis of research in the field of corneal refractive surgery over the past 40 years in order to describe the current international status and to identify most influential factors, while highlighting research hotspots. Methods A bibliometric analysis based on the Web of Science Core Collection (WoSCC) was used to analyze the publication trends in research related to myopic corneal refractive surgery. VOSviewer v.1.6.10 was used to construct the knowledge map in order to visualize the publications, distribution of countries, international collaborations, author productivity, source journals, cited references, keywords, and research hotspots in this field. Results A total of 4,680 publications on myopic corneal refractive surgery published between 1979 and 2022 were retrieved. The United States has published the most papers, with Emory University contributing to the most citations. The Journal of Cataract and Refractive Surgery published the greatest number of articles, and the top 10 cited references mainly focused on outcomes and wound healing in refractive surgery. Previous research emphasized "radial keratotomy (RK)" and excimer laser-associated operation methods. The keywords containing femtosecond (FS) laser associated with "small incision lenticule extraction (SMILE)" and its "safety" had higher burst strength, indicating a shift of operation methods and coinciding with the global trends in refractive surgery. The document citation network was clustered into five groups: (1) outcomes of refractive surgery: (2) preoperative examinations for refractive surgery were as follows: (3) complications of myopic corneal refractive surgery; (4) corneal wound healing and cytobiology research related to photorefractive laser keratotomy; and (5) biomechanics of myopic corneal refractive surgery. Conclusion The bibliometric analysis in this study may provide scholars with valuable to information and help them better understand the global trends in myopic corneal refractive surgery research frontiers. Two stages of rapid development occurred around 1991 and 2013, shortly after the innovation of PRK and SMILE surgical techniques. The most cited articles mainly focused on corneal wound healing, clinical outcomes, ocular aberration, corneal ectasia, and corneal topography, representing the safety of the new techniques.
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Affiliation(s)
- Fang Yang
- Clinical College of Ophthalmology, Tianjin Medical University, Tianjin, China
- Department of Ophthalmology, Renmin Hospital, Hubei University of Medicine, Shiyan, China
| | - Yi Dong
- Clinical College of Ophthalmology, Tianjin Medical University, Tianjin, China
- Tianjin Eye Hospital, Tianjin Key Lab of Ophthalmology and Visual Science, Tianjin Eye Institute, Nankai University Affiliated Eye Hospital, Tianjin, China
| | - Chen Bai
- Department of General Surgery, Taihe Hospital, Hubei University of Medicine, Shiyan, China
| | - Mohammad Alzogool
- Tianjin Eye Hospital, Tianjin Key Lab of Ophthalmology and Visual Science, Tianjin Eye Institute, Nankai University Affiliated Eye Hospital, Tianjin, China
- School of Medicine, Nankai University, Tianjin, China
| | - Yan Wang
- Clinical College of Ophthalmology, Tianjin Medical University, Tianjin, China
- Tianjin Eye Hospital, Tianjin Key Lab of Ophthalmology and Visual Science, Tianjin Eye Institute, Nankai University Affiliated Eye Hospital, Tianjin, China
- Nankai Eye Institute, Nankai University, Tianjin, China
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Wang Y, Cao H, Chen W, Bao F, Elsheikh A. Editorial: How can corneal biomechanics help with clinical applications? Front Bioeng Biotechnol 2023; 11:1186938. [PMID: 37214299 PMCID: PMC10192889 DOI: 10.3389/fbioe.2023.1186938] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2023] [Accepted: 04/27/2023] [Indexed: 05/24/2023] Open
Affiliation(s)
- Yan Wang
- Tianjin Key Lab of Ophthalmology and Visual Science, Tianjin Eye Hospital, Tianjin Eye Institute, Nankai University Affiliated Eye Hospital, Tianjin, China
- Nankai University Eye Institute, Nankai University, Tianjin, China
| | - HuaZheng Cao
- Nankai University Eye Institute, Nankai University, Tianjin, China
- School of Medicine, Nankai University, Tianjin, China
| | - WeiYi Chen
- College of Biomedical Engineering, Taiyuan University of Technology, Taiyuan, China
| | - FangJun Bao
- Eye Hospital, Wenzhou Medical University, Wenzhou, China
| | - Ahmed Elsheikh
- School of Engineering, University of Liverpool, Liverpool, United Kingdom
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Liu S, Yu L, Zhao Y, Zhou X. Changes in the posterior corneal surface after femtosecond laser-assisted lenticule intrastromal keratoplasty (LIKE) performed into a pocket (SMI-LIKE) or under a flap (FS-LIKE). EYE AND VISION (LONDON, ENGLAND) 2023; 10:23. [PMID: 37122005 PMCID: PMC10150533 DOI: 10.1186/s40662-023-00337-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/21/2022] [Accepted: 03/16/2023] [Indexed: 05/02/2023]
Abstract
BACKGROUND To compare the changes in posterior corneal surface after small-incision lenticule intrastromal keratoplasty (SMI-LIKE) and femtosecond laser-assisted lenticule intrastromal keratoplasty (FS-LIKE) for hyperopia correction. METHODS In this prospective comparative randomized study, 23 eyes with hyperopia were recruited. Eyes were categorized into two groups-SMI-LIKE group (11 eyes) and FS-LIKE group (12 eyes). Lenticules from myopia small incision lenticule extraction were implanted into a pocket (SMI-LIKE group) or at a depth of 100 µm under a flap (FS-LIKE group). Posterior corneal elevations in the center, mid-periphery, and periphery, as well as mean keratometry of the posterior corneal surface (Kmb) were measured using a Pentacam over a three-month follow-up. RESULTS All surgeries were completed successfully and no complications occurred. At one day postoperatively, there was a slight backward change with SMI-LIKE and a forward change with FS-LIKE in the central region of the posterior corneal elevation. Conversely, the peripheral area showed forward displacement in SMI-LIKE and an apparent backward change in FS-LIKE. The mid-peripheral regions manifested a backward change after the procedure throughout the entire follow-up in both groups. Kmb exhibited flattening at one month postoperatively and subsequently returned to its original level at three months after SMI-LIKE while in FS-LIKE, Kmb steepened after lenticule implantation with a significant change noted at one day postoperatively (P = 0.001). CONCLUSIONS Posterior corneal surface after SMI-LIKE and FS-LIKE exhibited different change patterns in various corneal regions, with the most prominent change occurring at one day postoperatively during the three-month follow-up. TRIAL REGISTRATION Chinese Clinical Trial Registry: ChiCTR-ONC-16008300. Registered on Apr 18th, 2016. http://www.chictr.org.cn/edit.aspx?pid=14090&htm=4.
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Affiliation(s)
- Shengtao Liu
- Department of Ophthalmology and Optometry, Eye and ENT Hospital of Fudan University, Shanghai, China
- NHC Key Laboratory of Myopia, Chinese Academy of Medical Sciences, Fudan University, Shanghai, China
- Shanghai Research Center of Ophthalmology and Optometry, Shanghai, China
- Shanghai Engineering Research Center of Laser and Autostereoscopic 3D for Vision Care (20DZ2255000), Shanghai, China
- Affiliated Eye Hospital of Nanchang University, Nanchang, China
| | - Lanhui Yu
- Affiliated Eye Hospital of Nanchang University, Nanchang, China
| | - Yu Zhao
- Department of Ophthalmology and Optometry, Eye and ENT Hospital of Fudan University, Shanghai, China.
- NHC Key Laboratory of Myopia, Chinese Academy of Medical Sciences, Fudan University, Shanghai, China.
- Shanghai Research Center of Ophthalmology and Optometry, Shanghai, China.
- Shanghai Engineering Research Center of Laser and Autostereoscopic 3D for Vision Care (20DZ2255000), Shanghai, China.
| | - Xingtao Zhou
- Department of Ophthalmology and Optometry, Eye and ENT Hospital of Fudan University, Shanghai, China.
- NHC Key Laboratory of Myopia, Chinese Academy of Medical Sciences, Fudan University, Shanghai, China.
- Shanghai Research Center of Ophthalmology and Optometry, Shanghai, China.
- Shanghai Engineering Research Center of Laser and Autostereoscopic 3D for Vision Care (20DZ2255000), Shanghai, China.
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Wan Q, Yue S, Tang J, Wei R, Tang J, Ma K, Yin H, Deng YP. Prediction of Early Visual Outcome of Small-Incision Lenticule Extraction (SMILE) Based on Deep Learning. Ophthalmol Ther 2023; 12:1263-1279. [PMID: 36826752 PMCID: PMC10011351 DOI: 10.1007/s40123-023-00680-6] [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: 01/11/2023] [Accepted: 02/07/2023] [Indexed: 02/25/2023] Open
Abstract
INTRODUCTION Deep learning (DL) has been widely used to estimate clinical images. The objective of this project was to create DL models to predict the early postoperative visual acuity after small-incision lenticule extraction (SMILE) surgery. METHODS We enrolled three independent patient cohorts (a retrospective cohort and two prospective SMILE cohorts) who underwent the SMILE refractive correction procedure at two different refractive surgery centers from July to September 2022. The medical records and surgical videos were collected for further analysis. Based on the uncorrected visual acuity (UCVA) at 24 h postsurgery, the eyes were divided into two groups: those showing good recovery and those showing poor recovery. We then trained a DL model (Resnet50) to predict eyes with early postoperative visual acuity of patients in the retrospective cohort who had undergone SMILE surgery from surgical videos and subsequently validated the model's performance in the two prospective cohorts. Finally, Gradient-weighted Class Activation Mapping (Grad-CAM) was performed for interpretation of the model. RESULTS Among the 318 eyes (159 patients) enrolled in the study, 10,176 good quality femtosecond laser scanning images were obtained from the surgical videos. We observed that the developed DL model achieved a high accuracy of 96% for image prediction. The area under the curve (AUC) value of the DL model in the retrospective cohort was 0.962 and 0.998 in the training and validation datasets, respectively. The AUC values in two prospective cohorts were 0.959 and 0.936. At the video level, the trained machine learning (ML) model (XGBoost) also accurately distinguished patients with good or poor recovery. The AUC value of the ML model was 0.998 and 0.889 in the retrospective cohort (training and test datasets, respectively) and 1.000 and 0.984 in the two prospective cohorts. We also trained a DL model which can accurately distinguish suction loss (100%), black spots (85%), and opaque bubble layer (96%). The Grad-CAM heatmap indicated that our models can recognize the area of scanning and precisely identify intraoperative complications. CONCLUSIONS Our findings suggest that artificial intelligence (DL and ML model) can accurately predict the early postoperative visual acuity and intraoperative complications after SMILE surgery just using surgical videos or images, which may display a great importance for artificial intelligence in application of refractive surgeries.
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Affiliation(s)
- Qi Wan
- Department of Ophthalmology, West China Hospital of Sichuan University, Chengdu City, Sichuan Province, China
| | - Shali Yue
- Department of Ophthalmology, West China Hospital of Sichuan University, Chengdu City, Sichuan Province, China
| | - Jing Tang
- Department of Ophthalmology, The People's Hospital of Leshan, Leshan City, Sichuan Province, China
| | - Ran Wei
- Department of Ophthalmology, West China Hospital of Sichuan University, Chengdu City, Sichuan Province, China
| | - Jing Tang
- Department of Ophthalmology, West China Hospital of Sichuan University, Chengdu City, Sichuan Province, China
| | - Ke Ma
- Department of Ophthalmology, West China Hospital of Sichuan University, Chengdu City, Sichuan Province, China.
| | - Hongbo Yin
- Department of Ophthalmology, West China Hospital of Sichuan University, Chengdu City, Sichuan Province, China
| | - Ying-Ping Deng
- Department of Ophthalmology, West China Hospital of Sichuan University, Chengdu City, Sichuan Province, China.
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Zou H, Zhao X, Zhang J, Xu L, Fan Q, Zhang L, Chan TCY, Wang Y. The effects of programmed optical zones on achieved corneal refractive power with myopic astigmatism after small incision lenticule extraction (SMILE): a vector analysis. Int Ophthalmol 2023:10.1007/s10792-023-02649-7. [PMID: 36905461 DOI: 10.1007/s10792-023-02649-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2022] [Accepted: 02/19/2023] [Indexed: 03/12/2023]
Abstract
PURPOSE To evaluate the effects of different programmed optical zones (POZs) on achieved corneal refractive power (CRP) with myopic astigmatism after small incision lenticule extraction (SMILE). METHODS In total, 113 patients (113 eyes) were included in this retrospective study. The eyes were divided into two groups according to POZ: group A (6.5, 6.6, and 6.7 mm, n = 59) and group B (6.8, 6.9, and 7.0 mm, n = 54). Fourier vector analysis was applied to evaluate the error values between the attempted and achieved corneal refractive power (CRP). Alpins vector analysis was used to calculate surgically induced astigmatism (SIA), difference vector (DV), magnitude of error (ME), and astigmatism correction index (ACI). Multivariate regression analysis was performed to assess potential factors associated with the error values. RESULTS The error values in the group with large POZ were closer to zero, and significantly associated with the POZ at 2 and 4 mm of the cornea (β = - 0.50, 95% confidence interval [CI] [- 0.80, - 0.20]; β = - 0.37, 95% CI [- 0.63, - 0.10], P < 0.05, respectively). For the correction of astigmatism, the values of SIA, ME, and ACI were lower in group B than in group A (P < 0.05). The fitting curves between TIA and SIA were y = 0.83x + 0.19 (R2 = 0.84) and y = 1.05x + 0.04 (R2 = 0.90), respectively. CONCLUSIONS Smaller POZs resulted in higher error values between the achieved- and attempted-CRP in the SMILE procedure, which should be considered when performing surgery.
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Affiliation(s)
- Haohan Zou
- Clinical College of Ophthalmology, Tianjin Medical University, Tianjin, China.,Clinical College of Ophthalmology, Tianjin Eye Hospital, Tianjin Eye Institute, Tianjin Key Laboratory of Ophthalmology and Visual Science, Tianjin Medical University, No 4. Gansu Road, He-Ping District, Tianjin, 300020, China
| | - Xinheng Zhao
- Clinical College of Ophthalmology, Tianjin Eye Hospital, Tianjin Eye Institute, Tianjin Key Laboratory of Ophthalmology and Visual Science, Tianjin Medical University, No 4. Gansu Road, He-Ping District, Tianjin, 300020, China
| | - Jiamei Zhang
- Clinical College of Ophthalmology, Tianjin Eye Hospital, Tianjin Eye Institute, Tianjin Key Laboratory of Ophthalmology and Visual Science, Tianjin Medical University, No 4. Gansu Road, He-Ping District, Tianjin, 300020, China
| | - Lulu Xu
- Clinical College of Ophthalmology, Tianjin Eye Hospital, Tianjin Eye Institute, Tianjin Key Laboratory of Ophthalmology and Visual Science, Tianjin Medical University, No 4. Gansu Road, He-Ping District, Tianjin, 300020, China
| | - Qian Fan
- Clinical College of Ophthalmology, Tianjin Eye Hospital, Tianjin Eye Institute, Tianjin Key Laboratory of Ophthalmology and Visual Science, Tianjin Medical University, No 4. Gansu Road, He-Ping District, Tianjin, 300020, China
| | - Lin Zhang
- Clinical College of Ophthalmology, Tianjin Eye Hospital, Tianjin Eye Institute, Tianjin Key Laboratory of Ophthalmology and Visual Science, Tianjin Medical University, No 4. Gansu Road, He-Ping District, Tianjin, 300020, China
| | - Tommy C Y Chan
- Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong SAR, China.,Department of Ophthalmology, Hong Kong Sanatorium & Hospital, Hong Kong SAR, China
| | - Yan Wang
- Clinical College of Ophthalmology, Tianjin Eye Hospital, Tianjin Eye Institute, Tianjin Key Laboratory of Ophthalmology and Visual Science, Tianjin Medical University, No 4. Gansu Road, He-Ping District, Tianjin, 300020, China. .,Nankai University Eye Institute, Nankai University affiliated Eye Hospital, Nankai University, Tianjin, China.
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11
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Mao X, Ji S, Chen H, Dai J. Comparison of Postoperative Safety, Efficacy, and Visual Quality after SMILE for Myopic Patients with Different Corneal Thicknesses. Curr Eye Res 2023; 48:18-24. [PMID: 36285731 DOI: 10.1080/02713683.2022.2117382] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
PURPOSE To investigate the safety, efficacy, and visual quality of small incision lenticule extraction (SMILE) in different corneal thickness patients with myopia or myopic astigmatism. METHODS This prospective cohort study included 191 right eyes of 191 patients. Eyes were divided into three groups according to preoperative central corneal thickness (CCT) (Preoperative central corneal thickness (CCT) was the group indicator.) There were 31 eyes in the thin cornea group (CCT ≤500 um (μm), TC), 94 eyes in the moderate corneal thickness group (CCT ≥501 um (μm) and ≤550 um (μm), MD) and 66 eyes in the thick cornea group (CCT ≥550 um (μm), TK). Comparisons in uncorrected (UDVA) and best-corrected distance visual acuity (BDVA), manifest refractive spherical equivalent (SE), preoperative mesopic/photopic contrast sensitivity (CS), ocular higher-order aberrations (HOAs) at a 6mm analytical pupil diameter, and visual quality questionnaires were made (performed) among the three groups during the postoperative six months. Subgroup analyses were made based on preoperative SE. RESULTS The safety indices at six months were 1.15 ± 0.18, 1.14 ± 0.17, and 1.18 ± 0.17, respectively (p = 0.374), and the efficacy indices at six months were 1.07 ± 0.25, 1.12 ± 0.22, and 1.11 ± 0.21, respectively (p = 0.599). The postoperative SE was -0.07 ± 0.52D, -0.14 ± 0.38D, and -0.05 ± 0.46D after SMILE in the three groups, respectively (p = 0.376). No significant difference was found in mesopic/photopic CS, HOAs, and visual quality among different corneal thickness groups and SE groups. Postoperative SE and efficacy indices were the lowest in thin cornea eyes with ultra-high myopia (over -9.00 D). CONCLUSIONS SMILE provides comparable safety, efficacy, and visual quality results in different corneal thickness patients. Those with myopia higher than -9.00 D had less efficacy after surgery, especially in thin cornea patients.
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Affiliation(s)
- Xiuyu Mao
- Department of Ophthalmology, Zhongshan Hospital Affiliated to Fudan University, Shanghai, China.,Department of Ophthalmology, Eye & ENT Hospital Affiliated to Fudan University, Shanghai, China.,Key Laboratory of Myopia, Chinese Academy of Medical Sciences (Fudan University), Shanghai, China
| | - Shunmei Ji
- Department of Ophthalmology, Zhongshan Hospital Affiliated to Fudan University, Shanghai, China.,Department of Ophthalmology, Eye & ENT Hospital Affiliated to Fudan University, Shanghai, China.,Key Laboratory of Myopia, Chinese Academy of Medical Sciences (Fudan University), Shanghai, China
| | - Han Chen
- Department of Ophthalmology, Eye & ENT Hospital Affiliated to Fudan University, Shanghai, China.,Department of Ophthalmology, Fujian Provincial Hospital, Fujian, China
| | - Jinhui Dai
- Department of Ophthalmology, Zhongshan Hospital Affiliated to Fudan University, Shanghai, China.,Department of Ophthalmology, Eye & ENT Hospital Affiliated to Fudan University, Shanghai, China.,Key Laboratory of Myopia, Chinese Academy of Medical Sciences (Fudan University), Shanghai, China
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12
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Gao W, Zhao X, Wang Y. Change in the corneal material mechanical property for small incision lenticule extraction surgery. Front Bioeng Biotechnol 2023; 11:1034961. [PMID: 36890912 PMCID: PMC9986312 DOI: 10.3389/fbioe.2023.1034961] [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: 09/02/2022] [Accepted: 02/10/2023] [Indexed: 02/22/2023] Open
Abstract
Purpose: To assess the distribution characteristics and related factors of stress-strain index (SSI) values and discuss changes in biomechanical parameters, including SSI, after small incision lenticule extraction (SMILE) surgery. Methods: This study included 253 patients who underwent SMILE (253 eyes). SSI and other biomechanical parameters were measured using corneal visualization Scheimpflug technology before and 3 months after surgery. The data collected included SSI, central corneal thickness (CCT), and eight other dynamic corneal response parameters. The Kolmogorov-Smirnov test, Pearson and partial correlation analyses, and paired-sample t-tests were used for statistical analyses. Results: Both pre-op SSI and ΔSSI follow a normal distribution, while post-op SSI does not follow a normal distribution. The decline in SSI after SMILE surgery was not statistically significant, and the data dispersion of SSI after SMILE surgery was close to that before surgery (p > 0.05). No statistical correlation was noted between SSI values and age and pre-op CCT (all p > 0.05). However, both pre- and post-op SSI values decreased with increasing degree of myopia (all p < 0.05), and weakly correlated with preoperative intraocular pressure and biomechanically corrected intraocular pressure (all p < 0.05). Other biomechanical parameters changed significantly after surgery (all p < 0.001). After SMILE, the magnitude of the deformation at the highest concave, deformation ratio, and integral radius increased significantly (all p < 0.001), while the Ambrosio relational thickness horizontal, stiffness parameter A1, and Corvis biomechanical index decreased significantly (p < 0.001). Conclusion: SSI, which reflects essential corneal material attributes, differs from other corneal biomechanical parameters and remains stable before and after SMILE surgery, and can be used as an indicator to evaluate changes in corneal material properties after SMILE surgery.
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Affiliation(s)
- Wenjing Gao
- Clinical College of Ophthalmology, Tianjin Medical University, Tianjin, China.,Tianjin Key Lab of Ophthalmology and Visual Science, Tianjin Eye Institute, Tianjin Eye Hospital, Tianjin, China.,Nankai University Eye Institute, Nankai University Affiliated Eye Hospital, Nankai University, Tianjin, China
| | - Xinheng Zhao
- Clinical College of Ophthalmology, Tianjin Medical University, Tianjin, China.,Tianjin Key Lab of Ophthalmology and Visual Science, Tianjin Eye Institute, Tianjin Eye Hospital, Tianjin, China.,Nankai University Eye Institute, Nankai University Affiliated Eye Hospital, Nankai University, Tianjin, China
| | - Yan Wang
- Clinical College of Ophthalmology, Tianjin Medical University, Tianjin, China.,Tianjin Key Lab of Ophthalmology and Visual Science, Tianjin Eye Institute, Tianjin Eye Hospital, Tianjin, China.,Nankai University Eye Institute, Nankai University Affiliated Eye Hospital, Nankai University, Tianjin, China
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13
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Clinical Evaluation of Corneal Biomechanics following Laser Refractive Surgery in Myopic Eyes: A Review of the Literature. J Clin Med 2022; 12:jcm12010243. [PMID: 36615041 PMCID: PMC9821300 DOI: 10.3390/jcm12010243] [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: 11/21/2022] [Revised: 12/18/2022] [Accepted: 12/23/2022] [Indexed: 12/31/2022] Open
Abstract
The role of corneal biomechanics in laser vision correction (LVC) is currently being raised in the assessment of postoperative corneal ectasia risk. The aim of the paper was to evaluate the changes in corneal biomechanics after LVC procedures based on a systematic review of current studies. The results of a search of the literature in the PubMed, Science Direct, Google Scholar, and Web of Science databases were selected for final consideration according to the PRISMA 2020 flow diagram. Included in our review were 17 prospective clinical studies, with at least 6 months of follow-up time. Corneal biomechanical properties were assessed by Ocular Response Analyzer (ORA), or Corvis ST. The results of the study revealed the highest corneal biomechanics reduction after laser in situ keratomileusis (LASIK) followed by small incision lenticule extraction (SMILE) and surface procedures, such as photorefractive keratectomy (PRK) or laser-assisted sub-epithelial keratectomy (LASEK). In SMILE procedure treatment planning, the use of thicker caps preserves the corneal biomechanics. Similarly, reduction of flap thickness in LASIK surgery maintains the corneal biomechanical strength. Future prospective clinical trials with standardization of the study groups and surgical parameters are needed to confirm the results of the current review.
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Li FF, Yang YZ, Bao FJ, Cheng D, Zhu J, Ye YF. Comparison of Astigmatic Correction With and Without Cross-axis Alignment During Small Incision Lenticule Extraction. J Refract Surg 2022; 38:624-631. [DOI: 10.3928/1081597x-20220830-01] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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15
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Han T, Zhao L, Shen Y, Chen Z, Yang D, Zhang J, Sekundo W, Shah R, Tian J, Zhou X. Twelve-year global publications on small incision lenticule extraction: A bibliometric analysis. Front Med (Lausanne) 2022; 9:990657. [PMID: 36160168 PMCID: PMC9493269 DOI: 10.3389/fmed.2022.990657] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2022] [Accepted: 08/22/2022] [Indexed: 11/13/2022] Open
Abstract
Purpose To analyze the development process of small incision lenticule extraction (SMILE) surgery in a 12-year period. Methods We conducted a literature search for SMILE research from 2011 to 2022 using the Science Citation Index Expanded (SCIE) of the Web of Science Core Collection (WoSCC). The VOS viewer, and CiteSpace software were used to perform the bibliometric analysis. Publication language, annual growth trend, countries/regions and institutions, journals, keywords, references, and citation bursts were analyzed. Results A total of 731 publications from 2011 to 2022 were retrieved. Annual publication records grew from two to more than 100 during this period. China had the highest number of publications (n = 326). Sixty-five keywords that appeared more than four times were classified into six clusters: femtosecond laser technology, dry eye, biomechanics, visual quality, complications, and hyperopia. Conclusion The number of literatures has been growing rapidly in the past 12 years. Our study provides a deep insight into publications on SMILE for researchers and clinicians with bibliometric analysis for the first time.
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Affiliation(s)
- Tian Han
- Department of Ophthalmology, Eye and ENT Hospital of Fudan University, Shanghai, China
- NHC Key Laboratory of Myopia, Fudan University, Shanghai, China
- Research Center of Ophthalmology and Optometry Shanghai, Shanghai, China
- Shanghai Engineering Research Center of Laser and Autostereoscopic 3D for Vision Care (20DZ2255000), Shanghai, China
| | - Liang Zhao
- Evidence-Based Medicine Center, School of Basic Medical Sciences, Lanzhou University, Lanzhou, Gansu, China
- Key Laboratory of Evidence-Based Medicine and Knowledge Translation of Gansu Province, Lanzhou, China
- The School of Nursing, Lanzhou University, Lanzhou, Gansu, China
| | - Yang Shen
- Department of Ophthalmology, Eye and ENT Hospital of Fudan University, Shanghai, China
- NHC Key Laboratory of Myopia, Fudan University, Shanghai, China
- Research Center of Ophthalmology and Optometry Shanghai, Shanghai, China
- Shanghai Engineering Research Center of Laser and Autostereoscopic 3D for Vision Care (20DZ2255000), Shanghai, China
| | - Zhi Chen
- Department of Ophthalmology, Eye and ENT Hospital of Fudan University, Shanghai, China
- NHC Key Laboratory of Myopia, Fudan University, Shanghai, China
- Research Center of Ophthalmology and Optometry Shanghai, Shanghai, China
- Shanghai Engineering Research Center of Laser and Autostereoscopic 3D for Vision Care (20DZ2255000), Shanghai, China
| | - Dong Yang
- Department of Ophthalmology, Eye and ENT Hospital of Fudan University, Shanghai, China
- NHC Key Laboratory of Myopia, Fudan University, Shanghai, China
- Research Center of Ophthalmology and Optometry Shanghai, Shanghai, China
- Shanghai Engineering Research Center of Laser and Autostereoscopic 3D for Vision Care (20DZ2255000), Shanghai, China
| | - Jiaoyan Zhang
- Evidence-Based Medicine Center, School of Basic Medical Sciences, Lanzhou University, Lanzhou, Gansu, China
- Key Laboratory of Evidence-Based Medicine and Knowledge Translation of Gansu Province, Lanzhou, China
- The School of Nursing, Lanzhou University, Lanzhou, Gansu, China
| | - Walter Sekundo
- The Department of Ophthalmology, Philipps University of Marburg, Marburg, Germany
| | - Rupal Shah
- New Vision Laser Centers, Vadodara, Gujarat, India
| | - Jinhui Tian
- Evidence-Based Medicine Center, School of Basic Medical Sciences, Lanzhou University, Lanzhou, Gansu, China
- Key Laboratory of Evidence-Based Medicine and Knowledge Translation of Gansu Province, Lanzhou, China
- *Correspondence: Jinhui Tian,
| | - Xingtao Zhou
- Department of Ophthalmology, Eye and ENT Hospital of Fudan University, Shanghai, China
- NHC Key Laboratory of Myopia, Fudan University, Shanghai, China
- Research Center of Ophthalmology and Optometry Shanghai, Shanghai, China
- Shanghai Engineering Research Center of Laser and Autostereoscopic 3D for Vision Care (20DZ2255000), Shanghai, China
- Xingtao Zhou,
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Piao J, Wang S, Tao Y, Zhou YH, Li Y. Corneal epithelial remodeling after femtosecond laser-assisted in situ keratomileusis combined with intraoperative accelerated corneal collagen crosslinking for myopia: a retrospective study. BMC Ophthalmol 2022; 22:349. [PMID: 35987632 PMCID: PMC9392929 DOI: 10.1186/s12886-022-02570-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Accepted: 08/10/2022] [Indexed: 11/10/2022] Open
Abstract
Abstract
Background
This study analyzed regional corneal thickness remodeling, biomechanical properties, and visual outcomes after femtosecond laser-assisted in situ keratomileusis combined with intraoperative accelerated corneal collagen crosslinking (LASIK Xtra) for myopia.
Methods
This retrospective study analyzed 21 consecutive patients (18 women, three men; 42 eyes) who were treated with LASIK Xtra. All treatments were performed with ultraviolet-A (energy, 2.7 J/cm2; irradiance, 30 mW/cm2), using continuous (90 s) illumination. Postoperative values of corneal biometrics and visual outcomes were compared with preoperative values. Corneal thickness changes were evaluated using anterior segment optical coherence tomography. All patients were followed up for 12-month postoperatively. Preoperative and postoperative data were compared statistically using the paired t-test for normally distributed parameters and the Wilcoxon rank-sum test and Friedman analysis of variance with Bonferroni correction for non-normally distributed data.
Results
Uncorrected distance visual acuity (UDVA) significantly improved at 6-month after surgery (P < 0.001). The central and inner regional corneal epithelial thickness significantly increased after LASIK Xtra (P < 0.05 for all), while the peripheral corneal epithelial thickness remained stable at 12-month after surgery. There was also a statistically significant decreased in the stromal thickness at most locations (P < 0.05 for all), except in the outer superior and outer superior-temporal regions.
Conclusions
LASIK Xtra provided improvement in UDVA, corneal curvature, and corneal biomechanical stability. Because the results of this retrospective study results depended on the cohort members’ past information, it was inferred and confirmed that regular corneal thickness remodeling occurred after treatment.
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Cao H, Zhang L, Liang S, Chen X, Jhanji V, Wang Y. Predictive factors of posterior corneal shift after small incision lenticule extraction: a 5-year follow-up study. Acta Ophthalmol 2022; 100:e1431-e1438. [PMID: 35488809 DOI: 10.1111/aos.15166] [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: 09/22/2021] [Revised: 04/01/2022] [Accepted: 04/18/2022] [Indexed: 11/29/2022]
Abstract
PURPOSE The aim of this study was to determine risk factors affecting changes in posterior corneal elevation (PCE) and predict the 5-year stability after small incision lenticule extraction (SMILE). METHODS This retrospective, longitudinal study enrolled 161 patients post-SMILE. The PCE values were measured at the apex, thinnest, maximal and 24 other prespecified preoperative points and at 6 months, 1 year and 5 years postoperatively. RESULTS Posterior corneas exhibited time-dependent, region-dependent and angle-dependent changes. For every dioptre increase in the absolute preoperative spherical equivalent (SE), 10-μm decrease in the central corneal thickness (CCT), 10-μm increase in the maximum lenticule thickness (MLT), 10-μm decrease in the residual bed thickness (RBT), 10% increase in the percentage ablation depth (PAD, MLT divided by CCT) and 10% decrease in the percentage stromal bed thickness (PSBT, RBT divided by CCT), PCE exhibited average forward displacements of 0.2-0.4, 0.2-0.7, 0.1-0.2, 0.1-0.3, 0.6-1.0 and 0.5-1.1 μm, respectively (p < 0.05). PSBT was the variable with the highest accuracy in predicting 5-year stability of posterior corneas (area under curve = 0.75). The cut-off values of SE, CCT, MLT, RBT, PAD and PSBT for increased PCE were -8.00 to -8.31 D, 481.0-498.5 μm, 139.5-144.5 μm, 255.5-263.5 μm, 26.9-28.3% and 48.9-52.6%, respectively. CONCLUSION Eyes with thinner corneas, higher myopia requiring greater MLT and lower RBT exhibited greater predispositions towards posterior protrusion. The thresholds for preventing forward posterior corneal displacement were 26.9-28.3% for PAD and 48.9-52.6% for PSBT. Prediction of posterior corneal stability is useful for assessing surgical risks post-SMILE.
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Affiliation(s)
- Huazheng Cao
- Clinical College of Ophthalmology Tianjin Medical University Tianjin China
| | - Lin Zhang
- Clinical College of Ophthalmology Tianjin Medical University Tianjin China
- Tianjin Key Laboratory of Ophthalmology and Visual Science, Tianjin Eye Hospital, Tianjin Eye Institute Nankai University Affiliated Eye Hospital Tianjin China
| | - Shuang Liang
- Clinical College of Ophthalmology Tianjin Medical University Tianjin China
| | - Xuan Chen
- Clinical College of Ophthalmology Tianjin Medical University Tianjin China
| | - Vishal Jhanji
- Department of Ophthalmology University of Pittsburgh School of Medicine Pittsburgh PA USA
| | - Yan Wang
- Clinical College of Ophthalmology Tianjin Medical University Tianjin China
- Tianjin Key Laboratory of Ophthalmology and Visual Science, Tianjin Eye Hospital, Tianjin Eye Institute Nankai University Affiliated Eye Hospital Tianjin China
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Zhang Y, Sun X, Chen Y. Comparison of Corneal Optical Quality After SMILE, Wavefront-Optimized LASIK and Topography-Guided LASIK for Myopia and Myopic Astigmatism. Front Med (Lausanne) 2022; 9:870330. [PMID: 35449802 PMCID: PMC9016141 DOI: 10.3389/fmed.2022.870330] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2022] [Accepted: 03/08/2022] [Indexed: 11/13/2022] Open
Abstract
Purpose To compare visual outcomes and corneal optical quality after small incision lenticule extraction (SMILE), wavefront-optimized (WFO) FS-LASIK, and topography-guided customized ablation treatment (TCAT) FS-LASIK for myopia. Methods This prospective case-series study included 283 eyes of 283 myopic patients who underwent SMILE or FS-LASIK. There were 102, 100, and 81 eyes in the SMILE group, WFO group and TCAT group, respectively. The tomography system (Sirius) was used to measure corneal aberrations and optical quality. Results At postoperative 1 and 6 months, there were no significant differences in uncorrected distance visual acuity and corrected distance visual acuity among the three groups (P > 0.05). Postoperative manifest refractive spherical equivalent was similar among the groups (P > 0.05). There was statistically significant difference in cylinder at 1 month among the three groups, with the highest mean value in TCAT group (P < 0.05). The corneal optical path difference, root mean square of corneal astigmatism and strehl ratio were the most superior in the TCAT group at postoperative 1 and 6 months (P < 0.05). Conclusion SMILE, WFO FS-LASIK, and TCAT FS-LASIK provided similar visual results. The corneal visual quality after TCAT FS-LASIK was the best.
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Affiliation(s)
- Yu Zhang
- Department of Ophthalmology, Peking University Third Hospital, Beijing, China.,Beijing Key Laboratory of Restoration of Damaged Ocular Nerve, Beijing, China
| | - Xiaoxiao Sun
- Department of Ophthalmology, Peking University Third Hospital, Beijing, China
| | - Yueguo Chen
- Department of Ophthalmology, Peking University Third Hospital, Beijing, China.,Beijing Key Laboratory of Restoration of Damaged Ocular Nerve, Beijing, China
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Goupillou P, Boutillier G, Naguszewski D, Muraine M. Long-term follow-up of bilateral ectasia after laser-assisted Small-Incision Lenticule Extraction (SMILE) with known risk factors. Eur J Ophthalmol 2022; 33:NP14-NP17. [PMID: 35234069 DOI: 10.1177/11206721221085397] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
PURPOSE To report the long-term follow-up of bilateral ectasia after laser-assisted small-incision lenticule extraction (SMILE) with known risk factors. CASE REPORT We report the case of a 23-year-old woman. Preoperative refraction was - 7.25 -2.00 × 20 in the right eye and -7.25 -1.50 × 155 in the left eye. Maximal keratometry was 47.32 diopters and 48.37 diopters, respectively, which was a contraindication to Laser Assisted In Situ Keratomileusis (LASIK) and a SMILE was proposed in 2015. One year after surgery, ectasia developed in the left eye and crosslinking (CXL) was performed. Two years after surgery, ectasia also developed in the right eye and CXL was also performed, leading to stabilization in both eyes five years after surgery. CONCLUSIONS Known contraindications for LASIK are also contraindications for the performance of refractive surgery with SMILE. CXL is an efficient treatment of post-SMILE corneal ectasia.
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Comparison of visual outcomes between 120-µm and 140-µm cap thicknesses 12 months after small incision lenticule extraction. Lasers Med Sci 2022; 37:2667-2673. [PMID: 35217941 DOI: 10.1007/s10103-022-03534-y] [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: 08/03/2021] [Accepted: 02/21/2022] [Indexed: 10/19/2022]
Abstract
To compare visual and refractive outcomes as well as changes in high-order aberrations in patients with 120- versus 140-µm cap thicknesses 12 months after small incision lenticule extraction. Ninety-four patients were randomized to receive small incision lenticule extraction with either a 120-µm cap thickness (n = 47) or a 140-µm cap thickness (n = 47) to treat myopia or myopic astigmatism, if not both. In an analysis of right eyes only during the 12-month follow-up period, uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), refractive outcomes, and high-order aberrations were evaluated. The distribution of patients by age and sex between the groups did not differ significantly (P = .803 and P = .680, respectively). CDVA, spherical and cylindrical refraction, and changes in total high-order aberration, spherical aberration, coma, and trefoil were similar between the groups at 6 and 12 months, postoperatively. However, UDVA was statistically significantly higher in patients with 140-μm cap thicknesses than with 120-μm cap thicknesses at 6 and 12 months postoperatively (P < .001 and P < .001, respectively). Patients with 140-µm cap thickness showed greater improvement in UDVA than ones with 120-µm cap thickness at 12-month follow-up (P = .005). Both 120- and 140-μm cap thicknesses in small incision lenticule extraction were safe and effective thicknesses for correcting myopia or myopic astigmatism. The patients with 140-μm cap thickness had better improvement in UDVA after 12-month follow-up compared to patients with 120-μm cap thickness.
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Chang JY, Lin PY, Hsu CC, Liu CJL. Comparison of clinical outcomes of LASIK, Trans-PRK, and SMILE for correction of myopia. J Chin Med Assoc 2022; 85:145-151. [PMID: 34861667 DOI: 10.1097/jcma.0000000000000674] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
Transepithelial photorefractive keratectomy (Trans-PRK), laser-assisted in situ keratomileusis (LASIK), and small incision lenticule extraction (SMILE) are three mainstay refractive surgeries worldwide. The applicability, efficacy, safety, and predictability of these different techniques are quite similar. Trans-PRK has the strongest biostability, earliest return to normal corneal sensitivity but the longest recovery time, most uncomfortable postoperative experience, and possibility of corneal haze. LASIK possesses the fastest visual rehabilitation but the slowest corneal nerve reinnervation, and flap displacement is possibly lifelong. SMILE incurs no flap-related complications and has intermediate vision recovery time and biomechanics compared with Trans-PRK and LASIK. However, it lacks the cyclotorsion-compensation system, eye-tracking system, and customized treatment profile for high astigmatism or irregular corneal surface. This review aims to introduce the mechanisms, pros, and cons of these three types of refractive surgery. With full understanding, practitioners could advise patients on the most suitable treatment of choice.
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Affiliation(s)
- Jin-Yu Chang
- Department of Ophthalmology, Taipei Veterans General Hospital, Taipei, Taiwan, ROC
| | - Pei-Yu Lin
- Department of Ophthalmology, Taipei Veterans General Hospital, Taipei, Taiwan, ROC
- School of Medicine, National Yang Ming Chiao Tung University, Taipei, Taiwan, ROC
| | - Chih-Chien Hsu
- Department of Ophthalmology, Taipei Veterans General Hospital, Taipei, Taiwan, ROC
- School of Medicine, National Yang Ming Chiao Tung University, Taipei, Taiwan, ROC
| | - Catherine Jui-Ling Liu
- Department of Ophthalmology, Taipei Veterans General Hospital, Taipei, Taiwan, ROC
- School of Medicine, National Yang Ming Chiao Tung University, Taipei, Taiwan, ROC
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He S, Luo Y, Chen P, Ye Y, Zheng H, Lan M, Zhuang J, Yu K. Prospective, Randomized, Contralateral Eye Comparison of Functional Optical Zone, and Visual Quality After SMILE and FS-LASIK for High Myopia. Transl Vis Sci Technol 2022; 11:13. [PMID: 35133403 PMCID: PMC8842633 DOI: 10.1167/tvst.11.2.13] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose To compare the functional optical zone (FOZ) and visual quality after small-incision lenticule extraction (SMILE) and femtosecond laser-assisted laser in situ keratomileusis (FS-LASIK) in correcting high myopia. Methods Ninety-two eyes of 46 high myopic patients with the same programmed optical zone (POZ) received SMILE in one eye and FS-LASIK in the contralateral eye. FOZ was calculated using a refractive power method. The decentration, visual outcomes, wavefront aberrations, contrast sensitivity, and quality of vision (QoV) questionnaire were analyzed at 6 months postoperatively. Results The postoperative visual and refractive outcomes were comparable between SMILE and FS-LASIK. The FOZ for SMILE (5.62 ± 0.31 mm) was larger than for FS-LASIK (5.35 ± 0.28 mm; P < 0.001). Moreover, the total decentration for SMILE (0.29 ± 0.14 mm) was greater than in FS-LASIK (0.22 ± 0.11 mm; P < 0.001). The induced change in spherical aberration was less for SMILE than for FS-LASIK (P < 0.001). There was better contrast sensitivity under the mesopic condition with glare for SMILE than for FS-LASIK (P = 0.024). However, no significant difference was found in QoV scores between the two groups. Conclusions SMILE created a larger FOZ and greater decentration than FS-LASIK when the same POZ was designed in high myopia. Objective and subjective visual symptoms were comparable between SMILE and FS-LASIK. Translational Relevance The differences in FOZ and decentration between SMILE and FS-LASIK have little effect on vision outcomes. Surgeons should consider the FOZ and decentration in surgical options in high myopia.
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Affiliation(s)
- Shengyu He
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Guangdong Provincial Clinical Research Center for Ocular Diseases, Sun Yat-sen University, Guangzhou, People's Republic of China
| | - Yiqi Luo
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Guangdong Provincial Clinical Research Center for Ocular Diseases, Sun Yat-sen University, Guangzhou, People's Republic of China
| | - Pei Chen
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Guangdong Provincial Clinical Research Center for Ocular Diseases, Sun Yat-sen University, Guangzhou, People's Republic of China
| | - Yiming Ye
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Guangdong Provincial Clinical Research Center for Ocular Diseases, Sun Yat-sen University, Guangzhou, People's Republic of China
| | - Hua Zheng
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Guangdong Provincial Clinical Research Center for Ocular Diseases, Sun Yat-sen University, Guangzhou, People's Republic of China
| | - Min Lan
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Guangdong Provincial Clinical Research Center for Ocular Diseases, Sun Yat-sen University, Guangzhou, People's Republic of China
| | - Jing Zhuang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Guangdong Provincial Clinical Research Center for Ocular Diseases, Sun Yat-sen University, Guangzhou, People's Republic of China
| | - Keming Yu
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Guangdong Provincial Clinical Research Center for Ocular Diseases, Sun Yat-sen University, Guangzhou, People's Republic of China
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Comparison of astigmatic correction with and without limbal marking during small incision lenticule extraction. J Cataract Refract Surg 2022; 48:924-928. [DOI: 10.1097/j.jcrs.0000000000000889] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2021] [Accepted: 01/10/2022] [Indexed: 11/26/2022]
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Tian M, Jian W, Miao H, Li M, Xia F, Zhou X. Five-Year Follow-Up of Visual Outcomes and Optical Quality After Small Incision Lenticule Extraction for Moderate and High Myopia. Ophthalmol Ther 2021; 11:355-363. [PMID: 34905159 PMCID: PMC8770774 DOI: 10.1007/s40123-021-00436-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2021] [Accepted: 11/19/2021] [Indexed: 11/26/2022] Open
Abstract
Introduction This study investigated the long-term visual and optical quality changes after small incision lenticule extraction (SMILE) for the correction of moderate to high myopia. Methods Forty-one eyes of 41 patients with a mean spherical equivalent (SE) of − 6.74 ± 1.45 D undergoing SMILE were enrolled. Preoperative and 1-month, 3-month, 1-year and 5-year postoperative follow-up examinations were performed including visual acuity, manifest refraction, corneal aberrations and contrast sensitivity. An optical quality analysis system was used to measure objective scatter index (OSI), Strehl ratio (SR) and modulation transfer function cutoff frequency (MTFcutoff). Results The safety and efficacy indices were 1.09 ± 0.12 and 1.03 ± 0.17, respectively, at the 5-year follow-up. No significant changes in SE from 1 month to 5 years postoperatively were found. The OSI significantly increased at 1 and 3 months postoperatively (p < 0.01 and p < 0.01) and declined at 1 and 5 years (p = 0.81 and p = 0.87). MTFcutoff and SR showed similar trends. Coma, spherical aberration and total higher-order aberration significantly increased after SMILE (p < 0.01) and remained stable from 1 month to 5 years after surgery (p > 0.05). Contrast sensitivity in the photopic and mesopic condition showed no significant changes during 5-year follow-up (p > 0.05). Conclusion The SMILE procedure is satisfactory in terms of optical quality for correcting moderate and high myopia in the long-term period. Trial Registration ChiCTR-ONRC-13003114.
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Affiliation(s)
- Mi Tian
- Eye Institute and Department of Ophthalmology, Eye & ENT Hospital, Fudan University, 19# Baoqing Road, Shanghai, 200031, People's Republic of China
- NHC Key Laboratory of Myopia (Fudan University), Key Laboratory of Myopia, Chinese Academy of Medical Sciences, Shanghai, 200031, People's Republic of China
- Shanghai Research Center of Ophthalmology and Optometry, Shanghai, People's Republic of China
- Shanghai Engineering Research Center of Laser and Autostereoscopic 3D for Vision Care (20DZ2255000), Shanghai, People's Republic of China
| | - Weijun Jian
- Eye Institute and Department of Ophthalmology, Eye & ENT Hospital, Fudan University, 19# Baoqing Road, Shanghai, 200031, People's Republic of China
- NHC Key Laboratory of Myopia (Fudan University), Key Laboratory of Myopia, Chinese Academy of Medical Sciences, Shanghai, 200031, People's Republic of China
- Shanghai Research Center of Ophthalmology and Optometry, Shanghai, People's Republic of China
- Shanghai Engineering Research Center of Laser and Autostereoscopic 3D for Vision Care (20DZ2255000), Shanghai, People's Republic of China
| | - Huamao Miao
- Eye Institute and Department of Ophthalmology, Eye & ENT Hospital, Fudan University, 19# Baoqing Road, Shanghai, 200031, People's Republic of China
- NHC Key Laboratory of Myopia (Fudan University), Key Laboratory of Myopia, Chinese Academy of Medical Sciences, Shanghai, 200031, People's Republic of China
- Shanghai Research Center of Ophthalmology and Optometry, Shanghai, People's Republic of China
- Shanghai Engineering Research Center of Laser and Autostereoscopic 3D for Vision Care (20DZ2255000), Shanghai, People's Republic of China
| | - Meng Li
- Eye Institute and Department of Ophthalmology, Eye & ENT Hospital, Fudan University, 19# Baoqing Road, Shanghai, 200031, People's Republic of China
- NHC Key Laboratory of Myopia (Fudan University), Key Laboratory of Myopia, Chinese Academy of Medical Sciences, Shanghai, 200031, People's Republic of China
- Shanghai Research Center of Ophthalmology and Optometry, Shanghai, People's Republic of China
- Shanghai Engineering Research Center of Laser and Autostereoscopic 3D for Vision Care (20DZ2255000), Shanghai, People's Republic of China
| | - Fei Xia
- Eye Institute and Department of Ophthalmology, Eye & ENT Hospital, Fudan University, 19# Baoqing Road, Shanghai, 200031, People's Republic of China
- NHC Key Laboratory of Myopia (Fudan University), Key Laboratory of Myopia, Chinese Academy of Medical Sciences, Shanghai, 200031, People's Republic of China
- Shanghai Research Center of Ophthalmology and Optometry, Shanghai, People's Republic of China
- Shanghai Engineering Research Center of Laser and Autostereoscopic 3D for Vision Care (20DZ2255000), Shanghai, People's Republic of China
| | - Xingtao Zhou
- Eye Institute and Department of Ophthalmology, Eye & ENT Hospital, Fudan University, 19# Baoqing Road, Shanghai, 200031, People's Republic of China.
- NHC Key Laboratory of Myopia (Fudan University), Key Laboratory of Myopia, Chinese Academy of Medical Sciences, Shanghai, 200031, People's Republic of China.
- Shanghai Research Center of Ophthalmology and Optometry, Shanghai, People's Republic of China.
- Shanghai Engineering Research Center of Laser and Autostereoscopic 3D for Vision Care (20DZ2255000), Shanghai, People's Republic of China.
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Bao F, Chen W, Zheng X, Miao Y, Zhu M, Akiti S, Li Y, Weng Z, Wang J, Zhang P, Chen S, Elsheikh A. Changes in Corneal Biomechanical Properties in PRK Followed by Two Accelerated CXL Energy Doses in Rabbit Eyes. J Refract Surg 2021; 37:853-860. [PMID: 34914559 DOI: 10.3928/1081597x-20210830-03] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
PURPOSE To evaluate whether photorefractive keratectomy (PRK) combined with the two commonly delivered energy doses in accelerated corneal cross-linking (A-CXL) could help the cornea maintain its preoperative stiffness level. METHODS A total of 72 corneas of 36 healthy white Japanese rabbits were randomly divided into four equal groups. The groups included an untreated control group and three that had undergone PRK. After tissue ablation, one of the latter three groups (PRK group) was left untreated, whereas the other two were exposed to riboflavin (0.22% concentration by volume) and ultraviolet-A (370 nm) with the same irradiation (30 mW/cm2) but different CXL energy doses of 1.8 J/cm2 (PXL group) and 2.7 J/cm2 (PXH group). Dynamic Scheimpflug analyzer (Corvis ST; Oculus Optikgeräte GmbH) measurements of stiffness parameter at first applanation (SP-A1), Stress-Strain Index (SSI), and other dynamic corneal response parameters were taken 3 days preoperatively and 1 month postoperatively. Subsequently, ex vivo inflation testing was performed and the tangent modulus of each specimen was estimated using an inverse analysis process. RESULTS In comparison to the control group, the tangent modulus at a stress of 10 kPa decreased by 8.9% in the PRK group and increased by 10.6% and 22.4% in the PXL and PXH groups, respectively. SP-A1 decreased postoperatively in the PRK group (P < .05), indicating an overall stiffness reduction of -7.4, -3.5, and -5.3 mm Hg/mm in PRK, PXL, and PXH groups, respectively. The material stiffness parameter SSI remained almost unchanged in the PRK group (P = .989), increased slightly in the PXL group (8.3%, P = .077), and increased significantly in the PXH group (11.1%) (P < .05). CONCLUSIONS Biomechanical deterioration following PRK was significant and could not be fully compensated for by ACXL with either 1.8 or 2.7 J/cm2 doses. The increased value of corneal overall stiffness was higher in A-CXL with 2.7 J/cm2 energy than with 1.8 J/cm2 energy. [J Refract Surg. 2021;37(12):853-860.].
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26
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Zhang D, Qin X, Zhang H, Li L. Time-varying regularity of changes in biomechanical properties of the corneas after removal of anterior corneal tissue. Biomed Eng Online 2021; 20:113. [PMID: 34801040 PMCID: PMC8606087 DOI: 10.1186/s12938-021-00948-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2021] [Accepted: 11/03/2021] [Indexed: 11/13/2022] Open
Abstract
Background The corneal biomechanical properties with the prolongation of time after corneal refractive surgery are important for providing a mechanical basis for the occurrence of clinical phenomena such as iatrogenic keratectasia and refractive regression. The aim of this study was to explore the changes of corneal elastic modulus, and stress relaxation properties from the 6-month follow-up observations of rabbits after a removal of anterior corneal tissue in simulation to corneal refractive surgery. Methods The anterior corneal tissue, 6 mm in diameter and 30–50% of the original corneal thickness, the left eye of the rabbit was removed, and the right eye was kept as the control. The rabbits were normally raised and nursed for 6 months, during which corneal morphology data, and both of corneal hysteresis (CH) and corneal resistance factor (CRF) were gathered. Uniaxial tensile tests of corneal strips were performed at months 1, 3, and 6 from 7 animals, and corneal collagen fibrils were observed at months 1, 3, and 6 from 1 rabbit, respectively. Results Compared with the control group, there were statistical differences in the curvature radius at week 2 and month 3, and both CH and CRF at months 1, 2, and 6 in experiment group; there were statistical differences in elastic modulus at 1, 3, and month 6, and stress relaxation degree at month 3 in experiment group. The differences in corneal elastic modulus, stress relaxation degree and the total number of collagen fibrils between experiment and control groups varied gradually with time, and showed significant changes at the 3rd month after the treatment. Conclusions Corneas after a removal of anterior corneal tissue undergo dynamic changes in corneal morphology and biomechanical properties. The first 3 months after treatment could be a critical period. The variation of corneal biomechanical properties is worth considering in predicting corneal deformation after a removal of anterior corneal tissue.
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Affiliation(s)
- Di Zhang
- School of Biomedical Engineering, Capital Medical University, Beijing, 100069, China.,Beijing Key Laboratory of Fundamental Research on Biomechanics in Clinical Application, Capital Medical University, Beijing, 100069, China
| | - Xiao Qin
- School of Biomedical Engineering, Capital Medical University, Beijing, 100069, China.,Beijing Key Laboratory of Fundamental Research on Biomechanics in Clinical Application, Capital Medical University, Beijing, 100069, China
| | - Haixia Zhang
- School of Biomedical Engineering, Capital Medical University, Beijing, 100069, China. .,Beijing Key Laboratory of Fundamental Research on Biomechanics in Clinical Application, Capital Medical University, Beijing, 100069, China.
| | - Lin Li
- School of Biomedical Engineering, Capital Medical University, Beijing, 100069, China. .,Beijing Key Laboratory of Fundamental Research on Biomechanics in Clinical Application, Capital Medical University, Beijing, 100069, China.
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Zeng X, Qi P, Li M, Cheng Z, Lin L, Liu W, Wang Y, Zhang N. Nonlinear optical properties of human cornea measured by spectral domain Z-scan method. OPTICS EXPRESS 2021; 29:38870-38878. [PMID: 34808930 DOI: 10.1364/oe.441731] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/29/2021] [Accepted: 10/23/2021] [Indexed: 05/22/2023]
Abstract
In the myopia correction surgery by femtosecond laser, such as Laser in Situ Keratomileusis (LASIK) and Small Incision Lenticule Extraction (SMILE), the nonlinear refractive index of the cornea may cause the deviation of cutting depth. In order to improve the cornea cutting's accuracy and reduce the possibility of undercorrection, the nonlinear refractive index coefficient n2 of the human cornea must be measured with high accuracy. The spectral domain Z-scan technique can measure n2 of the highly scattering biological tissues with much better signal to noise ratio and thus better accuracy than the conventional methods. In this paper, the n2 coefficient of one ex-vivo human corneal sample was measured by the spectral domain Z-scan technique. Experimental results show that as this corneal sample gradually dehydrates, its n2 coefficients are 1.1 ± 0.1×10-19 m2/W, 1.4 ± 0.2×10-19 m2/W and 1.6 ± 0.2 ×10-19 m2/W respectively for the corneal sample with water contents of 89%, 82%, and 78%. The increase of the water content reduces the value of n2, which is reasonable since the nonlinear refractive index coefficient of water is one order of magnitude smaller than that of the cornea.
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28
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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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Abstract
A lenticule of intrastromal corneal tissue was cut together with 2 small incisions of 3.0 mm using a low-energy femtosecond laser system, FEMTO LDV Z8; 1 incision led to the posterior plane and 1 to the anterior, allowing dissection of the lenticule. When needed, recentering of the treatment area was possible without repeating the docking stage. Five eyes were operated, and a complete dissection and removal of the lenticule was achieved in all cases without any intraoperative complications. In addition, at postoperative day 1, all patients had a clear cornea. In conclusion, guided lenticule extraction using a low-energy femtosecond laser was a promising and easy procedure.
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Song Y, Fang L, Zhu Q, Du R, Guo B, Gong J, Huang J. Biomechanical responses of the cornea after small incision lenticule extraction (SMILE) refractive surgery based on a finite element model of the human eye. MATHEMATICAL BIOSCIENCES AND ENGINEERING : MBE 2021; 18:4212-4225. [PMID: 34198433 DOI: 10.3934/mbe.2021211] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
PURPOSE To investigate the biomechanical responses of the human cornea after small incision lenticule extraction (SMILE) procedures, especially their effects of SMILE surgery on stress and strain. METHODS Based on finite element analysis, a three-dimensional (3D) model of the human eye was established to simulate SMILE refractive surgery procedures. Stress and strain values were calculated by inputting the intraocular pressure (IOP). RESULTS After SMILE refractive surgery procedures, the stress and strain of the anterior and posterior corneal surfaces were significantly increased. The equivalent stress and strain on the anterior and posterior corneal surfaces increased with increasing diopter and were concentrated in the central area, whereas the values of stress and strain at the incision site on the anterior surface of the cornea were approximately 0. Compared with the anterior corneal surface, the stress and strain of the posterior surface were larger. Increasing IOP caused an approximately linear change in stress and a nonlinear increase in corneal strain. In addition, we found that the incision sizes and direction had less of an influence on stress and strain. In summary, SMILE surgery increased the equivalent stress and strain on the human cornea. CONCLUSIONS The equivalent stress and strain of the anterior and posterior human corneal surfaces increased after SMILE refractive surgery; these increases were particularly noticeable on the posterior surface of the cornea.
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Affiliation(s)
- Yinyu Song
- Key Laboratory of Nondestructive Test (Ministry of Education), Nanchang Hangkong University, Nanchang 330063, China
| | - Lihua Fang
- Key Laboratory of Nondestructive Test (Ministry of Education), Nanchang Hangkong University, Nanchang 330063, China
| | - Qinyue Zhu
- Key Laboratory of Nondestructive Test (Ministry of Education), Nanchang Hangkong University, Nanchang 330063, China
| | - Ruirui Du
- Key Laboratory of Nondestructive Test (Ministry of Education), Nanchang Hangkong University, Nanchang 330063, China
| | - Binhui Guo
- Key Laboratory of Nondestructive Test (Ministry of Education), Nanchang Hangkong University, Nanchang 330063, China
| | - Jiahui Gong
- Key Laboratory of Nondestructive Test (Ministry of Education), Nanchang Hangkong University, Nanchang 330063, China
| | - Jixia Huang
- Key Laboratory of Nondestructive Test (Ministry of Education), Nanchang Hangkong University, Nanchang 330063, China
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Abstract
The emergence of SMILE in the last decade has provided an alternative to LASIK for patients considering cornea laser refractive surgery. SMILE offers a novel approach using the femtosecond laser to create an intrastromal lenticule that can be removed through a small three to four millimeter incision.The purpose of this study is to review the recent literature on popular SMILE claims - reduced iatrogenic dry eye, better recovery of corneal sensation, and a biomechanically stronger cornea - summarize the published outcomes, and determine which claims are myths versus realities.SMILE is still in its infancy as a refractive technique in the US after recent USFDA approval for its treatment of myopia astigmatism in October 2018. Future randomized controlled studies are needed to compare its outcomes to LASIK, which has well-documented good visual outcomes, rapid postoperative recovery, and good safety profile.
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Affiliation(s)
- Grace Huang
- Massachusetts Eye and Ear, Department of Ophthalmology, Harvard Medical School, Boston, MA, USA.,Boston Eye Group, Brookline, MA, USA
| | - Samir Melki
- Massachusetts Eye and Ear, Department of Ophthalmology, Harvard Medical School, Boston, MA, USA.,Boston Eye Group, Brookline, MA, USA
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Zhao X, Zhang L, Ma J, Li M, Zhang J, Zhao X, Wang Y. Comparison of Wavefront-Guided Femtosecond LASIK and Optimized SMILE for Correction of Moderate-to-High Astigmatism. J Refract Surg 2021; 37:166-173. [PMID: 34038300 DOI: 10.3928/1081597x-20201230-01] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
PURPOSE To compare refractive outcomes, higher order aberrations (HOAs), and the changes in contrast sensitivity after wavefront-guided femtosecond laser-assisted in situ keratomileusis (WFG LASIK) and optimized small incision lenticule extraction (SMILE) for moderate-to-high astigmatism correction. METHODS This prospective, randomized study included 87 eyes: 40 eyes in the WFG LASIK group and 47 eyes in the SMILE group. Manual cyclotorsion compensation by marking the horizontal axis before SMILE surgery was used for optimized SMILE. Refractive diopter, aberrations, and contrast sensitivity were assessed 3 months postoperatively. The Alpins vector analysis method was used to analyze the astigmatic changes after surgery. RESULTS There were no significant differences in the corrected distance visual acuity and refraction between the two groups after surgery. The fitted curve of surgically induced astigmatism versus target induced astigmatism was described as y = 0.9905 x + 0.0009 in the WFG LASIK group and y = 0.9672 x + 0.0026 in the SMILE group. The percentage of corneal astigmatism axis change within 5 degrees was statistically significant (chi-square test: 10.632, P = .001). HOAs increased in both the WFG LASIK and SMILE groups after surgery (t = -3.655, P = .001, t = -3.784, P = .001, respectively). However, comparison of the changes of HOAs between both groups was not significant (t = -0.565, P = .575). The improvement in contrast sensitivity in the WFG LASIK group was significantly higher than that in the SMILE group. CONCLUSIONS WFG LASIK and optimized SMILE can achieve similar outcomes for astigmatism correction. Optimized SMILE with marking could achieve good astigmatism correction, even without an eye tracking system. [J Refract Surg. 2021;37(3):166-173.].
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Seven-year observation of posterior corneal elevation after small incision lenticule extraction (SMILE) in patients with moderate and high myopia. J Cataract Refract Surg 2021; 47:1398-1402. [PMID: 33770391 DOI: 10.1097/j.jcrs.0000000000000639] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2020] [Accepted: 03/03/2021] [Indexed: 11/26/2022]
Abstract
Purpose To investigate the long-term changes in posterior corneal elevation in moderate and high myopia after small incision lenticule extraction (SMILE). Setting Eye & ENT Hospital, Fudan University. Design Prospective case series. Methods Thirty-three eyes of 20 patients (30.1+/-9.5 years, 7 male and 13 female, spherical equivalent [SE] range -4.00 to -8.75 D, average SE -6.25+/-1.29 D) who underwent SMILE were included. Changes in the posterior corneal elevation at central points (PCE), the thinnest point (PTE), the maximal point (PME), and an additional 20 points within the 4-mm area of the best-fit sphere were evaluated with a Pentacam (Oculus Optikgerate GmbH, Wetzlar, Germany) during a 7-year follow-up period. Mixed linear models were used to evaluate changes with P-values <0.05. Correlations of elevation changes and residual bed thickness (RBT) were also evaluated. Results No ectasia was observed among the 33 eyes. The safety index was 1.08, and the efficacy index was 1.03. The mean change in PCE at 1, 3, 5, and 7 years was -1.42+/-0.95, -2.67+/-0.98, -2.44+/-1.06, and -1.91+/-0.92 [micro]m, respectively. Significant differences were found at 3, 5, and 7 years (P=0.007, 0.023, and 0.040, respectively). PTE was significantly reduced at each time point compared to baseline. The mean change was -2.82+/-1.19, -3.55+/-1.22, -3.47+/-1.32, and -2.39+/-1.15 [micro]m, respectively (P=0.019, 0.004, 0.010, and 0.039, respectively). PME changed 2.45+/-1.02 [micro]m at 7 years compared to baseline (P=0.017). The changes in PCE and PME negatively correlated with the RBT. Conclusions Long-term posterior corneal elevation was stable in moderate and high myopia after SMILE.
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Fu Y, Yin Y, Wu X, Li Y, Xiang A, Lu Y, Fu Q, Hu T, Du K, Wen D. Clinical outcomes after small-incision lenticule extraction versus femtosecond laser-assisted LASIK for high myopia: A meta-analysis. PLoS One 2021; 16:e0242059. [PMID: 33556075 PMCID: PMC7870077 DOI: 10.1371/journal.pone.0242059] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2020] [Accepted: 10/27/2020] [Indexed: 11/19/2022] Open
Abstract
AIM To compare postoperative clinical outcomes of high myopia after small-incision lenticule extraction (SMILE) and femtosecond laser-assisted laser in situ keratomileusis (FS-LASIK). METHODS From March 2018 to July 2020, PubMed, MEDLINE, Embase, the Cochrane Library, and several Chinese databases were comprehensively searched. The studies meeting the criteria were selected and included; the data were extracted by 2 independent authors. The clinical outcome parameters were analyzed with RevMan 5.3. RESULTS This meta-analysis included twelve studies involving 766 patients (1400 eyes: 748 receiving SMILE and 652 receiving FS-LASIK). Pooled results revealed no significant differences in the following outcomes: the logarithm of the mean angle of resolution (logMAR) of postoperative uncorrected distance visual acuity (weighted mean difference (WMD) = -0.01, 95% confidence interval (CI): -0.02 to 0.00, I2 = 0%, P = 0.07 at 1 mo; WMD = -0.00, 95% CI: -0.01 to 0.01, I2 = 0%, P = 0.83 at 3 mo; WMD = -0.00, 95% CI: -0.01 to 0.00, I2 = 32%, P = 0.33 in the long term), and the postoperative mean refractive spherical equivalent (WMD = -0.03, 95% CI: -0.09 to 0.03, I2 = 13%, P = 0.30). However, the SMILE group had significantly better postoperative corrected distance visual acuity (CDVA) than the FS-LASIK group (WMD = -0.04, 95% CI, -0.05 to -0.02, I2 = 0%, P<0.00001). In the long term, postoperative total higher-order aberration (WMD = -0.09, 95% CI: -0.10 to -0.07, I2 = 7%, P<0.00001) and postoperative spherical aberration (WMD = -0.15, 95% CI: -0.19 to -0.11, I2 = 29%, P<0.00001) were lower in the SMILE group than in the FS-LASIK group; a significant difference was also found in postoperative coma (WMD = -0.05, 95% CI: -0.06 to -0.03, I2 = 30%, P<0.00001). CONCLUSION For patients with high myopia, both SMILE and FS-LASIK are safe, efficacious and predictable. However, the SMILE group demonstrated advantages over the FS-LASIK group in terms of postoperative CDVA, while SMILE induced less aberration than FS-LASIK. It remains to be seen whether SMILE can provide better visual quality than FS-LASIK; further comparative studies focused on high myopia are necessary.
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Affiliation(s)
- Yanyan Fu
- Department of Ophthalmology, XiangYa Hospital, Central South University, Changsha, Hunan, China
- Eye Center of Xiangya Hospital, Central South University, Changsha, Hunan, China
- Hunan Key Laboratory of Ophthalmology, Changsha, Hunan, China
| | - Yewei Yin
- Department of Ophthalmology, XiangYa Hospital, Central South University, Changsha, Hunan, China
- Eye Center of Xiangya Hospital, Central South University, Changsha, Hunan, China
- Hunan Key Laboratory of Ophthalmology, Changsha, Hunan, China
| | - Xiaoying Wu
- Department of Ophthalmology, XiangYa Hospital, Central South University, Changsha, Hunan, China
- Eye Center of Xiangya Hospital, Central South University, Changsha, Hunan, China
- Hunan Key Laboratory of Ophthalmology, Changsha, Hunan, China
| | - Yuanjun Li
- Department of Ophthalmology, XiangYa Hospital, Central South University, Changsha, Hunan, China
- Eye Center of Xiangya Hospital, Central South University, Changsha, Hunan, China
- Hunan Key Laboratory of Ophthalmology, Changsha, Hunan, China
| | - Aiqun Xiang
- Department of Ophthalmology, XiangYa Hospital, Central South University, Changsha, Hunan, China
- Eye Center of Xiangya Hospital, Central South University, Changsha, Hunan, China
- Hunan Key Laboratory of Ophthalmology, Changsha, Hunan, China
| | - Ying Lu
- Department of Ophthalmology, XiangYa Hospital, Central South University, Changsha, Hunan, China
- Eye Center of Xiangya Hospital, Central South University, Changsha, Hunan, China
- Hunan Key Laboratory of Ophthalmology, Changsha, Hunan, China
| | - Qiuman Fu
- Department of Ophthalmology, XiangYa Hospital, Central South University, Changsha, Hunan, China
- Eye Center of Xiangya Hospital, Central South University, Changsha, Hunan, China
- Hunan Key Laboratory of Ophthalmology, Changsha, Hunan, China
| | - Tu Hu
- Department of Ophthalmology, XiangYa Hospital, Central South University, Changsha, Hunan, China
- Eye Center of Xiangya Hospital, Central South University, Changsha, Hunan, China
- Hunan Key Laboratory of Ophthalmology, Changsha, Hunan, China
| | - Kaixuan Du
- Department of Ophthalmology, XiangYa Hospital, Central South University, Changsha, Hunan, China
- Eye Center of Xiangya Hospital, Central South University, Changsha, Hunan, China
- Hunan Key Laboratory of Ophthalmology, Changsha, Hunan, China
| | - Dan Wen
- Department of Ophthalmology, XiangYa Hospital, Central South University, Changsha, Hunan, China
- Eye Center of Xiangya Hospital, Central South University, Changsha, Hunan, China
- Hunan Key Laboratory of Ophthalmology, Changsha, Hunan, China
- * E-mail:
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Effects of SMILE Surgery on Intraocular Pressure, Central Corneal Thickness, Axial Length, Peripapillary Retinal Nerve Fiber Layer, and Macular Ganglion Cell Complex Thickness. J Ophthalmol 2020. [DOI: 10.1155/2020/4934196] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Purpose. To evaluate the change in intraocular pressure (IOP), central corneal thickness (CCT), axial length, peripapillary retinal nerve fiber layer (RNFL) thickness, and macular ganglion cell complex (GCC) thickness after small incision lenticule extraction (SMILE) surgery. Methods. This prospective observational study was conducted in Espace Nouvelle Vision, Ophthalmological Clinic, Paris, France. Fifty eyes of 25 patients were enrolled in this study and underwent SMILE surgeries. IOP, central corneal thickness (CCT), axial length (AL), peripapillary RNFL thickness, and macular GCC thickness were measured before and at 3 months after SMILE. Results. The mean preoperative spherical equivalent was −3.15 ± 1.50 diopters (D), and the mean postoperative value was 0.15 ± 0.28 D. After SMILE surgery, IOP decreased from 15.03 ± 2.79 mmHg to 11.02 ± 2.73 mmHg and 10.02 ± 2.21 mmHg at 1 and 3 months, respectively (
for both comparisons). The mean decrease in measured IOP as a function of ablation depth was 0.065 ± 0.031 mmHg/μm. CCT decreased from 545.98 ± 26.61 μm to 478.40 ± 30.26 μm after SMILE surgery (
). AL decreased from 24.80 ± 0.84 mm to 24.70 ± 0.83 mm (
). There was no statistically significant change in mean peripapillary RNFL or mean GCC thickness after SMILE surgery. Conclusions. SMILE surgery modified IOP measurement, CCT, and AL but did not change peripapillary RNFL and macular GCC thicknesses. The postoperative drop in measured IOP might be explained by the decreased CCT. An accurate re-evaluation of AL should be performed before cataract surgery among post-SMILE patients.
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Sachdev GS, Ramamurthy S. Decade - long journey with small incision lenticule extraction: The learnings. Indian J Ophthalmol 2020; 68:2705-2710. [PMID: 33229646 PMCID: PMC7856951 DOI: 10.4103/ijo.ijo_2622_20] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Over the past decade, small incision lenticule extraction (SMILE) has revolutionized the field of keratorefractive surgery. With the promise of superior corneal biomechanics and reduced postoperative dry eye, SMILE afforded a distinct advantage over flap-based procedures. Our evolving understanding of the surgical technique and management of its unique complications has further enhanced the outcomes. This review will highlight specific pearls on various preoperative and intraoperative principles allowing optimization of outcomes with SMILE.
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Affiliation(s)
- Gitansha S Sachdev
- Refractive Services, The Eye Foundation, RS Puram, Coimbatore, Tamil Nadu, India
| | - Shreyas Ramamurthy
- Refractive Services, The Eye Foundation, RS Puram, Coimbatore, Tamil Nadu, India
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Asif MI, Bafna RK, Mehta JS, Reddy J, Titiyal JS, Maharana PK, Sharma N. Complications of small incision lenticule extraction. Indian J Ophthalmol 2020; 68:2711-2722. [PMID: 33229647 PMCID: PMC7856979 DOI: 10.4103/ijo.ijo_3258_20] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
The procedure of small incision lenticule extraction (SMILE) was introduced in 2011, and since then there has been an increase in the number of cases undergoing this procedure worldwide. The surgery has a learning curve and may be associated with problems in the intraoperative and postoperative periods. The intraoperative problems during SMILE surgery include the loss of suction, the occurrence of altered or irregular opaque bubble layer and black spots, difficulty in lenticular dissection and extraction, cap perforation, incision-related problems, and decentered ablation. Most of the postoperative problems are similar as in other laser refractive procedures, but with decreased incidence. The identification of risk factors, clinical features, and management of complications of SMILE help to obtain optimum refractive outcomes.
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Affiliation(s)
- Mohamed Ibrahime Asif
- Department of Ophthalmology, Dr Rajendra Prasad Centre for Ophthalmic Sciences, All India Institute of Medical Sciences, New Delhi, India
| | - Rahul Kumar Bafna
- Department of Ophthalmology, Dr Rajendra Prasad Centre for Ophthalmic Sciences, All India Institute of Medical Sciences, New Delhi, India
| | - Jodhbir Singh Mehta
- Singapore Eye Research Institute; Singapore National Eye Centre, 168751; Ophthalmology and Visual Sciences Academic Clinical Programme, Duke-NUS Medical School, Singapore
| | - Jagadesh Reddy
- Cataract and Refractive Services, Cornea Institute, L V Prasad Eye Institute, Hyderabad, Telangana, India
| | - Jeewan Singh Titiyal
- Department of Ophthalmology, Dr Rajendra Prasad Centre for Ophthalmic Sciences, All India Institute of Medical Sciences, New Delhi, India
| | - Prafulla K Maharana
- Department of Ophthalmology, Dr Rajendra Prasad Centre for Ophthalmic Sciences, All India Institute of Medical Sciences, New Delhi, India
| | - Namrata Sharma
- Department of Ophthalmology, Dr Rajendra Prasad Centre for Ophthalmic Sciences, All India Institute of Medical Sciences, New Delhi, India
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Primavera L, Canto-Cerdan M, Alio JL, Alio Del Barrio JL. Influence of age on small incision lenticule extraction outcomes. Br J Ophthalmol 2020; 106:341-348. [PMID: 33208352 DOI: 10.1136/bjophthalmol-2020-316865] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2020] [Revised: 09/27/2020] [Accepted: 10/31/2020] [Indexed: 11/04/2022]
Abstract
PURPOSE To evaluate the influence of patient's age at the time of surgery on small incision lenticule extraction (SMILE) refractive outcomes. METHODS This is a retrospective, consecutive, comparative study. We compared the refractive outcomes after myopic SMILE from two groups of patients divided by age (patients ≤35 and ≥40 years old). All eyes were evaluated preoperatively and at 1 and 6 months postoperatively. Main outcome measures were differences on efficacy, safety, predictability and astigmatic changes by vector analysis with ASSORT software between both study groups. RESULTS 102 matched eyes of 53 patients were included. Preoperatively, we evidenced no differences in the mean SE or astigmatism between groups. However, 6 months postoperatively we observed a significantly worse mean astigmatism (p=0.019), while not regarding SE, in the older population, with a trend towards undercorrection of the refractive cylinder in the ≥40 group. We also observed a statistically significant difference in the efficacy (0.86-1 month and 0.97-6 months in ≥40group vs 0.97-1 month and 1.07-6 months in the ≤35 group; p=0.003) and safety indexes (0.93-1 month and 1.04-6 months in ≥40 group vs 1.0-1 month and 1.11-6 months in the ≤35 group; p=0.008) at 6 months among groups. CONCLUSIONS Post-SMILE refractive outcomes in those patients over 40 years of age, although acceptable, are not as good as those obtained in younger patients, showing a significantly lower efficacy and safety indexes, and poorer astigmatic outcomes, with a tendency towards undercorrection. We hypothetise that the increased corneal stroma stiffness in the aged group modifies the post-SMILE corneal stroma remodelling capacity, thus affecting the SMILE refractive and visual response.
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Affiliation(s)
- Laura Primavera
- Cornea, Cataract and Refractive Surgery Unit, Vissum (Miranza Group), Alicante, Spain
| | - Mario Canto-Cerdan
- Cornea, Cataract and Refractive Surgery Unit, Vissum (Miranza Group), Alicante, Spain
| | - Jorge L Alio
- Cornea, Cataract and Refractive Surgery Unit, Vissum (Miranza Group), Alicante, Spain.,Division of Ophthalmology, School of Medicine, Universidad Miguel Hernández, Alicante, Spain
| | - Jorge L Alio Del Barrio
- Cornea, Cataract and Refractive Surgery Unit, Vissum (Miranza Group), Alicante, Spain .,Division of Ophthalmology, School of Medicine, Universidad Miguel Hernández, Alicante, Spain
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Tay E, Bajpai R. Visual recovery after small incision lenticule extraction (SMILE) in relation to pre-operative spherical equivalent. Graefes Arch Clin Exp Ophthalmol 2020; 259:1053-1060. [PMID: 33047249 DOI: 10.1007/s00417-020-04954-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2020] [Revised: 09/16/2020] [Accepted: 09/25/2020] [Indexed: 11/29/2022] Open
Abstract
PURPOSE To assess visual recovery after small incision lenticule extraction (SMILE) in relation to pre-operative spherical equivalent. METHODS Two hundred fourteen eyes of 107 patients were enrolled. Following surgery, patients were examined pre-operatively, 1 day, 2 weeks, 1 month and 3 months later. High myopia was defined as pre-operative spherical equivalent ≤ - 5 D. A linear mixed-effects model was used. RESULTS Mean ± standard deviation pre-operative spherical equivalent was - 5.30 ± 1.36 D that reduced significantly to 0.04 ± 0.70 D (p < 0.001) at 1 month and - 0.02 ± 0.66 D (p < 0.001) at 3 months. Mean pre-operative LogMAR uncorrected distance visual acuity ± SD was 0.97 ± 0.09 that improved significantly to 0.04 ± 0.06 at 2 weeks (p < 0.001), 0.01 ± 0.04 at 1 month (p < 0.001) and 0.01 ± 0.04 at 3 months (p < 0.001). Eighty-eight eyes (41.2%) had uncorrected distance visual acuities of 0.0 at 1 day, 154 eyes (72.0%) at 2 weeks,194 eyes (90.7%) at 1 month and 199 eyes (93.0%) at 3 months. Significantly more eyes with low myopia (> - 5 D) achieved acuities of 0.0 at 1 day and 2 weeks (p = 0.041 and p < 0.001). Post-operative acuities were not associated with refractive targets, laser cut energy settings or other variables. Two hundred nine eyes (97.7%) were within ± 0.5 D of target and 213 eyes (99.5%) were within ± 1 D. CONCLUSIONS SMILE for low myopia had faster visual recovery in the early post-operative period with no significant differences between groups detected by 1 and 3 months.
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Affiliation(s)
- Eugene Tay
- Singapore Eye Research Institute, The Academia, 20 College Road, Singapore, 169856, Singapore.
| | - Ram Bajpai
- School of Primary, Community and Social Care, Keele University, Keele, Staffordshire, ST5 5BG, UK
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Langer J, Priglinger S, Messmer EM, Dirisamer M, Shajari M, Mayer WJ. Penetrating keratoplasty after complicated small incision lenticule extraction a case report. Am J Ophthalmol Case Rep 2020; 19:100730. [PMID: 32637727 PMCID: PMC7327821 DOI: 10.1016/j.ajoc.2020.100730] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2019] [Revised: 03/17/2020] [Accepted: 04/27/2020] [Indexed: 10/28/2022] Open
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Wu Y, Wang Y, Zhang Z, Yu X, Zhao X. Quantitative Analysis of Human Corneal Lenticule Surface Microstructure Irregularity with 3D Optical Profiler Using White Light Interferometry. Curr Eye Res 2020; 46:461-469. [PMID: 32847425 DOI: 10.1080/02713683.2020.1809000] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
PURPOSE To quantitatively evaluate the cutting quality of small incision lenticule extraction (SMILE) by measuring human corneal lenticule surface roughness in different areas with white light interferometer. METHOD A white light interferometer was used to quantitatively measure the corneal lenticule surface roughness in different areas. Sixty-three myopic patients (102 eyes) who underwent SMILE surgery were recruited. The surface roughness of the central, pericentral, and peripheral parts of the corneal lenticule surface was measured in both the anterior and posterior planes. Differences in corneal lenticule surface roughness were analyzed between different myopic groups. RESULTS The surface roughness of the anterior plane of the corneal lenticule was lower than the posterior plane in various areas (central, pericentral, and peripheral parts) (P < .01). Surface roughness gradually increased from the center to the periphery, in both the anterior and posterior planes (P < .01). There were no significant differences in the surface roughness of the central part in both the anterior and posterior planes between the low and high myopic groups. The surface roughness of the high myopic group was higher than that of the low myopic group in the peripheral part (P < .01). There were no significant differences among the three cylinder-specific groups. There was no significant correlation between two paired eyes. A positive correlation between posterior central surface roughness and the percentage tissue altered score (PTA) was found (r = 0.248, P = .012). CONCLUSIONS The cutting surface of the corneal lenticule performed by femtosecond laser was evaluated with a white light interferometer and displayed inhomogeneity. Deeper cutting with higher myopia and some intraoperative complications, such as suction loss, may result in larger irregularities.
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Affiliation(s)
- Yanan Wu
- Clinical College of Ophthalmology, Tianjin Medical University, Tianjin, China.,Tianjin Key Lab of Ophthalmology and Visual Science, Tianjin Eye Hospital, Tianjin, China
| | - Yan Wang
- Clinical College of Ophthalmology, Tianjin Medical University, Tianjin, China.,Tianjin Key Lab of Ophthalmology and Visual Science, Tianjin Eye Hospital, Tianjin, China
| | - Zimiao Zhang
- Tianjin Key Laboratory of High Speed Cutting & Precision Machining, Tianjin University of Technology and Education, Tianjin, China
| | - Xingchen Yu
- Clinical College of Ophthalmology, Tianjin Medical University, Tianjin, China.,Tianjin Key Lab of Ophthalmology and Visual Science, Tianjin Eye Hospital, Tianjin, China
| | - Xinheng Zhao
- Clinical College of Ophthalmology, Tianjin Medical University, Tianjin, China.,Tianjin Key Lab of Ophthalmology and Visual Science, Tianjin Eye Hospital, Tianjin, China
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Fu D, Zhao Y, Zhou X. Corneal Biomechanical Properties after Small Incision Lenticule Extraction Surgery on Thin Cornea. Curr Eye Res 2020; 46:168-173. [PMID: 32643431 DOI: 10.1080/02713683.2020.1792507] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
PURPOSE To explore the biomechanical changes in thin corneas after the small incision lenticule extraction (SMILE) surgery. METHODS This prospective survey screened patients scheduled for the SMILE surgery from November 2017 to March 2018. Patients with thin corneas (central corneal thickness [CCT] ≤500 μm) and those with normal corneal thickness (CCT > 500 μm) were enrolled. Corneal biomechanics were examined by the ocular response analyser and Corvis ST, preoperatively and at 1 day, 3 weeks, and 3 months postoperatively. RESULTS Twenty-seven patients (46 eyes) with mean spherical equivalent of -5.1 ± 1.7 D were assigned to the thin cornea group, and 28 (45 eyes) cases with mean spherical equation of -5.3 ± 1.8 D were assigned to the control group. Safety and efficacy did not differ between the two age- and refraction-matched groups (safety index, 1.15 ± 0.14 vs 1.14 ± 0.17 [P = .7]; efficacy index, 1.11 ± 0.13 vs 1.16 ± 0.22 [P = .2]). All biomechanical parameters changed significantly after SMILE. The thin cornea group showed less decrease in the second applanation time (A2 Time), stiffness parameters at first applanation (SP-A1). Pooling data from two groups, lower CCT was correlated with less A2 Time change (r = 0.37, P < .01) and less SP-A1 change (r = -0.33, P < .01). Less bIOP change was correlated with higher residual stromal thickness index and thicker CCT (P = .003, R2 = 0.12). CONCLUSION Over a short-term observation period, less corneal biomechanic deterioration may have contributed to the safety of SMILE on thin cornea.
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Affiliation(s)
- Dan Fu
- Department of Ophthalmology, Eye and ENT Hospital of Fudan University , Shanghai, China.,NHC Key Laboratory of Myopic (Fudan University) , Shanghai, China.,Shanghai Research Centre of Ophthalmology and Optometry , Shanghai, China
| | - Yu Zhao
- Department of Ophthalmology, Eye and ENT Hospital of Fudan University , Shanghai, China.,NHC Key Laboratory of Myopic (Fudan University) , Shanghai, China.,Shanghai Research Centre of Ophthalmology and Optometry , Shanghai, China
| | - Xingtao Zhou
- Department of Ophthalmology, Eye and ENT Hospital of Fudan University , Shanghai, China.,NHC Key Laboratory of Myopic (Fudan University) , Shanghai, China.,Shanghai Research Centre of Ophthalmology and Optometry , Shanghai, China
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The best optical zone for small-incision lenticule extraction in high myopic patients. J Cataract Refract Surg 2020; 46:1302-1307. [PMID: 32569029 DOI: 10.1097/j.jcrs.0000000000000282] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
Small-incision lenticule extraction (SMILE) is an effective and safe procedure for the correction of myopia due to minimally invasive and noncorneal flap surgery. However, the SMILE procedure has certain requirements for corneal cap thickness, attempted refractive correction, residual stromal bed thickness, and optical zone diameter, which sometimes make surgeons hesitant to choose SMILE or other refractive surgeries. The requirements limit its use in patients with high myopia. The purpose of this review was to find the optimal parameters of SMILE through discussing the best optical zone for high myopic patients, the visual quality of different optical zones, the choice of corneal cap thickness, and their effects on corneal biomechanical parameters, so surgeons can provide reference recommendations for patients with high myopia in choosing a reasonable and safe procedure.
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Li H, Liu T, Mu B, Zhao X, Xue C, Shen M, Jhanji V, Wang Y. Biomechanical effect of ultraviolet-A-riboflavin cross-linking on simulated human corneal stroma model and its correlation with changes in corneal stromal microstructure. Exp Eye Res 2020; 197:108109. [PMID: 32565111 DOI: 10.1016/j.exer.2020.108109] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2020] [Revised: 05/11/2020] [Accepted: 06/02/2020] [Indexed: 12/28/2022]
Abstract
In this study, we established an experimental human corneal stroma model of simulated cornea tissue composed of thin anterior cornea strips layers obtained from small incision lenticular extraction (SMILE) surgery. We investigated the biomechanical effect of ultraviolet-A- riboflavin cross-linking at different depths of corneal stroma model and correlated it with stromal microstructural changes examined by transmission electron microscopy (TEM). Corneal strips were harvested from fresh human corneal lenticules obtained after SMILE surgery. Experimental models (n = 34) were established by superimposing the corneal lenticule strips until their thickness reached close to 500 μm. Corneal cross-linking (CXL) was performed subsequently using standard or accelerated protocol. Elasticity and viscosity were quantified using stress-strain extensometer. TEM was used to visualize the collagen fiber diameter and interfibrillar spacing. The relative change in Young's modulus (rel. ΔE) decreased nonlinearly with increasing stromal depth both in the standard and accelerated groups. Compared to the sham controls, the rel. ΔE in standard and accelerated CXL groups increased significantly in the anterior 400 μm and 275 μm depth, respectively. Also, the relative change in stress (rel. ΔS) was significantly lower after standard and accelerated CXL compared to sham controls. Depth analysis showed similar results for the elastic effect. TEM images showed a small, non-significant increase in fibril diameter. The interfibrillar spacing decreased significantly after standard and accelerated CXL in the anterior-mid stromal region. We noted that the increase of corneal stiffness correlated with decrease in interfibrillar spacing after CXL. The stiffening effect was depth dependent. The effect of accelerated CXL was less in the deep corneal stromal regions compared to standard CXL.
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Affiliation(s)
- Hongxun Li
- Clinical College of Ophthalmology, Tianjin Medical University, Tianjin, China; Tianjin Key Lab of Ophthalmology and Visual Science, Tianjin Eye Institute, Tianjin Eye Hospital Tianjin, China
| | - Taiwei Liu
- Department of Mechanics, School of Mechanical Engineering, Tianjin University, Tianjin, China
| | - Bokun Mu
- Clinical College of Ophthalmology, Tianjin Medical University, Tianjin, China; Tianjin Key Lab of Ophthalmology and Visual Science, Tianjin Eye Institute, Tianjin Eye Hospital Tianjin, China
| | - Xinheng Zhao
- Clinical College of Ophthalmology, Tianjin Medical University, Tianjin, China; Tianjin Key Lab of Ophthalmology and Visual Science, Tianjin Eye Institute, Tianjin Eye Hospital Tianjin, China
| | - Chao Xue
- Clinical College of Ophthalmology, Tianjin Medical University, Tianjin, China
| | - Min Shen
- Department of Mechanics, School of Mechanical Engineering, Tianjin University, Tianjin, China
| | - Vishal Jhanji
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Yan Wang
- Clinical College of Ophthalmology, Tianjin Medical University, Tianjin, China; Tianjin Key Lab of Ophthalmology and Visual Science, Tianjin Eye Institute, Tianjin Eye Hospital Tianjin, China.
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Liu L, Cheng W, Wu D, Chen L, Yu S, Zuo T, Zhang L, Yang K, Li H, Zhang H, Wei P, Ng ALK, Cheng GPM, Woo VCP, Yin J, Chiu K, Wang Y. The Differential Expression of Cytokines and Growth Factors After SMILE Compared With FS-LASIK in Rabbits. Invest Ophthalmol Vis Sci 2020; 61:55. [PMID: 32460319 PMCID: PMC7405797 DOI: 10.1167/iovs.61.5.55] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose To investigate the differential expression of cytokines and growth factors in the cornea and aqueous humor after small incision lenticule extraction (SMILE) compared with femtosecond LASIK (FS-LASIK) using rabbit model. Methods Sixteen eyes of 16 rabbits in each group underwent SMILE or FS-LASIK with refractive correction of −6.00 DS/−1.00 DC. Eight additional rabbits served as controls. Pre- and 24 hours, 1 week, 1 month, and 3 months postoperatively, slit-lamp and anterior segment optical coherence tomography were performed, followed by cornea and aqueous humor collection. Apoptosis and proliferation were evaluated with TUNEL assay and Ki-67 immunostaining, respectively. The mRNA and protein expression of cytokines and growth factors was determined by RT-qPCR and Western blotting, respectively. Cytokine levels in the aqueous humor were detected with ELISA. Results Compared with FS-LASIK, SMILE induced less apoptosis and proliferation in the cornea within 1 week postoperatively. Levels of IL-1β, TNF-α, and EGFR in the cornea were significantly increased after FS-LASIK compared with SMILE within 24 hours. Levels of IL-8 in the aqueous humor remained elevated until 1 week after FS-LASIK but not SMILE. TGF-β1 level was elevated up to 1 month after both procedures, while BFGF level was kept high within 1 month after SMILE but not FS-LASIK. Conclusions SMILE could induce significantly less acute inflammation than FS-LASIK in the cornea and aqueous humor. The differential expression of TGF-β1 and BFGF between two procedures until 1 month might contribute to the post-SMILE delayed recovery and underline the importance of continued treatment postoperatively.
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Changes in Corneal Volume at Different Areas and Its Correlation with Corneal Biomechanics after SMILE and FS-LASIK Surgery. J Ophthalmol 2020; 2020:1713979. [PMID: 32411425 PMCID: PMC7201767 DOI: 10.1155/2020/1713979] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Accepted: 03/06/2020] [Indexed: 11/17/2022] Open
Abstract
Purpose To investigate the variations of corneal volume (CV) after small incision lenticule extraction (SMILE) and femtosecond laser-assisted laser in situ keratomileusis (FS-LASIK) and analyze the influences of biomechanical properties on the changes of refraction and CV. Methods Ninety-seven eyes of 97 patients undergoing SMILE and FS-LASIK were included in this retrospective study. CV was measured with Scheimpflug-based corneal topography at preoperatively and at day 1, week 1, and months 1 and 3 postoperatively. CV measured within 5 mm diameter was defined as central region volume (CV5) and between 5 mm and 10 mm diameter was defined as peripheral region volume (CV5-10). An Ocular Response Analyzer (ORA) was used to assess corneal biomechanical properties including corneal hysteresis (CH) and corneal resistant factor (CRF). The reduction of study parameters (△) were calculated by subtracting the preoperative value at various time points from the postoperative values. Results CV had significant reduction after the SMILE and FS-LASIK procedure (P < 0.05). CV5 increased significantly from postoperative day 1 to month 3 (P < 0.001) in SMILE, while both CV5 and CV5-10 increased significantly in FS-LASIK (P < 0.001). The increase in CV5 after SMILE was 0.11 ± 0.16 mm3,which was significantly different from FS-LASIK (0.20 ± 0.13 mm3, P=0.004). In the SMILE group, △CV5 correlated with △CRF (r = 0.498, P < 0.001) and △CH (r = 0.374, P=0.007). In the FS-LASIK group, △CV5 and △CRF had a significant correlation (r = 0.363, P=0.012), but not with △CH. Conclusions Dynamic changes in corneal volume were found after SMILE and FS-LASIK surgery. The central region significantly increased after SMILE, while both central and peripheral regions increased following FS-LASIK in the early postoperative period. SMILE was associated with less change in biomechanical properties per unit of reduction in CV compared with FS-LASIK.
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Li H, Peng Y, Chen M, Tian L, Li D, Zhang F. Six modes of corneal topography for evaluation of ablation zones after small-incision lenticule extraction and femtosecond laser-assisted in situ keratomileusis. Graefes Arch Clin Exp Ophthalmol 2020; 258:1555-1563. [PMID: 32328759 DOI: 10.1007/s00417-020-04674-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2019] [Revised: 03/27/2020] [Accepted: 04/01/2020] [Indexed: 11/25/2022] Open
Abstract
PURPOSE To evaluate the ablation zone diameter (AZD) using six modes of corneal topography after small-incision lenticule extraction (SMILE) and femtosecond laser-assisted in situ keratomileusis (FS-LASIK) for myopia and to compare the programmed and postoperative AZDs METHODS: This retrospective comparative study included 86 right eyes in 86 patients who underwent SMILE or FS-LASIK at the Shandong Eye Institute between June 2016 and August 2017. Data were collected preoperatively and at 1, 3, and 6 months postoperatively using the Pentacam system. The AZD was determined using six modes of corneal topography: postoperative axial curvature topography (PACT), postoperative tangential curvature topography (PTCT), difference-axial curvature topography (DACT), difference-tangential curvature topography (DTCT), postoperative front elevation topography (PFET), and difference-corneal thickness topography (DCTT). The difference between the programmed and postoperative AZDs was compared between the groups of two surgical procedures. RESULTS At 3 months, the AZDs measured by PTCT, DTCT, and PFET after SMILE showed a significant decrease, while the AZD by DACT revealed an increase (P < 0.001), and the AZDs measured by PACT, PTCT, DACT, DTCT, PFET, and DCTT after FS-LASIK were all significantly decreased (P < 0.001), as compared with the programmed ablation zone values. The AZDs measured by DACT and DTCT after 3 months were larger in the SMILE group (P < 0.001); likewise, the differences between the programmed and postoperative AZDs were lower in the SMILE group (P < 0.001). Furthermore, PACT, PTCT, DACT, DTCT, and PFET indicated acceptable inter-observer reliability (ICC > 0.75). CONCLUSIONS In the treatment of myopia, the achieved topographic ablation zones after FS-LASIK were smaller than the theoretically designed ones. The AZDs after SMILE were larger than those after FS-LASIK, with an equivalent programmed value. The DACT may be more suitable for measuring postoperative ablation zones in clinic with clearer borders and favorable repeatability. This method may be potential for the measurement of ablation zones and further research on the visual quality after refractive surgery.
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Affiliation(s)
- Hua Li
- Department of Ophthalmology, Qilu Medical College of Shandong University, Jinan, 250012, China
- State Key Laboratory Cultivation Base, Shandong Provincial Key Laboratory of Ophthalmology, Shandong Eye Institute, Shandong First Medical University & Shandong Academy of Medical Sciences, Qingdao, 266071, Shandong, China
| | - Yusu Peng
- State Key Laboratory Cultivation Base, Shandong Provincial Key Laboratory of Ophthalmology, Shandong Eye Institute, Shandong First Medical University & Shandong Academy of Medical Sciences, Qingdao, 266071, Shandong, China
| | - Min Chen
- State Key Laboratory Cultivation Base, Shandong Provincial Key Laboratory of Ophthalmology, Shandong Eye Institute, Shandong First Medical University & Shandong Academy of Medical Sciences, Qingdao, 266071, Shandong, China.
| | - Le Tian
- State Key Laboratory Cultivation Base, Shandong Provincial Key Laboratory of Ophthalmology, Shandong Eye Institute, Shandong First Medical University & Shandong Academy of Medical Sciences, Qingdao, 266071, Shandong, China
| | - Dewei Li
- State Key Laboratory Cultivation Base, Shandong Provincial Key Laboratory of Ophthalmology, Shandong Eye Institute, Shandong First Medical University & Shandong Academy of Medical Sciences, Qingdao, 266071, Shandong, China
| | - Feifei Zhang
- State Key Laboratory Cultivation Base, Shandong Provincial Key Laboratory of Ophthalmology, Shandong Eye Institute, Shandong First Medical University & Shandong Academy of Medical Sciences, Qingdao, 266071, Shandong, China
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Small Incision Lenticule Extraction (SMILE) for Moderate and High Myopia: Seven-Year Outcomes of Refraction, Corneal Tomography, and Wavefront Aberrations. J Ophthalmol 2020; 2020:3825864. [PMID: 32377418 PMCID: PMC7195656 DOI: 10.1155/2020/3825864] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2020] [Accepted: 03/27/2020] [Indexed: 11/17/2022] Open
Abstract
Purpose To investigate the long-term outcomes of refraction, corneal tomography, and wavefront aberrations after small incision lenticule extraction (SMILE) for moderate and high myopia. Methods Prospective, nonconsecutive case series. A total of 26 patients (26 eyes) who underwent SMILE from May 2010 to March 2013 at the Fudan University Eye and ENT Hospital (Shanghai, China) were enrolled. The periods of follow-up were 1 month, 1 year, 5 years, and 7 years after surgery. The routine eye examinations included uncorrected distance visual acuity (UDVA) and corrected distance visual acuity (CDVA), manifest refraction, and corneal tomography. Results All surgeries were executed without any complications. At the final visit, an UDVA of 20/20 or better was achieved in 26 eyes (100%) and 11 eyes (42%) exhibited no change in CDVA. 9 eyes (35%) gained one line, 6 eyes (23%) gained two lines, and no eyes lost CDVA. 24 eyes (92%) and 26 eyes (100%) were within ±0.5 D and ±1.00 D of the target refraction, respectively. A mean refractive regression of −0.17 D was observed between 1 month and 7 years postoperatively. Mean corneal front curvature (MCFC) was significantly decreased between pre- and post-SMILE surgery (P < 0.0001). Higher-order aberrations (HOAs) and vertical coma were significantly increased after SMILE compared to those measured before surgery (all P < 0.001). There were no significant differences in trefoil and spherical aberration between pre- and post-SMILE surgery (all P > 0.05). Conclusion SMILE is an effective, safe, and stable procedure for moderate and high myopia, with relatively constant corneal stability and wavefront aberrations. This trial is registered with ChiCTR-ONRC-13003114.
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Li Y, Li S, Zhou J, Liu C, Xu M. Relationship between lipid layer thickness, incomplete blinking rate and tear film instability in patients with different myopia degrees after small-incision lenticule extraction. PLoS One 2020; 15:e0230119. [PMID: 32163466 PMCID: PMC7067460 DOI: 10.1371/journal.pone.0230119] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2019] [Accepted: 02/21/2020] [Indexed: 11/18/2022] Open
Abstract
Objective To elucidate the relationship between lipid layer thickness (LLT), incomplete blinking rate and tear film stability in patients with different myopia degrees after small-incision lenticule extraction (SMILE) and to determine whether there is a difference in the prevalence of dry eye disease (DED) after SMILE among patients with different myopia degrees. Methods Fifty patients (100 eyes) were enrolled in this study; they were divided into 3 groups according to the degree of spherical refraction: a low-myopia group (LMG; spherical refraction ≤-3.00 D, 20 eyes), a moderate-myopia group (MMG; -3.00 D < spherical refraction <-6.00 D, 40 eyes), and a high-myopia group (HMG; spherical refraction ≧-6.00 D, 40 eyes). Testing indicators included the ocular surface disease index (OSDI), fluorescein tear film breakup time (FBUT), corneal fluorescence staining (CFS), the Schirmer test (SI), lipid layer thickness (LLT), blink rate (BR) per 20 seconds, incomplete blinking rate, noninvasive keratograph assessment of first and average tear film breakup time (NIKBUTf, NIKBUTav), and tear meniscus height (TMH). Each indicator was evaluated preoperatively and postoperatively at 1 w, 1 mo and 3 mo. Results The mean age was 29.12±5.95 years. There were no significant differences among the three groups (p>0.05), except preoperative age (p = 0.006). There were significant differences in the FBUT among the three groups at postoperative 1 w and 1 mo (p<0.05). There were significant differences in the incomplete blinking rate and FBUT between the LMG and the HMG at postoperative 1 mo (p<0.05). The number of first tear film breakup points located beyond the 6 mm diameter of the cornea was higher in the HMG than in the other groups. The prevalence of DED in the LMG, the MMG, the HMG was 15%, 8% and 23%, respectively, at 1 w postoperative and 30%, 45% and 53%, respectively, at postoperative 1 mo. The change in LLT was significantly correlated with the changes in FBUT (r = 0.408, p<0.001) and incomplete blinking rate (r = -0.266, p = 0.007). The change in OSDI was negatively correlated with the change in SI (r = -0.502, p = 0.000). Conclusions The changes in LLT and incomplete blinking rate decreased the stability of the tear film. The changes in LLT, FBUT and incomplete blinking rate differed postoperatively with different myopia degrees. The prevalence of DED was higher in the HMG than in the other two groups.
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Affiliation(s)
- Yan Li
- Department of Ophthalmology, Aier School of Ophthalmology, Central South University, Changsha, Hunan Province, China
| | - Shaowei Li
- Department of Ophthalmology, Aier School of Ophthalmology, Central South University, Changsha, Hunan Province, China
- Department of Ophthalmology, Beijing Aier-Intech Eye Hospital, Beijing, China
- * E-mail: (SL); (JZ)
| | - Jihong Zhou
- Department of Ophthalmology, Beijing Aier-Intech Eye Hospital, Beijing, China
- * E-mail: (SL); (JZ)
| | - Chang Liu
- Department of Ophthalmology, Beijing Aier-Intech Eye Hospital, Beijing, China
| | - Man Xu
- Department of Ophthalmology, Beijing Aier-Intech Eye Hospital, Beijing, China
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Tay E, Bajpai R. Small incision lenticule extraction (SMILE) lenticule thickness readout compared to change in axial length measurements with the IOLMaster. Graefes Arch Clin Exp Ophthalmol 2019; 258:917-924. [PMID: 31773250 DOI: 10.1007/s00417-019-04529-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2018] [Revised: 09/12/2019] [Accepted: 10/28/2019] [Indexed: 11/28/2022] Open
Abstract
PURPOSE To compare theoretical values from the small incision lenticule extraction (SMILE) lenticule thickness readout with change in axial length measurements taken with the IOLMaster. METHODS We prospectively studied 214 eyes from 107 patients undergoing bilateral SMILE surgery for myopia or myopic astigmatism between December 2014 and May 2017 at an ophthalmological practice in Singapore. All eyes were examined pre-operatively and 1 and 3 months post-operatively with the IOLMaster following SMILE surgery. Achieved lenticule thickness was taken as the change in axial length after surgery. A linear mixed-effects model was used to examine changes in axial length, spherical equivalent and acuity over time. The relationships between change in axial length and theoretical lenticule thickness and spherical equivalent were examined with multiple linear regression analyses, and model prediction was assessed with adjusted R2 statistics. RESULTS Mean (95% confidence interval [CI]) spherical equivalent pre-operatively was - 5.25 (95% CI - 5.38 to - 5.12) diopters (D), at 1 month was 0.04 (95% CI - 0.09 to 0.17) D (p < 0.001), and at 3 months was - 0.02 (95% CI - 0.15 to 0.11) D (p < 0.001). Mean (95% CI) pre-operative axial length was 27,726 (95% CI 25,595 to 25,857) μm. Post-operative axial length at 1 month was significantly shorter at 25,595 (95% CI 25,464 to 25,726) μm (p < 0.001) with no change thereafter (p = 0.647). Pre-operative mean ± standard deviation (SD) refractive target was 0.24 (± 0.3) D, and mean difference between target and post-operative spherical equivalent at 1 month was 0.20 D (95% CI 0.16 to 0.25 D, p < 0.001). Multiple regression analysis showed that change in axial length at 1 month was, on average, 5% lower than theoretical lenticule thickness, indicating an average difference of 5.4 μm (95% CI 5.2 to 5.6 μm). Preoperative spherical equivalent predicted negative association with change in axial length at 1 month (β = - 14.8, 95% CI - 18.2 to - 11.3, adjusted R2 = 0.457, p < 0.001). CONCLUSIONS Calculated lenticule thickness values were less than expected, and post-operative refractive outcomes at 1 month showed a slight under-correction. Further research in this area is needed to validate these findings.
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Affiliation(s)
- Eugene Tay
- Singapore Eye Research Institute, The Academia, 20 College Road, Singapore, 169856, Singapore.
| | - Ram Bajpai
- Centre for Population Health Sciences, Lee Kong Chian School of Medicine, Nanyang Technological University, 11 Mandalay Road, Singapore, 308232, Singapore.,School of Primary, Community and Social Care, Keele University, Staffordshire, ST5 5BG, United Kingdom
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