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Suchand Sandeep CS, Khairyanto A, Aung T, Vadakke Matham M. Bessel Beams in Ophthalmology: A Review. MICROMACHINES 2023; 14:1672. [PMID: 37763835 PMCID: PMC10536271 DOI: 10.3390/mi14091672] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/2023] [Revised: 08/22/2023] [Accepted: 08/23/2023] [Indexed: 09/29/2023]
Abstract
The achievable resolution of a conventional imaging system is inevitably limited due to diffraction. Dealing with precise imaging in scattering media, such as in the case of biomedical imaging, is even more difficult owing to the weak signal-to-noise ratios. Recent developments in non-diffractive beams such as Bessel beams, Airy beams, vortex beams, and Mathieu beams have paved the way to tackle some of these challenges. This review specifically focuses on non-diffractive Bessel beams for ophthalmological applications. The theoretical foundation of the non-diffractive Bessel beam is discussed first followed by a review of various ophthalmological applications utilizing Bessel beams. The advantages and disadvantages of these techniques in comparison to those of existing state-of-the-art ophthalmological systems are discussed. The review concludes with an overview of the current developments and the future perspectives of non-diffractive beams in ophthalmology.
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Affiliation(s)
- C. S. Suchand Sandeep
- Centre for Optical and Laser Engineering, School of Mechanical and Aerospace Engineering, Nanyang Technological University, Singapore 639798, Singapore
| | - Ahmad Khairyanto
- Centre for Optical and Laser Engineering, School of Mechanical and Aerospace Engineering, Nanyang Technological University, Singapore 639798, Singapore
| | - Tin Aung
- Singapore Eye Research Institute, Singapore National Eye Centre, Singapore 169856, Singapore
- Duke-NUS Medical School, National University of Singapore, Singapore 169857, Singapore
| | - Murukeshan Vadakke Matham
- Centre for Optical and Laser Engineering, School of Mechanical and Aerospace Engineering, Nanyang Technological University, Singapore 639798, Singapore
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Keller MJ, Gast TJ, King BJ. Advancements in high-resolution imaging of the iridocorneal angle. FRONTIERS IN OPHTHALMOLOGY 2023; 3:1229670. [PMID: 38983074 PMCID: PMC11182319 DOI: 10.3389/fopht.2023.1229670] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/26/2023] [Accepted: 07/31/2023] [Indexed: 07/11/2024]
Abstract
High-resolution imaging methods of the iridocorneal angle (ICA) will lead to enhanced understanding of aqueous humor outflow mechanisms and a characterization of the trabecular meshwork (TM) morphology at the cellular level will help to better understand glaucoma mechanics (e.g., cellular level biomechanics of the particulate glaucomas). This information will translate into immense clinical value, leading to more informed and customized treatment selection, and improved monitoring of procedural interventions that lower intraocular pressure (IOP). Given ICA anatomy, imaging modalities that yield intrinsic optical sectioning or 3D imaging capability will be useful to aid in the visualization of TM layers. This minireview examines advancements in imaging the ICA in high-resolution.
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Affiliation(s)
- Matthew J Keller
- School of Optometry, Indiana University, Bloomington, IN, United States
| | - Thomas J Gast
- School of Optometry, Indiana University, Bloomington, IN, United States
| | - Brett J King
- School of Optometry, Indiana University, Bloomington, IN, United States
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3
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Flat variable liquid crystal diffractive spiral axicon enabling perfect vortex beams generation. Sci Rep 2023; 13:2385. [PMID: 36765189 PMCID: PMC9918518 DOI: 10.1038/s41598-023-29164-0] [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: 08/31/2022] [Accepted: 01/31/2023] [Indexed: 02/12/2023] Open
Abstract
A transparent variable diffractive spiral axicon (DSA) based on a single LC cell is presented. The manufactured DSA can be switched between 24 different configurations, 12 convergent and 12 divergent, where the output angle is varied as a function of the applied topological charge. The active area of the device is created using a direct laser writing technique in indium-tin oxide coated glass substrates. Liquid crystal is used to modulate the phase of the incoming beam generating the different DSA configurations. The DSA consists in 24 individually driven transparent spiral shaped electrodes, each introducing a specific phase retardation. In this article, the manufacture and characterization of the tunable DSA is presented and the performance of the DSA is experimentally demonstrated and compared to the corresponding simulations.
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Carmichael-Martins A, Gast TJ, Burns SA, Walker BR, King BJ. Characterization of the human iridocorneal angle in vivo using a custom design goniolens with OCT gonioscopy. BIOMEDICAL OPTICS EXPRESS 2022; 13:4652-4667. [PMID: 36187241 PMCID: PMC9484429 DOI: 10.1364/boe.465317] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/27/2022] [Revised: 07/18/2022] [Accepted: 07/27/2022] [Indexed: 06/16/2023]
Abstract
Intraocular pressure (IOP) is the only modifiable risk factor for glaucoma progression, and many treatments target the trabecular meshwork (TM). Imaging this region in vivo is challenging due to optical limitations of imaging through the cornea at high angles. We propose a gonioscopic OCT approach using a custom goniolens and a commercially available OCT device to improve imaging of the TM, Schlemm's canal (SC) and adjacent structures within the iridocorneal angle (ICA). The goniolens is modified with a plano-convex focusing lens and placed on the eye optically mated with goniogel and aided by a 3D adjustable mount. Gonioscopic OCT volume scans are acquired to image SC. Transverse enface images allowed measurements of SC over a 45° section of the ICA for the first time and revealed locations of SC narrowing. The band of extracanalicular limbal lamina and corneoscleral bands were imaged in most subjects and these bands were confirmed using exterior OCT imaging. The polarization dependence of the visibility of these structures is studied by polarization rotation the OCT beam with a half-wave plate, allowing increased contrast of SC. Gonioscopic OCT has successfully been used to image the human ICA in 3D in vivo. This approach provides more detailed characterization of the TM and SC, enhancing their contrast against their birefringent backgrounds.
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Affiliation(s)
| | - Thomas J. Gast
- School of Optometry, Indiana University, Bloomington, Indiana 47401, USA
| | - Stephen A. Burns
- School of Optometry, Indiana University, Bloomington, Indiana 47401, USA
| | - Brittany R. Walker
- School of Optometry, Indiana University, Bloomington, Indiana 47401, USA
| | - Brett J. King
- School of Optometry, Indiana University, Bloomington, Indiana 47401, USA
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Porporato N, Bell KC, Perera SA, Aung T. Non-optical coherence tomography modalities for assessment of angle closure. Taiwan J Ophthalmol 2021; 12:409-414. [PMID: 36660111 PMCID: PMC9843576 DOI: 10.4103/tjo.tjo_41_21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2021] [Accepted: 09/26/2021] [Indexed: 01/22/2023] Open
Abstract
Primary angle closure glaucoma is a leading cause of irreversible blindness, particularly in Asia. Its pathophysiology is based in the closure of the anterior chamber angle (ACA). In addition to gonioscopy (current reference standard), in the past decade, anterior segment optical coherence tomography (AS-OCT) has been incorporated in routine ophthalmic practice to help assess the configuration of the ACA. Especially in nonspecialist ophthalmology practice, gonioscopy may be less frequently performed and AS-OCT may not be available, leading to the need of other anterior segment evaluation methods. Evaluating the anterior chamber depth (ACD) has long been recognized as screening tool for primary angle-closure glaucoma. It can be measured with several devices, such as Scheimpflug photography and the scanning peripheral ACD analyzer. It can also be estimated with the oblique flashlight test and van Herick technique (limbal ACD assessment). More recently, goniophotographic systems have been developed to produce images of the ACA similar to those seen with manual gonioscopy. NGS-1 automated gonioscope (NIDEK Co, Gamagori, Japan) and the RetCam (Natus Medical Incorporated, Pleasanton, CA) are commercially available. However, NGS-1 is the only one with a specialized software for ACA imaging. Several prototype devices are currently being developed, such as the GonioPEN and axicon lens assisted gonioscopy. This article aims to review different modalities of ACA assessment, beyond AS-OCT, and compare their relative advantages and disadvantages.
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Affiliation(s)
- Natalia Porporato
- Singapore National Eye Centre, Singapore Eye Research Institute, Singapore,Department of Ophthalmology, DUKE-NUS Medical School, Singapore
| | - Katharina C. Bell
- Singapore National Eye Centre, Singapore Eye Research Institute, Singapore,Department of Ophthalmology, DUKE-NUS Medical School, Singapore
| | - Shamira A. Perera
- Singapore National Eye Centre, Singapore Eye Research Institute, Singapore,Department of Ophthalmology, DUKE-NUS Medical School, Singapore
| | - Tin Aung
- Singapore National Eye Centre, Singapore Eye Research Institute, Singapore,Department of Ophthalmology, DUKE-NUS Medical School, Singapore,Department of Visual Science, Yong Loo Lin School of Medicine, National University of Singapore, Singapore,Address for correspondence: Prof. Tin Aung, Singapore National Eye Center, 11, Third Hospital Avenue, 168751, Singapore. E-mail:
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Nair RV, Murukeshan VM. (Cu2O-Au) – Graphene - Au layered structures as efficient near Infra - Red SERS substrates. Sci Rep 2020; 10:4152. [PMID: 32139732 PMCID: PMC7058041 DOI: 10.1038/s41598-020-60874-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2019] [Accepted: 11/14/2019] [Indexed: 11/13/2022] Open
Abstract
Near Infra-Red Surface Enhanced Raman Spectroscopy (NIR SERS) has gained huge attention in recent years as the conventional visible SERS suffers from overwhelming fluorescence background from the fluorophore resulting in the masking of Raman signals. In this paper, we propose a novel multi-layered SERS substrate- (Cu2O - Au) - Graphene – Au - for efficient NIR SERS applications. The proposed structure has a monolayer of Cu2O - Au core-shell particles on a Au substrate with 1 nm thick graphene spacer layer. Mie simulations are used to optimize the aspect ratios of core-shell particles to shift their plasmon resonances to NIR region using MieLab software. Further, Finite Difference Time Domain (FDTD) simulations using Lumerical software are used for the design of the multiparticle layered SERS substrate as MieLab software works only for single particle systems. Designed structure is shown to provide high field enhancement factor of the order of 108 at an excitation of 1064 nm thus ensuring the possibility of using the proposed structure as efficient NIR SERS substrate which could probably be used for various NIR sensing applications.
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Anterior Chamber Angle Assessment Techniques: A Review. J Clin Med 2020; 9:jcm9123814. [PMID: 33255754 PMCID: PMC7759936 DOI: 10.3390/jcm9123814] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2020] [Revised: 11/21/2020] [Accepted: 11/24/2020] [Indexed: 12/16/2022] Open
Abstract
Assessment of the anterior chamber angle (ACA) is an essential part of the ophthalmological examination. It is intrinsically related to the diagnosis and treatment of glaucoma and has a role in its prevention. Although slit-lamp gonioscopy is considered the gold-standard technique for ACA evaluation, its poor reproducibility and the long learning curve are well-known shortcomings. Several new imaging techniques for angle evaluation have been developed in the recent years. However, whether these instruments may replace or not gonioscopy in everyday clinical practice remains unclear. This review summarizes the last findings in ACA evaluation, focusing on new instruments and their application to the clinical practice. Special attention will be given to the comparison between these new techniques and traditional slit-lamp gonioscopy. Whereas ultrasound biomicroscopy and anterior segment optical coherence tomography provide quantitative measurements of the anterior segment’s structures, new gonio-photographic systems allow for a qualitative assessment of angle findings, similarly to gonioscopy. Recently developed deep learning algorithms provide an automated classification of angle images, aiding physicians in taking faster and more efficient decisions. Despite new imaging techniques made analysis of the ACA more objective and practical, the ideal method for ACA evaluation has still to be determined.
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Buffault J, Labbé A, Hamard P, Brignole-Baudouin F, Baudouin C. [The trabecular meshwork: Structure, function and clinical implications. A review of the littérature (French translation of the article)]. J Fr Ophtalmol 2020; 43:779-793. [PMID: 32807552 DOI: 10.1016/j.jfo.2020.04.022] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Revised: 04/17/2020] [Accepted: 04/22/2020] [Indexed: 11/26/2022]
Abstract
Glaucoma is a blinding optic neuropathy, the main risk factor for which is increased intraocular pressure (IOP). The trabecular meshwork, located within the iridocorneal angle, is the main pathway for drainage of aqueous humor (AH) out of the eye, and its dysfunction is responsible for the IOP elevation. The trabecular meshwork is a complex, fenestrated, three-dimensional structure composed of trabecular meshwork cells (TMC) interdigitated into a multilayered organization within the extracellular matrix (ECM). The purpose of this literature review is to provide an overview of current understanding of the trabecular meshwork and its pathophysiology in glaucoma. Thus, we will present the main anatomical and cellular bases for the regulation of aqueous humor outflow resistance, the pathophysiological mechanisms involved in trabecular dysfunction in the various types of glaucoma, as well as current and future therapeutic strategies targeting the trabecular meshwork.
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Affiliation(s)
- J Buffault
- Service d'ophtalmologie, centre hospitalier national d'ophtalmologie des Quinze-Vingts, IHU FOReSIGHT, 28, rue de Charenton, 75012 Paris, France.
| | - A Labbé
- Service d'ophtalmologie, centre hospitalier national d'ophtalmologie des Quinze-Vingts, IHU FOReSIGHT, 28, rue de Charenton, 75012 Paris, France; Service d'ophtalmologie, hôpital Ambroise-Paré, AP-HP, 9, avenue Charles-de-Gaulle, 92100 Boulogne-Billancourt, France; Inserm, CNRS, institut de la vision, Sorbonne université, 17, rue Moreau, 75012 Paris, France
| | - P Hamard
- Service d'ophtalmologie, centre hospitalier national d'ophtalmologie des Quinze-Vingts, IHU FOReSIGHT, 28, rue de Charenton, 75012 Paris, France
| | - F Brignole-Baudouin
- Inserm, CNRS, institut de la vision, Sorbonne université, 17, rue Moreau, 75012 Paris, France; Service de biologie médicale, centre hospitalier national d'ophtalmologie des Quinze-Vingts, IHU FOReSIGHT, 28, rue de Charenton, 75012 Paris, France
| | - C Baudouin
- Service d'ophtalmologie, centre hospitalier national d'ophtalmologie des Quinze-Vingts, IHU FOReSIGHT, 28, rue de Charenton, 75012 Paris, France; Service d'ophtalmologie, hôpital Ambroise-Paré, AP-HP, 9, avenue Charles-de-Gaulle, 92100 Boulogne-Billancourt, France; Inserm, CNRS, institut de la vision, Sorbonne université, 17, rue Moreau, 75012 Paris, France
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9
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The trabecular meshwork: Structure, function and clinical implications. A review of the literature. J Fr Ophtalmol 2020; 43:e217-e230. [PMID: 32561029 DOI: 10.1016/j.jfo.2020.05.002] [Citation(s) in RCA: 51] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2020] [Revised: 04/25/2020] [Accepted: 05/27/2020] [Indexed: 02/06/2023]
Abstract
Glaucoma is a blinding optic neuropathy, the main risk factor for which is increased intraocular pressure (IOP). The trabecular meshwork, located within the iridocorneal angle, is the main pathway for drainage of aqueous humor (AH) out of the eye, and its dysfunction is responsible for the IOP elevation. The trabecular meshwork is a complex, fenestrated, three-dimensional structure composed of trabecular meshwork cells (TMC) interdigitated into a multilayered organization within the extracellular matrix (ECM). The purpose of this literature review is to provide an overview of current understanding of the trabecular meshwork and its pathophysiology in glaucoma. Thus, we will present the main anatomical and cellular bases for the regulation of aqueous humor outflow resistance, the pathophysiological mechanisms involved in trabecular dysfunction in the various types of glaucoma, as well as current and future therapeutic strategies targeting the trabecular meshwork.
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10
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Hong XJJ, Suchand Sandeep CS, Shinoj VK, Aung T, Barathi VA, Baskaran M, Murukeshan VM. Noninvasive and Noncontact Sequential Imaging of the Iridocorneal Angle and the Cornea of the Eye. Transl Vis Sci Technol 2020; 9:1. [PMID: 32821473 PMCID: PMC7401920 DOI: 10.1167/tvst.9.5.1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2019] [Accepted: 12/22/2019] [Indexed: 12/26/2022] Open
Abstract
Purpose High-resolution imaging of the critical anatomic structures of the eye, especially of the anterior chamber, in vivo, remains a challenge, even with currently available state-of-the-art medical imaging techniques. This study aims for the noninvasive and noncontact sequential imaging of the iridocorneal angle, especially the trabecular meshwork (TM) and the cornea of the eye in high-resolution using a newly developed imaging platform. Methods Bessel beam scanned light sheet fluorescence microscopy is used to attain high-resolution images of the TM. The ability of the Bessel beam to self-reconstruct around obstacles increases the image contrast at the TM region inside eye by reducing scattering and shadow artifacts. With minimal modifications, the excitation arm of the developed imaging system is adapted for noncontact, high-resolution corneal imaging. Results High-resolution images of the TM structures and cellular-level corneal structures are obtained in ex vivo porcine eyes, and subsequently in New Zealand white rabbit, in vivo. The spatial resolution of the developed system is 2.19 µm and has a noncontact working distance of 20 mm. Conclusions A high-resolution imaging platform for noncontact sequential imaging of the TM and the cornea of the eye is developed. This imaging system is expected to be of potential interest in the evaluation and diagnosis of glaucoma and corneal diseases. Translational Relevance The developed prototype offers the plausibility of in vivo, noncontact, and high-resolution imaging of the iridocorneal angle and cornea of the eye that will aid clinicians in diagnosing open-angle glaucoma and corneal diseases better.
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Affiliation(s)
- Xun Jie Jeesmond Hong
- Centre for Optical and Laser Engineering, School of Mechanical and Aerospace Engineering, Nanyang Technological University, Singapore
| | - C S Suchand Sandeep
- Centre for Optical and Laser Engineering, School of Mechanical and Aerospace Engineering, Nanyang Technological University, Singapore.,Singapore Centre for 3D Printing, School of Mechanical and Aerospace Engineering, Nanyang Technological University, Singapore
| | - V K Shinoj
- Centre for Optical and Laser Engineering, School of Mechanical and Aerospace Engineering, Nanyang Technological University, Singapore.,Currently with Union Christian College, Department of Physics, Kerala, India
| | - Tin Aung
- Singapore Eye Research Institute (SERI) & Singapore National Eye Center (SNEC), Singapore.,Department of Ophthalmology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Veluchamy Amutha Barathi
- Singapore Eye Research Institute (SERI) & Singapore National Eye Center (SNEC), Singapore.,Department of Ophthalmology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore.,The Ophthalmology & Visual Sciences Academic Clinical Program, Duke-NUS Medical School, Singapore
| | - Mani Baskaran
- Singapore Eye Research Institute (SERI) & Singapore National Eye Center (SNEC), Singapore.,The Ophthalmology & Visual Sciences Academic Clinical Program, Duke-NUS Medical School, Singapore
| | - Vadakke Matham Murukeshan
- Centre for Optical and Laser Engineering, School of Mechanical and Aerospace Engineering, Nanyang Technological University, Singapore
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11
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Porporato N, Baskaran M, Husain R, Aung T. Recent advances in anterior chamber angle imaging. Eye (Lond) 2020; 34:51-59. [PMID: 31666710 PMCID: PMC7002644 DOI: 10.1038/s41433-019-0655-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2019] [Accepted: 10/09/2019] [Indexed: 02/06/2023] Open
Abstract
Differentiating the two main forms of primary glaucoma (open-angle and closed-angle glaucoma) depends on the correct assessment of the anterior chamber angle (ACA). This assessment will determine the management plan and prognosis for the disease. The standard method of examining the angle has been, for many years, slit-lamp gonioscopy. This method, although clinically still useful, is less robust for patient follow up and clinical research, given its low reproducibility. Several imaging technologies have been developed in recent years to improve the evaluation of the ACA and overcome the shortcomings of gonioscopy. These recent advances include three-dimensional and 360° analysis by Swept-Source OCT (SS-OCT, CASIA, Tomey, Nagoya, Japan), the introduction of deep learning algorithms for automatic imaging classification and new goniophotographic systems. SS-OCT allows for the first time the assessment of the circumferential extension of angle closure with moderate to good diagnostic performance compared with gonioscopy. Deep learning algorithms are showing promising results for the automation of imaging analysis, and may potentially save physicians' time in regards of the interpretation of the images. Lastly, goniophotograph systems have the distinct advantage of recordability of gonioscopic findings and are most closely matched to the findings of slit-lamp gonioscopy.
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Affiliation(s)
- Natalia Porporato
- Singapore Eye Research Institute/Singapore National Eye Center, Singapore, Singapore
| | - Mani Baskaran
- Singapore Eye Research Institute/Singapore National Eye Center, Singapore, Singapore
| | - Rahat Husain
- Singapore Eye Research Institute/Singapore National Eye Center, Singapore, Singapore
| | - Tin Aung
- Singapore Eye Research Institute/Singapore National Eye Center, Singapore, Singapore.
- Department of Ophthalmology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore.
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12
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Suchand Sandeep CS, Sarangapani S, Hong XJJ, Aung T, Baskaran M, Murukeshan VM. Optical sectioning and high resolution visualization of trabecular meshwork using Bessel beam assisted light sheet fluorescence microscopy. JOURNAL OF BIOPHOTONICS 2019; 12:e201900048. [PMID: 31419077 DOI: 10.1002/jbio.201900048] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/02/2019] [Revised: 07/09/2019] [Accepted: 08/13/2019] [Indexed: 05/08/2023]
Abstract
Glaucoma, one of the leading causes of blindness, is an eye disease caused by irregularities in the ocular aqueous outflow system causing an elevated intraocular pressure. High resolution imaging of the aqueous outflow system comprising trabecular meshwork is immensely valuable to vision analysts and clinicians in comprehending the disease state for the efficacious analysis and treatment of glaucoma. Currently available ocular imaging devices are unable to deliver high resolution images for the visualization of the trabecular meshwork. A method to obtain high resolution (sub-micrometer) images of the trabecular meshwork using Bessel-Gauss beam scanned light sheet fluorescence microscopy is presented and the optical sectioning capability of this technique to obtain three-dimensional volumetric images of the trabecular meshwork of an intact eye without any physical dissection is demonstrated. Figure: Three-dimensional visualization of trabecular meshwork of porcine eye.
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Affiliation(s)
- C S Suchand Sandeep
- Singapore Centre for 3D Printing, School of Mechanical & Aerospace Engineering, Nanyang Technological University, Singapore
| | - Sreelatha Sarangapani
- Centre for Optical and Laser Engineering (COLE), School of Mechanical & Aerospace Engineering, Nanyang Technological University, Singapore
| | - Xun J J Hong
- Centre for Optical and Laser Engineering (COLE), School of Mechanical & Aerospace Engineering, Nanyang Technological University, Singapore
| | - Tin Aung
- Singapore Eye Research Institute, Singapore National Eye Centre, Singapore
- Department of Ophthalmology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Mani Baskaran
- Singapore Eye Research Institute, Singapore National Eye Centre, Singapore
- EYE-ACP, Duke-NUS Medical School, Singapore
| | - Vadakke M Murukeshan
- Centre for Optical and Laser Engineering (COLE), School of Mechanical & Aerospace Engineering, Nanyang Technological University, Singapore
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King BJ, Burns SA, Sapoznik KA, Luo T, Gast TJ. High-Resolution, Adaptive Optics Imaging of the Human Trabecular Meshwork In Vivo. Transl Vis Sci Technol 2019; 8:5. [PMID: 31588370 PMCID: PMC6753965 DOI: 10.1167/tvst.8.5.5] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2018] [Accepted: 06/24/2019] [Indexed: 12/22/2022] Open
Abstract
Purpose To image the human trabecular meshwork (TM) in vivo using adaptive optics gonioscopy (AOG) with approximately 2-μm lateral resolution. Methods An existing Indiana University adaptive optics scanning laser ophthalmoscope was altered by adding a 12-mm button lens to a clinical gonioscopic lens allowing high-resolution imaging of the human iridocorneal angle. First an anatomic model eye was used to refine the imaging technique and then nine participants (7 controls and 2 participants with pigment dispersion syndrome) were imaged. Results All nine participants were successfully imaged without adverse events. High-resolution imaging of the human TM was achieved allowing for visualization of the TM beams, and presumed endothelial cells. Uveal meshwork beams in controls averaged 25.5 μm (range, 15.2–44.7) in diameter with pores averaging 42.6 μm (range, 22.3–51.4) while the corneoscleral meshwork pores averaged 8.9 μm (range, 7.7–12.1). Differences in appearance of the uveal and corneoscleral meshwork were noted between the two participants with pigment dispersion syndrome and the controls. These included nearly absent spacing between the beams and enlarged endothelial cells with hyperreflective areas. Conclusions AOG allows for near cellular level resolution of the human TM in vivo. This may allow for further understanding of age-related changes that occur as well as provide a deeper understanding of medical and surgical alterations for the treatment of glaucoma. Translational Relevance Further development of this approach may allow for direct measurements at a micometer level in vivo of changes that occur in the human trabecular meshwork with glaucoma and therapeutic interventions.
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Affiliation(s)
- Brett J King
- School of Optometry, Indiana University, Bloomington, IN, USA
| | - Stephen A Burns
- School of Optometry, Indiana University, Bloomington, IN, USA
| | | | - Ting Luo
- School of Optometry, Indiana University, Bloomington, IN, USA
| | - Thomas J Gast
- School of Optometry, Indiana University, Bloomington, IN, USA
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Shi Y, Yang X, Marion KM, Francis BA, Sadda SR, Chopra V. Novel and Semiautomated 360-Degree Gonioscopic Anterior Chamber Angle Imaging in Under 60 Seconds. ACTA ACUST UNITED AC 2019; 2:215-223. [DOI: 10.1016/j.ogla.2019.04.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2019] [Revised: 03/25/2019] [Accepted: 04/01/2019] [Indexed: 11/26/2022]
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15
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Perinchery SM, Haridas A, Shinde A, Buchnev O, Murukeshan VM. Breaking diffraction limit of far-field imaging via structured illumination Bessel beam microscope (SIBM). OPTICS EXPRESS 2019; 27:6068-6082. [PMID: 30876200 DOI: 10.1364/oe.27.006068] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/22/2018] [Accepted: 01/08/2019] [Indexed: 06/09/2023]
Abstract
Breaking the diffraction limit in imaging microscopes with far-field imaging options has always been the thrust challenge for optical engineers and biologists over the years. Although structured illumination microscopy and Bessel beam assisted imaging has shown the capability of imaging with sub-diffraction resolutions, they rely on the use of objective lenses with large numerical apertures (NA). Hence, they fail to sustain resolutions at larger working distances. In this context, we demonstrate a method for nanoscale resolution imaging at longer working distances, named as Structured Illumination Bessel Microscopy (SIBM). The proposed method is envisaged for both biological and engineering applications that necessitate high imaging resolutions at large working distances.
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Zhang D, Zhu L, Chen J, Wang R, Wang P, Ming H, Badugu R, Rosenfeld M, Zhan Q, Kuang C, Liu X, Lakowicz JR. Conversion of isotropic fluorescence into a long-range non-diverging beam. Methods Appl Fluoresc 2018; 6:024003. [DOI: 10.1088/2050-6120/aa9949] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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17
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Hong XJJ, Shinoj VK, Murukeshan VM, Baskaran M, Aung T. Preclinical imaging of iridocorneal angle and fundus using a modified integrated flexible handheld probe. J Med Imaging (Bellingham) 2017; 4:026001. [PMID: 28413809 DOI: 10.1117/1.jmi.4.2.026001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2017] [Accepted: 03/21/2017] [Indexed: 11/14/2022] Open
Abstract
A flexible handheld imaging probe consisting of a [Formula: see text] charge-coupled device camera, light-emitting diode light sources, and near-infrared laser source is designed and developed. The imaging probe is designed with specifications to capture the iridocorneal angle images and posterior segment images. Light propagation from the anterior chamber of the eye to the exterior is considered analytically using Snell's law. Imaging of the iridocorneal angle region and fundus is performed on ex vivo porcine samples and subsequently on small laboratory animals, such as the New Zealand white rabbit and nonhuman primate, in vivo. The integrated flexible handheld probe demonstrates high repeatability in iridocorneal angle and fundus documentation. The proposed concept and methodology are expected to find potential application in the diagnosis, prognosis, and management of glaucoma.
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Affiliation(s)
- Xun Jie Jeesmond Hong
- Nanyang Technological University, Centre for Optical and Laser Engineering, School of Mechanical and Aerospace Engineering, Singapore
| | - Vengalathunadakal K Shinoj
- Nanyang Technological University, Centre for Optical and Laser Engineering, School of Mechanical and Aerospace Engineering, Singapore
| | - Vadakke Matham Murukeshan
- Nanyang Technological University, Centre for Optical and Laser Engineering, School of Mechanical and Aerospace Engineering, Singapore
| | - Mani Baskaran
- Singapore Eye Research Institute and Singapore National Eye Centre, Singapore.,Duke-NUS Medicine School, EYE-ACP, Singapore
| | - Tin Aung
- Singapore Eye Research Institute and Singapore National Eye Centre, Singapore.,Duke-NUS Medicine School, EYE-ACP, Singapore.,Yong Loo Lin School of Medicine, Department of Ophthalmology, Singapore
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18
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Perinchery SM, Shinde A, Matham MV. Imaging behind opaque obstacle: a potential method for guided in vitro needle placement. BIOMEDICAL OPTICS EXPRESS 2016; 7:5308-5324. [PMID: 28018744 PMCID: PMC5175571 DOI: 10.1364/boe.7.005308] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/22/2016] [Revised: 11/21/2016] [Accepted: 11/21/2016] [Indexed: 05/08/2023]
Abstract
We report a simple real time optical imaging concept using an axicon lens to image the object kept behind opaque obstacles in free space. The proposed concept underlines the importance and advantages of using an axicon lens compared to a conventional lens to image behind the obstacle. The potential of this imaging concept is demonstrated by imaging the insertion of surgical needle in biological specimen in real time, without blocking the field of view. It is envisaged that this proposed concepts and methodology can make a telling impact in a wide variety of areas especially for diagnostics, therapeutics and microscopy applications.
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