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Duan Z, Yuan M, Liu Z, Pei W, Jiang K, Li L, Shen G. An Ultrasensitive Ti 3C 2T x MXene-based Soft Contact Lens for Continuous and Nondestructive Intraocular Pressure Monitoring. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2024; 20:e2309785. [PMID: 38377279 DOI: 10.1002/smll.202309785] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/27/2023] [Revised: 01/08/2024] [Indexed: 02/22/2024]
Abstract
Wearable soft contact lens sensors for continuous and nondestructive intraocular pressure (IOP) monitoring are highly desired as glaucoma and postoperative myopia patients grow, especially as the eyestrain crowd increases. Herein, a smart closed-loop system is presented that combines a Ti3C2Tx MXene-based soft contact lens (MX-CLS) sensor, wireless data transmission units, display, and warning components to realize continuous and nondestructive IOP monitoring/real-time display. The fabricated MX-CLS device exhibits an extremely high sensitivity of 7.483 mV mmHg-1, good linearity on silicone eyeballs, excellent stability under long-term pressure-release measurement, sufficient transparency with 67.8% transmittance under visible illumination, and superior biocompatibility with no discomfort when putting the MX-CLS sensor onto the Rabbit eyes. After integrating with the wireless module, users can realize real-time monitoring and warning of IOP via smartphones, the demonstrated MX-CLS device together with the IOP monitoring/display system opens up promising platforms for Ti3C2Tx materials as the base for multifunctional contact lens-based sensors and continuous and nondestructive IOP measurement system.
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Affiliation(s)
- Zhongyi Duan
- School of Integrated Circuits and Electronics, Beijing Institute of Technology, Beijing, 100081, P. R. China
| | - Miao Yuan
- State Key Laboratory of Integrated Optoelectronics Institute of Semiconductors, Chinese Academy of Sciences, Beijing, 100083, P. R. China
| | - Zhiduo Liu
- School of Physics, Beijing Institute of Technology, Beijing, 100081, P. R. China
| | - Weihua Pei
- State Key Laboratory of Integrated Optoelectronics Institute of Semiconductors, Chinese Academy of Sciences, Beijing, 100083, P. R. China
| | - Kai Jiang
- Faculty of Hepato-Pancreato-Biliary Surgery, Chinese PLA General Hospital, Institute of Hepatobiliary Surgery of Chinese PLA & Key Laboratory of Digital Hepatobiliary Surgery, Beijing, 100853, P. R. China
| | - La Li
- School of Integrated Circuits and Electronics, Beijing Institute of Technology, Beijing, 100081, P. R. China
| | - Guozhen Shen
- School of Integrated Circuits and Electronics, Beijing Institute of Technology, Beijing, 100081, P. R. China
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Li X, Chen W, Li H, Shen B, He J, Gao H, Bin F, Li H, Xiao D. Temperature Self-Compensating Intelligent Wireless Measuring Contact Lens for Quantitative Intraocular Pressure Monitoring. ACS APPLIED MATERIALS & INTERFACES 2024; 16:22522-22531. [PMID: 38651323 DOI: 10.1021/acsami.4c02289] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/25/2024]
Abstract
Flexible bioelectronic devices that can perform real-time and accurate intraocular pressure (IOP) monitoring in both clinical and home settings hold significant implications for the diagnosis and treatment of glaucoma, yet they face challenges due to the open physiological environment of the ocular. Herein, we develop an intelligent wireless measuring contact lens (WMCL) incorporating a dual inductor-capacitor-resistor (LCR) resonant system to achieve temperature self-compensation for quantitative IOP monitoring in different application environments. The WMCL utilizes a compact circuitry design, which enables the integration of low-frequency and high-frequency resonators within a single layer of a sensing circuit without causing visual impairment. Mechanically guided microscale 3D encapsulation strategy combined with flexible circuit printing techniques achieves the surface-adaptive fabrication of the WMCL. The specific design of frequency separation imparts distinct temperature response characteristics to the dual resonators, and the linear combination of the dual resonators can eliminate the impact of temperature variations on measurement accuracy. The WMCL demonstrates outstanding sensitivity and linearity in monitoring the IOP of porcine eyes in vitro while maintaining satisfactory measurement accuracy even with internal temperature variations exceeding 10 °C. Overcoming the impact of temperature variations on IOP monitoring from the system level, the WMCL showcases immense potential as the next generation of all-weather IOP monitoring devices.
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Affiliation(s)
- Xu Li
- Institute of Advanced Structure Technology, Beijing Institute of Technology, Beijing 100081, China
| | - Wei Chen
- Beijing Friendship Hospital, Capital Medical University, Beijing 100050, China
- Beijing University of Technology, Beijing 100124, China
| | - Hongyang Li
- Beijing Friendship Hospital, Capital Medical University, Beijing 100050, China
| | - Biwen Shen
- Institute of Advanced Structure Technology, Beijing Institute of Technology, Beijing 100081, China
| | - Jiangang He
- Avic Chengdu Aircraft Design & Research Institute, Chengdu 610041, China
| | - Huanlin Gao
- Institute of Advanced Structure Technology, Beijing Institute of Technology, Beijing 100081, China
| | - Fengjiao Bin
- Institute of Advanced Structure Technology, Beijing Institute of Technology, Beijing 100081, China
| | - Hui Li
- Institute of Advanced Structure Technology, Beijing Institute of Technology, Beijing 100081, China
| | - Dengbao Xiao
- Institute of Advanced Structure Technology, Beijing Institute of Technology, Beijing 100081, China
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Campigotto A, Campbell RJ, Lai Y. Correlation between corneal and contact lens deformation with changes in intraocular pressure for wearable monitoring systems. Eye (Lond) 2023; 37:2055-2060. [PMID: 36302975 PMCID: PMC10333185 DOI: 10.1038/s41433-022-02285-y] [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: 02/18/2022] [Revised: 09/11/2022] [Accepted: 10/07/2022] [Indexed: 11/09/2022] Open
Abstract
OBJECTIVE The aim of this work is to evaluate the extent to which the eye's curvature deformation, due to changes in the intraocular pressure (IOP), can be directly tracked by an overlying contact lens. METHOD In this experimental study, using 12 cadaveric eyes, the IOP was increased from 10 to 36 mmHg, while video imaging was used to capture the three experimental variations. The deformation of the bare eye was used as a control, while the deformation of an overlying silicone grided contact lens and an overlying microfluidic IOP-sensing contact lens were examined and compared. RESULTS The relation between the slope of the radius of corneal curvature versus the IOP for both the bare eye and the marker contact lens yielded a linear relationship with a R2 value of 0.83. The microfluidic contact lens resulted in an average performance of 0.40 mm indicator movement/mmHg (SD 0.006). Comparing the slope of the marker contact lens deformation, to the performance of the microfluidic contact lens resulted in a R2 value of 0.78. The strain map of the overlaying grided contact lens showed most deformation occurring along the outer edge of the lens with increased deformation as increase IOP occurs; as well as with some negative, compressive movement near the central points. CONCLUSION The deformation from the curvature of the eye is significant enough from 10 to 36 mmHg that a silicone contact lens can capture and mimic those changes. The results show promise for optimization in contact lens-based IOP monitoring.
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Affiliation(s)
- Angelica Campigotto
- Department of Mechanical and Materials Engineering, Queen's University, Kingston, ON, Canada
| | - Robert J Campbell
- Department of Ophthalmology, Queen's University, Kingston, ON, Canada
- Department of Ophthalmology, Kingston Health Sciences Centre, Kingston, ON, Canada
| | - Yongjun Lai
- Department of Mechanical and Materials Engineering, Queen's University, Kingston, ON, Canada.
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Development of eye phantom for mimicking the deformation of the human cornea accompanied by intraocular pressure alterations. Sci Rep 2022; 12:20670. [PMID: 36450788 PMCID: PMC9712605 DOI: 10.1038/s41598-022-24948-2] [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: 12/30/2021] [Accepted: 11/22/2022] [Indexed: 12/02/2022] Open
Abstract
Comparative studies between artificial eyeball phantoms and in-vivo human subjects were carried out to better understanding the structural deformation of the cornea under varying intraocular pressure (IOP). The IOP-induced deformation and the tension of the cornea were measured by using an optical coherence tomography and noncontact tonometer readings, respectively. The dependence of the central cornea thickness (CCT) and corneal radius of curvature (CRC) on the IOP differed significantly between the full eyeball phantom (FEP) and cornea eyeball phantom (CEP) models. While the CCT changes were very similar between the two models, the relation between the CRC and the IOP was dependent on the type of eye phantom. For the CEP, the CRC drastically decreased as internal pressure increased. However, we found that the changes in the CRC of FEP was dependent on initial CCT under zero IOP (CCT0). When CCT0 was less than 460 μm, the CRC slightly decreased as IOP increased. Meanwhile, the CRC increased as IOP increased if CCT0 was 570 μm. A constitutive mechanical model was proposed to describe the response of the cornea accompanied by the changes in IOP. In vivo measurements on human subjects under both noninvasive and invasive conditions revealed that the relation between the CRC on the IOP is much closer to those observed from FEP. Considering the observed structural deformation of human cornea, we found that FEP mimics the human eye more accurately than the CEP. In addition, the tonometry readings of IOP show that the values from the CEP were overestimated, while those from the FEP were not. For these reasons, we expect that the FEP could be suitable for the estimation of true IOP and allow performance testing of tonometers for medical checkups and other clinical uses.
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Jin G, Liu Z, Wang L, Zhu Y, Luo L, Liu Y. Corneal Biometric Features and Their Association With Axial Length in High Myopia. Am J Ophthalmol 2022; 238:45-51. [PMID: 34896081 DOI: 10.1016/j.ajo.2021.11.031] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2021] [Revised: 11/19/2021] [Accepted: 11/21/2021] [Indexed: 11/19/2022]
Abstract
PURPOSE To characterize the morphologic features of corneal parameters and their correlation with axial length (AL) elongation in patients with high axial myopia. DESIGN Cross-sectional comparative study. METHODS A total of 299 eyes with high myopia (299 patients) and 266 eyes of age- and sex-matched control subjects (266 patients) were examined by anterior segment swept-source optical coherence tomography (SS-OCT) and an IOL Master. Central corneal thickness (CCT), thinnest corneal thickness (TCT), corneal volume (CV), and anterior corneal curvature (CC), posterior CC, and total CC were obtained, and their correlation with AL was investigated using multiple linear regression model. RESULTS The CCT, TCT, CV, and anterior, posterior, and total CC of patients with high myopia were smaller than those of the control subjects. The CCT, TCT, and CV had a continuous downward trend with AL. However, CC decreased rapidly with AL when AL was <26 mm and the slope decreased when AL was 26 to 28 mm. This linear association was absent when AL was >28 mm. Multiple linear regression showed that the CCT (β = -1.98, P = .007), TCT (β = -1.63, P = .019), and CV (β = -0.13, P = .001) were associated with AL. Anterior, posterior, and total CCs were negatively associated with AL when AL was <26 mm (all P < .001) and when AL was between 26 and 28 mm (all P < .05). CONCLUSIONS CC decreases may serve as a refractive compensation on myopia when AL is <28 mm. However, this effect does not exist when AL is >28 mm. Consideration should be given to the special distribution of cornea curvature for IOL calculations in subjects with high myopia.
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Affiliation(s)
- Guangming Jin
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangdong Provincial Clinical Research Center for Ocular Diseases, Guangzhou 510060, China
| | - Zhenzhen Liu
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangdong Provincial Clinical Research Center for Ocular Diseases, Guangzhou 510060, China
| | - Lanhua Wang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangdong Provincial Clinical Research Center for Ocular Diseases, Guangzhou 510060, China
| | - Yi Zhu
- and the Department of Molecular and Cellular Pharmacology (Y.Z.), University of Miami Miller School of Medicine, Miami, Florida, USA
| | - Lixia Luo
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangdong Provincial Clinical Research Center for Ocular Diseases, Guangzhou 510060, China.
| | - Yizhi Liu
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangdong Provincial Clinical Research Center for Ocular Diseases, Guangzhou 510060, China.
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Qin X, Tian L, Zhang H, Zhang D, Jie Y, Zhang HX, Li L. Determine Corneal Biomechanical Parameters by Finite Element Simulation and Parametric Analysis Based on ORA Measurements. Front Bioeng Biotechnol 2022; 10:862947. [PMID: 35497338 PMCID: PMC9043460 DOI: 10.3389/fbioe.2022.862947] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2022] [Accepted: 03/23/2022] [Indexed: 11/14/2022] Open
Abstract
Purpose: The Ocular Response Analyzer (ORA) is one of the most commonly used devices to measure corneal biomechanics in vivo. Until now, the relationship between the output parameters and corneal typical biomechanical parameters was not clear. Hence, we defined the output parameters of ORA as ORA output parameters. This study aims to propose a method to determine corneal biomechanical parameters based on ORA measurements by finite element simulation and parametric analysis. Methods: Finite element analysis was used to simulate the mechanics process of ORA measurements with different intraocular pressure (IOP), corneal geometrical parameters and corneal biomechanical parameters. A simplified geometrical optics model was built to simulate the optical process of the measurements to extract ORA output parameters. After that, 70% of the simulated data was used to establish the quantitative relationship between corneal biomechanical parameters and ORA output parameters by parametric analysis and 30% of the simulated data was used to validate the established model. Besides, ten normal subjects were included to evaluate the normal range of corneal biomechanical parameters calculated from ORA. Results: The quantitative relationship between corneal biomechanical parameters and ORA output parameters is established by combining parametric analysis with finite element simulation. The elastic modulus (E) and relaxation limit (G∞) of the ten normal subjects were 0.65 ± 0.07 MPa and 0.26 ± 0.15, respectively. Conclusions: A method was proposed to determine corneal biomechanical parameters based on the results of ORA measurements. The magnitude of the corneal biomechanical parameters calculated according to our method was reasonable.
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Affiliation(s)
- Xiao Qin
- Beijing Key Laboratory of Fundamental Research on Biomechanics in Clinical Application, School of Biomedical Engineering, Capital Medical University, Beijing, China
- Medical Science Research Center, Department of Otolaryngology, Peking Union Medical College Hospital, Shuaifuyuan 1, Dongcheng District, Beijing, China
| | - Lei Tian
- Beijing Institute of Ophthalmology, Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing Ophthalmology & Visual Sciences Key Laboratory, Beijing, China
- Beijing Advanced Innovation Center for Big Data-Based Precision Medicine, Beihang University and Capital Medical University, Beijing Tongren Hospital, Beijing, China
| | - Hui Zhang
- Beijing Key Laboratory of Fundamental Research on Biomechanics in Clinical Application, School of Biomedical Engineering, Capital Medical University, Beijing, China
| | - Di Zhang
- Beijing Key Laboratory of Fundamental Research on Biomechanics in Clinical Application, School of Biomedical Engineering, Capital Medical University, Beijing, China
| | - Ying Jie
- Beijing Institute of Ophthalmology, Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing Ophthalmology & Visual Sciences Key Laboratory, Beijing, China
- *Correspondence: Ying Jie, ; Hai-Xia Zhang, ; Lin Li,
| | - Hai-Xia Zhang
- Beijing Key Laboratory of Fundamental Research on Biomechanics in Clinical Application, School of Biomedical Engineering, Capital Medical University, Beijing, China
- *Correspondence: Ying Jie, ; Hai-Xia Zhang, ; Lin Li,
| | - Lin Li
- Beijing Key Laboratory of Fundamental Research on Biomechanics in Clinical Application, School of Biomedical Engineering, Capital Medical University, Beijing, China
- *Correspondence: Ying Jie, ; Hai-Xia Zhang, ; Lin Li,
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7
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A soft and transparent contact lens for the wireless quantitative monitoring of intraocular pressure. Nat Biomed Eng 2021; 5:772-782. [PMID: 33941897 DOI: 10.1038/s41551-021-00719-8] [Citation(s) in RCA: 58] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2019] [Accepted: 03/22/2021] [Indexed: 02/02/2023]
Abstract
Continuous detection of raised intraocular pressure (IOP) could benefit the monitoring of patients with glaucoma. Current contact lenses with embedded sensors for measuring IOP are rigid, bulky, partially block vision or are insufficiently sensitive. Here, we report the design and testing in volunteers of a soft and transparent contact lens for the quantitative monitoring of IOP in real time using a smartphone. The contact lens incorporates a strain sensor, a wireless antenna, capacitors, resistors, stretchable metal interconnects and an integrated circuit for wireless communication. In rabbits, the lens provided measurements that match those of a commercial tonometer. In ten human participants, the lens proved to be safe, and reliably provided accurate quantitative measurements of IOP without inducing inflammation.
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8
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Dennyson Savariraj A, Salih A, Alam F, Elsherif M, AlQattan B, Khan AA, Yetisen AK, Butt H. Ophthalmic Sensors and Drug Delivery. ACS Sens 2021; 6:2046-2076. [PMID: 34043907 PMCID: PMC8294612 DOI: 10.1021/acssensors.1c00370] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2021] [Accepted: 05/17/2021] [Indexed: 12/15/2022]
Abstract
Advances in multifunctional materials and technologies have allowed contact lenses to serve as wearable devices for continuous monitoring of physiological parameters and delivering drugs for ocular diseases. Since the tear fluids comprise a library of biomarkers, direct measurement of different parameters such as concentration of glucose, urea, proteins, nitrite, and chloride ions, intraocular pressure (IOP), corneal temperature, and pH can be carried out non-invasively using contact lens sensors. Microfluidic contact lens sensor based colorimetric sensing and liquid control mechanisms enable the wearers to perform self-examinations at home using smartphones. Furthermore, drug-laden contact lenses have emerged as delivery platforms using a low dosage of drugs with extended residence time and increased ocular bioavailability. This review provides an overview of contact lenses for ocular diagnostics and drug delivery applications. The designs, working principles, and sensing mechanisms of sensors and drug delivery systems are reviewed. The potential applications of contact lenses in point-of-care diagnostics and personalized medicine, along with the significance of integrating multiplexed sensing units together with drug delivery systems, have also been discussed.
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Affiliation(s)
| | - Ahmed Salih
- Department
of Mechanical Engineering, Khalifa University
of Science and Technology, Abu Dhabi, United Arab Emirates
| | - Fahad Alam
- Department
of Mechanical Engineering, Khalifa University
of Science and Technology, Abu Dhabi, United Arab Emirates
| | - Mohamed Elsherif
- Department
of Mechanical Engineering, Khalifa University
of Science and Technology, Abu Dhabi, United Arab Emirates
| | - Bader AlQattan
- Department
of Mechanical Engineering, Khalifa University
of Science and Technology, Abu Dhabi, United Arab Emirates
| | - Ammar A. Khan
- Department
of Chemical Engineering, Imperial College
London, London SW7 2AZ, United Kingdom
| | - Ali K. Yetisen
- Department
of Physics, Lahore University of Management
Sciences, Lahore Cantonment 54792, Lahore, Pakistan
| | - Haider Butt
- Department
of Mechanical Engineering, Khalifa University
of Science and Technology, Abu Dhabi, United Arab Emirates
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Xu J, Li R, Xu H, Yang Y, Zhang S, Ren T. Recent progress of continuous intraocular pressure monitoring. NANO SELECT 2021. [DOI: 10.1002/nano.202100137] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Affiliation(s)
- Jiandong Xu
- Institute of Microelectronics Tsinghua University Beijing 100084 China
- Beijing National Research Center for Information Science and Technology (BNRist) Tsinghua University Beijing 100084 China
| | - Ruisong Li
- Department of Electrical Engineering and Computer Science and Department of Bioengineering College of Engineering University of California Berkeley California 94720 USA
| | - Haokai Xu
- Institute of Microelectronics Tsinghua University Beijing 100084 China
- Beijing National Research Center for Information Science and Technology (BNRist) Tsinghua University Beijing 100084 China
| | - Yi Yang
- Institute of Microelectronics Tsinghua University Beijing 100084 China
- Beijing National Research Center for Information Science and Technology (BNRist) Tsinghua University Beijing 100084 China
| | - Sheng Zhang
- Shenzhen International Graduate School Tsinghua University Shenzhen 518055 China
| | - Tian‐Ling Ren
- Institute of Microelectronics Tsinghua University Beijing 100084 China
- Beijing National Research Center for Information Science and Technology (BNRist) Tsinghua University Beijing 100084 China
- Center for Flexible Electronics Technology Tsinghua University Beijing 100084 China
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10
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Kim TY, Shin S, Choi H, Jeong SH, Myung D, Hahn SK. Smart Contact Lenses with a Transparent Silver Nanowire Strain Sensor for Continuous Intraocular Pressure Monitoring. ACS APPLIED BIO MATERIALS 2021; 4:4532-4541. [PMID: 35006789 PMCID: PMC10867858 DOI: 10.1021/acsabm.1c00267] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Continuous intraocular pressure (IOP) monitoring can provide a paradigm shift in the management of patients with glaucoma as a facile alternative to conventional diagnostic methods. However, the low sensitivity and functional instability of current IOP sensors have limited their clinical utility in the management of glaucoma. Here, we have developed a smart contact lens integrated with a transparent silver nanowire IOP strain sensor and wireless circuits for noninvasive, continuous IOP monitoring. After confirming the robust stability of the IOP sensor within the smart contact lens in the presence of tears and repeated eyelid blink model cycles, we were able to monitor IOP changes on polydimethylsiloxane model eyes in vitro. In vivo tests demonstrated that our fully integrated wireless smart contact lens could successfully monitor the change in IOP in living rabbit eyes, which was clearly validated by the conventional invasive tonometer IOP test. Taken together, we could confirm the feasibility of our smart contact lens as a noninvasive platform for continuous IOP monitoring of glaucoma patients.
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Affiliation(s)
- Tae Yeon Kim
- Department of Materials Science and Engineering, Pohang University of Science and Technology (POSTECH), 77 Cheongam-ro, Nam-gu, Pohang, Gyeongbuk 37673, Korea
| | - Sangbaie Shin
- PHI BIOMED Co., 168 Yeoksam-ro, Gangnam-gu, Seoul 06248, South Korea
| | - Hyunsik Choi
- Department of Materials Science and Engineering, Pohang University of Science and Technology (POSTECH), 77 Cheongam-ro, Nam-gu, Pohang, Gyeongbuk 37673, Korea
| | - Sang Hoon Jeong
- Department of Materials Science and Engineering, Pohang University of Science and Technology (POSTECH), 77 Cheongam-ro, Nam-gu, Pohang, Gyeongbuk 37673, Korea
| | - David Myung
- Department of Ophthalmology and Chemical Engineering, Stanford University, 443 Via Ortega, Stanford, California 94305, United States
| | - Sei Kwang Hahn
- Department of Materials Science and Engineering, Pohang University of Science and Technology (POSTECH), 77 Cheongam-ro, Nam-gu, Pohang, Gyeongbuk 37673, Korea
- PHI BIOMED Co., 168 Yeoksam-ro, Gangnam-gu, Seoul 06248, South Korea
- Department of Ophthalmology and Chemical Engineering, Stanford University, 443 Via Ortega, Stanford, California 94305, United States
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11
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Effect of variations of corneal physiology on novel non-invasive intraocular pressure monitoring soft contact lens. Biomed Microdevices 2021; 23:16. [PMID: 33725182 DOI: 10.1007/s10544-021-00555-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/22/2021] [Indexed: 10/21/2022]
Abstract
Glaucoma is the leading cause of irreversible blindness around the world. With its slow asymptomatic progression, there is an emphasis on early detection and frequent monitoring. A novel microfluidic contact lens has been established as a potential way to track the fluctuations of the intraocular pressure (IOP) which is a key indicator for diagnosing and monitoring glaucoma progression. The purpose of this article is to determine the effect of physiological variations of the eye on the performance of the microfluidic contact lens. Ultrasound biomicroscopy (UBM) was used to measure the central corneal thickness (CCT) and radius of corneal curvature (RCC) for a series of 16 fresh enucleated porcine eyes. The effect of these corneal anatomic features on device performance was then assessed by systematically adjusting intraocular pressure from 10 to 34 mmHg and monitoring the device indicator response. The performance of the microfluidic contact lens was determined by finding the amount the indicator fluid shifted in position as a result of 1 mmHg IOP increase. The relationship between IOP and indicator fluid was found to be linear for all eyes. The slope of the indicator fluid movement as a result of the IOP was evaluated against the CCT and RCC of each porcine eye. This yielded low correlation coefficients, 0.057 for CCT and 0.024 for RCC, meaning that these physiological differences showed no systematic impact on the measurements made with the contact lens.
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12
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Yang C, Huang X, Li X, Yang C, Zhang T, Wu Q, liu D, Lin H, Chen W, Hu N, Xie X. Wearable and Implantable Intraocular Pressure Biosensors: Recent Progress and Future Prospects. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2021; 8:2002971. [PMID: 33747725 PMCID: PMC7967055 DOI: 10.1002/advs.202002971] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/04/2020] [Revised: 10/24/2020] [Indexed: 05/09/2023]
Abstract
Biosensors worn on or implanted in eyes have been garnering substantial attention since being proven to be an effective means to acquire critical biomarkers for monitoring the states of ophthalmic disease, diabetes. Among these disorders, glaucoma, the second leading cause of blindness globally, usually results in irreversible blindness. Continuous intraocular pressure (IOP) monitoring is considered as an effective measure, which provides a comprehensive view of IOP changes that is beyond reach for the "snapshots" measurements by clinical tonometry. However, to satisfy the applications in ophthalmology, the development of IOP sensors are required to be prepared with biocompatible, miniature, transparent, wireless and battery-free features, which are still challenging with many current fabrication processes. In this work, the recent advances in this field are reviewed by categorizing these devices into wearable and implantable IOP sensors. The materials and structures exploited for engineering these IOP devices are presented. Additionally, their working principle, performance, and the potential risk that materials and device architectures may pose to ocular tissue are discussed. This review should be valuable for preferable structure design, device fabrication, performance optimization, and reducing potential risk of these devices. It is significant for the development of future practical IOP sensors.
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Affiliation(s)
- Cheng Yang
- State Key Laboratory of Optoelectronic Materials and TechnologiesGuangdong Province Key Laboratory of Display Material and TechnologySchool of Electronics and Information TechnologyThe First Affiliated Hospital of Sun Yat‐Sen UniversitySun Yat‐Sen UniversityGuangzhou510006China
| | - Xinshuo Huang
- State Key Laboratory of Optoelectronic Materials and TechnologiesGuangdong Province Key Laboratory of Display Material and TechnologySchool of Electronics and Information TechnologyThe First Affiliated Hospital of Sun Yat‐Sen UniversitySun Yat‐Sen UniversityGuangzhou510006China
| | - Xiangling Li
- State Key Laboratory of Optoelectronic Materials and TechnologiesGuangdong Province Key Laboratory of Display Material and TechnologySchool of Electronics and Information TechnologyThe First Affiliated Hospital of Sun Yat‐Sen UniversitySun Yat‐Sen UniversityGuangzhou510006China
- School of Biomedical EngineeringSun Yat‐Sen UniversityGuangzhou510006China
| | - Chengduan Yang
- State Key Laboratory of Optoelectronic Materials and TechnologiesGuangdong Province Key Laboratory of Display Material and TechnologySchool of Electronics and Information TechnologyThe First Affiliated Hospital of Sun Yat‐Sen UniversitySun Yat‐Sen UniversityGuangzhou510006China
| | - Tao Zhang
- State Key Laboratory of Optoelectronic Materials and TechnologiesGuangdong Province Key Laboratory of Display Material and TechnologySchool of Electronics and Information TechnologyThe First Affiliated Hospital of Sun Yat‐Sen UniversitySun Yat‐Sen UniversityGuangzhou510006China
- School of Biomedical EngineeringSun Yat‐Sen UniversityGuangzhou510006China
| | - Qianni Wu
- State Key Laboratory of OphthalmologyZhongshan Ophthalmic CenterSun Yat‐Sen UniversityGuangzhou510060China
| | - Dong liu
- State Key Laboratory of OphthalmologyZhongshan Ophthalmic CenterSun Yat‐Sen UniversityGuangzhou510060China
| | - Haotian Lin
- State Key Laboratory of OphthalmologyZhongshan Ophthalmic CenterSun Yat‐Sen UniversityGuangzhou510060China
| | - Weirong Chen
- State Key Laboratory of OphthalmologyZhongshan Ophthalmic CenterSun Yat‐Sen UniversityGuangzhou510060China
| | - Ning Hu
- State Key Laboratory of Optoelectronic Materials and TechnologiesGuangdong Province Key Laboratory of Display Material and TechnologySchool of Electronics and Information TechnologyThe First Affiliated Hospital of Sun Yat‐Sen UniversitySun Yat‐Sen UniversityGuangzhou510006China
| | - Xi Xie
- State Key Laboratory of Optoelectronic Materials and TechnologiesGuangdong Province Key Laboratory of Display Material and TechnologySchool of Electronics and Information TechnologyThe First Affiliated Hospital of Sun Yat‐Sen UniversitySun Yat‐Sen UniversityGuangzhou510006China
- State Key Laboratory of OphthalmologyZhongshan Ophthalmic CenterSun Yat‐Sen UniversityGuangzhou510060China
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Gedde SJ, Vinod K, Wright MM, Muir KW, Lind JT, Chen PP, Li T, Mansberger SL. Primary Open-Angle Glaucoma Preferred Practice Pattern®. Ophthalmology 2021; 128:P71-P150. [DOI: 10.1016/j.ophtha.2020.10.022] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2020] [Accepted: 10/20/2020] [Indexed: 12/17/2022] Open
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Maeng B, Chang HK, Park J. Photonic crystal-based smart contact lens for continuous intraocular pressure monitoring. LAB ON A CHIP 2020; 20:1740-1750. [PMID: 32347844 DOI: 10.1039/c9lc01268k] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Glaucoma is a very common disease after cataracts and is dangerous enough to cause irreversible blindness. However, often the main symptom of glaucoma is difficult to recognize because it may be absent or appear late, so the risk of blindness is greater. Intraocular pressure (IOP) is a well-known primary factor indicating glaucoma. In this study, we demonstrate a smart IOP sensor embedded in a contact lens that works through visual color changes without an external power source such as a battery or RF-based wireless power transfer. A microhydraulic amplification mechanism is adopted to enhance the range of color change from a photonic crystal (PC)-based flexible membrane whose lattice distance between nanostructures varies according to the morphology changes of an eyeball caused by IOP. The performance of the sensor is quantitatively demonstrated using an artificial silicone eye model for in vitro evaluation and a porcine eyeball for ex vivo verification. It has a limit of detection (LOD) of 3.2 and 5.12 mmHg, which was measured and evaluated using a spectrometer and a smartphone camera, respectively. The results prove that our sensor embedded in the contact lens can continuously monitor the IOP change using color change, and a smartphone camera can be used as a quantitative IOP measurement system in a noninvasive manner without an expensive optical spectrometer.
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Affiliation(s)
- Bohee Maeng
- Department of Mechanical Engineering, Sogang University, 35 Baekbeom-ro, Mapo-gu, Seoul 04107, Republic of Korea.
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Campigotto A, Lai Y. A novel non‐invasive wearable sensor for intraocular pressure measurement. ACTA ACUST UNITED AC 2020. [DOI: 10.1002/mds3.10086] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
- Angelica Campigotto
- Department of Mechanical Engineering Queen’s University Kingston Ontario Canada
| | - Yongjun Lai
- Department of Mechanical Engineering Queen’s University Kingston Ontario Canada
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Mariacher S, Laubichler P, Wendelstein J, Mariacher M, Bolz M. Preoperative intraocular pressure as a strong predictive factor for intraocular pressure rise during vacuum application in femtosecond laser-assisted cataract surgery. Acta Ophthalmol 2019; 97:e1123-e1129. [PMID: 31386801 DOI: 10.1111/aos.14149] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2018] [Accepted: 05/05/2019] [Indexed: 01/06/2023]
Abstract
PURPOSE To evaluate the effect of preoperative intraocular pressure (IOP) and the vacuum level on IOP during femtosecond laser-assisted cataract surgery. METHODS Intraocular pressure was measured in 40 enucleated porcine eyes by intracameral manometry prior, during and after vacuum application using the VICTUS femtosecond laser platform (Bausch&Lomb, Technolas Perfect Vision GmbH, Germany). Twenty combinations of different preoperative IOP levels (12, 16, 20 and 24 mmHg) and different vacuum levels (350-550 mbar) were investigated. RESULTS Multivariate regression analysis indicated that both the vacuum level (beta = 0.138; p < 0.001) but much stronger the preoperative IOP (beta = 0.861; p < 0.001) were predictive factors for IOP rise during vacuum application. Mean IOP was 28.23 ± 3.86, 34.23 ± 3.92, 40.35 ± 4.41 and 46.82 ± 4.11 mmHg in groups with baseline IOP of 12, 16, 20 and 24 mmHg, respectively. In the 350, 450 and 550 mbar group, and mean IOP was 35.85 ± 7.85, 37.33 ± 7.90 and 39.00 ± 8.04 mmHg, respectively. Lowering the preoperative IOP by 2 mmHg and reducing the vacuum from maximum to minimum resulted in a similar reduction in IOP during vacuum application (-3.10 ± 0.79 mmHg versus -3.15 ± 0.88 mmHg; p = 0.015). Furthermore, decreasing the baseline IOP from 20 to 12 mmHg resulted in a 30.0% reduction in intraoperative IOP. CONCLUSION Preoperative IOP was a stronger predictive factor for intraoperative IOP rise than the applied vacuum level. Measurements and critical interpretation of preoperative IOP in a preliminary examination could help estimating the individual risk of significant IOP rise during femtosecond laser-assisted cataract surgery and could help taking early countermeasures in selected cases. Due to the porcine ex vivo model, further studies are needed to verify these findings.
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Affiliation(s)
- Siegfried Mariacher
- Department for Ophthalmology and Optometry Kepler University HospitalJohannes Kepler University Linz Linz Austria
| | - Peter Laubichler
- Department for Ophthalmology and Optometry Kepler University HospitalJohannes Kepler University Linz Linz Austria
| | - Jascha Wendelstein
- Department for Ophthalmology and Optometry Kepler University HospitalJohannes Kepler University Linz Linz Austria
| | - Martina Mariacher
- Department for Ophthalmology and Optometry Kepler University HospitalJohannes Kepler University Linz Linz Austria
| | - Matthias Bolz
- Department for Ophthalmology and Optometry Kepler University HospitalJohannes Kepler University Linz Linz Austria
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Sanchez I, Martin R. Advances in diagnostic applications for monitoring intraocular pressure in Glaucoma: A review. JOURNAL OF OPTOMETRY 2019; 12:211-221. [PMID: 31405810 PMCID: PMC6978552 DOI: 10.1016/j.optom.2018.12.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/24/2018] [Revised: 11/20/2018] [Accepted: 12/12/2018] [Indexed: 05/24/2023]
Abstract
Continuous intraocular pressure (IOP) monitoring for improving glaucoma diagnosis and treatment has remained a challenge for the past 60 years because glaucoma is the second leading cause of irreversible blindness worldwide. Several devices with different measurement principles and recently developed biosensors with semiconductor materials offer exciting properties. However, none of these devices for continuous IOP monitoring have been fully integrated into clinical practice, primarily due to technical problems. This review summarizes state-of-the-art biosensors developed for IOP monitoring by explaining their basic functions and applications, the main technology (pressure transductors, piezoresistive sensors, capacitive sensors, and resonant sensors), measurement approach (noninvasive, minimally invasive or invasive (surgically implantable)), and telemetry characteristics. To provide updated information for clinicians and researchers, we also describe the advantages and limitations of the application of these new sensors to eye care management. Despite significant improvements in IOP biosensor technology, the accuracy of their measurements must be improved to obtain a clear equivalence with actual IOP (measured in units of mmHg) to facilitate their clinical application. In addition, telemetry systems may be simplified to prevent adverse outcomes for patients and to guarantee the safety of stored data.
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Affiliation(s)
- Irene Sanchez
- Universidad de Valladolid, Departamento de Física Teórica, Atómica y Óptica, Paseo de Belén, 7, Campus Miguel Delibes, Valladolid 47011, Spain; Universidad de Valladolid, Instituto Universitario de Oftalmobiología Aplicada (IOBA), Paseo de Belén, 17, Campus Miguel Delibes, Valladolid 47011, Spain; Optometry Research Group, IOBA Eye Institute, School of Optometry, University of Valladolid, Valladolid 47011, Spain.
| | - Raul Martin
- Universidad de Valladolid, Departamento de Física Teórica, Atómica y Óptica, Paseo de Belén, 7, Campus Miguel Delibes, Valladolid 47011, Spain; Universidad de Valladolid, Instituto Universitario de Oftalmobiología Aplicada (IOBA), Paseo de Belén, 17, Campus Miguel Delibes, Valladolid 47011, Spain; Optometry Research Group, IOBA Eye Institute, School of Optometry, University of Valladolid, Valladolid 47011, Spain; School of Health Professions, Plymouth University, Plymouth PL68BH, UK
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Corneal Stiffness and Its Relationship With Other Corneal Biomechanical and Nonbiomechanical Parameters in Myopic Eyes of Chinese Patients. Cornea 2018; 37:881-885. [PMID: 29634670 DOI: 10.1097/ico.0000000000001605] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
PURPOSE To investigate corneal stiffness and analyze its possible influence on other corneal biomechanical and nonbiomechanical parameters in myopic eyes of Chinese patients. METHODS A total of 387 healthy (right) myopic eyes were included in this study. Corneal visualization Scheimpflug technology was used to measure the corneal stiffness parameter at the first applanation (SP-A1), deformation amplitude ratio at 1.0 and at 2.0 mm, biomechanically corrected intraocular pressure (bIOP), and corneal deformation parameters during the first applanation (A1: A1-time, A1-length, and A1-velocity), second applanation (A2; A2-time, A2-length, and A2-velocity), and highest concavity (HC; HC-time, HC-radius, HC deformation amplitude, and HC peak distance). The Pentacam was used to evaluate central corneal thickness, mean corneal curvature (Km), anterior corneal central elevation, and corneal asphericity (Q value) of the anterior cornea. RESULTS The mean SP-A1 and bIOP values were 90.46 ± 15.39 mm Hg/mm and 13.5 ± 1.85 mm Hg, respectively. The SP-A1 increased with age (β = 0.41 [95% CI, 0.28%-0.54%]; P < 0.0001). Corneal stiffness was positively correlated with central corneal thickness, uncorrected intraocular pressure, and bIOP and was also significantly correlated with all corneal deformation parameters (P < 0.05), except A1-length, HC-time, and HC peak distance. Corneal stiffness was negatively correlated with central corneal elevation of the anterior surface (r = -0.124, P = 0.014) and mean corneal curvature (r = -0.114, P = 0.025) and positively correlated with the Q value of the anterior surface (r = 0.109, P = 0.032). CONCLUSIONS Corneal stiffness increased with age. Stronger corneal stiffness may be related to flattening of the cornea and higher intraocular pressure.
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Zappone B, Patil NJ, Lombardo M, Lombardo G. Transient viscous response of the human cornea probed with the Surface Force Apparatus. PLoS One 2018; 13:e0197779. [PMID: 29799859 PMCID: PMC5969749 DOI: 10.1371/journal.pone.0197779] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2018] [Accepted: 05/08/2018] [Indexed: 01/07/2023] Open
Abstract
Knowledge of the biomechanical properties of the human cornea is crucial for understanding the development of corneal diseases and impact of surgical treatments (e.g., corneal laser surgery, corneal cross-linking). Using a Surface Force Apparatus we investigated the transient viscous response of the anterior cornea from donor human eyes compressed between macroscopic crossed cylinders. Corneal biomechanics was analyzed using linear viscoelastic theory and interpreted in the framework of a biphasic model of soft hydrated porous tissues, including a significant contribution from the pressurization and viscous flow of fluid within the corneal tissue. Time-resolved measurements of tissue deformation and careful determination of the relaxation time provided an elastic modulus in the range between 0.17 and 1.43 MPa, and fluid permeability of the order of 10−13 m4/(N∙s). The permeability decreased as the deformation was increased above a strain level of about 10%, indicating that the interstitial space between fibrils of the corneal stromal matrix was reduced under the effect of strong compression. This effect may play a major role in determining the observed rate-dependent non-linear stress-strain response of the anterior cornea, which underlies the shape and optical properties of the tissue.
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Affiliation(s)
- Bruno Zappone
- Consiglio Nazionale delle Ricerche, Istituto di Nanotecnologia (CNR-Nanotec), Rende (CS), Italy
- * E-mail: (BZ); (GL)
| | | | | | - Giuseppe Lombardo
- Consiglio Nazionale delle Ricerche, Istituto per i Processi Chimico-Fisici (CNR-IPCF), Messina, Italy
- * E-mail: (BZ); (GL)
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Hatami-Marbini H, Jayaram SM. UVA/riboflavin collagen crosslinking stiffening effects on anterior and posterior corneal flaps. Exp Eye Res 2018; 176:53-58. [PMID: 29777678 DOI: 10.1016/j.exer.2018.05.014] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2018] [Revised: 05/04/2018] [Accepted: 05/15/2018] [Indexed: 10/16/2022]
Abstract
The UVA/riboflavin collagen crosslinking (CXL) is one of the treatment procedure for stopping the progression of keratoconus. The inclusion criterion for this procedure is a minimum corneal thickness of 400 μm, which is not often met in patients with advanced keratoconus. Preoperatively swelling thin corneas was shown to stabilize the keratectasia without any postoperative endothelial damage. Recently, we have shown that swelling porcine corneas prior to the CXL treatment had no significant effect on the resulting improvement in their tensile properties. In the present study, we extended this previous study and characterized the stiffening effects of CXL on anterior and posterior flaps as a function of their hydration. A DSAEK system was used to excise 10 mm corneal flaps from 80 porcine corneas. Individual flaps were crosslinked at different initial hydration levels by using riboflavin solutions composed of different dextran concentrations; the thickness was taken as a measure of flap hydration. A DMA machine was used to measure the tensile properties either immediately after the CXL treatment or after the thickness (hydration) of the crosslinked samples was brought down to a specific value. The average thickness of anterior groups was 670 μm, 540 μm, and 410 μm, and the average thickness of posterior groups was 845 μm, 650 μm, and 440 μm. It was found that although CXL significantly increased the tensile properties of all anterior groups, it had an insignificant effect on the stiffness of posterior flaps. Furthermore, except for the posterior flaps in 845 μm and 650 μm thickness groups, decreasing the hydration significantly increased the tensile modulus (p < 0.05). Finally, the anterior flaps that were crosslinked at higher hydration, i.e. swollen before CXL, showed significantly less amount of stiffening in comparison with those crosslinked at lower hydration when the tensile property measurement was done at similar hydration (p < 0.05).
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Affiliation(s)
- Hamed Hatami-Marbini
- Computational Biomechanics Research Laboratory, Mechanical and Industrial Engineering Department, University of Illinois at Chicago, Chicago, IL, USA.
| | - Sandeep M Jayaram
- Computational Biomechanics Research Laboratory, Mechanical and Industrial Engineering Department, University of Illinois at Chicago, Chicago, IL, USA
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Vitish-Sharma P, Acheson AG, Stead R, Sharp J, Abbas A, Hovan M, Maxwell-Armstrong C, Guo B, King AJ. Can the SENSIMED Triggerfish ® lens data be used as an accurate measure of intraocular pressure? Acta Ophthalmol 2018; 96:e242-e246. [PMID: 28391622 DOI: 10.1111/aos.13456] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2016] [Accepted: 03/05/2017] [Indexed: 11/27/2022]
Abstract
PURPOSE The SENSIMED Triggerfish® contact lens sensor (CLS) has an embedded micro-sensor that captures spontaneous circumferential changes at the corneoscleral junction and transmits them via an antenna to a device where these measurements are stored. During laparoscopic colorectal surgery, patients are placed in Trendelenburg position which has been shown to increase intraocular pressure (IOP). Laparoscopic colorectal surgery requires both pneumoperitoneum and Trendelenburg positioning; therefore, IOP can vary significantly. We aimed to assess whether circumferential changes in the corneoscleral area can be correlated to IOP changes measured using Tono-pen® XL applanation tonometer during laparoscopic colorectal surgery. METHOD Patients undergoing laparoscopic colorectal resections were included. On the day of surgery, baseline IOP was taken and the SENSIMED Triggerfish® CLS was then set up in one eye of the patient. During surgery (whilst under general anaesthetic), IOP measurements were taken in the contralateral eye using a Tono-pen® XL applanation tonometer every hour and any time the table was moved to record the fluctuations of IOP during surgery and any association with position change. The timings of these readings were documented. RESULTS Twenty patients were included in this study (six males, 14 females). Average age was 64.6 years (SD = 16.3). The fluctuation in IOP measured in the reference eye ranged between 6.3 and 46.7 mmHg. The mean correlation coefficient between CLS output measurements and these IOP measurements was r = 0.291 (95% CI). CONCLUSION Our results showed a weak correlation between the SENSIMED Triggerfish® CLS data output and IOP measurements taken using the Tono-pen® XL applanation tonometer.
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Affiliation(s)
- Parveen Vitish-Sharma
- Gastrointestinal Surgery; Nottingham Digestive Diseases Centre; National Institute for Health Research, Biomedical Research Unit; Queen's Medical Centre; Nottingham University Hospitals and University of Nottingham; Nottingham UK
| | - Austin G. Acheson
- Gastrointestinal Surgery; Nottingham Digestive Diseases Centre; National Institute for Health Research, Biomedical Research Unit; Queen's Medical Centre; Nottingham University Hospitals and University of Nottingham; Nottingham UK
| | - Richard Stead
- Ophthalmology Department; Queens Medical Centre; Nottingham University NHS Trust; Nottingham UK
| | - John Sharp
- Ophthalmology Department; Queens Medical Centre; Nottingham University NHS Trust; Nottingham UK
| | - Ali Abbas
- Ophthalmology Department; Queens Medical Centre; Nottingham University NHS Trust; Nottingham UK
| | - Marta Hovan
- Ophthalmology Department; Queens Medical Centre; Nottingham University NHS Trust; Nottingham UK
| | - Charles Maxwell-Armstrong
- Gastrointestinal Surgery; Nottingham Digestive Diseases Centre; National Institute for Health Research, Biomedical Research Unit; Queen's Medical Centre; Nottingham University Hospitals and University of Nottingham; Nottingham UK
| | - Boliang Guo
- Medical Statistics; Faculty of Medicine & Health Sciences; University of Nottingham; Nottingham UK
| | - Anthony J. King
- Ophthalmology Department; Queens Medical Centre; Nottingham University NHS Trust; Nottingham UK
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Aptel F, Weinreb RN, Chiquet C, Mansouri K. 24-h monitoring devices and nyctohemeral rhythms of intraocular pressure. Prog Retin Eye Res 2016; 55:108-148. [PMID: 27477112 DOI: 10.1016/j.preteyeres.2016.07.002] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2016] [Revised: 07/07/2016] [Accepted: 07/12/2016] [Indexed: 01/26/2023]
Abstract
Intraocular pressure (IOP) is not a fixed value and varies over both the short term and periods lasting several months or years. In particular, IOP is known to vary throughout the 24-h period of a day, defined as a nyctohemeral rhythm in humans. In clinical practice, it is crucial to evaluate the changes in IOP over 24 h in several situations, including the diagnosis of ocular hypertension and glaucoma (IOP is often higher at night) and to optimize the therapeutic management of glaucoma. Until recently, all evaluations of 24-h IOP rhythm were performed using repeated IOP measurements, requiring individuals to be awakened for nocturnal measurements. This method may be imperfect, because it is not physiologic and disturbs the sleep architecture, and also because it provides a limited number of time point measurements not sufficient to finely asses IOP changes. These limitations may have biased previous descriptions of physiological IOP rhythm. Recently, extraocular and intraocular devices integrating a pressure sensor for continuous IOP monitoring have been developed and are available for use in humans. The objective of this article is to present the contributions of these new 24-h monitoring devices for the study of the nyctohemeral rhythms. In healthy subjects and untreated glaucoma subjects, a nyctohemeral rhythm is consistently found and frequently characterized by a mean diurnal IOP lower than the mean nocturnal IOP, with a diurnal bathyphase - usually in the middle or at the end of the afternoon - and a nocturnal acrophase, usually in the middle or at the end of the night.
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Affiliation(s)
- Florent Aptel
- Inserm U1042, Hypoxia and Physiopathology Laboratory, University Grenoble Alpes, Grenoble, France; Department of Ophthalmology, University Hospital, CHU Grenoble, Grenoble, France
| | - Robert N Weinreb
- Hamilton Glaucoma Center, Shiley Eye Center and Department of Ophthalmology, University of California, San Diego, La Jolla, CA, USA
| | - Christophe Chiquet
- Inserm U1042, Hypoxia and Physiopathology Laboratory, University Grenoble Alpes, Grenoble, France; Department of Ophthalmology, University Hospital, CHU Grenoble, Grenoble, France
| | - Kaweh Mansouri
- Glaucoma Center, Montchoisi Clinic, Swiss Vision Network, Lausanne, Switzerland; Department of Ophthalmology, University of Colorado School of Medicine, Denver, CO, USA.
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Whitford C, Joda A, Jones S, Bao F, Rama P, Elsheikh A. Ex vivo testing of intact eye globes under inflation conditions to determine regional variation of mechanical stiffness. EYE AND VISION 2016; 3:21. [PMID: 27512719 PMCID: PMC4979203 DOI: 10.1186/s40662-016-0052-8] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/27/2015] [Accepted: 07/23/2016] [Indexed: 11/10/2022]
Abstract
BACKGROUND The eye globe exhibits significant regional variation of mechanical behaviour. The aim of this present study is to develop a new experimental technique for testing intact eye globes in a form that is representative of in vivo conditions, and therefore suitable for determining the material properties of the complete outer ocular tunic. METHODS A test rig has been developed to provide closed-loop control of either applied intra-ocular pressure or resulting apical displacement; measurement of displacements across the external surface of the eye globe using high-resolution digital cameras and digital image correlation software; prevention of rigid-body motion and protection of the ocular surface from environmental drying. The method has been demonstrated on one human and one porcine eye globe, which were cyclically loaded. Finite element models based on specimen specific tomography, free from rotational symmetry, were used along with experimental pressure-displacement data in an inverse analysis process to derive the mechanical properties of tissue in different regions of the eye's outer tunic. RESULTS The test method enabled monitoring of mechanical response to intraocular pressure variation across the surface of the eye globe. For the two eyes tested, the method showed a gradual change in the sclera's stiffness from a maximum at the limbus to a minimum at the posterior pole, while in the cornea the stiffness was highest at the centre and lowest in the peripheral zone. Further, for both the sclera and cornea, the load-displacement behaviour did not vary significantly between loading cycles. CONCLUSIONS The first methodology capable of mechanically testing intact eye globes, with applied loads and boundary conditions that closely represent in vivo conditions is introduced. The method enables determination of the regional variation in mechanical behaviour across the ocular surface.
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Affiliation(s)
- Charles Whitford
- School of Engineering, University of Liverpool, Liverpool, L69 3GH UK
| | - Akram Joda
- School of Engineering, University of Liverpool, Liverpool, L69 3GH UK ; Department of Mechanical Engineering, King Faisal University, Hofuf, Saudi Arabia
| | - Steve Jones
- School of Engineering, University of Liverpool, Liverpool, L69 3GH UK
| | - Fangjun Bao
- Eye Hospital, WenZhou Medical University, WenZhou, China
| | - Paolo Rama
- Ophthalmology Department, San Raffaelle Hospital, Milan, Italy
| | - Ahmed Elsheikh
- School of Engineering, University of Liverpool, Liverpool, L69 3GH UK ; National Institute for Health Research (NIHR) Biomedical Research Centre at Moorfields Eye Hospital NHS Foundation Trust and UCL Institute of Ophthalmology, London, UK
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Xu SC, Gauthier AC, Liu J. The Application of a Contact Lens Sensor in Detecting 24-Hour Intraocular Pressure-Related Patterns. J Ophthalmol 2016; 2016:4727423. [PMID: 27525110 PMCID: PMC4976175 DOI: 10.1155/2016/4727423] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2016] [Accepted: 06/22/2016] [Indexed: 11/17/2022] Open
Abstract
Glaucoma is one of the leading causes of blindness worldwide. Recent studies suggest that intraocular pressure (IOP) fluctuations, peaks, and rhythm are important factors in disease advancement. Yet, current glaucoma management remains hinged on single IOP measurements during clinic hours. To overcome this limitation, 24-hour IOP monitoring devices have been employed and include self-tonometry, permanent IOP, and temporary IOP monitoring. This review discusses each IOP measuring strategy and focuses on the recently FDA-approved contact lens sensor (CLS). The CLS records IOP-related ocular patterns for 24 hours continuously. Using the CLS, IOP-related parameters have been found to be associated with the rate of visual field progression in primary open-angle glaucoma, disease progression in primary angle-closure glaucoma, and various clinical variables in ocular hypertension. The CLS has been used to quantify blink rate and limbal strain and measure the circadian rhythm in a variety of disease states including normal-tension glaucoma and thyroid eye disease. The effects of various IOP-lowering interventions were also characterized using the CLS. CLS provides a unique, safe, and well-tolerated way to study IOP-related patterns in a wide range of disease states. IOP-related patterns may help identify patients most at risk for disease progression and assist with the development of tailored treatments.
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Affiliation(s)
- Sarah C. Xu
- Department of Ophthalmology and Visual Science, Yale University School of Medicine, New Haven, CT 06510, USA
- Department of Ophthalmology, Mayo Clinic, Rochester, MN 55905, USA
| | - Angela C. Gauthier
- Department of Ophthalmology and Visual Science, Yale University School of Medicine, New Haven, CT 06510, USA
| | - Ji Liu
- Department of Ophthalmology and Visual Science, Yale University School of Medicine, New Haven, CT 06510, USA
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Mitsubayashi K, Arakawa T. Cavitas Sensors: Contact Lens Type Sensors & Mouthguard Sensors. ELECTROANAL 2016. [DOI: 10.1002/elan.201600083] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Affiliation(s)
- Kohji Mitsubayashi
- Department of Biomedical Devices and Instrumentation, Institute of Biomaterials and Bioengineering Tokyo Medical and Dental University 2–3–10 Kanda-Surugadai Chiyoda-ku, Tokyo 101–0062 JAPAN
| | - Takahiro Arakawa
- Department of Biomedical Devices and Instrumentation, Institute of Biomaterials and Bioengineering Tokyo Medical and Dental University 2–3–10 Kanda-Surugadai Chiyoda-ku, Tokyo 101–0062 JAPAN
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Nuyen B, Mansouri K. Detecting IOP Fluctuations in Glaucoma Patients. Open Ophthalmol J 2016; 10:44-55. [PMID: 27014387 PMCID: PMC4780505 DOI: 10.2174/1874364101610010044] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2015] [Revised: 08/18/2015] [Accepted: 08/18/2015] [Indexed: 11/12/2022] Open
Abstract
Lowering intraocular pressure (IOP) remains the guiding principle of glaucoma management. Although IOP is the only treatable risk factor, its 24-hour behavior is poorly understood. Current glaucoma management usually relies on single IOP measurements during clinic hours, even though IOP is a dynamic parameter with rhythms dependent on individual patients. It has further been shown that most glaucoma patients have their highest IOP measurements outside clinic hours. The fact that these IOP peaks go largely undetected may explain why certain patients progress in their disease despite treatment. Nevertheless, single IOP measurements have determined all major clinical guidelines regarding glaucoma treatment. Other potentially informative parameters, such as fluctuations in IOP and peak IOP, have been neglected, and effects of IOP-lowering interventions on such measures are largely unknown. Continuous 24-hour IOP monitoring has been an interest for more than 50 years, but only recent technological advances have provided clinicians with a device for such an endeavor. This review discusses current uses and shortcomings of current measurement techniques, and provides an overview on current and future methods for 24-hour IOP assessment. It may be possible to incorporate continuous IOP monitoring into clinical practice, potentially to reduce glaucoma-related vision loss.
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Affiliation(s)
- Brenda Nuyen
- Hamilton Glaucoma Center and Department of Ophthalmology, University of California, San Diego, La Jolla, California, USA
| | - Kaweh Mansouri
- Glaucoma Center, Montchoisi Clinic, Genolier Swiss Vision Network, Lausanne, Switzerland
- Department of Ophthalmology, University of Colorado School of Medicine, Aurora, Colorado, USA
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Benoit A, Latour G, Marie-Claire SK, Allain JM. Simultaneous microstructural and mechanical characterization of human corneas at increasing pressure. J Mech Behav Biomed Mater 2015; 60:93-105. [PMID: 26773650 DOI: 10.1016/j.jmbbm.2015.12.031] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2015] [Revised: 09/23/2015] [Accepted: 12/22/2015] [Indexed: 11/24/2022]
Abstract
The cornea, through its shape, is the main contributor to the eye׳s focusing power. Pathological alterations of the cornea strongly affect the eye power. To improve treatments, complex biomechanical models have been developed based on the architecture and mechanical properties of the collagen network in the stroma, the main layer of the cornea. However, direct investigations of the structure of the stroma, as well as its link to the mechanical response, remained limited. We propose here an original set up, associating nonlinear optical imaging and mechanical testing. By using polarization resolved Second Harmonic signals, we simultaneously quantified micrometer (orientation of the collagen lamellae) and nanometer (local disorder within lamellae) scale corneal organization. We showed that the organization of the lamellae changes along the stroma thickness. Then, we measured simultaneously the deformation on the epithelial side of the cornea and the reorientation of the collagen lamellae for increasing intraocular pressure levels, from physiological ones to pathological ones. We showed that the observed deformation is not correlated to initial orientation, but to the reorganization of the lamellae in the stroma. Our results, by providing a direct multi-scale observation, will be useful for the development of more accurate biomechanical models.
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Affiliation(s)
- Aurélie Benoit
- LMS, École polytechnique, CNRS, Université Paris-Saclay, 91128 Palaiseau, France
| | - Gaël Latour
- LOB, École polytechnique, CNRS, Inserm U1128, Université Paris-Saclay, 91128 Palaiseau cedex, France; IMNC, Univ. Paris-Sud, Univ. Paris-Diderot, CNRS, Université Paris-Saclay, 91405 Orsay cedex, France
| | | | - Jean-Marc Allain
- LMS, École polytechnique, CNRS, Université Paris-Saclay, 91128 Palaiseau, France.
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Mansouri K, Medeiros FA, Weinreb RN. Effect of glaucoma medications on 24-hour intraocular pressure-related patterns using a contact lens sensor. Clin Exp Ophthalmol 2015; 43:787-95. [PMID: 26152693 DOI: 10.1111/ceo.12567] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2014] [Accepted: 06/03/2015] [Indexed: 11/26/2022]
Abstract
BACKGROUND The aim of this article was to study the circadian intraocular pressure (IOP)-related effects of ocular hypotensive medications using a contact lens sensor (CLS). DESIGN This is a university-based prospective, randomized, crossover trial. PARTICIPANTS A total of 23 patients with primary open-angle glaucoma participated. METHODS Patients underwent ambulatory recording of IOP-related patterns for 24 h in one eye during 3 monthly sessions using a CLS. Patients were untreated in session 1 (S1), were randomized to one of four classes of glaucoma drops for S2 and had a prostaglandin analogue add-on for S3. MAIN OUTCOME MEASURES Changes in IOP-related patterns were defined using (i) slopes from wake/sitting to sleep/supine; (ii) cosinor rhythmometry modelling; and (iii) area under receiver operating curve (AUC) of sleep period. RESULTS Mean patient age was 63.8 ± 11.8 years. Positive linear slopes were seen from wake/sitting to sleep/supine at S1 (17.1 ± 14.2 mVeq/h) and S2 (5.5 ± 23.9 mVeq/h) and negative slopes at S3 (-1.9 ± 29.4 mVeq/h) (S1-S2, P = 0.01; S1-S3, P = 0.02). In the prostaglandin group, slopes changed significantly with introduction of drops (S1-S2, P < 0.024), whereas they did not in a mixed group combining the three other classes (S1-S2, P = 0.060). Overall, cosinor amplitudes were 98.4 ± 46.5 mVeq (S1), 113.0 ± 35.6 mVeq (S2) and 109.6 ± 58.3 mVeq (S3) (S1-S2, P = 0.23; S1-S3, P = 0.66; S2-S3, P = 0.93). AUC were 91.8 ± 63.0 mVeq (S1), 76.3 ± 102.7 mVeq (S2) and 19.9 ± 135.8 mVeq (S3). Differences between sessions were not statistically significant (S1-S2, P = 0.541; S1-S3, P = 0.083; S2-S3, P = 0.092). CONCLUSIONS Prostaglandin analogues, but not other medications, seem to flatten the IOP-related increase at transition of the wake/sitting to the sleep/supine period, but do not seem to have an effect on acrophase and amplitude.
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Affiliation(s)
- Kaweh Mansouri
- Hamilton Glaucoma Center and Shiley Eye Center, Department of Ophthalmology, University of California, San Diego, California, USA.,Glaucoma Center, Montchoisi Clinic, Genolier Swiss Vision Network, Lausanne, Switzerland
| | - Felipe A Medeiros
- Hamilton Glaucoma Center and Shiley Eye Center, Department of Ophthalmology, University of California, San Diego, California, USA
| | - Robert N Weinreb
- Hamilton Glaucoma Center and Shiley Eye Center, Department of Ophthalmology, University of California, San Diego, California, USA
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Abstract
Glaucoma is the second leading cause of blindness worldwide and intraocular pressure (IOP) is currently its only modifiable risk factor. Peak IOP has for a long time been considered as a major contributor to glaucoma progression, but its effects may depend not only on its magnitude, but also on its time course. The IOP is nowadays considered to be a dynamic parameter with a circadian rhythm and spontaneous changes. The current practice of punctual measuring the IOP during office hours is therefore a suboptimal approach, which does not take into account the natural fluctuation of IOP. Because of its static nature a single IOP measurement in sitting position fails to document the true range of an individual's IOP, peak IOP, or variation throughout the day. Phasing means monitoring a patient's IOP during the daytime or over a 24-hour period. This can provide additional information in the management of glaucoma patients. This review focuses on the current insight of non-invasive IOP monitoring as a method of obtaining more complete IOP profiles. Invasive techniques using an implantable sensor are beyond the scope of this review.
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Affiliation(s)
- Stefan De Smedt
- Department of Ophthalmology, AZ St Maarten, Mechelen, Belgium
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Kazemi A, McLaren JW, Sit AJ. Continuous Monitoring of Intraocular Pressure: An Overview of New Techniques. CURRENT OPHTHALMOLOGY REPORTS 2015. [DOI: 10.1007/s40135-015-0066-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Akova-Budak B, Kıvanç SA. Does corneal hysteresis correlate with endothelial cell density? Med Sci Monit 2015; 21:1460-3. [PMID: 25994302 PMCID: PMC4450604 DOI: 10.12659/msm.893589] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Background Our aim was to determine if there is a correlation between corneal biomechanical properties, endothelial cell count, and corneal pachymetry in healthy corneas. Material/Methods Ninety-two eyes of all subjects underwent complete ocular examination, including intraocular pressure measurement by Goldmann applanation tonometer, objective refraction, and slit-lamp biomicroscopy. Topographic measurements and corneal pachymetry were performed using a Scheimpflug-based (Pentacam, Oculus, Germany) corneal topographer. Corneal hysteresis (CH) and corneal resistance factor (CRF) were measured with an Ocular Response Analyzer (ORA, Reichert Ophthalmic Instruments, Buffalo, NY). Endothelial cell count measurement was done using a specular microscope (CellChek, Konan, USA). Results Right eye values of the subjects were taken for the study. The mean CH was 11.5±1.7 mmHg and the mean CRF was 11.2±1.4 mmHg. Mean intraocular pressure was 15.3±2.3 mmHg. The mean endothelial cell count was 2754±205 cells/mm2. No correlation was found between biomechanical properties of cornea and endothelial cell count. There was a significant positive correlation between CH, CRF, and corneal thickness (p<0.001; r=0.79). Conclusions The corneal biomechanical properties significantly correlated with corneal thickness. We found no correlation between CH and CRF with the endothelial cell density in normal subjects.
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Affiliation(s)
- Berna Akova-Budak
- Department of Ophthalmology, Uludag University, School of Medicine, Bursa, Turkey
| | - Sertaç Argun Kıvanç
- Department of Ophthalmology, Uludag University, School of Medicine, Bursa, Turkey
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Abstract
PURPOSE OF REVIEW To review current status and future of ambulatory 24-h intraocular pressure monitoring. Despite important advances in the diagnosis and management of glaucoma during the last decade, the fundamental understanding of intraocular pressure, its only modifiable risk factor, remains elusive. The current practice of single intraocular pressure measurements during a clinic visit does not adequately reflect the variability of intraocular pressure throughout the 24-h day. RECENT FINDINGS There has been considerable progress recently with the prototype and commercial introduction of continuous 24-h intraocular pressure monitoring devices. Implantable intraocular pressure sensors have the advantage to directly measure intraocular pressure over many months and years, whereas temporary (contact lens based) approaches provide a noninvasive alternative for repeated 24-h periods. This review provides an overview of implantable devices as well as a critical assessment of a 24-h contact lens sensor. SUMMARY Recent advances in microelectromechanical systems and nanoelectromechanical systems have enabled the development of 24-h intraocular pressure monitoring devices. Once these technologies have shown their safety and efficacy, larger questions as to the data interpretation and handling will arise. It is likely that the use of 24-h intraocular pressure monitoring will herald fundamental changes in our understanding and management of glaucoma.
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Abstract
According to the World Health Organization, glaucoma is the leading cause of irreversible blindness worldwide. Although intraocular pressure (IOP) is not considered any more to be a defining feature of the disease, its lowering remains the only treatment option for glaucoma. Therefore, accurate and precise measurement of IOP is the cornerstone of glaucoma. Intraocular pressure is a highly dynamic physiological parameter with individual circadian rhythms. The main limitation of current tonometry methods remains the static and mostly office-based nature of their measurements. This review provides a brief historical overview on tonometry and discusses current tonometry instruments. In recent years, approaches to 24-hour IOP monitoring have been introduced, and there is hope that they may become part of routine clinical management in the future.
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Affiliation(s)
- Brenda Nuyen
- From the *Hamilton Glaucoma Center and the Department of Ophthalmology, University of California, San Diego, La Jolla, CA; †Glaucoma Sector, Department of Ophthalmology, Geneva University Hospitals, Geneva, Switzerland; and ‡Department of Ophthalmology, University of Colorado School of Medicine, Denver, CO
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Agnifili L, Mastropasqua R, Frezzotti P, Fasanella V, Motolese I, Pedrotti E, Iorio AD, Mattei PA, Motolese E, Mastropasqua L. Circadian intraocular pressure patterns in healthy subjects, primary open angle and normal tension glaucoma patients with a contact lens sensor. Acta Ophthalmol 2015; 93:e14-21. [PMID: 24720477 DOI: 10.1111/aos.12408] [Citation(s) in RCA: 94] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2013] [Accepted: 03/04/2014] [Indexed: 11/27/2022]
Abstract
PURPOSE To examine the circadian intraocular pressure (IOP) patterns in healthy subjects, in primary open angle and normal tension glaucoma (POAG; NTG) using a contact lens sensor (CLS; Sensimed Triggerfish, Lausanne, Switzerland). METHODS This was an observational, nonrandomized study. Ten healthy subjects (Group 1, 10 eyes) and 20 glaucomatous patients [20 eyes, 10 with POAG (Group 2) and 10 with NTG (Group 3)] were enrolled. All patients were controlled with prostaglandin analogues. The 24-hr IOP pattern was the main outcome. The morning (6AM-11AM), afternoon/evening (noon-11PM) and night (midnight-5AM) subperiod patterns, peaks and prolonged peaks (>1 hr) were secondary outcomes. RESULTS Mean 24-hr IOP pattern showed a nocturnal acrophase in all groups. Patterns were significantly different among groups (p = 0.02), with highest nocturnal IOP values in POAG. Prolonged peaks were more common in patients with glaucoma (70%) than in healthy subjects (33.3%) (p < 0.001). Significant differences were found for Groups 2 and 3 in the morning versus afternoon/evening (p = 0.019 and p = 0.035, Bonferroni correction), morning versus night (p = 0.005 and p < 0.0001) and afternoon/evening versus night periods comparisons (p < 0.0001 for both groups). In Group 1, patterns significantly differed in the morning versus night and afternoon/evening versus night period comparisons (p < 0.0001). CONCLUSIONS Continuous 24-hr IOP monitoring with the CLS revealed a nocturnal acrophase in healthy subjects and, more markedly, in glaucoma. Because the diurnal IOP profile seems not to predict the nocturnal rhythm, the circadian IOP pattern should be evaluated in clinical practice. These findings may be worthwhile for the management of glaucoma.
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Affiliation(s)
- Luca Agnifili
- Department of Medicine and Aging Science; Ophthalmology Clinic; University G. d'Annunzio of Chieti-Pescara; Chieti Italy
| | - Rodolfo Mastropasqua
- Ophthalmology Unit; Department of Neurological Neuropsychological, Morphological and Movement Sciences; University of Verona; Verona Italy
| | - Paolo Frezzotti
- Department of Medicine, Surgery and Neuroscience; Ophthalmology Clinic; University of Siena; Siena Italy
| | - Vincenzo Fasanella
- Department of Medicine and Aging Science; Ophthalmology Clinic; University G. d'Annunzio of Chieti-Pescara; Chieti Italy
| | - Ilaria Motolese
- Department of Medicine, Surgery and Neuroscience; Ophthalmology Clinic; University of Siena; Siena Italy
| | - Emilio Pedrotti
- Ophthalmology Unit; Department of Neurological Neuropsychological, Morphological and Movement Sciences; University of Verona; Verona Italy
| | - Angelo Di Iorio
- Department of Medicine and Aging Science; Laboratory of Clinical Epidemiology and Aging; University G. d'Annunzio of Chieti-Pescara; Chieti Italy
| | - Peter A. Mattei
- Department of Medicine and Aging Science; Ophthalmology Clinic; University G. d'Annunzio of Chieti-Pescara; Chieti Italy
| | - Eduardo Motolese
- Department of Medicine, Surgery and Neuroscience; Ophthalmology Clinic; University of Siena; Siena Italy
| | - Leonardo Mastropasqua
- Department of Medicine and Aging Science; Ophthalmology Clinic; University G. d'Annunzio of Chieti-Pescara; Chieti Italy
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Lombardo G, Serrao S, Rosati M, Lombardo M. Analysis of the viscoelastic properties of the human cornea using Scheimpflug imaging in inflation experiment of eye globes. PLoS One 2014; 9:e112169. [PMID: 25397674 PMCID: PMC4232387 DOI: 10.1371/journal.pone.0112169] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2014] [Accepted: 10/13/2014] [Indexed: 11/18/2022] Open
Abstract
PURPOSE To demonstrate a Scheimpflug-based imaging procedure for investigating the depth- and time-dependent strain response of the human cornea to inflation testing of whole eye globes. METHODS Six specimens, three of which with intact corneal epithelium, were mounted in a customized apparatus within a humidity and temperature-monitored wet chamber. Each specimen was subjected to two mechanical tests in order to measure corneal strain resulting from application of cyclic (cyclic regimen) and constant (creep regimen) stress by changing the intra-ocular pressure (IOP) within physiological ranges (18-42 mmHg). Corneal shape changes were analyzed as a function of IOP and both corneal stress-strain curves and creep curves were generated. RESULTS The procedure was highly accurate and repeatable. Upon cyclic stress application, a biomechanical corneal elasticity gradient was found in the front-back direction. The average Young's modulus of the anterior cornea ranged between 2.28±0.87 MPa and 3.30±0.90 MPa in specimens with and without intact epithelium (P = 0.05) respectively. The Young's modulus of the posterior cornea was on average 0.21±0.09 MPa and 0.17±0.06 MPa (P>0.05) respectively. The time-dependent strain response of the cornea to creep testing was quantified by fitting data to a modified Zener model for extracting both the relaxation time and compliance function. CONCLUSION Cyclic and creep mechanical tests are valuable for investigating the strain response of the intact human cornea within physiological IOP ranges, providing meaningful results that can be translated to clinic. The presence of epithelium influences the results of anterior corneal shape changes when monitoring deformation via Scheimpflug imaging in inflation experiments of whole eye globes.
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Affiliation(s)
- Giuseppe Lombardo
- CNR-IPCF, Unit of Support of Cosenza, Ponte P. Bucci, 87036 Rende, Italy
- Vision Engineering Italy S.r.l., Via Adda 7, 00198 Rome, Italy
- * E-mail: (ML); (GL)
| | | | - Marianna Rosati
- Fondazione G.B. Bietti IRCCS, Via Livenza 3, 00198 Rome, Italy
| | - Marco Lombardo
- Fondazione G.B. Bietti IRCCS, Via Livenza 3, 00198 Rome, Italy
- * E-mail: (ML); (GL)
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Lee TE, Yoo C, Hwang JY, Lin S, Kim YY. Comparison of Intraocular Pressure Measurements between Icare Pro Rebound Tonometer and Tono-Pen XL Tonometer in Supine and Lateral Decubitus Body Positions. Curr Eye Res 2014; 40:923-9. [PMID: 25271991 DOI: 10.3109/02713683.2014.964416] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
PURPOSE To compare intraocular pressure (IOP) measurements obtained using the Icare Pro rebound tonometer and Tono-Pen XL tonometer in supine and lateral decubitus body positions. METHODS One-hundred eyes of 50 subjects (normal volunteers or glaucoma suspects) were enrolled in this prospective observational study. IOP was measured in both eyes using the Icare Pro and Tono-Pen XL in the sitting position and the recumbent positions including supine, right lateral decubitus and left lateral decubitus. IOP was measured five minutes after assuming each of the recumbent postures in a randomized sequence. The eye on the lower side in the lateral decubitus position was termed as the dependent eye. Agreement of IOP readings between the Icare Pro and Tono-Pen was assessed in all recumbent positions. Differences of IOP readings (ΔIOP) between the two tonometers and their correlations with ocular parameters were also assessed in all positions. RESULTS The IOP readings obtained using Icare Pro and Tono-Pen showed good correlations in supine and lateral decubitus positions (all r > 0.7, p < 0.005), although Icare Pro readings were higher than Tono-Pen readings (all p < 0.001) in all positions. The ΔIOP showed a weakly positive correlation with central corneal thickness in both eyes, whereas such a positive correlation was found only in the dependent eye in the lateral decubitus positions (r = 0.307-0.531, all p < 0.005). Both the spherical equivalents and axial lengths were not correlated with ΔIOP in all positions. CONCLUSION IOP readings obtained with Tono-Pen and Icare Pro tonometers showed good agreement in supine as well as in lateral decubitus positions, although Icare readings were higher than Tono-Pen readings in all positions. Such differences in IOP readings between the different tonometers need to be considered when measuring IOPs in various body positions.
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Affiliation(s)
- Tae-Eun Lee
- Department of Ophthalmology, Korea University College of Medicine , Seoul , Korea and
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Sunaric-Megevand G, Leuenberger P, Preußner PR. Assessment of the Triggerfish contact lens sensor for measurement of intraocular pressure variations. Acta Ophthalmol 2014; 92:e414-5. [PMID: 24888768 DOI: 10.1111/aos.12455] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Hatami-Marbini H, Rahimi A. The relation between hydration and mechanical behavior of bovine cornea in tension. J Mech Behav Biomed Mater 2014; 36:90-7. [DOI: 10.1016/j.jmbbm.2014.03.011] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2014] [Revised: 03/15/2014] [Accepted: 03/18/2014] [Indexed: 11/30/2022]
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Xia D, Zhang S, Hjortdal JØ, Li Q, Thomsen K, Chevallier J, Besenbacher F, Dong M. Hydrated human corneal stroma revealed by quantitative dynamic atomic force microscopy at nanoscale. ACS NANO 2014; 8:6873-82. [PMID: 24833346 DOI: 10.1021/nn5015837] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The structures and mechanical properties of human tissues are significantly influenced by water. The functionality of the human cornea can be linked to the hydrated collagen fibers. By applying quantitative dynamic atomic force microscopy to investigate morphological and mechanical property variations of corneal stroma under different hydration levels, we found that the collagen fibers in the stromal tissue show the specific periodicities and the stiffness of giga-Pa magnitude at 40% humidity. However, under increasing hydration, the collagen fibers clearly show nanoparticle structures along the fibers with the stiffness in mega-Pa magnitude. By increasing the hydration time, the stroma regains the fiber structure but with larger diameter. The age-dependency in stiffness was further investigated. The interplay of structures and nanomechanical mapping may be applied for the future diagnosis and assessment or even pathologic analysis.
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Affiliation(s)
- Dan Xia
- Interdisciplinary Nanoscience Center (iNANO), Centre for DNA Nanotechnology (CDNA), Aarhus University , 8000 Aarhus, Denmark
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Ford MR, Sinha Roy A, Rollins AM, Dupps WJ. Serial biomechanical comparison of edematous, normal, and collagen crosslinked human donor corneas using optical coherence elastography. J Cataract Refract Surg 2014; 40:1041-7. [PMID: 24767794 PMCID: PMC4035481 DOI: 10.1016/j.jcrs.2014.03.017] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2014] [Revised: 03/15/2014] [Accepted: 03/16/2014] [Indexed: 01/01/2023]
Abstract
PURPOSE To noninvasively evaluate the effects of corneal hydration and collagen crosslinking (CXL) on the mechanical behavior of the cornea. SETTING Cleveland Clinic Cole Eye Institute, Cleveland, Ohio, USA. DESIGN Experimental study. METHODS An optical coherence elastography (OCE) technique was used to measure the displacement behavior of 5 pairs of debrided human donor globes in 3 serial states as follows: edematous, normal thickness, and after riboflavin-ultraviolet-A-mediated CXL. During micromotor-controlled axial displacements with a curved goniolens at physiologic intraocular pressure (IOP), serial optical coherence tomography scans were obtained to allow high-resolution intrastromal speckle tracking and displacement measurements over the central 4.0 mm of the cornea. RESULTS With no imposed increase in IOP, the mean lateral to imposed axial displacement ratios were 0.035 μm/μm ± 0.037 (SD) in edematous corneas, 0.021 ± 0.02 μm/μm in normal thickness corneas, and 0.014 ± 0.009 μm/μm in post-CXL corneas. The differences were statistically significant (P<.05, analysis of variance) and indicated a 40% increase in lateral stromal resistance with deturgescence and a further 33% mean increase in relative stiffness with CXL. CONCLUSIONS Serial perturbations of the corneal hydration state and CXL had significant effects on corneal biomechanical behavior. With an axially applied stress from a nonapplanating contact lens, displacements along the direction of the collagen lamellae were 2 orders of magnitude lower than axial deformations. These experiments show the ability of OCE to quantify clinically relevant mechanical property differences under physiologic conditions. FINANCIAL DISCLOSURES Proprietary or commercial disclosures are listed after the references.
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Affiliation(s)
- Matthew R Ford
- From the Department of Biomedical Engineering (Ford, Rollins), Case Western Reserve University, the Cleveland Clinic Cole Eye Institute (Ford, Sinha Roy, Dupps), and the Department of Biomedical Engineering (Dupps), Cleveland Clinic Lerner Research Institute, Cleveland, Ohio, USA
| | - Abhijit Sinha Roy
- From the Department of Biomedical Engineering (Ford, Rollins), Case Western Reserve University, the Cleveland Clinic Cole Eye Institute (Ford, Sinha Roy, Dupps), and the Department of Biomedical Engineering (Dupps), Cleveland Clinic Lerner Research Institute, Cleveland, Ohio, USA
| | - Andrew M Rollins
- From the Department of Biomedical Engineering (Ford, Rollins), Case Western Reserve University, the Cleveland Clinic Cole Eye Institute (Ford, Sinha Roy, Dupps), and the Department of Biomedical Engineering (Dupps), Cleveland Clinic Lerner Research Institute, Cleveland, Ohio, USA
| | - William J Dupps
- From the Department of Biomedical Engineering (Ford, Rollins), Case Western Reserve University, the Cleveland Clinic Cole Eye Institute (Ford, Sinha Roy, Dupps), and the Department of Biomedical Engineering (Dupps), Cleveland Clinic Lerner Research Institute, Cleveland, Ohio, USA.
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Yung E, Trubnik V, Katz LJ. An overview of home tonometry and telemetry for intraocular pressure monitoring in humans. Graefes Arch Clin Exp Ophthalmol 2014; 252:1179-88. [DOI: 10.1007/s00417-014-2668-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2013] [Revised: 04/29/2014] [Accepted: 05/06/2014] [Indexed: 11/24/2022] Open
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Hatami-Marbini H, Rahimi A. Effects of bathing solution on tensile properties of the cornea. Exp Eye Res 2014; 120:103-8. [DOI: 10.1016/j.exer.2013.11.017] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2013] [Revised: 11/21/2013] [Accepted: 11/26/2013] [Indexed: 11/29/2022]
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Mansouri K, Weinreb RN. Meeting an unmet need in glaucoma: continuous 24-h monitoring of intraocular pressure. Expert Rev Med Devices 2014; 9:225-31. [DOI: 10.1586/erd.12.14] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Kim S, Roy S. Microelectromechanical systems and nephrology: the next frontier in renal replacement technology. Adv Chronic Kidney Dis 2013; 20:516-35. [PMID: 24206604 PMCID: PMC3866020 DOI: 10.1053/j.ackd.2013.08.006] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2013] [Accepted: 08/22/2013] [Indexed: 11/11/2022]
Abstract
Microelectromechanical systems (MEMS) are playing a prominent role in the development of many new and innovative biomedical devices, but they remain a relatively underused technology in nephrology. The future landscape of clinical medicine and research will only see further expansion of MEMS-based technologies in device designs and applications. This enthusiasm stems from the ability to create small-scale device features with high precision in a cost-effective manner. MEMS also offers the possibility to integrate multiple components into a single device. The adoption of MEMS has the potential to revolutionize how nephrologists manage kidney disease by improving the delivery of renal replacement therapies and enhancing the monitoring of physiologic parameters. To introduce nephrologists to MEMS, this review will first define relevant terms and describe the basic processes used to fabricate devices. Next, a survey of MEMS devices being developed for various biomedical applications will be illustrated with current examples. Finally, MEMS technology specific to nephrology will be highlighted and future applications will be examined. The adoption of MEMS offers novel avenues to improve the care of kidney disease patients and assist nephrologists in clinical practice. This review will serve as an introduction for nephrologists to the exciting world of MEMS.
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Affiliation(s)
- Steven Kim
- Department of Bioengineering & Therapeutic Sciences, Schools of Pharmacy and Medicine, University of California, San Francisco, San Francisco, CA 94158
- Division of Nephrology, Department of Medicine, School of Medicine, University of California, San Francisco, San Francisco, CA 94158
| | - Shuvo Roy
- Department of Bioengineering & Therapeutic Sciences, Schools of Pharmacy and Medicine, University of California, San Francisco, San Francisco, CA 94158
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Hoffmann EM, Lamparter J, Mirshahi A, Elflein H, Hoehn R, Wolfram C, Lorenz K, Adler M, Wild PS, Schulz A, Mathes B, Blettner M, Pfeiffer N. Distribution of central corneal thickness and its association with ocular parameters in a large central European cohort: the Gutenberg health study. PLoS One 2013; 8:e66158. [PMID: 23936291 PMCID: PMC3731336 DOI: 10.1371/journal.pone.0066158] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2012] [Accepted: 05/02/2013] [Indexed: 11/18/2022] Open
Abstract
Main objective To evaluate the distribution of central corneal thickness (CCT) in a large German cohort and to analyse its relationship with intraocular pressure and further ocular factors. Design Population-based, prospective, cohort study. Methods The Gutenberg Health Study (GHS) cohort included 4,698 eligible enrollees of 5,000 subjects (age range 35–74 years) who participated in the survey from 2007 to 2008. All participants underwent an ophthalmological examination including slitlamp biomicroscopy, intraocular pressure measurement, central corneal thickness measurement, fundus examination, and were given a questionnaire regarding glaucoma history. Furthermore, all subjects underwent fundus photography and visual field testing using frequency doubling perimetry. Results Mean CCT was 557.3±34.3 µm (male) and 551.6±35.2 µm in female subjects (Mean CCT from right and left eyes). Younger male participants (35–44 years) presented slightly thicker CCT than those older. We noted a significant CCT difference of 4 µm between right and left eyes, but a high correlation between eyes (Wilcoxon test for related samples: p<0.0001). Univariable linear regression stratified by gender showed that IOP was correlated with CCT (p<0.0001). A 10 µm increase in CCT led to an increase in IOP between 0.35–0.38 mm Hg, depending on the eye and gender. Multivariable linear regression analysis revealed correlations between gender, spherical equivalent (right eyes), and CCT (p<.0001 and p = 0.03, respectively). Conclusions We observed positive correlations between CCT and IOP and gender. CCT was not correlated with age, contact lens wear, positive family history for glaucoma, lens status, or iris colour.
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Affiliation(s)
- Esther M Hoffmann
- University Medical Centre, Department of Ophthalmology, Mainz, Germany.
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Abstract
Although intraocular pressure (IOP) is the only treatable risk factor for glaucoma, its 24-hour behavior is poorly understood. Conflicting information is available in the literature with regard to the importance and predictive value of IOP peaks and fluctuations on the risk of glaucoma development and progression. This may be secondary to lack of prospective studies designed to address this issue. This article critically reviews the current evidence for the importance of 24-h IOP measurements in glaucoma and discusses shortcomings of current methods to assess 24-h IOP data, drawing attention to new developments in this field.
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Affiliation(s)
- Kaweh Mansouri
- Hamilton Glaucoma Center, Department of Ophthalmology, University of California, San Diego, La Jolla, California 92093-0946, USA
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Chang CJ, Yang HH, Chang CA, Wu R, Tsai HY. The Influence of Orthokeratology on Intraocular Pressure Measurements. Semin Ophthalmol 2013; 28:210-5. [DOI: 10.3109/08820538.2013.768679] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Affiliation(s)
- Chia-Jen Chang
- Graduate Institute of Biochemical Sciences and Technology, Chaoyang University of Technology, Taichung, Taiwan, Republic of China.
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Corneal Biomechanical Properties and their Correlates with Healing Process after Descemetic versus Pre-Descemetic Lamellar Keratoplasty. Eur J Ophthalmol 2013; 23:652-657. [PMID: 23539463 DOI: 10.5301/ejo.5000279] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
PURPOSE To evaluate the influence of the wound-healing process on corneal biomechanics in patients after 2 types of deep anterior lamellar keratoplasty: Descemetic with total stromal resection vs pre-Descemetic with deep stromal dissection. METHODS This prospective comparative study consisted of 32 eyes of 32 patients. Patients were divided into 2 groups: Descemetic (17 eyes) and pre-Descemetic (15 eyes). Reichert ocular response analyzer was used to measure corneal hysteresis (CH) and corneal resistance factor (CRF) at 1 and 3 months postoperatively. Central corneal thickness (CCT) was measured using ultrasonic pachymetry. In vivo confocal microscopy was also used to study the corneal wound-healing process and to correlate these events with the corneal biomechanics postoperatively in both groups. RESULTS Both mean CH and mean CRF were significantly lower in the Descemetic than the pre-Descemetic group at 1 and 3 months postoperatively (p≤0.0001). The reflectivity of activated keratocytes at both the interface and wound edge was less in the Descemetic than the pre-Descemetic group at all times as revealed by the confocal microscopy. No statistically significant difference in mean CCT was found between both groups at 1 and 3 months. Subsequent and progressive decrease in interface reflectivity of activated keratocytes was presented in both groups. CONCLUSIONS Healing process at the interface is key to optimal corneal integrity. In the pre-Descemetic group, stroma-to-stroma healing stimulated more activated keratocytes and hence stronger healing response, providing superior corneal biomechanics. Significant positive correlation between the intensity of the keratocyte activation and corneal integrity was found.
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Mansouri K, Medeiros FA, Tafreshi A, Weinreb RN. Continuous 24-hour monitoring of intraocular pressure patterns with a contact lens sensor: safety, tolerability, and reproducibility in patients with glaucoma. ACTA ACUST UNITED AC 2013; 130:1534-9. [PMID: 22892888 DOI: 10.1001/archophthalmol.2012.2280] [Citation(s) in RCA: 122] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
OBJECTIVE To examine the safety, tolerability, and reproducibility of intraocular pressure (IOP) patterns during repeated continuous 24-hour IOP monitoring with a contact lens sensor. METHODS Forty patients suspected of having glaucoma (n = 21) or with established glaucoma (n = 19) were studied. Patients participated in two 24-hour IOP monitoring sessions (S1 and S2) at a 1-week interval (SENSIMED Triggerfish CLS; Sensimed AG). Patients pursued daily activities, and sleep behavior was not controlled. Incidence of adverse events and tolerability (visual analog scale score) were assessed. Reproducibility of signal patterns was assessed using Pearson correlations. RESULTS The mean (SD) age of the patients was 55.5 (15.7) years, and 60% were male. Main adverse events were blurred vision (82%), conjunctival hyperemia (80%), and superficial punctate keratitis (15%). The mean (SD) visual analog scale score was 27.2 (18.5) mm in S1 and 23.8 (18.7) mm in S2 (P = .22). Overall correlation between the 2 sessions was 0.59 (0.51 for no glaucoma medication and 0.63 for glaucoma medication) (P = .12). Mean (SD) positive linear slopes of the sensor signal from wake to 2 hours into sleep were detected in both sessions for the no glaucoma medication group (S1: 0.40 [0.34], P < .001; S2: 0.33 [0.30], P < .01) but not for the glaucoma medication group (S1: 0.24 [0.60], P = .06; S2: 0.40 [0.40], P < .001). CONCLUSIONS Repeated use of the contact lens sensor demonstrated good safety and tolerability. The recorded IOP patterns showed fair to good reproducibility, suggesting that data from continuous 24-hour IOP monitoring may be useful in the management of patients with glaucoma. TRIAL REGISTRATION clinicaltrials.gov Identifier: NCT01319617.
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