1
|
Chen K, Abbasi N, Wong A, Bizheva K. In vivo, contactless, cellular resolution imaging of the human cornea with Powell lens based line field OCT. Sci Rep 2024; 14:22553. [PMID: 39343797 PMCID: PMC11439927 DOI: 10.1038/s41598-024-73402-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: 06/14/2024] [Accepted: 09/17/2024] [Indexed: 10/01/2024] Open
Abstract
Potentially blinding corneal diseases alter the morphology of the human cornea. At the early stages of disease development, these changes occur at the cellular level. The ability to visualize and quantify such changes can lead to early diagnostics of corneal pathologies, which is pivotal for the long-term preservation of vision. Here we present a Powell Lens-based Line-Field Optical Coherence Tomography system that combines high spatial resolution (2.4 μm × 2.2 μm × 1.7 μm (x × y × z)) in biological tissue, sufficient to resolve individual cells, high sensitivity (90.5 dB), sufficient to image the semi-transparent human cornea, and fast image acquisition rate (~ 2,400 fps), sufficient to suppress most involuntary eye motion artifacts and allow for contactless, in-vivo imaging of the cellular structure of the human cornea. Volumetric images acquired in-vivo from corneas of healthy subjects show epithelial, endothelial and keratocytes cells, as well as sub-basal and stromal nerves. The system's high axial resolution also allows for volumetric morphometry of the corneal endothelium, Descemet's membrane and the pre-Descemet's (Dua) layer.
Collapse
Affiliation(s)
- Keyu Chen
- Department of Physics and Astronomy, University of Waterloo, Waterloo, Canada
| | - Nima Abbasi
- Systems Design Engineering Department, University of Waterloo, Waterloo, Canada
| | - Alexander Wong
- Systems Design Engineering Department, University of Waterloo, Waterloo, Canada
| | - Kostadinka Bizheva
- Department of Physics and Astronomy, University of Waterloo, Waterloo, Canada.
- Systems Design Engineering Department, University of Waterloo, Waterloo, Canada.
- School of Optometry and Vision Sciences, University of Waterloo, Waterloo, Canada.
| |
Collapse
|
2
|
Abbasi N, Chen K, Wong A, Bizheva K. Computational approach for correcting defocus and suppressing speckle noise in line-field optical coherence tomography images. BIOMEDICAL OPTICS EXPRESS 2024; 15:5491-5504. [PMID: 39296416 PMCID: PMC11407272 DOI: 10.1364/boe.530569] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/20/2024] [Revised: 07/12/2024] [Accepted: 08/14/2024] [Indexed: 09/21/2024]
Abstract
The trade-off between transverse resolution and depth-of-focus (DOF) typical for optical coherence tomography (OCT) systems based on conventional optics, prevents "single-shot" acquisition of volumetric OCT images with sustained high transverse resolution over the entire imaging depth. Computational approaches for correcting defocus and higher order aberrations in OCT images developed in the past require highly stable phase data, which poses a significant technological challenge. Here, we present an alternative computational approach to sharpening OCT images and reducing speckle noise, based on intensity OCT data. The novel algorithm uses non-local priors to model correlated speckle noise within a maximum a posteriori framework to generate sharp and noise-free images. The performance of the algorithm was tested on images of plant tissue (cucumber) and in-vivo healthy human cornea, acquired with line-field spectral domain OCT (LF-SD-OCT) systems. The novel algorithm effectively suppressed speckle noise and sharpened or recovered morphological features in the OCT images for depths up to 13×DOF (depth-of-focus) relative to the focal plane.
Collapse
Affiliation(s)
- Nima Abbasi
- Department of Systems Design Engineering, University of Waterloo, Waterloo, Ontario, Canada
| | - Keyu Chen
- Department of Physics and Astronomy, University of Waterloo, Waterloo, Ontario, Canada
| | - Alexander Wong
- Department of Systems Design Engineering, University of Waterloo, Waterloo, Ontario, Canada
| | - Kostadinka Bizheva
- Department of Systems Design Engineering, University of Waterloo, Waterloo, Ontario, Canada
- Department of Physics and Astronomy, University of Waterloo, Waterloo, Ontario, Canada
- School of Optometry and Vision Sciences, University of Waterloo, Waterloo, Ontario, Canada
| |
Collapse
|
3
|
Fei K, Luo Z, Chen Y, Huang Y, Li S, Mazlin V, Boccara AC, Yuan J, Xiao P. Cellular structural and functional imaging of donor and pathological corneas with label-free dual-mode full-field optical coherence tomography. BIOMEDICAL OPTICS EXPRESS 2024; 15:3869-3888. [PMID: 38867788 PMCID: PMC11166435 DOI: 10.1364/boe.525116] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/28/2024] [Revised: 05/10/2024] [Accepted: 05/14/2024] [Indexed: 06/14/2024]
Abstract
In this study, a dual-mode full-field optical coherence tomography (FFOCT) was customized for label-free static and dynamic imaging of corneal tissues, including donor grafts and pathological specimens. Static images effectively depict relatively stable structures such as stroma, scar, and nerve fibers, while dynamic images highlight cells with active intracellular metabolism, specifically for corneal epithelial cells. The dual-mode images complementarily demonstrate the 3D microstructural features of the cornea and limbus. Dual-modal imaging reveals morphological and functional changes in corneal epithelial cells without labeling, indicating cellular apoptosis, swelling, deformation, dynamic signal alterations, and distinctive features of inflammatory cells in keratoconus and corneal leukoplakia. These findings propose dual-mode FFOCT as a promising technique for cellular-level cornea and limbus imaging.
Collapse
Affiliation(s)
- Keyi Fei
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou 510060, China
| | - Zhongzhou Luo
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou 510060, China
| | - Yupei Chen
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou 510060, China
| | - Yuancong Huang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou 510060, China
| | - Saiqun Li
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou 510060, China
| | - Viacheslav Mazlin
- Institut Langevin, ESPCI Paris, PSL Research University, CNRS, 1 rue Jussieu, Paris 75005, France
| | - Albert Claude Boccara
- Institut Langevin, ESPCI Paris, PSL Research University, CNRS, 1 rue Jussieu, Paris 75005, France
| | - Jin Yuan
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou 510060, China
| | - Peng Xiao
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou 510060, China
| |
Collapse
|
4
|
Zhang Y, Han X, Luo J, Zhang Q, He X. Viscoelasticity quantification of cancerous tongue using intraoral optical coherence elastography: a preliminary study. BIOMEDICAL OPTICS EXPRESS 2024; 15:3480-3491. [PMID: 38855658 PMCID: PMC11161336 DOI: 10.1364/boe.519078] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/17/2024] [Revised: 04/04/2024] [Accepted: 04/04/2024] [Indexed: 06/11/2024]
Abstract
Quantifying the biomechanical properties of the tongue is significant for early diagnosis of tongue carcinoma. Therefore, an intraoral optical coherence elastography system based on a miniature probe was proposed here to evaluate the viscoelasticity of in vivo tongue for the first time. Results of experiments with Sprague-Dawley rats indicate that considerable elasticity diversity occurred between cancerous and normal tongues, and the corresponding ratio of their Young's modulus was evaluated to be 3.74. It is also found that, viscosity in diseased tissue is smaller than that in normal tissue. Additionally, healthy, transitional and cancerous regions in the cancerous tongue can be distinguished easily by calculating viscoelasticity characteristics. Based on this preliminary attempt, our method with advantages of noninvasive, high-resolution, high-sensitivity and real-time detection and convenient operation may have good potential to become a useful tool for tongue carcinoma assessment after further optimization.
Collapse
Affiliation(s)
- Yubao Zhang
- Key Laboratory of Opto-Electronic Information Science and Technology of Jiangxi Province and Jiangxi Engineering Laboratory for Optoelectronics Testing Technology, Nanchang Hangkong University, Nanchang, P. R., China
| | - Xiao Han
- Key Laboratory of Opto-Electronic Information Science and Technology of Jiangxi Province and Jiangxi Engineering Laboratory for Optoelectronics Testing Technology, Nanchang Hangkong University, Nanchang, P. R., China
- School of Instrument Science and Opto-Electronics Engineering, Beihang University, Beijing, P. R., China
| | - Jiahui Luo
- Key Laboratory of Opto-Electronic Information Science and Technology of Jiangxi Province and Jiangxi Engineering Laboratory for Optoelectronics Testing Technology, Nanchang Hangkong University, Nanchang, P. R., China
| | - Qin Zhang
- Key Laboratory of Opto-Electronic Information Science and Technology of Jiangxi Province and Jiangxi Engineering Laboratory for Optoelectronics Testing Technology, Nanchang Hangkong University, Nanchang, P. R., China
| | - Xingdao He
- Key Laboratory of Opto-Electronic Information Science and Technology of Jiangxi Province and Jiangxi Engineering Laboratory for Optoelectronics Testing Technology, Nanchang Hangkong University, Nanchang, P. R., China
- School of Instrument Science and Opto-Electronics Engineering, Beihang University, Beijing, P. R., China
| |
Collapse
|
5
|
Setchfield K, Gorman A, Simpson AHRW, Somekh MG, Wright AJ. Effect of skin color on optical properties and the implications for medical optical technologies: a review. JOURNAL OF BIOMEDICAL OPTICS 2024; 29:010901. [PMID: 38269083 PMCID: PMC10807857 DOI: 10.1117/1.jbo.29.1.010901] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/13/2023] [Revised: 12/15/2023] [Accepted: 12/26/2023] [Indexed: 01/26/2024]
Abstract
Significance Skin color affects light penetration leading to differences in its absorption and scattering properties. COVID-19 highlighted the importance of understanding of the interaction of light with different skin types, e.g., pulse oximetry (PO) unreliably determined oxygen saturation levels in people from Black and ethnic minority backgrounds. Furthermore, with increased use of other medical wearables using light to provide disease information and photodynamic therapies to treat skin cancers, a thorough understanding of the effect skin color has on light is important for reducing healthcare disparities. Aim The aim of this work is to perform a thorough review on the effect of skin color on optical properties and the implication of variation on optical medical technologies. Approach Published in vivo optical coefficients associated with different skin colors were collated and their effects on optical penetration depth and transport mean free path (TMFP) assessed. Results Variation among reported values is significant. We show that absorption coefficients for dark skin are ∼ 6 % to 74% greater than for light skin in the 400 to 1000 nm spectrum. Beyond 600 nm, the TMFP for light skin is greater than for dark skin. Maximum transmission for all skin types was beyond 940 nm in this spectrum. There are significant losses of light with increasing skin depth; in this spectrum, depending upon Fitzpatrick skin type (FST), on average 14% to 18% of light is lost by a depth of 0.1 mm compared with 90% to 97% of the remaining light being lost by a depth of 1.93 mm. Conclusions Current published data suggest that at wavelengths beyond 940 nm light transmission is greatest for all FSTs. Data beyond 1000 nm are minimal and further study is required. It is possible that the amount of light transmitted through skin for all skin colors will converge with increasing wavelength enabling optical medical technologies to become independent of skin color.
Collapse
Affiliation(s)
- Kerry Setchfield
- University of Nottingham, Faculty of Engineering, Optics and Photonics Research Group, Nottingham, United Kingdom
| | - Alistair Gorman
- University of Edinburgh, School of Engineering, Edinburgh, United Kingdom
| | - A. Hamish R. W. Simpson
- University of Edinburgh, Department of Orthopaedics, Division of Clinical and Surgical Sciences, Edinburgh, United Kingdom
| | - Michael G. Somekh
- University of Nottingham, Faculty of Engineering, Optics and Photonics Research Group, Nottingham, United Kingdom
- Zhejiang Lab, Hangzhou, China
| | - Amanda J. Wright
- University of Nottingham, Faculty of Engineering, Optics and Photonics Research Group, Nottingham, United Kingdom
| |
Collapse
|
6
|
Zhu L, Makita S, Tamaoki J, Zhu Y, Mukherjee P, Lim Y, Kobayashi M, Yasuno Y. Polarization-artifact reduction and accuracy improvement of Jones-matrix polarization-sensitive optical coherence tomography by multi-focus-averaging based multiple scattering reduction. BIOMEDICAL OPTICS EXPRESS 2024; 15:256-276. [PMID: 38223182 PMCID: PMC10783893 DOI: 10.1364/boe.509763] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/19/2023] [Revised: 12/04/2023] [Accepted: 12/05/2023] [Indexed: 01/16/2024]
Abstract
Polarization-sensitive optical coherence tomography (PS-OCT) is a promising biomedical imaging tool for the differentiation of various tissue properties. However, the presence of multiple-scattering (MS) signals can degrade the quantitative polarization measurement accuracy. We demonstrate a method to reduce MS signals and increase the measurement accuracy of Jones matrix PS-OCT. This method suppresses MS signals by averaging multiple Jones matrix volumes measured using different focal positions. The MS signals are decorrelated among the volumes by focus position modulation and are thus reduced by averaging. However, the single scattering signals are kept consistent among the focus-modulated volumes by computational refocusing. We validated the proposed method using a scattering phantom and a postmortem medaka fish. The results showed reduced artifacts in birefringence and degree-of-polarization uniformity measurements, particularly in deeper regions in the samples. This method offers a practical solution to mitigate MS-induced artifacts in PS-OCT imaging and improves quantitative polarization measurement accuracy.
Collapse
Affiliation(s)
- Lida Zhu
- Computational Optics Group, University of Tsukuba, Tsukuba, Ibaraki, Japan
| | - Shuichi Makita
- Computational Optics Group, University of Tsukuba, Tsukuba, Ibaraki, Japan
| | - Junya Tamaoki
- Department of Molecular and Developmental
Biology, Institute of Medicine, University of
Tsukuba, Tsukuba, Ibaraki, Japan
| | - Yiqiang Zhu
- Computational Optics Group, University of Tsukuba, Tsukuba, Ibaraki, Japan
| | - Pradipta Mukherjee
- Computational Optics Group, University of Tsukuba, Tsukuba, Ibaraki, Japan
| | - Yiheng Lim
- Computational Optics Group, University of Tsukuba, Tsukuba, Ibaraki, Japan
| | - Makoto Kobayashi
- Department of Molecular and Developmental
Biology, Institute of Medicine, University of
Tsukuba, Tsukuba, Ibaraki, Japan
| | - Yoshiaki Yasuno
- Computational Optics Group, University of Tsukuba, Tsukuba, Ibaraki, Japan
| |
Collapse
|
7
|
Mazlin V. Optical tomography in a single camera frame using fringe-encoded deep-learning full-field OCT. BIOMEDICAL OPTICS EXPRESS 2024; 15:222-236. [PMID: 38223177 PMCID: PMC10783898 DOI: 10.1364/boe.506664] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2023] [Revised: 11/29/2023] [Accepted: 12/03/2023] [Indexed: 01/16/2024]
Abstract
Optical coherence tomography is a valuable tool for in vivo examination thanks to its superior combination of axial resolution, field-of-view and working distance. OCT images are reconstructed from several phases that are obtained by modulation/multiplexing of light wavelength or optical path. This paper shows that only one phase (and one camera frame) is sufficient for en face tomography. The idea is to encode a high-frequency fringe patterns into the selected layer of the sample using low-coherence interferometry. These patterns can then be efficiently extracted with a high-pass filter enhanced via deep learning networks to create the tomographic full-field OCT view. This brings 10-fold improvement in imaging speed, considerably reducing the phase errors and incoherent light artifacts related to in vivo movements. Moreover, this work opens a path for low-cost tomography with slow consumer cameras. Optically, the device resembles the conventional time-domain full-field OCT without incurring additional costs or a field-of-view/resolution reduction. The approach is validated by imaging in vivo cornea in human subjects. Open-source and easy-to-follow codes for data generation/training/inference with U-Net/Pix2Pix networks are provided to be used in a variety of image-to-image translation tasks.
Collapse
Affiliation(s)
- Viacheslav Mazlin
- Institut Langevin, ESPCI Paris, PSL University, CNRS, 1 rue Jussieu, 75005 Paris, France
- Quinze-Vingts National Eye Hospital, 28 Rue de Charenton, 75012 Paris, France
| |
Collapse
|
8
|
Sperlich K, Bohn S, Reichert KM, Stolz H, Guthoff RF, Stachs O, Allgeier S. [Chromatic Swept-Source Laser Scanning - Concept for a Cell-Resolving Confocal Laser Slit Lamp?]. Klin Monbl Augenheilkd 2023; 240:1375-1382. [PMID: 38092004 DOI: 10.1055/a-2184-9382] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2023]
Abstract
BACKGROUND The in vivo characterisation of corneal epithelial tissue morphology is of considerable importance for diagnosis, disease prognosis, and the development of a treatment strategy for ocular surface diseases. In contrast to many alternative methods, in vivo corneal confocal microscopy (CCM) not only provides a macroscopic description of the corneal tissue but also allows its visualisation with cellular resolution. However, the translation of CCM from research to clinical practice is significantly limited by the complex and still largely manual operation of available CCM systems. In addition, for cross-sectional images, and analogously to conventional slit lamp microscopy, volume data must be acquired in time-consuming depth scans due to the frontal orientation of the image field in CCM, from which depth slices can subsequently be calculated. The pure acquisition time is already in the range of seconds, and additionally, motion artefacts have to be corrected in a sophisticated way. MATERIALS AND METHODS This paper presents the concept and optics simulation of a new imaging technique based on a swept-source laser in combination with special chromatic optics. Here, the laser periodically changes its wavelength and is focused at different depths due to the wavelength-dependent aberration of the chromatic optics. RESULTS The optics simulation results promise good optical resolution at a total imaging depth of 145 µm. CONCLUSION The long-term goal is cell-resolving in vivo corneal confocal microscopy in real time with differently oriented sectioning directions.
Collapse
Affiliation(s)
- Karsten Sperlich
- Klinik und Poliklinik für Augenheilkunde, Universitätsmedizin Rostock, Deutschland
- Department Leben, Licht & Materie, Universität Rostock, Deutschland
| | - Sebastian Bohn
- Klinik und Poliklinik für Augenheilkunde, Universitätsmedizin Rostock, Deutschland
- Department Leben, Licht & Materie, Universität Rostock, Deutschland
| | - Klaus-Martin Reichert
- Institut für Automation und angewandte Informatik, Karlsruher Institut für Technologie (KIT), Eggenstein-Leopoldshafen, Deutschland
| | | | - Rudolf F Guthoff
- Klinik und Poliklinik für Augenheilkunde, Universitätsmedizin Rostock, Deutschland
- Department Leben, Licht & Materie, Universität Rostock, Deutschland
| | - Oliver Stachs
- Klinik und Poliklinik für Augenheilkunde, Universitätsmedizin Rostock, Deutschland
- Department Leben, Licht & Materie, Universität Rostock, Deutschland
| | - Stephan Allgeier
- Institut für Automation und angewandte Informatik, Karlsruher Institut für Technologie (KIT), Eggenstein-Leopoldshafen, Deutschland
| |
Collapse
|
9
|
Pattan HF, Liu X, Tankam P. Non-invasive in vivo imaging of human corneal microstructures with optical coherence microscopy. BIOMEDICAL OPTICS EXPRESS 2023; 14:4888-4900. [PMID: 37791273 PMCID: PMC10545177 DOI: 10.1364/boe.495242] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Revised: 08/06/2023] [Accepted: 08/16/2023] [Indexed: 10/05/2023]
Abstract
Non-invasive imaging systems with cellular-level resolution offer the opportunity to identify biomarkers of the early stage of corneal diseases, enabling early intervention, monitoring of disease progression, and evaluating treatment efficacy. In this study, a non-contact polarization-dependent optical coherence microscope (POCM) was developed to enable non-invasive in vivo imaging of human corneal microstructures. The system integrated quarter-wave plates into the sample and reference arms of the interferometer to enable deeper penetration of light in tissues as well as mitigate the strong specular reflection from the corneal surface. A common-path approach was adopted to enable control over the polarization in a free space configuration, thus alleviating the need for a broadband polarization-maintained fiber. The POCM achieved volumetric imaging of corneal microstructures, including endothelial cells over a field of view 0.5 × 0.5 mm2 with an almost isotropic resolution of ∼2.2 µm and a volume (500 × 500 × 2048 voxels) rate of 1 Hz. A self-interference approach between the corneal surface and underlying layers was also developed to lessen the corneal curvature and axial motion artifacts, thus enabling high-resolution imaging of microstructures in the anterior cornea, including squamous epithelial cells, wing epithelial cells, basal epithelial cells, sub-basal nerve plexus, and stromal keratocytes.
Collapse
Affiliation(s)
- Hadiya F. Pattan
- School of Optometry, Indiana University, Bloomington, IN, 47405, USA
| | - Xiao Liu
- School of Optometry, Indiana University, Bloomington, IN, 47405, USA
| | - Patrice Tankam
- School of Optometry, Indiana University, Bloomington, IN, 47405, USA
- Intelligent Systems Engineering, Luddy School of Informatics, Computing, and Engineering, Indiana University, Bloomington, IN, 47405, USA
| |
Collapse
|
10
|
Alhaddad S, Thouvenin O, Boccara M, Boccara C, Mazlin V. Comparative analysis of full-field OCT and optical transmission tomography. BIOMEDICAL OPTICS EXPRESS 2023; 14:4845-4861. [PMID: 37791282 PMCID: PMC10545181 DOI: 10.1364/boe.494585] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/02/2023] [Revised: 07/25/2023] [Accepted: 07/26/2023] [Indexed: 10/05/2023]
Abstract
This work compares two tomographic imaging technologies, time-domain full-field optical coherence tomography (FFOCT) working in reflection and optical transmission tomography (OTT), using a new optical setup that combines both. We show that, due to forward-scattering properties, the axial sectioning and contrast in OTT can be optimized by tuning illumination. The influence of sample scattering and thickness are discussed. We illustrate the comparison of the two methods in static (morphology) and dynamic (metabolic contrast) regimes using cell cultures, tissues and entire organisms emphasizing the advantages of both approaches.
Collapse
Affiliation(s)
- Samer Alhaddad
- Institut Langevin, ESPCI Paris, PSL University, CNRS, 1 rue Jussieu, 75005 Paris, France
| | - Olivier Thouvenin
- Institut Langevin, ESPCI Paris, PSL University, CNRS, 1 rue Jussieu, 75005 Paris, France
| | - Martine Boccara
- Institut de Systématique, Evolution, Biodiversité (ISYEB), Muséum National d’Histoire Naturelle, Sorbonne Université, EPHE, UA, CNRS ; CP 50, 57 rue Cuvier, 75005 Paris, France
| | - Claude Boccara
- Institut Langevin, ESPCI Paris, PSL University, CNRS, 1 rue Jussieu, 75005 Paris, France
| | - Viacheslav Mazlin
- Institut Langevin, ESPCI Paris, PSL University, CNRS, 1 rue Jussieu, 75005 Paris, France
| |
Collapse
|
11
|
Miażdżyk M, Consejo A, Iskander DR. OCT based corneal densitometry: the confounding effect of epithelial speckle. BIOMEDICAL OPTICS EXPRESS 2023; 14:3871-3880. [PMID: 37799674 PMCID: PMC10549732 DOI: 10.1364/boe.489054] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/02/2023] [Revised: 06/06/2023] [Accepted: 06/12/2023] [Indexed: 10/07/2023]
Abstract
Corneal densitometry is a clinically validated method for objectively assessing the transparency of stroma. The technique is currently dominated by Scheimpflug technology. Still, optical coherence tomography (OCT), in which examination of the statistical properties of corneal speckle is undertaken, has also been considered to assess corneal densitometry. In-vivo, the stroma is observed via the epithelium. However, the effect of this external layer on stromal densitometry has not been considered as yet. This study aims to quantify the influence of epithelium integrity on corneal OCT densitometry. OCT images from eleven freshly enucleated porcine eyes before and after epithelial debridement were used. OCT densitometry was investigated at different stromal depths using four metrics of speckle statistics. Results indicate that there exist statistically significant differences in speckle statistics for a given stromal depth depending on the presence or absence of the epithelium. The estimation error in speckle statistics can reach over 20% depending on the stromal depth. The anterior stroma densitometry values are the ones most affected by epithelial integrity. In conclusion, if OCT densitometry stromal parameters are to be considered in absolute terms, it is essential to consider the confounding effect of the epithelial layer in the analysis.
Collapse
Affiliation(s)
- Maria Miażdżyk
- Department of Biomedical Engineering,
Wroclaw University of Science and Technology, Wybrzeze Wyspianskiego 27, 50-370 Wroclaw, Poland
| | - Alejandra Consejo
- Department of Applied Physics, University of Zaragoza, Zaragoza, Spain
- Aragon Institute for Engineering Research (I3A), University of Zaragoza, Zaragoza, Spain
| | - D. Robert Iskander
- Department of Biomedical Engineering,
Wroclaw University of Science and Technology, Wybrzeze Wyspianskiego 27, 50-370 Wroclaw, Poland
| |
Collapse
|
12
|
Han L, Bizheva K. Correcting spatial-spectral crosstalk and chromatic aberrations in broadband line-scan spectral-domain OCT images. BIOMEDICAL OPTICS EXPRESS 2023; 14:3344-3361. [PMID: 37497512 PMCID: PMC10368066 DOI: 10.1364/boe.488881] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Revised: 05/30/2023] [Accepted: 06/02/2023] [Indexed: 07/28/2023]
Abstract
Digital correction of optical aberrations allows for high-resolution imaging across the full depth range in optical coherence tomography (OCT). Many digital aberration correction (DAC) methods have been proposed in the past to evaluate and correct monochromatic error in OCT images. However, other factors that deteriorate the image quality have not been fully investigated. Specifically, in a broadband line-scan spectral-domain OCT system (LS-SD-OCT), photons with different wavelengths scattered from the same transverse location and in the imaged object will be projected onto different spatial coordinates onto the 2D camera sensor, which in this work is defined as spatial-spectral crosstalk. In addition, chromatic aberrations in both axial and lateral directions are not negligible for broad spectral bandwidths. Here we present a novel approach to digital recovery of the spatial resolution in images acquired with a broadband LS-SD-OCT, which addresses these two main factors that limit the effectiveness of DAC for restoring diffraction-limited resolution in LS-SD-OCT images. In the proposed approach, spatial-spectral crosstalk and chromatic aberrations are suppressed by the registration of monochromatic sub-band tomograms that are digitally corrected for aberrations. The new method was validated by imaging a standard resolution target, a microspheres phantom, and different biological tissues. LS-SD-OCT technology combined with the proposed novel image reconstruction method could be a valuable research tool for various biomedical and clinical applications.
Collapse
Affiliation(s)
- Le Han
- Department of Physics and Astronomy, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
| | - Kostadinka Bizheva
- Department of Physics and Astronomy, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
- Department of Systems Design Engineering, University of Waterloo, Waterloo, Ontario, Canada
- School of Optometry and Vision Science, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
| |
Collapse
|
13
|
Zhang J, Mazlin V, Fei K, Boccara AC, Yuan J, Xiao P. Time-domain full-field optical coherence tomography (TD-FF-OCT) in ophthalmic imaging. Ther Adv Chronic Dis 2023; 14:20406223231170146. [PMID: 37152350 PMCID: PMC10161339 DOI: 10.1177/20406223231170146] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2022] [Accepted: 03/29/2023] [Indexed: 05/09/2023] Open
Abstract
Ocular imaging plays an irreplaceable role in the evaluation of eye diseases. Developing cellular-resolution ophthalmic imaging technique for more accurate and effective diagnosis and pathogenesis analysis of ocular diseases is a hot topic in the cross-cutting areas of ophthalmology and imaging. Currently, ocular imaging with traditional optical coherence tomography (OCT) is limited in lateral resolution and thus can hardly resolve cellular structures. Conventional OCT technology obtains ultra-high resolution at the expense of a certain imaging range and cannot achieve full field of view imaging. In the early years, Time-domain full-field OCT (TD-FF-OCT) has been mainly used for ex vivo ophthalmic tissue studies, limited by the low speed and low full-well capacity of existing two-dimensional (2D) cameras. The recent improvements in system design opened new imaging possibilities for in vivo applications thanks to its distinctive optical properties of TD-FF-OCT such as a spatial resolution almost insensitive to aberrations, and the possibility to control the curvature of the optical slice. This review also attempts to look at the future directions of TD-FF-OCT evolution, for example, the potential transfer of the functional-imaging dynamic TD-FF-OCT from the ex vivo into in vivo use and its expected benefit in basic and clinical ophthalmic research. Through non-invasive, wide-field, and cellular-resolution imaging, TD-FF-OCT has great potential to be the next-generation imaging modality to improve our understanding of human eye physiology and pathology.
Collapse
Affiliation(s)
- Jinze Zhang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, China
| | - Viacheslav Mazlin
- ESPCI Paris, PSL University, CNRS, Langevin Institute, Paris, France
| | - Keyi Fei
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, China
| | | | - Jin Yuan
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Jinsui Road 7, Guangzhou 510060, Guangdong, China
| | - Peng Xiao
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Jinsui Road 7, Guangzhou 510060, Guangdong, China
| |
Collapse
|
14
|
Khan S, Neuhaus K, Thaware O, Ni S, Ju MJ, Redd T, Huang D, Jian Y. Corneal imaging with blue-light optical coherence microscopy. BIOMEDICAL OPTICS EXPRESS 2022; 13:5004-5014. [PMID: 36187260 PMCID: PMC9484440 DOI: 10.1364/boe.465707] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/03/2022] [Revised: 08/17/2022] [Accepted: 08/17/2022] [Indexed: 06/16/2023]
Abstract
Corneal imaging is important for the diagnostic and therapeutic evaluation of many eye diseases. Optical coherence tomography (OCT) is extensively used in ocular imaging due to its non-invasive and high-resolution volumetric imaging characteristics. Optical coherence microscopy (OCM) is a technical variation of OCT that can image the cornea with cellular resolution. Here, we demonstrate a blue-light OCM as a low-cost and easily reproducible system to visualize corneal cellular structures such as epithelial cells, endothelial cells, keratocytes, and collagen bundles within stromal lamellae. Our blue-light OCM system achieved an axial resolution of 12 µm in tissue over a 1.2 mm imaging depth, and a lateral resolution of 1.6 µm over a field of view of 750 µm × 750 µm.
Collapse
Affiliation(s)
- Shanjida Khan
- Casey Eye Institute, Oregon Health & Science University, Portland, OR 97239, USA
- Department of Biomedical Engineering, Oregon Health & Science University, Portland, OR 97239, USA
| | - Kai Neuhaus
- Casey Eye Institute, Oregon Health & Science University, Portland, OR 97239, USA
| | - Omkar Thaware
- Casey Eye Institute, Oregon Health & Science University, Portland, OR 97239, USA
- Department of Biomedical Engineering, Oregon Health & Science University, Portland, OR 97239, USA
| | - Shuibin Ni
- Casey Eye Institute, Oregon Health & Science University, Portland, OR 97239, USA
- Department of Biomedical Engineering, Oregon Health & Science University, Portland, OR 97239, USA
| | - Myeong Jin Ju
- Department of Ophthalmology and Visual
Sciences, University of British Columbia,
Vancouver, BC, Canada
- School of Biomedical Engineering,
University of British Columbia, Vancouver,
BC, Canada
| | - Travis Redd
- Casey Eye Institute, Oregon Health & Science University, Portland, OR 97239, USA
| | - David Huang
- Casey Eye Institute, Oregon Health & Science University, Portland, OR 97239, USA
- Department of Biomedical Engineering, Oregon Health & Science University, Portland, OR 97239, USA
| | - Yifan Jian
- Casey Eye Institute, Oregon Health & Science University, Portland, OR 97239, USA
- Department of Biomedical Engineering, Oregon Health & Science University, Portland, OR 97239, USA
| |
Collapse
|
15
|
Han L, Tan B, Hosseinaee Z, Chen LK, Hileeto D, Bizheva K. Line-scanning SD-OCT for in-vivo, non-contact, volumetric, cellular resolution imaging of the human cornea and limbus. BIOMEDICAL OPTICS EXPRESS 2022; 13:4007-4020. [PMID: 35991928 PMCID: PMC9352278 DOI: 10.1364/boe.465916] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2022] [Accepted: 06/08/2022] [Indexed: 05/12/2023]
Abstract
In-vivo, non-contact, volumetric imaging of the cellular and sub-cellular structure of the human cornea and limbus with optical coherence tomography (OCT) is challenging due to involuntary eye motion that introduces both motion artifacts and blur in the OCT images. Here we present the design of a line-scanning (LS) spectral-domain (SD) optical coherence tomography system that combines 2 × 3 × 1.7 µm (x, y, z) resolution in biological tissue with an image acquisition rate of ∼2,500 fps, and demonstrate its ability to image in-vivo and without contact with the tissue surface, the cellular structure of the human anterior segment tissues. Volumetric LS-SD-OCT images acquired over a field-of-view (FOV) of 0.7 mm × 1.4 mm reveal fine morphological details in the healthy human cornea, such as epithelial and endothelial cells, sub-basal nerves, as well as the cellular structure of the limbal crypts, the palisades of Vogt (POVs) and the blood microvasculature of the human limbus. LS-SD-OCT is a promising technology that can assist ophthalmologists with the early diagnostics and optimal treatment planning of ocular diseases affecting the human anterior eye.
Collapse
Affiliation(s)
- Le Han
- Department of Physics and Astronomy,
University of Waterloo, Waterloo, Ontario
N2L 3G1, Canada
- Contributed equally
| | - Bingyao Tan
- Department of Physics and Astronomy,
University of Waterloo, Waterloo, Ontario
N2L 3G1, Canada
- School of Chemical and Biomedical
Engineering, Nanyang Technological
University, 637460, Singapore
- SERI-NTU Advanced Ocular
Engineering (STANCE), 639798, Singapore
- Singapore Eye Research Institute,
Singapore National Eye Center, 169856,
Singapore
- Contributed equally
| | - Zohreh Hosseinaee
- Department of Physics and Astronomy,
University of Waterloo, Waterloo, Ontario
N2L 3G1, Canada
- Department of Systems Design Engineering,
University of Waterloo, Waterloo, Ontario
N2L 3G1, Canada
| | - Lin Kun Chen
- Department of Physics and Astronomy,
University of Waterloo, Waterloo, Ontario
N2L 3G1, Canada
| | - Denise Hileeto
- School of Optometry and Vision Science,
University of Waterloo, Waterloo, Ontario
N2L 3G1, Canada
| | - Kostadinka Bizheva
- Department of Physics and Astronomy,
University of Waterloo, Waterloo, Ontario
N2L 3G1, Canada
- Department of Systems Design Engineering,
University of Waterloo, Waterloo, Ontario
N2L 3G1, Canada
- School of Optometry and Vision Science,
University of Waterloo, Waterloo, Ontario
N2L 3G1, Canada
| |
Collapse
|
16
|
Alexopoulos P, Madu C, Wollstein G, Schuman JS. The Development and Clinical Application of Innovative Optical Ophthalmic Imaging Techniques. Front Med (Lausanne) 2022; 9:891369. [PMID: 35847772 PMCID: PMC9279625 DOI: 10.3389/fmed.2022.891369] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2022] [Accepted: 05/23/2022] [Indexed: 11/22/2022] Open
Abstract
The field of ophthalmic imaging has grown substantially over the last years. Massive improvements in image processing and computer hardware have allowed the emergence of multiple imaging techniques of the eye that can transform patient care. The purpose of this review is to describe the most recent advances in eye imaging and explain how new technologies and imaging methods can be utilized in a clinical setting. The introduction of optical coherence tomography (OCT) was a revolution in eye imaging and has since become the standard of care for a plethora of conditions. Its most recent iterations, OCT angiography, and visible light OCT, as well as imaging modalities, such as fluorescent lifetime imaging ophthalmoscopy, would allow a more thorough evaluation of patients and provide additional information on disease processes. Toward that goal, the application of adaptive optics (AO) and full-field scanning to a variety of eye imaging techniques has further allowed the histologic study of single cells in the retina and anterior segment. Toward the goal of remote eye care and more accessible eye imaging, methods such as handheld OCT devices and imaging through smartphones, have emerged. Finally, incorporating artificial intelligence (AI) in eye images has the potential to become a new milestone for eye imaging while also contributing in social aspects of eye care.
Collapse
Affiliation(s)
- Palaiologos Alexopoulos
- Department of Ophthalmology, NYU Langone Health, NYU Grossman School of Medicine, New York, NY, United States
| | - Chisom Madu
- Department of Ophthalmology, NYU Langone Health, NYU Grossman School of Medicine, New York, NY, United States
| | - Gadi Wollstein
- Department of Ophthalmology, NYU Langone Health, NYU Grossman School of Medicine, New York, NY, United States
- Department of Biomedical Engineering, NYU Tandon School of Engineering, Brooklyn, NY, United States
- Center for Neural Science, College of Arts & Science, New York University, New York, NY, United States
| | - Joel S. Schuman
- Department of Ophthalmology, NYU Langone Health, NYU Grossman School of Medicine, New York, NY, United States
- Department of Biomedical Engineering, NYU Tandon School of Engineering, Brooklyn, NY, United States
- Center for Neural Science, College of Arts & Science, New York University, New York, NY, United States
- Department of Electrical and Computer Engineering, NYU Tandon School of Engineering, Brooklyn, NY, United States
| |
Collapse
|
17
|
Auksorius E, Borycki D, Wegrzyn P, Žičkienė I, Adomavičius K, Sikorski BL, Wojtkowski M. Multimode fiber as a tool to reduce cross talk in Fourier-domain full-field optical coherence tomography. OPTICS LETTERS 2022; 47:838-841. [PMID: 35167538 DOI: 10.1364/ol.449498] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/24/2021] [Accepted: 12/28/2021] [Indexed: 06/14/2023]
Abstract
Fourier-domain full-field optical coherence tomography (FD-FF-OCT) is an emerging tool for high-speed eye imaging. However, cross-talk formation in images limits the imaging depth. To this end, we have recently shown that reducing spatial coherence with a fast deformable membrane can suppress the noise but over a limited axial range and with substantial data processing. Here, we demonstrate that a multimode fiber with carefully chosen parameters enables cross-talk-free imaging over a long axial range and without significant artifacts. We also show that it can be used to image the human retina and choroid in vivo with exceptional contrast.
Collapse
|
18
|
Mazlin V, Xiao P, Irsch K, Scholler J, Groux K, Grieve K, Fink M, Boccara AC. Optical phase modulation by natural eye movements: application to time-domain FF-OCT image retrieval. BIOMEDICAL OPTICS EXPRESS 2022; 13:902-920. [PMID: 35284184 PMCID: PMC8884228 DOI: 10.1364/boe.445393] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/07/2021] [Revised: 12/10/2021] [Accepted: 12/10/2021] [Indexed: 05/24/2023]
Abstract
Eye movements are commonly seen as an obstacle to high-resolution ophthalmic imaging. In this context we study the natural axial movements of the in vivo human eye and show that they can be used to modulate the optical phase and retrieve tomographic images via time-domain full-field optical coherence tomography (TD-FF-OCT). This approach opens a path to a simplified ophthalmic TD-FF-OCT device, operating without the usual piezo motor-camera synchronization. The device demonstrates in vivo human corneal images under the different image retrieval schemes (2-phase and 4-phase) and different exposure times (3.5 ms, 10 ms, 20 ms). Data on eye movements, acquired with a spectral-domain OCT with axial eye tracking (180 B-scans/s), are used to study the influence of ocular motion on the probability of capturing high-signal tomographic images without phase washout. The optimal combinations of camera acquisition speed and amplitude of piezo modulation are proposed and discussed.
Collapse
Affiliation(s)
- Viacheslav Mazlin
- ESPCI Paris, PSL University, CNRS, Langevin Institute, 1 Rue Jussieu, 75005 Paris, France
| | - Peng Xiao
- ESPCI Paris, PSL University, CNRS, Langevin Institute, 1 Rue Jussieu, 75005 Paris, France
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, 510060, Guangzhou, China
| | - Kristina Irsch
- Vision Institute, Sorbonne University, CNRS, INSERM, 17 Rue Moreau, 75012 Paris, France
- Quinze-Vingts National Ophthalmology Hospital, 28 Rue de Charenton, 75012 Paris, France
| | - Jules Scholler
- ESPCI Paris, PSL University, CNRS, Langevin Institute, 1 Rue Jussieu, 75005 Paris, France
- Wyss Center for Bio and Neuroengineering, Chem. des Mines 9, 1202 Geneva, Switzerland
| | - Kassandra Groux
- ESPCI Paris, PSL University, CNRS, Langevin Institute, 1 Rue Jussieu, 75005 Paris, France
| | - Kate Grieve
- Vision Institute, Sorbonne University, CNRS, INSERM, 17 Rue Moreau, 75012 Paris, France
- Quinze-Vingts National Ophthalmology Hospital, 28 Rue de Charenton, 75012 Paris, France
| | - Mathias Fink
- ESPCI Paris, PSL University, CNRS, Langevin Institute, 1 Rue Jussieu, 75005 Paris, France
| | - A. Claude Boccara
- ESPCI Paris, PSL University, CNRS, Langevin Institute, 1 Rue Jussieu, 75005 Paris, France
| |
Collapse
|
19
|
Schenk MS, Wartak A, Buehler V, Zhao J, Tearney GJ, Birngruber R, Kassumeh S. Advances in Imaging of Subbasal Corneal Nerves With Micro-Optical Coherence Tomography. Transl Vis Sci Technol 2021; 10:22. [PMID: 34779835 PMCID: PMC8606792 DOI: 10.1167/tvst.10.13.22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose To investigate the most peripheral corneal nerve plexus using high-resolution micro-optical coherence tomography (µOCT) imaging and to assess µOCT's clinical potential as a screening tool for corneal and systemic diseases. Methods An experimental high-resolution (1.5 × 1.5 × 1 µm) µOCT setup was applied for three-dimensional imaging of the subbasal nerve plexus in nonhuman primates (NHPs) and swine within 3 hours postmortem. Morphologic features of subbasal nerves in µOCT were compared to β3 tubulin-stained fluorescence confocal microscopy (FCM). Parameters such as nerve density, nerve distribution, and imaging repeatability were evaluated, using semiautomatic image analysis in form of a custom corneal surface segmentation algorithm and NeuronJ. Results Swine and NHP corneas showed the species-specific nerve morphology in both imaging modalities. Most fibers showed a linear course, forming a highly parallel pattern, converging in a vortex with overall nerve densities varying between 9.51 and 24.24 mm/mm2. The repeatability of nerve density quantification of the µOCT scans as approximately 88% in multiple image recordings of the same cornea. Conclusions Compared to the current gold standard of FCM, µOCT's larger field of view of currently 1 × 1 mm increases the conclusiveness of density measurements, which, coupled with µOCT's feature of not requiring direct contact, shows promise for future clinical application. The nerve density quantification may be relevant for screening for systemic disease (e.g., peripheral neuropathy). Translational Relevance Technological advances in OCT technology may enable a quick assessment of corneal nerve density, which could be valuable evaluating ophthalmic and systemic peripheral innervation.
Collapse
Affiliation(s)
- Merle S Schenk
- Wellman Center for Photomedicine, Massachusetts General Hospital, Boston, MA, USA.,Department of Ophthalmology, Ludwig-Maximilians-University Munich, Munich, Germany
| | - Andreas Wartak
- Wellman Center for Photomedicine, Massachusetts General Hospital, Boston, MA, USA.,Department of Dermatology, Harvard Medical School, Harvard University, Boston, MA, USA
| | - Verena Buehler
- Wellman Center for Photomedicine, Massachusetts General Hospital, Boston, MA, USA.,Institute of Biomedical Optics, University of Luebeck, Luebeck, Germany
| | - Jie Zhao
- Wellman Center for Photomedicine, Massachusetts General Hospital, Boston, MA, USA
| | - Guillermo J Tearney
- Wellman Center for Photomedicine, Massachusetts General Hospital, Boston, MA, USA.,Department of Pathology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA.,Harvard-MIT Division of Health Sciences and Technology, Cambridge, MA, USA
| | - Reginald Birngruber
- Wellman Center for Photomedicine, Massachusetts General Hospital, Boston, MA, USA.,Institute of Biomedical Optics, University of Luebeck, Luebeck, Germany
| | - Stefan Kassumeh
- Wellman Center for Photomedicine, Massachusetts General Hospital, Boston, MA, USA.,Department of Ophthalmology, Ludwig-Maximilians-University Munich, Munich, Germany
| |
Collapse
|
20
|
Auksorius E. Fourier-domain full-field optical coherence tomography with real-time axial imaging. OPTICS LETTERS 2021; 46:4478-4481. [PMID: 34525026 DOI: 10.1364/ol.435104] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/23/2021] [Accepted: 08/11/2021] [Indexed: 06/13/2023]
Abstract
Fourier-domain full-field optical coherence tomography (FD-FF-OCT) is a fast interferometric imaging technique capable of volumetric sample imaging. However, half of the backscattered light from a sample is lost as it passes through a 50/50 beam splitter, which is at the heart of almost every interferometer. Here, it is demonstrated that this light could be extracted by spatially splitting the illumination pupil plane and detecting it with a separate camera. When a line camera is used to detect the recovered signal, it enables real-time axial imaging of the human cornea in vivo, which serves as a useful visual feedback for aligning a patient for imaging.
Collapse
|
21
|
Herrera-Pereda R, Taboada Crispi A, Babin D, Philips W, Holsbach Costa M. A Review On digital image processing techniques for in-Vivo confocal images of the cornea. Med Image Anal 2021; 73:102188. [PMID: 34340102 DOI: 10.1016/j.media.2021.102188] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2020] [Revised: 06/12/2021] [Accepted: 07/16/2021] [Indexed: 12/27/2022]
Abstract
This work reviews the scientific literature regarding digital image processing for in vivo confocal microscopy images of the cornea. We present and discuss a selection of prominent techniques designed for semi- and automatic analysis of four areas of the cornea (epithelium, sub-basal nerve plexus, stroma and endothelium). The main context is image enhancement, detection of structures of interest, and quantification of clinical information. We have found that the preprocessing stage lacks of quantitative studies regarding the quality of the enhanced image, or its effects in subsequent steps of the image processing. Threshold values are widely used in the reviewed methods, although generally, they are selected empirically and manually. The image processing results are evaluated in many cases through comparison with gold standards not widely accepted. It is necessary to standardize values to be quantified in terms of sensitivity and specificity of methods. Most of the reviewed studies do not show an estimation of the computational cost of the image processing. We conclude that reliable, automatic, computer-assisted image analysis of the cornea is still an open issue, constituting an interesting and worthwhile area of research.
Collapse
Affiliation(s)
- Raidel Herrera-Pereda
- Departamento de Bioinformática, Facultad de Ciencias y Tecnologías Computacionales, Universidad de las Ciencias Informáticas (UCI), Carretera a San Antonio de los Baños Km 2 1/2, Torrens, Boyeros, La Habana, Cuba; TELIN-IPI, Ghent University - imec, Belgium.
| | - Alberto Taboada Crispi
- Centro de Investigaciones de la Informática, Universidad Central "Marta Abreu" de Las Villas (UCLV), Carretera a Camajuaní, km 5 1/2, Santa Clara, VC, CP 54830, Cuba
| | | | | | - Márcio Holsbach Costa
- Department of Electrical and Electronic Engineering, Federal University of Santa Catarina, Florianópolis, SC, Brazil
| |
Collapse
|
22
|
Barolle V, Scholler J, Mecê P, Chassot JM, Groux K, Fink M, Claude Boccara A, Aubry A. Manifestation of aberrations in full-field optical coherence tomography. OPTICS EXPRESS 2021; 29:22044-22065. [PMID: 34265978 DOI: 10.1364/oe.419963] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/15/2021] [Accepted: 04/28/2021] [Indexed: 05/25/2023]
Abstract
We report on a theoretical model for image formation in full-field optical coherence tomography (FFOCT). Because the spatial incoherence of the illumination acts as a virtual confocal pinhole in FFOCT, its imaging performance is equivalent to a scanning time-gated coherent confocal microscope. In agreement with optical experiments enabling a precise control of aberrations, FFOCT is shown to have nearly twice the resolution of standard imaging at moderate aberration level. Beyond a rigorous study on the sensitivity of FFOCT with respect to aberrations, this theoretical model paves the way towards an optimized design of adaptive optics and computational tools for high-resolution and deep imaging of biological tissues.
Collapse
|
23
|
Puyo L, David C, Saad R, Saad S, Gautier J, Sahel JA, Borderie V, Paques M, Atlan M. Laser Doppler holography of the anterior segment for blood flow imaging, eye tracking, and transparency assessment. BIOMEDICAL OPTICS EXPRESS 2021; 12:4478-4495. [PMID: 34457427 PMCID: PMC8367265 DOI: 10.1364/boe.425272] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/18/2021] [Revised: 05/28/2021] [Accepted: 05/30/2021] [Indexed: 05/04/2023]
Abstract
Laser Doppler holography (LDH) is a full-field blood flow imaging technique able to reveal human retinal and choroidal blood flow with high temporal resolution. We here report on using LDH in the anterior segment of the eye without making changes to the instrument. Blood flow in the bulbar conjunctiva and episclera as well as in corneal neovascularization can be effectively imaged. We additionally demonstrate simultaneous holographic imaging of the anterior and posterior segments by simply adapting the numerical propagation distance to the plane of interest. We used this feature to track the movements of the retina and pupil with high temporal resolution. Finally, we show that the light backscattered by the retina can be used for retro-illumination of the anterior segment. Hence digital holography can reveal opacities caused by absorption or diffusion in the cornea and eye lens.
Collapse
Affiliation(s)
- Léo Puyo
- Centre Hospitalier National d’Ophtalmologie des Quinze-Vingts, INSERM-DHOS CIC 1423, 28 rue de Charenton, 75012 Paris, France
- Paris Eye Imaging, France
- Institute of Biomedical Optics, University of Lübeck. Peter-Monnik-Weg 4, 23562 Lübeck, Germany
| | - Clémentine David
- Centre Hospitalier National d’Ophtalmologie des Quinze-Vingts, INSERM-DHOS CIC 1423, 28 rue de Charenton, 75012 Paris, France
| | - Rana Saad
- Centre Hospitalier National d’Ophtalmologie des Quinze-Vingts, INSERM-DHOS CIC 1423, 28 rue de Charenton, 75012 Paris, France
- Paris Eye Imaging, France
| | - Sami Saad
- Centre Hospitalier National d’Ophtalmologie des Quinze-Vingts, INSERM-DHOS CIC 1423, 28 rue de Charenton, 75012 Paris, France
| | - Josselin Gautier
- Centre Hospitalier National d’Ophtalmologie des Quinze-Vingts, INSERM-DHOS CIC 1423, 28 rue de Charenton, 75012 Paris, France
- Paris Eye Imaging, France
| | - José Alain Sahel
- Centre Hospitalier National d’Ophtalmologie des Quinze-Vingts, INSERM-DHOS CIC 1423, 28 rue de Charenton, 75012 Paris, France
- Paris Eye Imaging, France
- Department of Ophthalmology, The University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA
- Institut de la Vision, Sorbonne Université, INSERM, CNRS, 17 Rue Moreau, 75012 Paris, France
| | - Vincent Borderie
- Centre Hospitalier National d’Ophtalmologie des Quinze-Vingts, INSERM-DHOS CIC 1423, 28 rue de Charenton, 75012 Paris, France
| | - Michel Paques
- Centre Hospitalier National d’Ophtalmologie des Quinze-Vingts, INSERM-DHOS CIC 1423, 28 rue de Charenton, 75012 Paris, France
- Paris Eye Imaging, France
- Institut de la Vision, Sorbonne Université, INSERM, CNRS, 17 Rue Moreau, 75012 Paris, France
| | - Michael Atlan
- Paris Eye Imaging, France
- Institut Langevin, CNRS, PSL University, ESPCI Paris, 1 rue Jussieu, 75005 Paris, France
| |
Collapse
|
24
|
Auksorius E, Borycki D, Wojtkowski M. Multimode fiber enables control of spatial coherence in Fourier-domain full-field optical coherence tomography for in vivo corneal imaging. OPTICS LETTERS 2021; 46:1413-1416. [PMID: 33720200 DOI: 10.1364/ol.417178] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/09/2020] [Accepted: 02/15/2021] [Indexed: 05/08/2023]
Abstract
Fourier-domain full-field optical coherence tomography (FD-FF-OCT) has recently emerged as a fast alternative to point-scanning confocal OCT in eye imaging. However, when imaging the cornea with FD-FF-OCT, a spatially coherent laser can focus down on the retina to a spot that exceeds the maximum permissible exposure level. Here we demonstrate that a long multimode fiber with a small core can be used to reduce the spatial coherence of the laser and, thus, enable ultrafast in vivo volumetric imaging of the human cornea without causing risk to the retina.
Collapse
|
25
|
Tsai MR, Ho TS, Wu YH, Lu CW. In vivo dual-mode full-field optical coherence tomography for differentiation of types of melanocytic nevi. JOURNAL OF BIOMEDICAL OPTICS 2021; 26:JBO-200353LR. [PMID: 33624460 PMCID: PMC7901856 DOI: 10.1117/1.jbo.26.2.020501] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Accepted: 02/03/2021] [Indexed: 05/04/2023]
Abstract
SIGNIFICANCE Melanocytic nevi represent the most common dermal melanocytic lesions in humans. Nevus is typically diagnosed clinically with the naked eye or with dermoscopy. However, it is essential to identify the type of nevus by invasive biopsy for histopathological examination. The use of noninvasive imaging tools can be used to evaluate the types of nevi to reduce unnecessary excisions of benign entities. AIM To evaluate the feasibility of using en face and cross-sectional full-field optical coherence tomography (FF-OCT) in differentiation of melanocytic nevi that can facilitate the reduction of unnecessary excisions of benign entities. APPROACH Dual-mode Mirau-type FF-OCT for cross-sectional imaging (B-scan) and en face imaging were used to distinguish the types of nevi. RESULTS Although the B-scan reveals the distribution of melanosomes, users can set a specific depth of the en face image to explore the morphology of surrounding skin cells instantly. According to the locations of nevus nests, the different types of nevi, including junction nevus and compound nevus, can be identified using this dual-mode FF-OCT system. CONCLUSIONS Combining B-scan and en face imaging in vivo FF-OCT enables the examination and navigation of skin tissues in real time and in three dimensions.
Collapse
Affiliation(s)
| | | | - Yu-Hung Wu
- Mackay Memorial Hospital, Department of Dermatology, Taipei, Taiwan
- Mackay Medical College, Department of Medicine, New Taipei City, Taiwan
| | - Chih-Wei Lu
- Apollo Medical Optics, Ltd., Taipei, Taiwan
- Address all correspondence to Chih-Wei Lu,
| |
Collapse
|
26
|
Wartak A, Schenk MS, Bühler V, Kassumeh SA, Birngruber R, Tearney GJ. Micro-optical coherence tomography for high-resolution morphologic imaging of cellular and nerval corneal micro-structures. BIOMEDICAL OPTICS EXPRESS 2020; 11:5920-5933. [PMID: 33149996 PMCID: PMC7587290 DOI: 10.1364/boe.402971] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/15/2020] [Revised: 08/31/2020] [Accepted: 09/13/2020] [Indexed: 05/15/2023]
Abstract
We demonstrate the highest resolution (1.5×1.5×1 µm) micrometer optical coherence tomography (µOCT) imaging of the morphologic micro-structure of excised swine and non-human primate corneas. Besides epithelial, stromal, and endothelial cell morphology, this report focuses on investigating the most peripheral corneal nerve fibers, the nerve fibers of the subbasal plexus (SBP). Alterations of SBP nerve density and composition are reportedly linked to major neurologic disorders, such as diabetic neuropathy, potentially indicating earliest onsets of denervation. Here, the fine, hyperreflective, epithelial nerve structures located just above Bowman's membrane, are i) visualized using our µOCT prototype, ii) validated by comparison to fluorescence confocal microscopy (including selective immunohistochemical staining), and iii) segmented using state-of-the-art image processing. Here, we also introduce polarization sensitive (PS) µOCT imaging, demonstrating, to the best of our knowledge, the highest resolution corneal PS-OCT scans reported to date.
Collapse
Affiliation(s)
- Andreas Wartak
- Wellman Center for Photomedicine, Massachusetts General Hospital, Boston, MA 02114, USA
- Department of Dermatology, Harvard Medical School, Harvard University, Boston, MA 02115, USA
- co-first authors
| | - Merle S. Schenk
- Wellman Center for Photomedicine, Massachusetts General Hospital, Boston, MA 02114, USA
- Department of Ophthalmology, University Hospital, LMU Munich, Munich 80336, Germany
- co-first authors
| | - Verena Bühler
- Wellman Center for Photomedicine, Massachusetts General Hospital, Boston, MA 02114, USA
- Institute of Biomedical Optics, University of Lübeck, Lübeck 23562, Germany
| | - Stefan A. Kassumeh
- Wellman Center for Photomedicine, Massachusetts General Hospital, Boston, MA 02114, USA
- Department of Ophthalmology, University Hospital, LMU Munich, Munich 80336, Germany
| | - Reginald Birngruber
- Wellman Center for Photomedicine, Massachusetts General Hospital, Boston, MA 02114, USA
- Institute of Biomedical Optics, University of Lübeck, Lübeck 23562, Germany
- co-senior authors
| | - Guillermo J. Tearney
- Wellman Center for Photomedicine, Massachusetts General Hospital, Boston, MA 02114, USA
- Department of Pathology, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA
- Harvard-MIT Division of Health Sciences and Technology, Cambridge, MA 02139, USA
- co-senior authors
| |
Collapse
|
27
|
Bohn S, Sperlich K, Stahnke T, Schünemann M, Stolz H, Guthoff RF, Stachs O. Multiwavelength confocal laser scanning microscopy of the cornea. BIOMEDICAL OPTICS EXPRESS 2020; 11:5689-5700. [PMID: 33149979 PMCID: PMC7587261 DOI: 10.1364/boe.397615] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/13/2020] [Revised: 07/31/2020] [Accepted: 08/25/2020] [Indexed: 05/04/2023]
Abstract
Confocal reflectance microscopy has demonstrated the ability to produce in vivo images of corneal tissue with sufficient cellular resolution to diagnose a broad range of corneal conditions. To investigate the spectral behavior of corneal reflectance imaging, a modified laser ophthalmoscope was used. Imaging was performed in vivo on a human cornea as well as ex vivo on porcine and lamb corneae. Various corneal layers were imaged at the wavelengths 488 nm, 518 nm, and 815 nm and compared regarding image quality and differences in the depicted structures. Besides the wavelength- and depth-dependent scattering background, which impairs the image quality, a varying spectral reflectance of certain structures could be observed. Based on the obtained results, this paper emphasizes the importance of choosing the appropriate light source for corneal imaging. For the examination of the epithelial layers and the endothelium, shorter wavelengths should be preferred. In the remaining layers, longer wavelength light has the advantage of less scattering loss and a potentially higher subject compliance.
Collapse
Affiliation(s)
- Sebastian Bohn
- Department of Ophthalmology, Rostock University Medical Center, 18057 Rostock, Germany
- Institute of Physics, University Rostock, 18059 Rostock, Germany
- Department of Life, Light & Matter, University Rostock, 18051 Rostock, Germany
- Co-first authors with equal contribution
| | - Karsten Sperlich
- Department of Ophthalmology, Rostock University Medical Center, 18057 Rostock, Germany
- Department of Life, Light & Matter, University Rostock, 18051 Rostock, Germany
- Co-first authors with equal contribution
| | - Thomas Stahnke
- Department of Ophthalmology, Rostock University Medical Center, 18057 Rostock, Germany
- Department of Life, Light & Matter, University Rostock, 18051 Rostock, Germany
| | - Melanie Schünemann
- Department of Ophthalmology, Rostock University Medical Center, 18057 Rostock, Germany
- Department of Life, Light & Matter, University Rostock, 18051 Rostock, Germany
| | - Heinrich Stolz
- Institute of Physics, University Rostock, 18059 Rostock, Germany
| | - Rudolf F Guthoff
- Department of Ophthalmology, Rostock University Medical Center, 18057 Rostock, Germany
- Department of Life, Light & Matter, University Rostock, 18051 Rostock, Germany
| | - Oliver Stachs
- Department of Ophthalmology, Rostock University Medical Center, 18057 Rostock, Germany
- Department of Life, Light & Matter, University Rostock, 18051 Rostock, Germany
| |
Collapse
|
28
|
Nishino T, Kobayashi A, Mori N, Yokogawa H, Sugiyama K. In vivo Imaging of Reis-Bücklers and Thiel-Behnke Corneal Dystrophies Using Anterior Segment Optical Coherence Tomography. Clin Ophthalmol 2020; 14:2601-2607. [PMID: 32982153 PMCID: PMC7490037 DOI: 10.2147/opth.s265136] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2020] [Accepted: 07/27/2020] [Indexed: 01/27/2023] Open
Abstract
Purpose To investigate in vivo corneal changes of genetically confirmed Reis–Bücklers corneal dystrophy (RBCD) and Thiel–Behnke corneal dystrophy (TBCD) using anterior segment optical coherence tomography (AS-OCT). Design A single-center, prospective, comparative case series. Methods Seven patients from 3 pedigrees (3 males, 4 females) with RBCD [Arg124Leu (R124L) heterozygous missense mutation of human transforming growth factor beta-induced (TGFBI) gene] and 4 patients from 3 pedigrees (3 males, 1 female) with TBCD [Arg555Gln (R555Q) heterozygous missense mutation of TGFBI gene] were examined. Six patients with RBCD and three patients with TBCD exhibited recurrence after corneal surgery including penetrating keratoplasty, phototherapeutic keratectomy, and electrolysis. All patients were examined by slit-lamp biomicroscopy followed by AS-OCT. Selected AS-OCT images of the cornea were evaluated qualitatively for changes in shape and degree of light reflection of corneal deposits. Results Slit-lamp biomicroscopy showed characteristic irregular gray opacities in Bowman’s layer in each dystrophy: a geographic pattern in RBCD and a honeycomb pattern in TBCD. In each dystrophy, distinct characteristic deposits were observed by AS-OCT as a banding lesion in Bowman’s layer and its adjacent epithelium/stroma. In RBCD, the banding lesion was highly reflective and sharply margined at the stroma. In contrast, deposits in TBCD in the same layer showed a saw-tooth pattern toward the epithelium and poorly margined at the stroma. Conclusion AS-OCT is able to clearly identify characteristic in vivo corneal microstructural changes associated with RBCD and TBCD. As a result, in vivo differentiation of RBCD and TBCD can be achieved.
Collapse
Affiliation(s)
- Tsubasa Nishino
- Department of Ophthalmology, Kanazawa University Graduate School of Medical Science, Kanazawa, Japan
| | - Akira Kobayashi
- Department of Ophthalmology, Kanazawa University Graduate School of Medical Science, Kanazawa, Japan
| | - Natsuko Mori
- Department of Ophthalmology, Kanazawa University Graduate School of Medical Science, Kanazawa, Japan
| | - Hideaki Yokogawa
- Department of Ophthalmology, Kanazawa University Graduate School of Medical Science, Kanazawa, Japan
| | - Kazuhisa Sugiyama
- Department of Ophthalmology, Kanazawa University Graduate School of Medical Science, Kanazawa, Japan
| |
Collapse
|
29
|
Canavesi C, Cogliati A, Hindman HB. Unbiased corneal tissue analysis using Gabor-domain optical coherence microscopy and machine learning for automatic segmentation of corneal endothelial cells. JOURNAL OF BIOMEDICAL OPTICS 2020; 25:1-17. [PMID: 32770867 PMCID: PMC7413309 DOI: 10.1117/1.jbo.25.9.092902] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/25/2020] [Accepted: 07/23/2020] [Indexed: 05/08/2023]
Abstract
SIGNIFICANCE An accurate, automated, and unbiased cell counting procedure is needed for tissue selection for corneal transplantation. AIM To improve accuracy and reduce bias in endothelial cell density (ECD) quantification by combining Gabor-domain optical coherence microscopy (GDOCM) for three-dimensional, wide field-of-view (1 mm2) corneal imaging and machine learning for automatic delineation of endothelial cell boundaries. APPROACH Human corneas stored in viewing chambers were imaged over a wide field-of-view with GDOCM without contacting the specimens. Numerical methods were applied to compensate for the natural curvature of the cornea and produce an image of the flattened endothelium. A convolutional neural network (CNN) was trained to automatically delineate the cell boundaries using 180 manually annotated images from six corneas. Ten additional corneas were imaged with GDOCM and compared with specular microscopy (SM) to determine performance of the combined GDOCM and CNN to achieve automated endothelial counts relative to current procedural standards. RESULTS Cells could be imaged over a larger area with GDOCM than SM, and more cells could be delineated via automatic cell segmentation than via manual methods. ECD obtained from automatic cell segmentation of GDOCM images yielded a correlation of 0.94 (p < 0.001) with the manual segmentation on the same images, and correlation of 0.91 (p < 0.001) with the corresponding manually counted SM results. CONCLUSIONS Automated endothelial cell counting on GDOCM images with large field of view eliminates selection bias and reduces sampling error, which both affect the gold standard of manual counting on SM images.
Collapse
Affiliation(s)
- Cristina Canavesi
- LighTopTech Corp., West Henrietta, New York, United States
- Address all correspondence to Cristina Canavesi, E-mail:
| | | | | |
Collapse
|
30
|
Weber TD, Mertz J. In vivo corneal and lenticular microscopy with asymmetric fundus retroillumination. BIOMEDICAL OPTICS EXPRESS 2020; 11:3263-3273. [PMID: 32637253 PMCID: PMC7316012 DOI: 10.1364/boe.391815] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/11/2020] [Revised: 05/12/2020] [Accepted: 05/15/2020] [Indexed: 05/07/2023]
Abstract
We describe a new technique for non-contact in vivo corneal and lenticular microscopy. It is based on fundus retro-reflection and back-illumination of the crystalline lens and cornea. To enhance phase-gradient contrast, we apply asymmetric illumination by illuminating one side of the fundus. The technique produces micron-scale lateral resolution images across a 1 mm diagonal field of view in the central cornea. We show representative images of the epithelium, the subbasal nerve plexus, large stromal nerves, dendritic immune cells, endothelial nuclei, and the anterior crystalline lens, demonstrating the potential of this instrument for clinical applications.
Collapse
Affiliation(s)
- Timothy D. Weber
- Department of Biomedical Engineering, Boston University, 44 Cummington Mall, Boston, MA 02215, USA
| | - Jerome Mertz
- Department of Biomedical Engineering, Boston University, 44 Cummington Mall, Boston, MA 02215, USA
- Photonics Center, Boston University, 8 Saint Mary’s Street, Boston, MA 02215, USA
| |
Collapse
|