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Shu N, He Y, Zhang Y. Research progress on measurement methods and clinical applications of corneal elastic modulus. Exp Eye Res 2024; 245:109974. [PMID: 38897271 DOI: 10.1016/j.exer.2024.109974] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2024] [Revised: 06/07/2024] [Accepted: 06/16/2024] [Indexed: 06/21/2024]
Abstract
Various corneal diseases are strongly associated with corneal biomechanical characteristics, and early measurement of patients' corneal biomechanics can be utilized in their diagnosis and treatment. Measurement methods for corneal biomechanical characteristics are classified into ex vivo and in vivo. Some of these methods can directly measure certain corneal biomechanical parameters, while others require indirect calculation through alternative methods. However, due to diversities in measurement techniques and environmental conditions, significant differences may exist in the corneal mechanical properties measured by these two methods. Therefore, comprehensive research on current measurement methods and the exploration of novel measurement techniques may have great clinical significance. The corneal elastic modulus, a critical indicator in corneal biomechanics, reflects the cornea's ability to return to its initial shape after undergoing stress. This review aims to provide a comprehensive summary of the corneal elastic modulus, which is a critical biomechanical parameter, and discuss its direct, indirect, and potential measurement methods and clinical applications.
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Affiliation(s)
- Nanqi Shu
- Department of Ophthalmology, The Second Hospital of Jilin University, Changchun, 130041, Jilin Province, China
| | - Yuxi He
- Department of Ophthalmology, The Second Hospital of Jilin University, Changchun, 130041, Jilin Province, China
| | - Yan Zhang
- Department of Ophthalmology, The Second Hospital of Jilin University, Changchun, 130041, Jilin Province, China; Department of Ophthalmology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200080, China.
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Sedaghat MR, Momeni-Moghaddam H, Yekta AA, Maddah N, Roberts CJ, Savardashtaki M. Early elastic and viscoelastic corneal biomechanical changes after photorefractive keratectomy and small incision lenticule extraction. Int Ophthalmol 2024; 44:302. [PMID: 38954134 DOI: 10.1007/s10792-024-03169-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2023] [Accepted: 06/15/2024] [Indexed: 07/04/2024]
Abstract
PURPOSE To compare early changes in the corneal biomechanical parameters after photorefractive keratectomy (PRK) and small incision lenticule extraction (SMILE) and their correlations with corneal shape parameters. METHODS One hundred twenty four eyes received myopic PRK and SMILE for similar amounts of myopia. Corneal tomography with Pentacam HR, biomechanical parameters using Corvis ST, and Ocular Response Analyzer (ORA) were evaluated before and 2 weeks after surgery. The change in each parameter was compared between groups, while the difference in central corneal thickness and cornea-compensated intraocular pressure measured before and after surgery were considered as covariates. RESULTS A significant reduction was seen in the corneal stiffness parameter at first applanation, and an increase in deformation amplitude ratio (DAR), and integrated inverse radius (IIR) in both groups after surgery (p < 0.001) Changes in DAR, and IIR were significantly greater in the SMILE than in the PRK group (p < 0.001) Corneal hysteresis (CH) and corneal resistance factor (CRF) decreased in both SMILE and PRK groups after surgery, (p < 0.001) with no statistically significant difference between groups (p > 0.05) Among new Corvis ST parameters, DAR showed a significant correlation with changes in Ambrosio relational thickness in both groups (p < 0.05). CONCLUSIONS Both techniques caused significant changes in corneal biomechanics in the early postoperative period, with greater elastic changes in the SMILE group compared to the PRK group, likely due to lower tension in the SMILE cap and thinner residual stromal bed in SMILE. There were no differences in viscoelastic changes between them, so the lower CH may reflect the volume of tissue removed.
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Affiliation(s)
| | - Hamed Momeni-Moghaddam
- Rehabilitation Sciences Research Center, Zahedan University of Medical Sciences, Zahedan, Iran.
| | - Abbas-Ali Yekta
- Department of Optometry, School of Paramedical Sciences, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Nasim Maddah
- Department of Optometry, School of Paramedical Sciences, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Cynthia J Roberts
- Department of Ophthalmology and Visual Sciences; and Department of Biomedical Engineering, The Ohio State University, Columbus, OH, USA
| | - Maryam Savardashtaki
- Department of Optometry, School of Paramedical Sciences, Mashhad University of Medical Sciences, Mashhad, Iran
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Yang F, Yang Z, Zhao S, Huang Y. To Investigate the Changes in Corneal Curvature and Its Correlation with Corneal Epithelial Remodeling After Trans-PRK and FS-LASIK. Curr Eye Res 2024:1-7. [PMID: 38867491 DOI: 10.1080/02713683.2024.2361728] [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: 09/08/2023] [Accepted: 05/23/2024] [Indexed: 06/14/2024]
Abstract
PURPOSE To evaluate curvature changes in different regions and their correlation with corneal epithelial remodeling in myopic patients undergoing femtosecond laser-assisted in situ keratomileusis (FS-LASIK) and transepithelial refractive keratectomy (Trans-PRK) after surgery. METHODS One hundred and sixty-three patients (163 right eyes) undergoing Trans-PRK and LASIK were evaluated for up to 6 months using anterior segment optical coherence tomography (OCT) to measure the epithelial thickness and corneal topography to measure corneal curvature in different areas (2 mm, 5 mm, and 7 mm). We calculated the curvature ΔK (ΔK = preoperative - postoperative), ΔK5-2 (ΔK5-2 = K5mm - K2mm), ΔK7-5 (ΔK7-5 = K7mm - K5mm), and the epithelial thickness ΔET5-2 (ΔET5-2 = ET5mm - ET2mm) and ΔET7-5 (ΔET7-5= ET7mm - ET5mm). RESULTS Corneal curvature flattened in each region of the two groups (all p < 0.001) and gradually steepened during the follow-up period. The Trans-PRK group flattened more significantly within 2 mm and 5 mm, while the FS-LASIK group at 7 mm. Both groups of ΔK decreased over time. Both groups of ΔK5-2 and ΔK7-5 gradually decreased during the follow-up period (P5-2=0.025 and P7-5 < 0.001 for Trans-PRK, P5-2 = 0.011 and P7-5 < 0.001 for FS-LASIK). The corneal epithelium of the two groups gradually thickened during the follow-up period, with Trans-PRK significantly thickening in the central and peripheral regions and FS-LASIK in the central and paracentral regions. There is a significant correlation between the ΔK5-2 and ΔET5-2, ΔK7-5 and ΔET7-5 (all r > 0.37, p < 0.001). CONCLUSIONS All groups showed significant curvature flattening after surgery and gradually steepening during the follow-up period. The corneal epithelium thickness in both groups of 17 regions became thicker,. In contrast, Trans-PRK group showed more significant thickening to the periphery and the central 5 mm area of the FS-LASIK. This study indicates a significant positive correlation between differences in epithelial thickening in different regions and differences in curvature changes in the corresponding areas PRK, FS-LASIK, curvature, corneal epithelial thickness.
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Affiliation(s)
- Fan Yang
- Eye Institute and School of Optometry, Tianjin Key Laboratory of Retinal Functions and Diseases, Tianjin Branch of National Clinical Research Center for Ocular Disease, Tianjin Medical University Eye Hospital, Tianjin, China
| | - Zheng Yang
- Eye Institute and School of Optometry, Tianjin Key Laboratory of Retinal Functions and Diseases, Tianjin Branch of National Clinical Research Center for Ocular Disease, Tianjin Medical University Eye Hospital, Tianjin, China
| | - Shaozhen Zhao
- Eye Institute and School of Optometry, Tianjin Key Laboratory of Retinal Functions and Diseases, Tianjin Branch of National Clinical Research Center for Ocular Disease, Tianjin Medical University Eye Hospital, Tianjin, China
| | - Yue Huang
- Eye Institute and School of Optometry, Tianjin Key Laboratory of Retinal Functions and Diseases, Tianjin Branch of National Clinical Research Center for Ocular Disease, Tianjin Medical University Eye Hospital, Tianjin, China
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Chen T, Li N, Ge T, Lin Y, Wu X, Gao H, Liu M. Regional analysis of posterior corneal elevation after laser refractive surgeries for correction of myopia of different degrees. Indian J Ophthalmol 2024; 72:824-830. [PMID: 38317325 PMCID: PMC11232844 DOI: 10.4103/ijo.ijo_2127_23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2023] [Accepted: 10/19/2023] [Indexed: 02/07/2024] Open
Abstract
PURPOSE To evaluate regional changes in the posterior corneal elevation after three laser refractive surgeries for correction of myopia of different degrees. SETTINGS AND DESIGN Retrospective, comparative, and non-randomized study. METHODS Two hundred patients (200 eyes) who underwent laser epithelial keratoplasty (LASEK), femtosecond-assisted laser in-situ keratomileusis (FS-LASIK), and small-incision lenticule extraction (SMILE) were included in this study. According to preoperative spherical equivalent (SE), each surgical group was divided into two refractive subgroups: low-to-moderate myopia (LM group) and high myopia (H group). The posterior corneal elevation from Pentacam Scheimpflug tomography was analyzed preoperatively and at 1 month, 3 months, 6 months, and 12 months postoperatively. Three subregions of the posterior cornea were divided in this study as the central, paracentral, and peripheral regions. STATISTICAL ANALYSIS USED Generalized Estimating Equations (GEE). RESULTS For all three surgical groups, similar changing trends were seen in the two refractive subgroups. H group presented a larger changing magnitude than the LM group in FS-LASIK over time ( P < 0.05), whereas no significant difference was noted in the two refractive subgroups of LASEK or SMILE ( P > 0.05). At 12 months postoperatively, the central posterior corneal elevation returned to the preoperative level in LASEK ( P > 0.05) but shifted forward significantly in FS-LASIK and SMILE ( P < 0.05). CONCLUSION Different posterior corneal regions respond differently to corneal refractive surgeries. LASEK, FS-LASIK, and SMILE demonstrate different trends in the regional changes in posterior corneal elevation. The corneal shape seems more stable in LASEK than in FS-LASIK and SMILE.
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Affiliation(s)
- Tong Chen
- Eye Institute of Shandong First Medical University, Eye Hospital of Shandong First Medical University (Shandong Eye Hospital), China
- State Key Laboratory Cultivation Base, Shandong Provincial Key Laboratory of Ophthalmology, China
- School of Ophthalmology, Shandong First Medical University, China
| | - Na Li
- Eye Institute of Shandong First Medical University, Eye Hospital of Shandong First Medical University (Shandong Eye Hospital), China
- State Key Laboratory Cultivation Base, Shandong Provincial Key Laboratory of Ophthalmology, China
- School of Ophthalmology, Shandong First Medical University, China
| | - Tian Ge
- Eye Institute of Shandong First Medical University, Eye Hospital of Shandong First Medical University (Shandong Eye Hospital), China
- State Key Laboratory Cultivation Base, Shandong Provincial Key Laboratory of Ophthalmology, China
- School of Ophthalmology, Shandong First Medical University, China
| | - Yue Lin
- Eye Institute of Shandong First Medical University, Eye Hospital of Shandong First Medical University (Shandong Eye Hospital), China
- State Key Laboratory Cultivation Base, Shandong Provincial Key Laboratory of Ophthalmology, China
- School of Ophthalmology, Shandong First Medical University, China
| | - Xiaohui Wu
- Eye Institute of Shandong First Medical University, Eye Hospital of Shandong First Medical University (Shandong Eye Hospital), China
- State Key Laboratory Cultivation Base, Shandong Provincial Key Laboratory of Ophthalmology, China
- School of Ophthalmology, Shandong First Medical University, China
| | - Hua Gao
- Eye Institute of Shandong First Medical University, Eye Hospital of Shandong First Medical University (Shandong Eye Hospital), China
- State Key Laboratory Cultivation Base, Shandong Provincial Key Laboratory of Ophthalmology, China
- School of Ophthalmology, Shandong First Medical University, China
| | - Mingna Liu
- Eye Institute of Shandong First Medical University, Eye Hospital of Shandong First Medical University (Shandong Eye Hospital), China
- State Key Laboratory Cultivation Base, Shandong Provincial Key Laboratory of Ophthalmology, China
- School of Ophthalmology, Shandong First Medical University, China
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Yoo TK, Kim D, Kim JS, Kim HS, Ryu IH, Lee IS, Kim JK, Na KH. Comparison of early visual outcomes after SMILE using VISUMAX 800 and VISUMAX 500 for myopia: a retrospective matched case-control study. Sci Rep 2024; 14:11989. [PMID: 38796537 PMCID: PMC11127987 DOI: 10.1038/s41598-024-62354-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2023] [Accepted: 05/16/2024] [Indexed: 05/28/2024] Open
Abstract
VISUMAX 800 was introduced to improve the patient experience and clinical outcomes of small incision lenticule extraction (SMILE). This was a retrospective, matched, and case-control study (1:2) controlled for preoperative central corneal thickness and refractive error that compared early refractive and visual outcomes after SMILE using VISUMAX 800 and VISUMAX 500 to treat myopia. We included 50 eyes that underwent the VISUMAX 800 SMILE and 100 eyes that underwent the VISUMAX 500 SMILE. SMILE using VISUMAX 800 was performed using the CentraLign aid for vertex centration. Cyclotorsion was controlled by an OcuLign assistant in the VISUMAX 800 group after corneal marking. Corneal higher-order aberrations (HOAs) were evaluated using a Pentacam 1 month after surgery. No differences were observed in the pre- and post-operative refractive and visual outcomes at 1 day, 1 month, and 6 months after surgery. VISUMAX 800 induced less total HOAs than VISUMAX 500 (P = 0.036). No statistically significant differences were observed in the amounts of induced spherical aberrations or vertical and horizontal comas. No differences were observed in the 1 month and 6 months refractive and visual outcomes between two SMILE procedures, except for VISUMAX 800, which resulted in lower postoperative total HOAs than VISUMAX 500.
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Affiliation(s)
- Tae Keun Yoo
- Department of Ophthalmology, Hangil Eye Hospital, 35 Bupyeong-daero, Bupyeong-gu, Incheon, 21388, South Korea.
- Department of Refractive Surgery, B&VIIT Eye Center, Seoul, South Korea.
| | - Dongyoung Kim
- Research and Development Department, VISUWORKS, Seoul, South Korea
| | - Jung Soo Kim
- Research and Development Department, VISUWORKS, Seoul, South Korea
| | - Hee Sun Kim
- Department of Refractive Surgery, B&VIIT Eye Center, Seoul, South Korea
| | - Ik Hee Ryu
- Department of Refractive Surgery, B&VIIT Eye Center, Seoul, South Korea
- Research and Development Department, VISUWORKS, Seoul, South Korea
| | - In Sik Lee
- Department of Refractive Surgery, B&VIIT Eye Center, Seoul, South Korea
| | - Jin Kuk Kim
- Department of Refractive Surgery, B&VIIT Eye Center, Seoul, South Korea
| | - Kun-Hoo Na
- Department of Refractive Surgery, B&VIIT Eye Center, Seoul, South Korea
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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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Abdel-Radi M, Eldaly Z, Alattar S, Goda I. Preservative-Free Topical Anesthetic Unit-Dose Eye Drops for the Management of Postoperative Pain Following Photorefractive Keratectomy. Ophthalmol Ther 2023; 12:3025-3038. [PMID: 37665497 PMCID: PMC10640409 DOI: 10.1007/s40123-023-00791-0] [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: 06/15/2023] [Accepted: 08/04/2023] [Indexed: 09/05/2023] Open
Abstract
INTRODUCTION Ocular pain is a common complication following photorefractive keratectomy (PRK). The level of patient satisfaction with current pain control strategies is not high. This study aims to assess the efficacy and safety of a novel regimen of preservative-free oxybuprocaine hydrochloride 0.4% unit-dose eye drops for post-PRK pain control. METHODS In a contralateral eye study, 144 eyes of 72 patients who underwent bilateral transepithelial PRK (TransPRK) were stratified into experimental and control groups. The experimental group received preservative-free oxybuprocaine hydrochloride 0.4% unit-dose eye drops five times daily postoperatively until complete epithelial healing, while the control group received sodium hyaluronate 0.2% instead. The main outcome measures were pain scores assessed by the verbal rating scale and visual analogue scale (VRS, VAS), the corneal epithelial defect (CED) area, epithelial healing duration evaluated by slit-lamp biomicroscopy and anterior segment optical coherence tomography (AS-OCT), and endothelial cell density (ECD) measured before and 1 month after surgery. RESULTS Pain scores assessed by VRS and VAS were significantly lower in the experimental group 8 h after surgery, and 1, 2, and 3 days postoperatively (P < 0.001). The mean CED area showed no significant differences between the two groups at different follow-ups (P value > 0.05). The corneal epithelial healing had a mean duration of 3.32 ± 0.47 days in both studied groups and was parallel in both eyes of each patient. In each group, 49 eyes (68%) and 72 eyes (100%) had a fully epithelialized surface on the third and fourth postoperative days, respectively. No significant changes were observed in the mean ECD 1 month following surgery in both groups (P value > 0.05). CONCLUSION Preservative-free oxybuprocaine hydrochloride 0.4% unit-dose eye drops are effective and safe in controlling early postoperative pain following TransPRK. The availability of the single-dose unit preparation can overcome the problem of topical anesthetic abuse. TRIAL REGISTRATION ClinicalTrials.gov Identifier: NCT05733741.
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Affiliation(s)
- Mahmoud Abdel-Radi
- Department of Ophthalmology, Assiut University Hospital, Assiut University, 6th Floor, Asyût , 71516, Egypt.
| | - Zeiad Eldaly
- Department of Ophthalmology, Assiut University Hospital, Assiut University, 6th Floor, Asyût , 71516, Egypt
| | - Sara Alattar
- Department of Ophthalmology, Assiut University Hospital, Assiut University, 6th Floor, Asyût , 71516, Egypt
| | - Islam Goda
- Department of Ophthalmology, Assiut University Hospital, Assiut University, 6th Floor, Asyût , 71516, Egypt
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Moshirfar M, Herron MS, Cha DS, Santos J, Payne CJ, Hoopes PC. Comparing Effective Optical Zones After Myopic Ablation Between LASIK, PRK, and SMILE With Correlation to Higher Order Aberrations. J Refract Surg 2023; 39:741-750. [PMID: 37937754 DOI: 10.3928/1081597x-20231016-02] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2023]
Abstract
PURPOSE To explore size, decentration, and eccentricity of effective optical zones (EOZs) in laser in situ keratomileusis (LASIK), photorefractive keratectomy (PRK), and small incision lenticule extraction (SMILE) and correlate them to higher order aberrations (HOAs). METHODS This was a retrospective chart review of 188 eyes that underwent refractive surgery for compound myopia (61 LASIK, 84 PRK, 43 SMILE). EOZ measurements were determined using 1-year postoperative Pentacam (Oculus Optikgeräte GmbH) tangential difference maps. HOA data were measured using Pentacam wavefront aberration Zernike polynomials. Correlations between EOZs and HOAs were analyzed. RESULTS The EOZs of LASIK and PRK are smaller than SMILE at 19.54 ± 1.44, 19.39 ± 1.66, and 22.18 ± 2.61 mm2, respectively (P < .001). No difference existed in absolute decentration from corneal vertex (P = .078) or pupil center (P = .131), but horizontal and vertical components differed significantly (P < .001). Smaller EOZ areas were correlated with greater spherical aberration induction (rLASIK = -0.378, rPRK = -0.555, rSMILE = -0.501) and total HOA induction in all groups. Absolute decentration from corneal vertex positively correlated with total HOA (rLASIK = 0.396, rPRK = 0.463, rSMILE = 0.399) and directional vertical coma induction negatively correlated with vertical decentration from the corneal vertex (rLASIK = -0.776, rPRK = -0.665, rSMILE = -0.576) in all groups. CONCLUSIONS SMILE results in a larger EOZ than LASIK and PRK, and absolute decentration remains comparable regardless of surgical reference center, despite horizontal/vertical differences. Surgical planning to ensure adequate EOZ size and centration may reduce induction of HOAs, including spherical aberrations and vertical coma. [J Refract Surg. 2023;39(11):741-750.].
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Li N, Liu M, Tian G, Chen T, Lin Y, Qi X, Shi W, Gao H. Effects of femtosecond laser-assisted minimally invasive lamellar keratoplasty (FL-MILK) on mild-to-moderate and advanced keratoconus. Graefes Arch Clin Exp Ophthalmol 2023; 261:2873-2882. [PMID: 37171602 DOI: 10.1007/s00417-023-06093-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2022] [Revised: 04/13/2023] [Accepted: 04/26/2023] [Indexed: 05/13/2023] Open
Abstract
PURPOSE To compare the outcomes of femtosecond laser-assisted minimally invasive lamellar keratoplasty (FL-MILK) for mild-to-moderate keratoconus (KC) and advanced KC. METHODS Prospective case series study. Sixty-three eyes of 56 patients with progressive KC underwent FL-MILK were divided into group 1 [mean keratometry (Kmean) ≤ 53D] and group 2 (Kmean > 53D). Best spectacle-corrected visual acuity (BSCVA), Kmean, maximum keratometry (Kmax), anterior central corneal elevation (ACE), stiffness parameter A1 (SP-A1) and deformation amplitude (DA) were evaluated preoperatively and up to 24 months postoperatively. RESULTS Mean BSCVA improved from 0.34 ± 0.13 logMAR preoperatively to 0.25 ± 0.13 logMAR at 24 months postoperatively in group 1 (F = 10.10, P < .0001), and from 0.54 ± 0.31 logMAR to 0.40 ± 0.26 logMAR (F = 9.06, P = .0002) in group 2. Group 2 showed an average Kmax reduction of 10.9 D and an average Kmean reduction of 3.9 D at 24 months postoperatively (both P < .0001), whereas no significant change was observed in group 1. Average ACE decreased from 19.2 ± 10.0 to 5.2 ± 8.4 at 24 months postoperatively in group 1 (F = 28.5, P < .0001), and from 46.2 ± 16.3 to 19.1 ± 9.0 (F = 49.6, P < .0001) in group 2; SP-A1 increased from 53.8 ± 12.7 mmHg/mm to 95.9 ± 20.2 mmHg/mm in group 1 (F = 70.0, P < .0001), and from 38.6 ± 13.4 mmHg/mm to 89.3 ± 18.2 mmHg/mm (F = 96.9, P < .0001) in group 2; DA decreased from 1.30 ± 0.14 mm to 1.17 ± 0.13 mm in group 1 (F = 14.0, P < .0001), and from 1.40 ± 0.16 mm to 1.18 ± 0.10 mm (F = 27.6, P < .0001) in group 2. CONCLUSIONS FL-MILK can stabilize progressive KC in mild-to-moderate cases and advanced cases at 24-month follow-up. Steeper corneas are more likely to undergo flattening after FL-MILK. CLINICAL TRIAL Date of registration: July 16, 2017. The title of the trail: www. CLINICALTRIALS gov Trial registration number: NCT03229239. The name of the trial registry: ClinicalTrials.gov.
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Affiliation(s)
- Na Li
- Eye Hospital of Shandong First Medical University (Shandong Eye Hospital), Eye Institute of Shandong First Medical University, 372 Jingsi Road, Jinan, 250021, China
- State Key Laboratory Cultivation Base, Shandong Provincial Key Laboratory of Ophthalmology, Jinan, 250021, China
- School of Ophthalmology, Shandong First Medical University, Jinan, 250021, China
| | - Mingna Liu
- Eye Hospital of Shandong First Medical University (Shandong Eye Hospital), Eye Institute of Shandong First Medical University, 372 Jingsi Road, Jinan, 250021, China
- State Key Laboratory Cultivation Base, Shandong Provincial Key Laboratory of Ophthalmology, Jinan, 250021, China
- School of Ophthalmology, Shandong First Medical University, Jinan, 250021, China
| | - Ge Tian
- Eye Hospital of Shandong First Medical University (Shandong Eye Hospital), Eye Institute of Shandong First Medical University, 372 Jingsi Road, Jinan, 250021, China
- State Key Laboratory Cultivation Base, Shandong Provincial Key Laboratory of Ophthalmology, Jinan, 250021, China
- School of Ophthalmology, Shandong First Medical University, Jinan, 250021, China
| | - Tong Chen
- Eye Hospital of Shandong First Medical University (Shandong Eye Hospital), Eye Institute of Shandong First Medical University, 372 Jingsi Road, Jinan, 250021, China
- State Key Laboratory Cultivation Base, Shandong Provincial Key Laboratory of Ophthalmology, Jinan, 250021, China
- School of Ophthalmology, Shandong First Medical University, Jinan, 250021, China
| | - Yue Lin
- Eye Hospital of Shandong First Medical University (Shandong Eye Hospital), Eye Institute of Shandong First Medical University, 372 Jingsi Road, Jinan, 250021, China
- State Key Laboratory Cultivation Base, Shandong Provincial Key Laboratory of Ophthalmology, Jinan, 250021, China
- School of Ophthalmology, Shandong First Medical University, Jinan, 250021, China
| | - Xiaolin Qi
- Eye Hospital of Shandong First Medical University (Shandong Eye Hospital), Eye Institute of Shandong First Medical University, 372 Jingsi Road, Jinan, 250021, China
- State Key Laboratory Cultivation Base, Shandong Provincial Key Laboratory of Ophthalmology, Jinan, 250021, China
- School of Ophthalmology, Shandong First Medical University, Jinan, 250021, China
| | - Weiyun Shi
- Eye Hospital of Shandong First Medical University (Shandong Eye Hospital), Eye Institute of Shandong First Medical University, 372 Jingsi Road, Jinan, 250021, China
- State Key Laboratory Cultivation Base, Shandong Provincial Key Laboratory of Ophthalmology, Jinan, 250021, China
- School of Ophthalmology, Shandong First Medical University, Jinan, 250021, China
| | - Hua Gao
- Eye Hospital of Shandong First Medical University (Shandong Eye Hospital), Eye Institute of Shandong First Medical University, 372 Jingsi Road, Jinan, 250021, China.
- State Key Laboratory Cultivation Base, Shandong Provincial Key Laboratory of Ophthalmology, Jinan, 250021, China.
- School of Ophthalmology, Shandong First Medical University, Jinan, 250021, China.
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10
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Moshirfar M, Theis JS, Cha DS, Porter KB, Payne CJ, Hoopes PC. Influence of Preoperative Parameters on the Ratio of Keratometric Change per Diopter of Attempted Spherical Equivalent (∆K/∆SEQ) for Myopic Correction Within LASIK, PRK, and SMILE. Clin Ophthalmol 2023; 17:2563-2573. [PMID: 37662649 PMCID: PMC10474859 DOI: 10.2147/opth.s423087] [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: 06/15/2023] [Accepted: 08/21/2023] [Indexed: 09/05/2023] Open
Abstract
Purpose To compare 3 of the most common corneal refractive procedures; PRK, LASIK, and SMILE assessing ΔK/ΔSEQ ratio and its correlation with preoperative demographics including age, keratometry, pachymetry, cylinder value, and attempted myopic correction. The goal was to analyze the relative strength of each preoperative parameter in accounting for changes in ∆K/∆SEQ. Patients and Methods A total of 370 eyes from 102 male and 97 female patients (173 eyes PRK, 153 LASIK, and 44 SMILE) with ages ranging from 20 to 51 underwent refractive surgery for myopia between -0.25 and -7.71 D manifest refraction spherical equivalent (MRSE). All surgeries were performed at a single surgery center in Draper, Utah. The Pentacam was used for all optical measurements and data were gathered pre-operatively and then again 1-year post-operatively. Only patients who achieved emmetropia at a visual acuity of 20/25 or better were included. Results The mean ΔK/ΔSEQ ratio for LASIK (0.839 ± 0.020) was significantly greater than that of PRK (0.775 ± 0.022) and SMILE (0.709 ± 0.046). Age was found to negatively correlate with ΔK/ΔSEQ for both LASIK (r = -0.177) and SMILE (r = -0.451) procedures. Pre-op keratometry was found to negatively correlate with ΔK/ΔSEQ for LASIK (r = -0.202) but not for PRK or SMILE. Pre-op pachymetry was not correlated with ΔK/ΔSEQ for any of the procedures. Attempted myopic spherical equivalent (SEQ) correction was positively correlated with ΔK/ΔSEQ for LASIK (r = 0.236), PRK (r = 0.459), and SMILE (r = 0.304). Lastly, pre-op cylinder value was found to be correlated to ΔK/ΔSEQ in SMILE (r = -0.367), but not in LASIK or PRK. Conclusion The ΔK/ΔSEQ ratio not only differs depending on the procedure being done but also by pre-operative factors such as age, keratometry, attempted correction, and cylinder value. Multiple linear regression analysis revealed that the attempted correction had the greatest effect on ∆K/∆SEQ out of all parameters in LASIK and PRK. For SMILE, age had the greatest predictive value of the change in ∆K/∆SEQ. While the exact effect of these parameters will vary by surgeon, all of these should be factored into a refractive surgeon's nomograms in order to achieve optimal visual outcomes for their patients.
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Affiliation(s)
- Majid Moshirfar
- Hoopes Vision Research Center, Hoopes Vision, Draper, UT, USA
- John A. Moran Eye Center, University of Utah School of Medicine, Salt Lake City, UT, USA
- Utah Lions Eye Bank, Murray, UT, USA
| | - Joshua S Theis
- University of Arizona College of Medicine Phoenix, Phoenix, AZ, USA
| | - David S Cha
- Saint Louis University School of Medicine, Saint Louis, MO, USA
| | - Kaiden B Porter
- University of Arizona College of Medicine Phoenix, Phoenix, AZ, USA
| | - Carter J Payne
- Hoopes Vision Research Center, Hoopes Vision, Draper, UT, USA
- Department of Ophthalmology, George Washington University School of Medicine and Health Sciences, Washington, DC, USA
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11
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Herber R, Vinciguerra R, Tredici C, Legrottaglie EF, Pillunat LE, Raiskup F, Vinciguerra P. Repeatability of corneal deformation response parameters by dynamic ultra-high-speed Scheimpflug imaging before and after corneal crosslinking. J Cataract Refract Surg 2023; 49:518-524. [PMID: 36700933 DOI: 10.1097/j.jcrs.0000000000001136] [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: 08/15/2022] [Accepted: 12/17/2022] [Indexed: 01/27/2023]
Abstract
PURPOSE To evaluate the repeatability of deformation corneal response (DCR) parameters before and after corneal crosslinking (CXL) compared with their untreated fellow eyes (uFEs). SETTING University Hospital Carl Gustav Carus, Dresden, Germany; IRCCS Humanitas Research Hospital, Rozzano, Milan, Italy. DESIGN Multicenter, interventional reliability analysis. METHODS 53 eyes of 53 patients with keratoconus who received CXL treatment after the disease progression (CXL group) were included. Patients were measured 3 times using a dynamic Scheimpflug analyzer to determine repeatability before and 1 month after CXL treatment. The uFEs were measured in the same way (uFE group). Reliability of DCR parameters was assessed by a coefficient of repeatability, coefficient of variation, and intraclass correlation coefficient (ICC). RESULTS The repeatability of DCR parameters did not change after CXL compared with the preoperative values for all investigated DCR parameters ( P > .05). In the uFE group, no statistically significant shift was observed regarding the repeatability ( P > .05). An ICC greater than 0.75 was achieved in both groups for almost all parameters. Concerning the biomechanical stiffening induced by CXL, integrated inverse radius and stress-strain index were found to be statistically significantly decreased and increased ( P < .001), respectively, both indicating stiffening. No changes were observed for the uFE group. CONCLUSIONS The study demonstrated highly repeatable measurements of the dynamic Scheimpflug analyzer before and after CXL. The improvement of certain DCR parameters after CXL confirmed the capability of the device to detect the stiffening effect.
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Affiliation(s)
- Robert Herber
- From the Department of Ophthalmology, Univ. Hospital Carl Gustav Carus, TU Dresden, Germany (Herber, Pillunat, Raiskup); Humanitas San Pio X Hospital, Milan, Italy (R. Vinciguerra); IRCCS Humanitas Research Hospital, Milan, Italy (Tredici, Legrottaglie, P. Vinciguerra); Department of Biomedical Sciences, Humanitas University, Milan, Italy (P. Vinciguerra)
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12
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Hashemi H, Roberts CJ, Elsheikh A, Mehravaran S, Panahi P, Asgari S. Corneal Biomechanics After SMILE, Femtosecond-Assisted LASIK, and Photorefractive Keratectomy: A Matched Comparison Study. Transl Vis Sci Technol 2023; 12:12. [PMID: 36928130 PMCID: PMC10029763 DOI: 10.1167/tvst.12.3.12] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/18/2023] Open
Abstract
Purpose To evaluate the change in corneal stiffness after small incision lenticule extraction (SMILE), femtosecond laser-assisted in situ keratomileusis (FS-LASIK), and photorefractive keratectomy (PRK). Methods Age, gender, spherical equivalent, and central corneal thickness (CCT)-matched cases undergoing SMILE with a 120-µ cap, FS-LASIK with a 110-µ flap, and PRK were enrolled. One-year change in the stress-strain index, stiffness parameter at first applanation, integrated inverse radius, deformation amplitude ratio at 2 mm, and deformation amplitude ratio at 1 mm were compared between the surgical groups by linear mixed-effect models. Results Within each surgical group, 120 eyes completed 1 year of follow-up. The residual stromal bed (RSB) thickness and (RSB/CCTpostop) were 348.1 ± 35.0 (0.74), 375.4 ± 31.0 (0.77) and 426.7 ± 2 µm (0.88) after SMILE, FS-LASIK, and PRK, respectively. The 1-year change in all biomechanical indices was significant, except the stress-strain index with PRK (P = 0.884). The change in all indices with SMILE were significantly greater than with FS-LASIK and with PRK (all P < 0.01), except the deformation amplitude ratio at 1 mm change between SMILE and FS-LASIK (P = 0.075). The changes in all indices with FS-LASIK were significantly greater than with PRK (all P < 0.05). Conclusions Although SMILE preserves the greatest amount of anterior cornea with a cap thickness of 120 µ, this also produces the smallest RSB and the greatest decrease in stiffness. Thus, the RSB is shown to be the predominant determinant of stiffness decreases, rather than the preserved anterior cornea. We recommend using a thinner cap to achieve a thicker RSB and a lesser decrease in the corneal stiffness in the SMILE procedure. Translational Relevance After refractive surgery, RSB is predominant determinant of stiffness decreases, rather than the preserved anterior cornea.
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Affiliation(s)
- Hassan Hashemi
- Noor Ophthalmology Research Center, Noor Eye Hospital, Tehran, Iran
| | - Cynthia J Roberts
- Department of Ophthalmology & Visual Sciences, Department of Biomedical Engineering, The Ohio State University, Columbus, OH, USA
| | - Ahmed Elsheikh
- School of Engineering, University of Liverpool, Liverpool, UK
- National Institute for Health Research (NIHR) Biomedical Research Centre for Ophthalmology, Moorfields Eye Hospital NHS Foundation Trust and UCL Institute of Ophthalmology, London, UK
- Beijing Advanced Innovation Center for Biomedical Engineering, Beihang University, Beijing, China
| | - Shiva Mehravaran
- School of Computer, Mathematical, and Natural Sciences, Morgan State University, Baltimore, MD, USA
| | - Parsa Panahi
- Noor Research Center for Ophthalmic Epidemiology, Noor Eye Hospital, Tehran, Iran
| | - Soheila Asgari
- Noor Ophthalmology Research Center, Noor Eye Hospital, Tehran, Iran
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13
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Li N, Chen T, Tian G, Lin Y, Meng Y, Gao H, Liu M. Changes in aberrations and biomechanics after femtosecond laser-assisted laser in situ keratomileusis (FS-LASIK) in eyes with high astigmatism: a retrospective case control study. BMC Ophthalmol 2023; 23:62. [PMID: 36782180 PMCID: PMC9923895 DOI: 10.1186/s12886-023-02809-4] [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] [Accepted: 02/06/2023] [Indexed: 02/15/2023] Open
Abstract
BACKGROUND To compare the 6-month changes in aberration and biomechanics after femtosecond laser-assisted laser in situ keratomileusis (FS-LASIK) for high astigmatism. METHODS In this retrospective case control study, 47 eyes with high astigmatism (≥ 2.5 D, HA group) and 47 eyes with low astigmatism (≤ 1.0 D, LA group) underwent FS-LASIK. Preoperative and follow-up examinations included visual outcomes, higher order aberrations (HOAs) and biomechanics. Biomechanical parameters include a deformation amplitude ratio of 2 mm (DA ratio 2 mm), integrated inverse radius (IIR), stiffness parameter at first applanation (SP-A1), and ambrosio relational thickness through the horizontal meridian (ARTh). RESULTS Six months postoperatively, there was no significant difference in the efficacy and safety index (both P > 0.05) between the two groups, but the cylinder was higher in the HA group. The HOAs increased significantly after surgery in both groups (all P < 0.05). Six months postoperatively, the changes in spherical aberration and HOAs were larger in the HA group (both P < 0.005), but there was no significant difference between the changes in coma (P > 0.05). Significant decreases in SP-A1 and ARTh and significant increases in the IIR and DA ratio of 2 mm (all P < 0.05) were observed after surgery in both groups. The changes in the DA ratio 2 mm, IIR, SP-A1, and ARTh were not significantly different between the groups. CONCLUSION FS-LASIK had relative comparable efficacy and safety in correcting high and low myopic astigmatism, with higher astigmatic under-correction in eyes with high astigmatism. High astigmatism in eyes after FS-LASIK could introduce larger corneal aberrations, but the impact on corneal stiffness was the same as that in eyes with low astigmatism.
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Affiliation(s)
- Na Li
- grid.490473.dEye Institute of Shandong First Medical University, Eye Hospital of Shandong First Medical University (Shandong Eye Hospital), 372 Jingsi Road, 250021 Jinan, China ,State Key Laboratory Cultivation Base, Shandong Provincial Key Laboratory of Ophthalmology, 372 Jingsi Road, 250021 Jinan, China ,grid.410638.80000 0000 8910 6733School of Ophthalmology, Shandong First Medical University, 372 Jingsi Road, 250021 Jinan, China
| | - Tong Chen
- grid.490473.dEye Institute of Shandong First Medical University, Eye Hospital of Shandong First Medical University (Shandong Eye Hospital), 372 Jingsi Road, 250021 Jinan, China ,State Key Laboratory Cultivation Base, Shandong Provincial Key Laboratory of Ophthalmology, 372 Jingsi Road, 250021 Jinan, China ,grid.410638.80000 0000 8910 6733School of Ophthalmology, Shandong First Medical University, 372 Jingsi Road, 250021 Jinan, China
| | - Ge Tian
- grid.490473.dEye Institute of Shandong First Medical University, Eye Hospital of Shandong First Medical University (Shandong Eye Hospital), 372 Jingsi Road, 250021 Jinan, China ,State Key Laboratory Cultivation Base, Shandong Provincial Key Laboratory of Ophthalmology, 372 Jingsi Road, 250021 Jinan, China ,grid.410638.80000 0000 8910 6733School of Ophthalmology, Shandong First Medical University, 372 Jingsi Road, 250021 Jinan, China
| | - Yue Lin
- grid.490473.dEye Institute of Shandong First Medical University, Eye Hospital of Shandong First Medical University (Shandong Eye Hospital), 372 Jingsi Road, 250021 Jinan, China ,State Key Laboratory Cultivation Base, Shandong Provincial Key Laboratory of Ophthalmology, 372 Jingsi Road, 250021 Jinan, China ,grid.410638.80000 0000 8910 6733School of Ophthalmology, Shandong First Medical University, 372 Jingsi Road, 250021 Jinan, China
| | - Yuan Meng
- grid.490473.dEye Institute of Shandong First Medical University, Eye Hospital of Shandong First Medical University (Shandong Eye Hospital), 372 Jingsi Road, 250021 Jinan, China ,State Key Laboratory Cultivation Base, Shandong Provincial Key Laboratory of Ophthalmology, 372 Jingsi Road, 250021 Jinan, China ,grid.410638.80000 0000 8910 6733School of Ophthalmology, Shandong First Medical University, 372 Jingsi Road, 250021 Jinan, China
| | - Hua Gao
- grid.490473.dEye Institute of Shandong First Medical University, Eye Hospital of Shandong First Medical University (Shandong Eye Hospital), 372 Jingsi Road, 250021 Jinan, China ,State Key Laboratory Cultivation Base, Shandong Provincial Key Laboratory of Ophthalmology, 372 Jingsi Road, 250021 Jinan, China ,grid.410638.80000 0000 8910 6733School of Ophthalmology, Shandong First Medical University, 372 Jingsi Road, 250021 Jinan, China
| | - Mingna Liu
- Eye Institute of Shandong First Medical University, Eye Hospital of Shandong First Medical University (Shandong Eye Hospital), 372 Jingsi Road, 250021, Jinan, China. .,State Key Laboratory Cultivation Base, Shandong Provincial Key Laboratory of Ophthalmology, 372 Jingsi Road, 250021, Jinan, China. .,School of Ophthalmology, Shandong First Medical University, 372 Jingsi Road, 250021, Jinan, China.
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14
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Bao F, Lopes BT, Zheng X, Ji Y, Wang J, Elsheikh A. Corneal Biomechanics Losses Caused by Refractive Surgery. Curr Eye Res 2023; 48:137-143. [PMID: 36001080 DOI: 10.1080/02713683.2022.2103569] [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: 02/08/2023]
Abstract
Recent advances, specifically in the understanding of the biomechanical properties of the cornea and its response to diseases and surgical interventions, have significantly improved the safety and surgical outcomes of corneal refractive surgery, whose popularity and demand continue to grow worldwide. However, iatrogenic keratectasia resulting from the deterioration in corneal biomechanics caused by surgical interventions, although rare, remains a global concern. On one hand, in vivo biomechanical evaluation, enabled by clinical imaging systems such as the ORA and the Corvis ST, has significantly improved the risk profiling of patients for iatrogenic keratectasia. That is despite the fact the biomechanical metrics provided by these systems are considered indicators of the cornea's overall stiffness rather than its intrinsic material properties. On the other hand, new surgical modalities including SMILE were introduced to offer superior biomechanical performance to LASIK, but this superiority could not be proven clinically, creating more myths than answers. The literature also includes sound evidence that tPRK provided the highest preservation of corneal biomechanics when compared to both LASIK and SMILE. The aim of this review is twofold; to discuss the importance of corneal biomechanical evaluation prior to refractive surgery, and to assess the current understanding of cornea's biomechanical deterioration caused by mainstream corneal refractive surgeries. The review has led to an observation that new imaging techniques, parameters and evaluation systems may be needed to reflect the true advantages of specific refractive techniques and when these advantages are significant enough to offer better protection against post-surgery complications.
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Affiliation(s)
- FangJun Bao
- Eye Hospital, Wenzhou Medical University, Wenzhou, China.,The Institute of Ocular Biomechanics, Wenzhou Medical University, Wenzhou, China
| | - Bernardo T Lopes
- School of Engineering, University of Liverpool, Liverpool, UK.,Department of Ophthalmology, Federal University of Sao Paulo (UNIFESP), Sao Paulo, Brazil
| | - XiaoBo Zheng
- Eye Hospital, Wenzhou Medical University, Wenzhou, China.,The Institute of Ocular Biomechanics, Wenzhou Medical University, Wenzhou, China
| | - YuXin Ji
- Eye Hospital, Wenzhou Medical University, Wenzhou, China
| | - JunJie Wang
- Eye Hospital, Wenzhou Medical University, Wenzhou, China.,The Institute of Ocular Biomechanics, Wenzhou Medical University, Wenzhou, China
| | - Ahmed Elsheikh
- School of Engineering, University of Liverpool, Liverpool, UK.,Beijing Advanced Innovation Centre for Biomedical Engineering, Beihang University, Beijing, China.,National Institute for Health Research (NIHR) Biomedical Research Centre for Ophthalmology, Moorfields Eye Hospital NHS Foundation Trust and UCL Institute of Ophthalmology, London, UK
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15
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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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16
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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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17
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Han T, Shi W, Chen Y, Shen Y, Xu Y, Zhou X. Predictive models for IOPs measured with NCT, GAT, and ORA among patients undergoing SMILE. Front Bioeng Biotechnol 2022; 10:1030458. [PMID: 36532578 PMCID: PMC9751611 DOI: 10.3389/fbioe.2022.1030458] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2022] [Accepted: 11/18/2022] [Indexed: 09/08/2023] Open
Abstract
Purpose: To develop predictive models for the intraocular pressure (IOP) of patients undergoing small incision lenticule extraction (SMILE) procedures, measured with a noncontact tonometer (NCT), Goldmann applanation tonometry (GAT), and an ocular response analyzer (ORA). Methods: In this prospective study, a total of 104 eyes (-6.23 ± 2.06 diopters) of 52 patients (24.38 ± 4.76 years) undergoing SMILE procedures were included. The intraocular pressure was measured (IOPNCT with NCT, IOPGAT with GAT, and IOPcc and IOPg with ORA) before surgery and at postoperative 6 months. Information on age, preoperative and attempted spherical equivalent (SE), ablation depth, preoperative values and postoperative changes in central corneal thickness (CCT), K1, K2, Km, corneal hysteresis (CH) and corneal resistance factor (CRF) values was collected in order to predict IOPs. Results: All surgeries were uneventful. At postoperative 6 months, the efficacy and safety index were 1.04 ± 0.15 and 1.08 ± 0.18, respectively. Significant decreases were detected in postoperative IOPNCT, IOPGAT, IOPcc, and IOPg compared to preoperative values (all p < 0.001). No relationship was found between any IOP and ablation depth, attempted SE, and preoperative SE, as well as CCTdifference (all p > 0.05). Predictive models for IOPs were constructed to predict preoperative values, and R 2 values were 67.5% (IOPNCT), 64.5% (IOPGAT), 78.7% (IOPcc), and 82.0% (IOPg). The prediction band of IOPNCT and IOPGAT was 7.4-15.1 mmHg and 8-16 mmHg, respectively. Conclusion: Predictive models for IOP measurements after SMILE procedures can be helpful in clinical practice.
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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
| | - Wanru Shi
- 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
| | - Yingjun 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
| | - 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
| | - Ye Xu
- 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
- 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
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