A novel corneal indentation device for comparison of corneal tangent modulus before and after FS-LASIK in vivo

Abstract Background Corneal refractive laser surgery is widely used to correct myopia and astigmatism due to its safety and effectiveness. However, postoperative changes in corneal biomechanics, such as corneal ectasia, can occur, necessitating a deeper understanding of these changes. Finite Element...

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Main Authors: Yan Zhang, Junyu Lin, Shu-Hao Lu, Jones Iok-Tong Chong, Cheng Yang, Jianqing Lan, Wenjuan Xie, Juan Li, David Chuen-Chun Lam, Dan Cao, Jin Zeng
Format: Article
Language:English
Published: BMC 2025-02-01
Series:BioMedical Engineering OnLine
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Online Access:https://doi.org/10.1186/s12938-025-01343-2
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author Yan Zhang
Junyu Lin
Shu-Hao Lu
Jones Iok-Tong Chong
Cheng Yang
Jianqing Lan
Wenjuan Xie
Juan Li
David Chuen-Chun Lam
Dan Cao
Jin Zeng
author_facet Yan Zhang
Junyu Lin
Shu-Hao Lu
Jones Iok-Tong Chong
Cheng Yang
Jianqing Lan
Wenjuan Xie
Juan Li
David Chuen-Chun Lam
Dan Cao
Jin Zeng
author_sort Yan Zhang
collection DOAJ
description Abstract Background Corneal refractive laser surgery is widely used to correct myopia and astigmatism due to its safety and effectiveness. However, postoperative changes in corneal biomechanics, such as corneal ectasia, can occur, necessitating a deeper understanding of these changes. Finite Element Analysis has shown promise in predicting surgical outcomes based on corneal biomechanics. Devices like the Ocular Response Analyser (ORA) and Corvis ST provide noninvasive ways to measure corneal biomechanics, aiding in the assessment of corneal behavior post-surgery. Young's modulus and tangent modulus are crucial parameters for describing corneal elasticity, but there is limited data on the changes in tangent modulus following Femtosecond Laser-Assisted LASIK (FS-LASIK) in humans. This study aimed to investigate the effect of FS-LASIK on the corneal tangent modulus using a novel corneal indentation device (CID). The study sought to explore changes in corneal tangent modulus after FS-LASIK, taking into account central corneal thickness (CCT) and corneal radius, to enhance our understanding of the biomechanical changes induced by this surgical procedure. Results Sixty-six patients (66 eyes) underwent FS-LASIK, resulting in significant changes in CCT, corneal radius, and Goldmann intraocular pressure (GAT IOP) 6 months post-surgery (△CCT = − 88 ± 31 µm, △corneal radius = 0.81 ± 0.30 mm, △GAT IOP = − 3.2 ± 2.4 mmHg, p < 0.001) 6 months after surgery. However, corneal stiffness did not significantly change (△ = − 0.002 ± 0.011, p < 0.2). The corneal tangent modulus showed a significant increase post-surgery (△ = 0.263 ± 0.146, p < 0.001), exhibiting a negative correlation with CCT (r = − 0.68, P < 0.001) and a positive correlation with corneal radius (r = 0.71, P < 0.001). For each 1 mm increase in corneal radius, there was a 0.23 MPa increase in corneal modulus, and for every 100 µm reduction in corneal thickness, there was a 0.14 MPa increase in corneal modulus. Conclusions The corneal tangent modulus, influenced by corneal radius and CCT, increased significantly following FS-LASIK. This study highlights the biomechanical changes induced by FS-LASIK, with implications for understanding corneal behavior post-surgery and its potential impact on patient outcomes.
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spelling doaj-art-613fdebbb5e94498b507b51b7fb1cf472025-08-20T03:03:50ZengBMCBioMedical Engineering OnLine1475-925X2025-02-0124111310.1186/s12938-025-01343-2A novel corneal indentation device for comparison of corneal tangent modulus before and after FS-LASIK in vivoYan Zhang0Junyu Lin1Shu-Hao Lu2Jones Iok-Tong Chong3Cheng Yang4Jianqing Lan5Wenjuan Xie6Juan Li7David Chuen-Chun Lam8Dan Cao9Jin Zeng10Department of Ophthalmology, Guangdong Eye Institute, Guangdong Provincial People’s Hospital, Guangdong Academy of Medical SciencesDepartment of Ophthalmology, Guangdong Eye Institute, Guangdong Provincial People’s Hospital, Guangdong Academy of Medical SciencesDepartment of Mechanical and Aerospace Engineering, The Hong Kong University of Science and TechnologyDepartment of Mechanical and Aerospace Engineering, The Hong Kong University of Science and TechnologyDepartment of Ophthalmology, Guangdong Eye Institute, Guangdong Provincial People’s Hospital, Guangdong Academy of Medical SciencesDepartment of Ophthalmology, Guangdong Eye Institute, Guangdong Provincial People’s Hospital, Guangdong Academy of Medical SciencesDepartment of Ophthalmology, Guangdong Eye Institute, Guangdong Provincial People’s Hospital, Guangdong Academy of Medical SciencesDepartment of Ophthalmology, Guangdong Eye Institute, Guangdong Provincial People’s Hospital, Guangdong Academy of Medical SciencesDepartment of Mechanical and Aerospace Engineering, The Hong Kong University of Science and TechnologyDepartment of Ophthalmology, Guangdong Eye Institute, Guangdong Provincial People’s Hospital, Guangdong Academy of Medical SciencesDepartment of Ophthalmology, Guangdong Eye Institute, Guangdong Provincial People’s Hospital, Guangdong Academy of Medical SciencesAbstract Background Corneal refractive laser surgery is widely used to correct myopia and astigmatism due to its safety and effectiveness. However, postoperative changes in corneal biomechanics, such as corneal ectasia, can occur, necessitating a deeper understanding of these changes. Finite Element Analysis has shown promise in predicting surgical outcomes based on corneal biomechanics. Devices like the Ocular Response Analyser (ORA) and Corvis ST provide noninvasive ways to measure corneal biomechanics, aiding in the assessment of corneal behavior post-surgery. Young's modulus and tangent modulus are crucial parameters for describing corneal elasticity, but there is limited data on the changes in tangent modulus following Femtosecond Laser-Assisted LASIK (FS-LASIK) in humans. This study aimed to investigate the effect of FS-LASIK on the corneal tangent modulus using a novel corneal indentation device (CID). The study sought to explore changes in corneal tangent modulus after FS-LASIK, taking into account central corneal thickness (CCT) and corneal radius, to enhance our understanding of the biomechanical changes induced by this surgical procedure. Results Sixty-six patients (66 eyes) underwent FS-LASIK, resulting in significant changes in CCT, corneal radius, and Goldmann intraocular pressure (GAT IOP) 6 months post-surgery (△CCT = − 88 ± 31 µm, △corneal radius = 0.81 ± 0.30 mm, △GAT IOP = − 3.2 ± 2.4 mmHg, p < 0.001) 6 months after surgery. However, corneal stiffness did not significantly change (△ = − 0.002 ± 0.011, p < 0.2). The corneal tangent modulus showed a significant increase post-surgery (△ = 0.263 ± 0.146, p < 0.001), exhibiting a negative correlation with CCT (r = − 0.68, P < 0.001) and a positive correlation with corneal radius (r = 0.71, P < 0.001). For each 1 mm increase in corneal radius, there was a 0.23 MPa increase in corneal modulus, and for every 100 µm reduction in corneal thickness, there was a 0.14 MPa increase in corneal modulus. Conclusions The corneal tangent modulus, influenced by corneal radius and CCT, increased significantly following FS-LASIK. This study highlights the biomechanical changes induced by FS-LASIK, with implications for understanding corneal behavior post-surgery and its potential impact on patient outcomes.https://doi.org/10.1186/s12938-025-01343-2Corneal tangent modulusCorneal biomechanicsCorneal stiffnessFemtosecond Laser-Assisted LASIKClinical trial
spellingShingle Yan Zhang
Junyu Lin
Shu-Hao Lu
Jones Iok-Tong Chong
Cheng Yang
Jianqing Lan
Wenjuan Xie
Juan Li
David Chuen-Chun Lam
Dan Cao
Jin Zeng
A novel corneal indentation device for comparison of corneal tangent modulus before and after FS-LASIK in vivo
BioMedical Engineering OnLine
Corneal tangent modulus
Corneal biomechanics
Corneal stiffness
Femtosecond Laser-Assisted LASIK
Clinical trial
title A novel corneal indentation device for comparison of corneal tangent modulus before and after FS-LASIK in vivo
title_full A novel corneal indentation device for comparison of corneal tangent modulus before and after FS-LASIK in vivo
title_fullStr A novel corneal indentation device for comparison of corneal tangent modulus before and after FS-LASIK in vivo
title_full_unstemmed A novel corneal indentation device for comparison of corneal tangent modulus before and after FS-LASIK in vivo
title_short A novel corneal indentation device for comparison of corneal tangent modulus before and after FS-LASIK in vivo
title_sort novel corneal indentation device for comparison of corneal tangent modulus before and after fs lasik in vivo
topic Corneal tangent modulus
Corneal biomechanics
Corneal stiffness
Femtosecond Laser-Assisted LASIK
Clinical trial
url https://doi.org/10.1186/s12938-025-01343-2
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