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Das V, Zhang F, Bower AJ, Li J, Liu T, Aguilera N, Alvisio B, Liu Z, Hammer DX, Tam J. Revealing speckle obscured living human retinal cells with artificial intelligence assisted adaptive optics optical coherence tomography. COMMUNICATIONS MEDICINE 2024; 4:68. [PMID: 38600290 PMCID: PMC11006674 DOI: 10.1038/s43856-024-00483-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2023] [Accepted: 03/13/2024] [Indexed: 04/12/2024] Open
Abstract
BACKGROUND In vivo imaging of the human retina using adaptive optics optical coherence tomography (AO-OCT) has transformed medical imaging by enabling visualization of 3D retinal structures at cellular-scale resolution, including the retinal pigment epithelial (RPE) cells, which are essential for maintaining visual function. However, because noise inherent to the imaging process (e.g., speckle) makes it difficult to visualize RPE cells from a single volume acquisition, a large number of 3D volumes are typically averaged to improve contrast, substantially increasing the acquisition duration and reducing the overall imaging throughput. METHODS Here, we introduce parallel discriminator generative adversarial network (P-GAN), an artificial intelligence (AI) method designed to recover speckle-obscured cellular features from a single AO-OCT volume, circumventing the need for acquiring a large number of volumes for averaging. The combination of two parallel discriminators in P-GAN provides additional feedback to the generator to more faithfully recover both local and global cellular structures. Imaging data from 8 eyes of 7 participants were used in this study. RESULTS We show that P-GAN not only improves RPE cell contrast by 3.5-fold, but also improves the end-to-end time required to visualize RPE cells by 99-fold, thereby enabling large-scale imaging of cells in the living human eye. RPE cell spacing measured across a large set of AI recovered images from 3 participants were in agreement with expected normative ranges. CONCLUSIONS The results demonstrate the potential of AI assisted imaging in overcoming a key limitation of RPE imaging and making it more accessible in a routine clinical setting.
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Affiliation(s)
- Vineeta Das
- National Eye Institute, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Furu Zhang
- National Eye Institute, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Andrew J Bower
- National Eye Institute, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Joanne Li
- National Eye Institute, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Tao Liu
- National Eye Institute, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Nancy Aguilera
- National Eye Institute, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Bruno Alvisio
- National Eye Institute, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Zhuolin Liu
- Center for Devices and Radiological Health, U.S. Food and Drug Administration, Silver Spring, MD, 20993, USA
| | - Daniel X Hammer
- Center for Devices and Radiological Health, U.S. Food and Drug Administration, Silver Spring, MD, 20993, USA
| | - Johnny Tam
- National Eye Institute, National Institutes of Health, Bethesda, MD, 20892, USA.
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2
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Kurokawa K, Nemeth M. Multifunctional adaptive optics optical coherence tomography allows cellular scale reflectometry, polarimetry, and angiography in the living human eye. BIOMEDICAL OPTICS EXPRESS 2024; 15:1331-1354. [PMID: 38404344 PMCID: PMC10890865 DOI: 10.1364/boe.505395] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/07/2023] [Revised: 01/15/2024] [Accepted: 01/16/2024] [Indexed: 02/27/2024]
Abstract
Clinicians are unable to detect glaucoma until substantial loss or dysfunction of retinal ganglion cells occurs. To this end, novel measures are needed. We have developed an optical imaging solution based on adaptive optics optical coherence tomography (AO-OCT) to discern key clinical features of glaucoma and other neurodegenerative diseases at the cellular scale in the living eye. Here, we test the feasibility of measuring AO-OCT-based reflectance, retardance, optic axis orientation, and angiogram at specifically targeted locations in the living human retina and optic nerve head. Multifunctional imaging, combined with focus stacking and global image registration algorithms, allows us to visualize cellular details of retinal nerve fiber bundles, ganglion cell layer somas, glial septa, superior vascular complex capillaries, and connective tissues. These are key histologic features of neurodegenerative diseases, including glaucoma, that are now measurable in vivo with excellent repeatability and reproducibility. Incorporating this noninvasive cellular-scale imaging with objective measurements will significantly enhance existing clinical assessments, which is pivotal in facilitating the early detection of eye disease and understanding the mechanisms of neurodegeneration.
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Affiliation(s)
- Kazuhiro Kurokawa
- Discoveries in Sight Research Laboratories, Devers Eye Institute, Legacy Research Institute, Legacy Health, Portland, OR 97232, USA
| | - Morgan Nemeth
- Discoveries in Sight Research Laboratories, Devers Eye Institute, Legacy Research Institute, Legacy Health, Portland, OR 97232, USA
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3
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Verma A, Magesan K, Mahalingam M, T A, Sadda SR, Corradetti G, Alagorie AR, Gnanaraj R, Sen P. Age-Related Alterations of the Macular Choroid in Healthy Eyes Assessed by Swept-Source Optical Coherence Tomography Angiography. Ophthalmic Surg Lasers Imaging Retina 2023; 54:526-534. [PMID: 37642439 DOI: 10.3928/23258160-20230728-01] [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: 08/31/2023]
Abstract
OBJECTIVE To analyze age-related changes in the choroid in healthy eyes using swept-source optical coherence tomography angiography (SS-OCTA). PATIENTS AND METHODS This was a cross-sectional, prospective, observational study enrolling 222 eyes of 116 healthy participants. SS-OCTA images were captured using the PLEX Elite 9000 (Carl Zeiss Meditec) with a 6 x 6 mm pattern centered on the fovea. Subfoveal choroidal thickness (CT) and choroidal volume (CV) were generated automatically through manufacturer tools available in the Advanced Retinal Imaging (ARI) hub network. Choroidal vascularity index (CVI) and choriocapillaris flow deficits (CCFD) were computed using ImageJ. RESULTS CV was found to be significantly higher in women than men. Overall, there was a significant positive correlation between CVI and CCFD, and a significant negative correlation between CT and CV with age. The relationship, however, was more complex, as a decade-wise analysis showed that CT and CV increased until the second decade, followed by a decrease until the sixth decade, and then an increase again in the seventh and eighth decades. CVI was highest in the seventh decade. In contrast, CCFD increased consistently with age and in all the Early Treatment of Diabetic Retinopathy Study (ETDRS) rings. CONCLUSION The choroidal blood flow and its thickness reduces as the age advances. While the choroidal flow deficits show a consistent increase with age and the distance from the foveal center, the relationship of other parameters with age is more complex. Having a normative database from healthy subjects is imperative for understanding the changes taking place in diseased states. Choroidal parameters can show significant variations with age. These differences are not uniform or consistent with age, highlighting the importance of a normative reference database to assess the significance of choroidal alterations associated with disease. [Ophthalmic Surg Lasers Imaging Retina 2023;54:526-534.].
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Kar D, Corradetti G, Swain TA, Clark ME, McGwin G, Owsley C, Sadda SR, Curcio CA. Choriocapillaris Impairment Is Associated With Delayed Rod-Mediated Dark Adaptation in Age-Related Macular Degeneration. Invest Ophthalmol Vis Sci 2023; 64:41. [PMID: 37768273 PMCID: PMC10540875 DOI: 10.1167/iovs.64.12.41] [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: 08/29/2023] [Accepted: 09/06/2023] [Indexed: 09/29/2023] Open
Abstract
Purpose Progress toward treatment and prevention of age-related macular degeneration (AMD) requires imaging end points that relate to vision. We investigated choriocapillaris flow signal deficits (FD%) and visual function in eyes of individuals aged ≥60 years, with and without AMD. Methods One eye of each participant in the baseline visit of the Alabama Study on Early Age-Related Macular Degeneration 2 (ALSTAR2; NCT04112667) was studied. AMD presence and severity was determined using the Age-Related Eye Disease Study (AREDS) grading system. FD% was quantified using macular spectral domain optical coherence tomography angiography (OCTA) scans. Vision tests included rod-mediated dark adaptation (RMDA), best-corrected visual acuity, and contrast sensitivity (photopic and mesopic), and microperimetric light sensitivity (scotopic, mesopic, and photopic). Presence of subretinal drusenoid deposits (SDD) was determined using multimodal imaging. Results In 410 study eyes of 410 participants (mean [SD] age = 71.7 years [5.9]), FD% was higher in early AMD (mean [SD] = 54.0% [5.5], N = 122) and intermediate AMD (59.8% [7.4], N = 92), compared to normal (52.1% [5.3], N = 196) eyes. Among visual functions evaluated, RMDA showed the strongest association with FD% (r = 0.35, P < 0.0001), followed by contrast sensitivity (r = -0.22, P < 0.0001). Eyes with SDD had worse FD% (58.3% [7.4], N = 87), compared to eyes without SDD (53.4% [6.0], N = 323, P = < 0.0001). Conclusions Choriocapillaris FD% were associated with AMD severity and with impaired vision, especially RMDA. Reduced metabolic transport and exchange across the choriocapillaris-Bruch's membrane retinal pigment epithelium (RPE) complex, a causal factor for high-risk soft drusen formation, also may impair photoreceptor sustenance from the circulation. This includes retinoid resupply, essential to dynamic rod function.
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Affiliation(s)
- Deepayan Kar
- Department of Ophthalmology and Visual Sciences, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, United States
| | - Giulia Corradetti
- Doheny Eye Institute, Los Angeles, California, United States
- Department of Ophthalmology, David Geffen School of Medicine at University of California, Los Angeles, California, United States
| | - Thomas A. Swain
- Department of Ophthalmology and Visual Sciences, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, United States
- Department of Epidemiology, School of Public Health, University of Alabama at Birmingham, Birmingham, Alabama, United States
| | - Mark E. Clark
- Department of Ophthalmology and Visual Sciences, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, United States
| | - Gerald McGwin
- Department of Ophthalmology and Visual Sciences, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, United States
- Department of Epidemiology, School of Public Health, University of Alabama at Birmingham, Birmingham, Alabama, United States
| | - Cynthia Owsley
- Department of Ophthalmology and Visual Sciences, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, United States
| | - SriniVas R. Sadda
- Doheny Eye Institute, Los Angeles, California, United States
- Department of Ophthalmology, David Geffen School of Medicine at University of California, Los Angeles, California, United States
| | - Christine A. Curcio
- Department of Ophthalmology and Visual Sciences, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, United States
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Ashourizadeh H, Fakhri M, Hassanpour K, Masoudi A, Jalali S, Roshandel D, Chen FK. Pearls and Pitfalls of Adaptive Optics Ophthalmoscopy in Inherited Retinal Diseases. Diagnostics (Basel) 2023; 13:2413. [PMID: 37510157 PMCID: PMC10377978 DOI: 10.3390/diagnostics13142413] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2023] [Revised: 07/12/2023] [Accepted: 07/18/2023] [Indexed: 07/30/2023] Open
Abstract
Adaptive optics (AO) retinal imaging enables individual photoreceptors to be visualized in the clinical setting. AO imaging can be a powerful clinical tool for detecting photoreceptor degeneration at a cellular level that might be overlooked through conventional structural assessments, such as spectral-domain optical coherence tomography (SD-OCT). Therefore, AO imaging has gained significant interest in the study of photoreceptor degeneration, one of the most common causes of inherited blindness. Growing evidence supports that AO imaging may be useful for diagnosing early-stage retinal dystrophy before it becomes apparent on fundus examination or conventional retinal imaging. In addition, serial AO imaging may detect structural disease progression in early-stage disease over a shorter period compared to SD-OCT. Although AO imaging is gaining popularity as a structural endpoint in clinical trials, the results should be interpreted with caution due to several pitfalls, including the lack of standardized imaging and image analysis protocols, frequent ocular comorbidities that affect image quality, and significant interindividual variation of normal values. Herein, we summarize the current state-of-the-art AO imaging and review its potential applications, limitations, and pitfalls in patients with inherited retinal diseases.
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Affiliation(s)
| | - Maryam Fakhri
- Ophthalmic Research Center, Research Institute for Ophthalmology and Vision Sciences, Shahid Beheshti University of Medical Sciences, Tehran 16666, Iran
| | - Kiana Hassanpour
- Ophthalmic Research Center, Research Institute for Ophthalmology and Vision Sciences, Shahid Beheshti University of Medical Sciences, Tehran 16666, Iran
| | - Ali Masoudi
- Stein Eye Institute, David Geffen School of Medicine, University of California, Los Angeles, CA 90095, USA
| | - Sattar Jalali
- Department of Physics, Central Tehran Branch, Islamic Azad University, Tehran 19558, Iran
| | - Danial Roshandel
- Centre for Ophthalmology and Visual Science, The University of Western Australia, Nedlands, WA 6009, Australia
- Ocular Tissue Engineering Laboratory, Lions Eye Institute, Nedlands, WA 6009, Australia
| | - Fred K Chen
- Centre for Ophthalmology and Visual Science, The University of Western Australia, Nedlands, WA 6009, Australia
- Ocular Tissue Engineering Laboratory, Lions Eye Institute, Nedlands, WA 6009, Australia
- Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, Melbourne, VIC 3002, Australia
- Ophthalmology, Department of Surgery, University of Melbourne, Melbourne, VIC 3010, Australia
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6
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Keles A, Karaman SK, Duzgun AC, Buyuksireci M, Bayraktaroglu MS. Association between lower extremity venous insufficiency and increased choroidal thickness. J Fr Ophtalmol 2023:S0181-5512(23)00120-1. [PMID: 36948916 DOI: 10.1016/j.jfo.2023.01.001] [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: 10/16/2022] [Accepted: 01/23/2023] [Indexed: 03/24/2023]
Abstract
PURPOSE The goal of this study is to investigate the association between the choroid and lower extremity venous insufficiency (LEVI). METHODS This prospective cross-sectional study includes 56 patients with LEVI and 50 age/sex-similar control subjects. Choroidal thickness (CT) measurements from 5 different points were captured from all participants by optical coherence tomography. In the group with LEVI on physical examination, reflux at the saphenofemoral junction, and the diameter of the great and small saphenous veins were evaluated via color Doppler ultrasonography. RESULTS The mean subfoveal CT was higher in the varicose group than in the control group (363.04±99.75μm vs. 320.30±73.46μm, P=0.013). In addition, the CTs at the temporal 3mm, temporal 1mm, nasal 1mm, and nasal 3mm distance from the fovea were higher in the LEVI group compared to the controls (for all, P<0.05). There was no correlation between CT and diameter of the great and small saphenous vein in patients with LEVI (for all, P>0.05). However, the great and small saphenous veins of patients with CT above 400μm were observed to be wider in patients with LEVI (P=0.027 and P=0.007, respectively). CONCLUSION Varicose veins can be a feature of systemic venous pathology. Another component of systemic venous disease may be increased CT. Patients with high CT should be investigated for susceptibility to LEVI.
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Affiliation(s)
- A Keles
- Department of Ophthalmology, Faculty of Medicine, Bilecik Seyh Edebali University, Bilecik, Turkey.
| | - S K Karaman
- Department of Ophthalmology, University of Health Sciences, Ankara Ulucanlar Eye Training and Research Hospital, Ankara, Turkey
| | - A C Duzgun
- Department of Cardiovascular Surgery, Ankara Training and Research Hospital, Ankara, Turkey
| | - M Buyuksireci
- Department of Radiology, Çorum Private Hospital, Çorum, Turkey
| | - M S Bayraktaroglu
- Department of Cardiovascular Surgery, Ankara Training and Research Hospital, Ankara, Turkey
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7
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Williams DR, Burns SA, Miller DT, Roorda A. Evolution of adaptive optics retinal imaging [Invited]. BIOMEDICAL OPTICS EXPRESS 2023; 14:1307-1338. [PMID: 36950228 PMCID: PMC10026580 DOI: 10.1364/boe.485371] [Citation(s) in RCA: 15] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/12/2023] [Accepted: 02/02/2023] [Indexed: 05/02/2023]
Abstract
This review describes the progress that has been achieved since adaptive optics (AO) was incorporated into the ophthalmoscope a quarter of a century ago, transforming our ability to image the retina at a cellular spatial scale inside the living eye. The review starts with a comprehensive tabulation of AO papers in the field and then describes the technological advances that have occurred, notably through combining AO with other imaging modalities including confocal, fluorescence, phase contrast, and optical coherence tomography. These advances have made possible many scientific discoveries from the first maps of the topography of the trichromatic cone mosaic to exquisitely sensitive measures of optical and structural changes in photoreceptors in response to light. The future evolution of this technology is poised to offer an increasing array of tools to measure and monitor in vivo retinal structure and function with improved resolution and control.
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Affiliation(s)
- David R. Williams
- The Institute of Optics and the Center for
Visual Science, University of Rochester,
Rochester NY, USA
| | - Stephen A. Burns
- School of Optometry, Indiana
University at Bloomington, Bloomington IN, USA
| | - Donald T. Miller
- School of Optometry, Indiana
University at Bloomington, Bloomington IN, USA
| | - Austin Roorda
- Herbert Wertheim School of Optometry and
Vision Science, University of California at Berkeley, Berkeley CA, USA
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8
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Agrawal R, Weng RC, Fonollosa A, Giralt L, Artaraz J, Yang P, Huang F, Tan B, Schmetterer L, Sen A, Gupta V, Xin W. Outcome Measures for Disease Monitoring in Intraocular Inflammatory and Infectious Diseases (OCTOMERIA): Understanding the Choroid in Uveitis with Optical Coherence Tomography (OCT). Ocul Immunol Inflamm 2023; 31:374-392. [PMID: 35201909 DOI: 10.1080/09273948.2022.2026414] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
PURPOSE To compare imaging modalities for the choroid of the eye, and evaluate various choroidal changes in uveitides entities. METHODS A comprehensive systematic literature review was conducted looking at current imaging modalities available to assess choroid architecture and commonly used parameters available to qualify and quantify choroidal changes, before looking at specific uveitides entities with choroidal involvement which have been broadly separated into non-infectious and infectious in etiology. RESULTS We describe the various modalities currently available to evaluate the choroid of the eye such as Ultrasound B Scan, ICGA, and OCT. Choroidal changes in various ocular and systemic diseases such as Behcet's Disease, Sarcoidosis, Syphillis, Tuberculosis, and many more have been reported and published. CONCLUSION Multiple choroidal tomographic and angiotomographic findings have been demonstrated for evaluation in uveitis. These findings can manifest in multiple ocular and systemic diseases, and can be illustrated using the various imaging modalities at present. Future advancements in choroidal imaging would help to adapt these findings into parameters for clinical practice to properly evaluate these ocular and systemic diseases.
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Affiliation(s)
- Rupesh Agrawal
- Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore.,National Healthcare Group Eye Institute, Tan Tock Seng Hospital, Singapore, Singapore.,Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore, Singapore.,Singapore Eye Research Institute, Singapore National Eye Centre, Singapore, Singapore.,Duke NUS Medical School, Singapore, Singapore
| | - Rei Chern Weng
- Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Alex Fonollosa
- Department of Ophthalmology, BioCruces Bizkaia Health Research Institute, Cruces University Hospital, University of the Basque Country, Barakaldo, Spain.,Retina Department, Instituto Oftalmológico Bilbao, Bilbao, Spain
| | - Lena Giralt
- Department of Ophthalmology, BioCruces Bizkaia Health Research Institute, Cruces University Hospital, University of the Basque Country, Barakaldo, Spain
| | - Joseba Artaraz
- Department of Ophthalmology, BioCruces Bizkaia Health Research Institute, Cruces University Hospital, University of the Basque Country, Barakaldo, Spain
| | - Peizeng Yang
- The First Affiliated Hospital of Chongqing Medical University, Chongqing Key Laboratory of Ophthalmology and Chongqing Eye Institute, Chongqing Branch of National Clinical Research Center for Ocular Diseases, Chongqing, China
| | - Fanfan Huang
- The First Affiliated Hospital of Chongqing Medical University, Chongqing Key Laboratory of Ophthalmology and Chongqing Eye Institute, Chongqing Branch of National Clinical Research Center for Ocular Diseases, Chongqing, China
| | - Bingyao Tan
- Singapore Eye Research Institute, Singapore National Eye Centre, Singapore, Singapore.,SERI-NTU Advanced Ocular Engineering (STANCE), Singapore, Singapore.,School of Chemical and Biomedical Engineering, Nanyang Technological University, Singapore, Singapore
| | - Leopold Schmetterer
- Singapore Eye Research Institute, Singapore National Eye Centre, Singapore, Singapore.,SERI-NTU Advanced Ocular Engineering (STANCE), Singapore, Singapore.,School of Chemical and Biomedical Engineering, Nanyang Technological University, Singapore, Singapore.,Academic Clinical Program, Duke-NUS Medical School, Singapore, Singapore.,Department of Clinical Pharmacology, Medical University of Vienna, Vienna, Austria.,Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria.,Ocular Imaging Department, Singapore Eye Research Institute, Institute of Molecular and Clinical Ophthalmology Basel Switzerland
| | - Alok Sen
- Department of Vitreo-Retina Services, Sadguru Netra Chikitsalaya, Chitrakoot, India.,The Bodhya Eye Consortium, India
| | - Vishali Gupta
- Department of Vitreoretina, Post Graduate Institute of Medical Education and Research, Chitrakoot, India
| | - Wei Xin
- National Healthcare Group Eye Institute, Tan Tock Seng Hospital, Singapore, Singapore
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Morgan JIW, Chui TYP, Grieve K. Twenty-five years of clinical applications using adaptive optics ophthalmoscopy [Invited]. BIOMEDICAL OPTICS EXPRESS 2023; 14:387-428. [PMID: 36698659 PMCID: PMC9841996 DOI: 10.1364/boe.472274] [Citation(s) in RCA: 14] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/02/2022] [Revised: 11/22/2022] [Accepted: 11/27/2022] [Indexed: 05/02/2023]
Abstract
Twenty-five years ago, adaptive optics (AO) was combined with fundus photography, thereby initiating a new era in the field of ophthalmic imaging. Since that time, clinical applications of AO ophthalmoscopy to investigate visual system structure and function in both health and disease abound. To date, AO ophthalmoscopy has enabled visualization of most cell types in the retina, offered insight into retinal and systemic disease pathogenesis, and been integrated into clinical trials. This article reviews clinical applications of AO ophthalmoscopy and addresses remaining challenges for AO ophthalmoscopy to become fully integrated into standard ophthalmic care.
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Affiliation(s)
- Jessica I. W. Morgan
- Scheie Eye Institute, Department of Ophthalmology, University of Pennsylvania, Philadelphia, PA 19104, USA
- Center for Advanced Retinal and Ocular Therapeutics, University of Pennsylvania, Philadelphia, PA 19104, USA
- Contributed equally
| | - Toco Y. P. Chui
- Department of Ophthalmology, The New York Eye and Ear Infirmary of Mount Sinai, New York, NY 10003, USA
- Contributed equally
| | - Kate Grieve
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, 17 rue Moreau, and CHNO des Quinze-Vingts, INSERM-DGOS CIC 1423, 28 rue de Charenton, F-75012 Paris, France
- Contributed equally
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10
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Liu Z, Zhang F, Zucca K, Agrawal A, Hammer DX. Ultrahigh-speed multimodal adaptive optics system for microscopic structural and functional imaging of the human retina. BIOMEDICAL OPTICS EXPRESS 2022; 13:5860-5878. [PMID: 36733751 PMCID: PMC9872887 DOI: 10.1364/boe.462594] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/28/2022] [Revised: 09/16/2022] [Accepted: 09/20/2022] [Indexed: 05/02/2023]
Abstract
We describe the design and performance of a multimodal and multifunctional adaptive optics (AO) system that combines scanning laser ophthalmoscopy (SLO) and optical coherence tomography (OCT) for simultaneous retinal imaging at 13.4 Hz. The high-speed AO-OCT channel uses a 3.4 MHz Fourier-domain mode-locked (FDML) swept source. The system achieves exquisite resolution and sensitivity for pan-macular and transretinal visualization of retinal cells and structures while providing a functional assessment of the cone photoreceptors. The ultra-high speed also enables wide-field scans for clinical usability and angiography for vascular visualization. The FDA FDML-AO system is a powerful platform for studying various retinal and neurological diseases for vision science research, retina physiology investigation, and biomarker development.
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Affiliation(s)
- Zhuolin Liu
- Center for Devices and Radiological Health
(CDRH), U. S. Food and Drug Administration (FDA), Silver Spring, Maryland 20993, USA
| | - Furu Zhang
- Center for Devices and Radiological Health
(CDRH), U. S. Food and Drug Administration (FDA), Silver Spring, Maryland 20993, USA
- Co-first author
| | - Kelvy Zucca
- Center for Devices and Radiological Health
(CDRH), U. S. Food and Drug Administration (FDA), Silver Spring, Maryland 20993, USA
| | - Anant Agrawal
- Center for Devices and Radiological Health
(CDRH), U. S. Food and Drug Administration (FDA), Silver Spring, Maryland 20993, USA
| | - Daniel X. Hammer
- Center for Devices and Radiological Health
(CDRH), U. S. Food and Drug Administration (FDA), Silver Spring, Maryland 20993, USA
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11
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Sampson DM, Dubis AM, Chen FK, Zawadzki RJ, Sampson DD. Towards standardizing retinal optical coherence tomography angiography: a review. LIGHT, SCIENCE & APPLICATIONS 2022; 11:63. [PMID: 35304441 PMCID: PMC8933532 DOI: 10.1038/s41377-022-00740-9] [Citation(s) in RCA: 33] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2021] [Revised: 02/01/2022] [Accepted: 02/14/2022] [Indexed: 05/11/2023]
Abstract
The visualization and assessment of retinal microvasculature are important in the study, diagnosis, monitoring, and guidance of treatment of ocular and systemic diseases. With the introduction of optical coherence tomography angiography (OCTA), it has become possible to visualize the retinal microvasculature volumetrically and without a contrast agent. Many lab-based and commercial clinical instruments, imaging protocols and data analysis methods and metrics, have been applied, often inconsistently, resulting in a confusing picture that represents a major barrier to progress in applying OCTA to reduce the burden of disease. Open data and software sharing, and cross-comparison and pooling of data from different studies are rare. These inabilities have impeded building the large databases of annotated OCTA images of healthy and diseased retinas that are necessary to study and define characteristics of specific conditions. This paper addresses the steps needed to standardize OCTA imaging of the human retina to address these limitations. Through review of the OCTA literature, we identify issues and inconsistencies and propose minimum standards for imaging protocols, data analysis methods, metrics, reporting of findings, and clinical practice and, where this is not possible, we identify areas that require further investigation. We hope that this paper will encourage the unification of imaging protocols in OCTA, promote transparency in the process of data collection, analysis, and reporting, and facilitate increasing the impact of OCTA on retinal healthcare delivery and life science investigations.
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Affiliation(s)
- Danuta M Sampson
- Surrey Biophotonics, Centre for Vision, Speech and Signal Processing and School of Biosciences and Medicine, The University of Surrey, Guildford, GU2 7XH, UK.
| | - Adam M Dubis
- NIHR Biomedical Research Centre at Moorfields Eye Hospital NHS Trust and UCL Institute of Ophthalmology, London, EC1V 2PD, UK
| | - Fred K Chen
- Centre for Ophthalmology and Visual Science (incorporating Lions Eye Institute), The University of Western Australia, Nedlands, Western Australia, 6009, Australia
- Department of Ophthalmology, Royal Perth Hospital, Perth, Western Australia, 6000, Australia
- Ophthalmology, Department of Surgery, University of Melbourne, Melbourne, Victoria, 3002, Australia
| | - Robert J Zawadzki
- Department of Ophthalmology & Vision Science, University of California Davis, Sacramento, CA, 95817, USA
| | - David D Sampson
- Surrey Biophotonics, Advanced Technology Institute, School of Physics and School of Biosciences and Medicine, University of Surrey, Guildford, Surrey, GU2 7XH, UK
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12
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Zouache MA. Variability in Retinal Neuron Populations and Associated Variations in Mass Transport Systems of the Retina in Health and Aging. Front Aging Neurosci 2022; 14:778404. [PMID: 35283756 PMCID: PMC8914054 DOI: 10.3389/fnagi.2022.778404] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2021] [Accepted: 01/13/2022] [Indexed: 11/17/2022] Open
Abstract
Aging is associated with a broad range of visual impairments that can have dramatic consequences on the quality of life of those impacted. These changes are driven by a complex series of alterations affecting interactions between multiple cellular and extracellular elements. The resilience of many of these interactions may be key to minimal loss of visual function in aging; yet many of them remain poorly understood. In this review, we focus on the relation between retinal neurons and their respective mass transport systems. These metabolite delivery systems include the retinal vasculature, which lies within the inner portion of the retina, and the choroidal vasculature located externally to the retinal tissue. A framework for investigation is proposed and applied to identify the structures and processes determining retinal mass transport at the cellular and tissue levels. Spatial variability in the structure of the retina and changes observed in aging are then harnessed to explore the relation between variations in neuron populations and those seen among retinal metabolite delivery systems. Existing data demonstrate that the relation between inner retinal neurons and their mass transport systems is different in nature from that observed between the outer retina and choroid. The most prominent structural changes observed across the eye and in aging are seen in Bruch’s membrane, which forms a selective barrier to mass transfers at the interface between the choroidal vasculature and the outer retina.
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13
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Tan B, Lim NA, Tan R, Gan ATL, Chua J, Nusinovici S, Cheung CMG, Chakravarthy U, Wong TY, Schmetterer L, Tan G. Combining retinal and choroidal microvascular metrics improves discriminative power for diabetic retinopathy. Br J Ophthalmol 2022:bjophthalmol-2021-319739. [PMID: 35140059 PMCID: PMC10359699 DOI: 10.1136/bjophthalmol-2021-319739] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2021] [Accepted: 01/13/2022] [Indexed: 01/04/2023]
Abstract
PURPOSE To use optical coherence tomography angiography (OCTA) parameters from both the retinal and choroidal microvasculature to detect the presence and severity of diabetic retinopathy (DR). METHOD This is a cross-sectional case-control study. OCTA parameters from retinal vasculature, fovea avascular zone (FAZ) and choriocapillaris were evaluated from 3×3 mm2 fovea-centred scans. Areas under the receiver operating characteristic (ROC) curve were used to compare the discriminative power on the presence of diabetes mellitus (DM), the presence of DR and need for referral: group 1 (no DM vs DM no DR), group 2 (no DR vs any DR) and group 3 (non-proliferative DR (NPDR) vs proliferative DR (PDR)). RESULTS 35 eyes from 27 participants with no DM and 132 eyes from 75 with DM were included. DR severity was classified into three groups: no DR group (62 eyes), NPDR (51 eyes), PDR (19 eyes). All retinal vascular parameters, FAZ parameters and choriocapillaris parameters were strongly altered with DR stages (p<0.01), except for the deep plexus FAZ area (p=0.619). Choriocapillaris parameters allowed to better discriminate between no DM versus DM no DR group compared with retinal parameters (areas under the ROC curve=0.954 vs 0.821, p=0.006). A classification model including retinal and choroidal microvasculature significantly improved the discrimination between DR and no DR compared with each parameter separately (p=0.029). CONCLUSIONS Evaluating OCTA parameters from both the retinal and choroidal microvasculature in 3×3 mm scans improves the discrimination of DM and early DR.
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Affiliation(s)
- Bingyao Tan
- Singapore Eye Research Institute, Singapore.,SERI-NTU Advanced Ocular Engineering (STANCE) Program, Singapore.,School of Chemical and Biomedical Engineering, Nanyang Technological University, Singapore
| | - Nicole-Ann Lim
- Singapore Eye Research Institute, Singapore.,Department of Ophthalmology, Yong Loo Lin School of Medicine, Singapore
| | - Rose Tan
- Singapore Eye Research Institute, Singapore.,Singapore National Eye Centre, Singapore
| | | | - Jacqueline Chua
- Singapore Eye Research Institute, Singapore.,SERI-NTU Advanced Ocular Engineering (STANCE) Program, Singapore.,Singapore National Eye Centre, Singapore.,Academic Clinical Program, Duke-NUS Medical School, Singapore
| | - Simon Nusinovici
- Singapore Eye Research Institute, Singapore.,Academic Clinical Program, Duke-NUS Medical School, Singapore
| | - Chui Ming Gemmy Cheung
- Singapore Eye Research Institute, Singapore.,Singapore National Eye Centre, Singapore.,Academic Clinical Program, Duke-NUS Medical School, Singapore
| | - Usha Chakravarthy
- School of Medicine, Dentistry and Biomedical Sciencens, Queen's University Belfast, Belfast, UK
| | - Tien Yin Wong
- Singapore Eye Research Institute, Singapore.,Singapore National Eye Centre, Singapore.,Academic Clinical Program, Duke-NUS Medical School, Singapore
| | - Leopold Schmetterer
- Singapore Eye Research Institute, Singapore.,SERI-NTU Advanced Ocular Engineering (STANCE) Program, Singapore.,School of Chemical and Biomedical Engineering, Nanyang Technological University, Singapore.,Department of Ophthalmology, Yong Loo Lin School of Medicine, Singapore.,Academic Clinical Program, Duke-NUS Medical School, Singapore.,Department of Clinical Pharmacology, Medical University of Vienna, Vienna, Austria
| | - Gavin Tan
- Singapore Eye Research Institute, Singapore .,Singapore National Eye Centre, Singapore.,Academic Clinical Program, Duke-NUS Medical School, Singapore
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14
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You QS, Camino A, Wang J, Guo Y, Flaxel CJ, Hwang TS, Huang D, Jia Y, Bailey ST. Geographic Atrophy Progression Is Associated With Choriocapillaris Flow Deficits Measured With Optical Coherence Tomographic Angiography. Invest Ophthalmol Vis Sci 2021; 62:28. [PMID: 34964802 PMCID: PMC8727307 DOI: 10.1167/iovs.62.15.28] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose The purpose of this study was to assess the associations between baseline choriocapillaris (CC) flow deficits and geographic atrophy (GA) progression. Methods In this prospective cohort study, patients with GA underwent 3 × 3-mm macular spectral-domain optical coherence tomographic angiography (OCTA) at baseline and follow-up visits. Annual GA enlargement rate was defined as change of square root of GA area in 12 months. Shadow areas due to iris, media opacity, retinal vessels, and drusen were excluded. CC vessel density (CC-VD) in non-GA areas was measured using a validated machine-learning-based algorithm. Low perfusion area (LPA) was defined as capillary density below the 0.1 percentile threshold of the same location of 40 normal healthy control eye. Focal perfusion loss (FPL) was defined as percentage of CC loss within LPA compared with normal controls. Results Ten patients with GA were enrolled and followed for 26 months on average. At baseline, the mean GA area was 0.84 ± 0.70 mm2. The mean CC-VD was 44.5 ± 15.2%, the mean LPA was 4.29 ± 2.6 mm2, and the mean FPL was 50.4 ± 28.2%. The annual GA enlargement rate was significantly associated with baseline CC-VD (r = -0.816, P = 0.004), LPA (r = 0.809, P = 0.005), and FPL (r = 0.800, P = 0.005), but not with age (r = 0.008, P = 0.98) and GA area (r = -0.362, P = 0.30). Conclusions Baseline CC flow deficits were significantly associated with a faster GA enlargement over the course of 1 year, suggesting the choriocapillaris perfusion outside of a GA area may play a role in GA progression.
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Affiliation(s)
- Qi Sheng You
- Casey Eye Institute, Oregon Health and Science University, Portland, Oregon, United States.,Kresge Eye Institute, Detroit Medical Center, Wayne State University, Detroit, Michigan, United States
| | - Acner Camino
- Casey Eye Institute, Oregon Health and Science University, Portland, Oregon, United States
| | - Jie Wang
- Casey Eye Institute, Oregon Health and Science University, Portland, Oregon, United States.,Department of Biomedical Engineering, Oregon Health & Science University, Portland, Oregon, United States
| | - Yukun Guo
- Casey Eye Institute, Oregon Health and Science University, Portland, Oregon, United States
| | - Christina J Flaxel
- Casey Eye Institute, Oregon Health and Science University, Portland, Oregon, United States
| | - Thomas S Hwang
- Casey Eye Institute, Oregon Health and Science University, Portland, Oregon, United States
| | - David Huang
- Casey Eye Institute, Oregon Health and Science University, Portland, Oregon, United States
| | - Yali Jia
- Casey Eye Institute, Oregon Health and Science University, Portland, Oregon, United States.,Department of Biomedical Engineering, Oregon Health & Science University, Portland, Oregon, United States
| | - Steven T Bailey
- Casey Eye Institute, Oregon Health and Science University, Portland, Oregon, United States
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15
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Abstract
Advances in retinal imaging are enabling researchers and clinicians to make precise noninvasive measurements of the retinal vasculature in vivo. This includes measurements of capillary blood flow, the regulation of blood flow, and the delivery of oxygen, as well as mapping of perfused blood vessels. These advances promise to revolutionize our understanding of vascular regulation, as well as the management of retinal vascular diseases. This review provides an overview of imaging and optical measurements of the function and structure of the ocular vasculature. We include general characteristics of vascular systems with an emphasis on the eye and its unique status. The functions of vascular systems are discussed, along with physical principles governing flow and its regulation. Vascular measurement techniques based on reflectance and absorption are briefly introduced, emphasizing ways of generating contrast. One of the prime ways to enhance contrast within vessels is to use techniques sensitive to the motion of cells, allowing precise measurements of perfusion and blood velocity. Finally, we provide a brief introduction to retinal vascular diseases.
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Affiliation(s)
- Stephen A Burns
- Indiana University School of Optometry, Bloomington, Indiana 47405, USA; , ,
| | - Ann E Elsner
- Indiana University School of Optometry, Bloomington, Indiana 47405, USA; , ,
| | - Thomas J Gast
- Indiana University School of Optometry, Bloomington, Indiana 47405, USA; , ,
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16
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Pandiyan VP, Jiang X, Kuchenbecker JA, Sabesan R. Reflective mirror-based line-scan adaptive optics OCT for imaging retinal structure and function. BIOMEDICAL OPTICS EXPRESS 2021; 12:5865-5880. [PMID: 34692221 PMCID: PMC8515964 DOI: 10.1364/boe.436337] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/08/2021] [Revised: 08/16/2021] [Accepted: 08/20/2021] [Indexed: 05/06/2023]
Abstract
Line-scan OCT incorporated with adaptive optics (AO) offers high resolution, speed, and sensitivity for imaging retinal structure and function in vivo. Here, we introduce its implementation with reflective mirror-based afocal telescopes, optimized for imaging light-induced retinal activity (optoretinography) and weak retinal reflections at the cellular scale. A non-planar optical design was followed based on previous recommendations with key differences specific to a line-scan geometry. The three beam paths fundamental to an OCT system -illumination/sample, detection, and reference- were modeled in Zemax optical design software to yield theoretically diffraction-limited performance over a 2.2 deg. field-of-view and 1.5 D vergence range at the eye's pupil. The performance for imaging retinal structure was exemplified by cellular-scale visualization of retinal ganglion cells, macrophages, foveal cones, and rods in human observers. The performance for functional imaging was exemplified by resolving the light-evoked optical changes in foveal cone photoreceptors where the spatial resolution was sufficient for cone spectral classification at an eccentricity 0.3 deg. from the foveal center. This enabled the first in vivo demonstration of reduced S-cone (short-wavelength cone) density in the human foveola, thus far observed only in ex vivo histological preparations. Together, the feasibility for high resolution imaging of retinal structure and function demonstrated here holds significant potential for basic science and translational applications.
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Affiliation(s)
- Vimal Prabhu Pandiyan
- Department of Ophthalmology, University of Washington School of Medicine, Seattle, WA 98109, USA
- Co-first authors with equal contribution
| | - Xiaoyun Jiang
- Department of Ophthalmology, University of Washington School of Medicine, Seattle, WA 98109, USA
- Co-first authors with equal contribution
| | - James A Kuchenbecker
- Department of Ophthalmology, University of Washington School of Medicine, Seattle, WA 98109, USA
| | - Ramkumar Sabesan
- Department of Ophthalmology, University of Washington School of Medicine, Seattle, WA 98109, USA
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17
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Ng DSC, Chan LKY, Ng CM, Lai TYY. Visualising the choriocapillaris: Histology, imaging modalities and clinical research - A review. Clin Exp Ophthalmol 2021; 50:91-103. [PMID: 34387023 DOI: 10.1111/ceo.13984] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2021] [Accepted: 08/09/2021] [Indexed: 01/02/2023]
Abstract
The choriocapillaris plays a considerable role in the normal physiology of the eye as well as in various diseases. Assessing the changes in the choriocapillaris can therefore provide important information about normal ageing and pathogenesis of visual impairment, and even some systemic diseases. In vivo imaging of the choriocapillaris has evolved from non-depth resolved, dye-based angiography to advanced, high-resolution optical coherence tomography angiography (OCTA). However, the intricate microvascular networks within the choriocapillaris are still beyond the resolving limits of most OCTA instruments. Knowledge of histology, meticulous image acquisition methods, recognition of artefact and post-acquisition processing techniques are necessary for optimising OCTA choriocapillaris images. Qualitative and quantitative analyses of the choriocapillaris provide clinical information in age-related macular degeneration (AMD), diabetic retinopathy (DR), pathologic myopia and central serous chorioretinopathy (CSC). Furthermore, studies have revealed choriocapillaris changes in posterior uveitis that are correlated with treatment outcome and have important prognostic significance. In addition to retinal diseases, choriocapillaris changes have been observed in systemic vascular diseases and complications associated with pregnancy.
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Affiliation(s)
- Danny Siu-Chun Ng
- Department of Ophthalmology & Visual Sciences, The Chinese University of Hong Kong, Hong Kong, China.,Hong Kong Eye Hospital, Mong Kok, Hong Kong
| | - Leo Ka-Yu Chan
- Department of Ophthalmology & Visual Sciences, The Chinese University of Hong Kong, Hong Kong, China.,Hong Kong Eye Hospital, Mong Kok, Hong Kong
| | - Ching Man Ng
- Department of Ophthalmology & Visual Sciences, The Chinese University of Hong Kong, Hong Kong, China
| | - Timothy Y Y Lai
- Department of Ophthalmology & Visual Sciences, The Chinese University of Hong Kong, Hong Kong, China.,2010 Retina & Macula Centre, Kowloon, Hong Kong
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18
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Bhalla M, Heisler M, Mammo Z, Ju MJ, Sarunic MV, Navajas EV, Warner S, Schendel S, Gill KS. Investigation of the Peripapillary Choriocapillaris in Normal Tension Glaucoma, Primary Open-angle Glaucoma, and Control Eyes. J Glaucoma 2021; 30:682-689. [PMID: 33927150 DOI: 10.1097/ijg.0000000000001861] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2020] [Accepted: 04/01/2021] [Indexed: 11/26/2022]
Abstract
PRECIS The peripapillary choriocapillaris (CC) was observed to be significantly impaired in normal tension glaucoma (NTG) subjects compared with normal controls using optical coherence tomography angiography (OCTA). PURPOSE The aim was to quantitatively evaluate the peripapillary CC in NTG, primary open-angle glaucoma (POAG), and control eyes using OCTA. MATERIALS AND METHODS Ninety eyes (30 controls, 30 NTG, and 30 POAG) from 73 patients were imaged using the Zeiss Plex Elite 9000. Five repeat 3×3 mm OCTA scans were acquired both nasally and temporally to the optic disc and subsequently averaged. Four CC flow deficit (FD) measures were calculated using the fuzzy C-means approach: FD density (FDD), mean FD size (MFDS), FD number (FDN), and FD area (FDA). RESULTS Temporal NTG CC parameters were associated with visual field index and mean deviation (P<0.05). The control group showed a significantly lower nasal FDD (nasal: 3.79±1.26%, temporal: 4.48±1.73%, P=0.03), FDN (nasal: 156.43±38.44, temporal: 178.40±45.68, P=0.02), and FDA (nasal: 0.22±0.08, temporal: 0.26±0.10, P=0.03) when compared with temporal optic disc. The NTG group showed a significantly higher FDD (NTG: 5.04±2.38%, control: 3.79±1.26%, P=0.03), FDN (NTG: 185.90±56.66, control: 156.43±38.44, P=0.04), and FDA (NTG: 0.30±0.14 mm2, control: 0.22±0.08 mm2, P=0.03) nasal to the optic disc compared with controls. CONCLUSIONS Association between CC parameters and glaucoma severity in NTG, but not POAG subjects, suggests vascular abnormalities may be a potential factor in the multifactorial process of glaucoma damage in NTG patients.
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Affiliation(s)
| | - Morgan Heisler
- School of Engineering Science, Simon Fraser University, Burnaby, BC, Canada
| | - Zaid Mammo
- Department of Ophthalmology and Visual Sciences
| | - Myeong Jin Ju
- Department of Ophthalmology and Visual Sciences
- School of Biomedical Engineering, University of British Columbia, Vancouver
| | - Marinko V Sarunic
- School of Engineering Science, Simon Fraser University, Burnaby, BC, Canada
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19
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Lejoyeux R, Benillouche J, Ong J, Errera MH, Rossi EA, Singh SR, Dansingani KK, da Silva S, Sinha D, Sahel JA, Freund KB, Sadda SR, Lutty GA, Chhablani J. Choriocapillaris: Fundamentals and advancements. Prog Retin Eye Res 2021; 87:100997. [PMID: 34293477 DOI: 10.1016/j.preteyeres.2021.100997] [Citation(s) in RCA: 50] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2021] [Revised: 07/02/2021] [Accepted: 07/13/2021] [Indexed: 12/19/2022]
Abstract
The choriocapillaris is the innermost structure of the choroid that directly nourishes the retinal pigment epithelium and photoreceptors. This article provides an overview of its hemovasculogenesis development to achieve its final architecture as a lobular vasculature, and also summarizes the current histological and molecular knowledge about choriocapillaris and its dysfunction. After describing the existing state-of-the-art tools to image the choriocapillaris, we report the findings in the choriocapillaris encountered in the most frequent retinochoroidal diseases including vascular diseases, inflammatory diseases, myopia, pachychoroid disease spectrum disorders, and glaucoma. The final section focuses on the development of imaging technology to optimize visualization of the choriocapillaris as well as current treatments of retinochoroidal disorders that specifically target the choriocapillaris. We conclude the article with pertinent unanswered questions and future directions in research for the choriocapillaris.
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Affiliation(s)
| | | | - Joshua Ong
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA
| | - Marie-Hélène Errera
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA
| | - Ethan A Rossi
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA; Department of Bioengineering, University of Pittsburgh Swanson School of Engineering, Pittsburgh, PA 15213, USA
| | - Sumit R Singh
- Jacobs Retina Center, Shiley Eye Institute, University of California San Diego, San Diego, CA, USA
| | - Kunal K Dansingani
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA
| | - Susana da Silva
- Department of Ophthalmology and Department of Developmental Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA
| | - Debasish Sinha
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA; Department of Cell Biology and Center for Biologic Imaging, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - José-Alain Sahel
- Rothschild Foundation, 75019, Paris, France; Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA; Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris, France; CHNO des Quinze-Vingts, INSERM-DGOS CIC 1423, Paris, France
| | - K Bailey Freund
- LuEsther T. Mertz Retinal Research Center, Manhattan Eye, Ear, and Throat Hospital, New York, NY, USA; Vitreous Retina Macula Consultants of New York, New York, NY, USA; Department of Ophthalmology, New York University of Medicine, New York, NY, USA; Edward S. Harkness Eye Institute, Columbia University Medical Center, New York, NY, USA
| | - SriniVas R Sadda
- Doheny Image Reading Center, Doheny Eye Institute, Los Angeles, CA, 90033, USA; Department of Ophthalmology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
| | - Gerard A Lutty
- Wilmer Ophthalmological Institute, Johns Hopkins Hospital, Baltimore, MD, 21287, USA
| | - Jay Chhablani
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA.
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20
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Llanas S, Linderman RE, Chen FK, Carroll J. Assessing the Use of Incorrectly Scaled Optical Coherence Tomography Angiography Images in Peer-Reviewed Studies: A Systematic Review. JAMA Ophthalmol 2021; 138:86-94. [PMID: 31774456 DOI: 10.1001/jamaophthalmol.2019.4821] [Citation(s) in RCA: 68] [Impact Index Per Article: 22.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Importance Individual differences in axial length affect the lateral magnification of in vivo retinal images and as a result can affect the accuracy of quantitative measurements made from these images. As measurements from optical coherence tomography angiography (OCTA) images are becoming increasingly used in the diagnosis and monitoring of a wide range of diseases, evaluating which studies use correctly scaled images is crucial to their interpretation. Objective To perform a systematic literature review to assess the percentage of articles that report correcting the scale of their OCTA images for individual differences in retinal magnification. Evidence Review A PubMed (MEDLINE) search was conducted for articles on OCTA retinal imaging published between June 1, 2015, and June 1, 2018. Initial results included 7552 articles. Initial exclusion criteria removed studies of animal models, as well as reviews, letters, replies, comments, and image-based or photographic essays. Articles not written in English and those that required purchase from non-English language websites were excluded. Articles that did not use OCTA for imaging the retina were also excluded. Remaining articles were reviewed in detail to assess whether the OCTA measurements required correct lateral scaling, and if so, whether axial length was reported or used to scale the images. We also determined the number of articles that mentioned the lack of correct lateral scaling as a limitation of the study. Findings A total of 989 articles were included in the detailed review. Of these, 509 were determined to require correct image scaling for their analyses, but only 41 (8.0%) report measuring and using axial length to correct the lateral scale of their OCTA images. Furthermore, of the 468 articles that did not correctly scale their images, only 18 (3.8%) mentioned this as a limitation to their study. Conclusions and Relevance These findings suggest that most peer-reviewed articles in PubMed that use quantitative OCTA measurements use incorrectly scaled images. This could call into question the conclusions of such studies and warrants consideration by OCTA manufacturers, physicians, authors, journal reviewers, and journal editors.
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Affiliation(s)
| | - Rachel E Linderman
- Department of Cell Biology, Neurobiology & Anatomy, Medical College of Wisconsin, Milwaukee
| | - Fred K Chen
- Centre for Ophthalmology and Visual Science (incorporating Lions Eye Institute), The University of Western Australia, Perth, Western Australia, Australia.,Department of Ophthalmology, Royal Perth Hospital, Perth, Western Australia, Australia.,Department of Ophthalmology, Perth Children's Hospital, Nedlands, Western Australia, Australia
| | - Joseph Carroll
- Department of Cell Biology, Neurobiology & Anatomy, Medical College of Wisconsin, Milwaukee.,Department of Ophthalmology & Visual Sciences, Medical College of Wisconsin, Milwaukee
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21
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Ali S, Gilani SBS, Shabbir J, Almulhim KS, Bugshan A, Farooq I. Optical coherence tomography's current clinical medical and dental applications: a review. F1000Res 2021; 10:310. [PMID: 33976868 PMCID: PMC8086034 DOI: 10.12688/f1000research.52031.1] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 03/31/2021] [Indexed: 11/20/2022] Open
Abstract
Optical coherence tomography (OCT) is a non-invasive investigative technique that is used to obtain high-resolution three-dimensional (3D) images of biological structures. This method is useful in diagnosing diseases of specific organs like the eye, where a direct biopsy cannot be conducted. Since its inception, significant advancements have been made in its technology. Apart from its initial application in ophthalmology for retinal imaging, substantial technological innovations in OCT brought by the research community have enabled its utilization beyond its original scope and allowed its application in many new clinical areas. This review presents a summary of the clinical applications of OCT in the field of medicine (ophthalmology, cardiology, otology, and dermatology) and dentistry (tissue imaging, detection of caries, analysis of dental polymer composite restorations, imaging of root canals, and diagnosis of oral cancer). In addition, potential advantages and disadvantages of OCT are also discussed.
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Affiliation(s)
- Saqib Ali
- Department of Biomedical Dental Sciences, College of Dentistry, Imam Abdulrahman Bin Faisal University, Dammam, Saudi Arabia
| | - Saqlain Bin Syed Gilani
- Department of Oral Biology, Islamic International Dental College, Riphah International University, Islamabad, Pakistan
| | - Juzer Shabbir
- Department of Operative Dentistry and Endodontics, Liaquat College of Medicine and Dentistry, Karachi, Pakistan
| | - Khalid S Almulhim
- Department of Restorative Dental Sciences, College of Dentistry, Imam Abdulrahman Bin Faisal University, Dammam, Saudi Arabia
| | - Amr Bugshan
- Department of Biomedical Dental Sciences, College of Dentistry, Imam Abdulrahman Bin Faisal University, Dammam, Saudi Arabia
| | - Imran Farooq
- Faculty of Dentistry, University of Toronto, Toronto, ON, M5G 1G6, Canada
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22
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Bedggood P, Metha A. Adaptive optics imaging of the retinal microvasculature. Clin Exp Optom 2021; 103:112-122. [DOI: 10.1111/cxo.12988] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2019] [Revised: 09/17/2019] [Accepted: 09/20/2019] [Indexed: 12/31/2022] Open
Affiliation(s)
- Phillip Bedggood
- Department of Optometry and Vision Sciences, The University of Melbourne, Melbourne, Australia,
| | - Andrew Metha
- Department of Optometry and Vision Sciences, The University of Melbourne, Melbourne, Australia,
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23
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SPATIAL DISTRIBUTION OF CHORIOCAPILLARIS IMPAIRMENT IN EYES WITH CHOROIDAL NEOVASCULARIZATION SECONDARY TO AGE-RELATED MACULAR DEGENERATION: A Quantitative OCT Angiography Study. Retina 2021; 40:428-445. [PMID: 31415449 DOI: 10.1097/iae.0000000000002556] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
PURPOSE To develop an optical coherence tomography angiography (OCTA)-based framework for quantitatively analyzing the spatial distribution of choriocapillaris (CC) impairment around choroidal neovascularization (CNV) secondary to age-related macular degeneration. METHODS In a retrospective, cross-sectional study, 400-kHz swept-source OCTA images from 7 eyes of 6 patients with CNV secondary to age-related macular degeneration were quantitatively analyzed using custom software. A lesion-centered zonal OCTA analysis technique-which portioned the field-of-view into zones relative to CNV boundaries-was developed to quantify the spatial dependence of CC flow deficits. RESULTS Quantitative, lesion-centered zonal analysis of CC OCTA images revealed highest flow-deficit percentages near CNV boundaries, decreasing in zones farther from the boundaries. Optical coherence tomography angiography using shorter (1.5 ms) interscan times revealed more severe flow deficits than OCTA using longer (3.0 ms) interscan times; however, spatial trends were similar for both interscan times. A detailed description of the OCTA processing steps and parameters was provided so as to elucidate their influence on quantitative measurements. CONCLUSION Impairment of the CC, assessed by flow-deficit percentages, was most prominent closest to CNV boundaries. The lesion-centered zonal analysis technique enabled quantitative CC measurements relative to focal lesions. Understanding how processing steps, imaging/processing parameters, and artifacts can affect quantitative CC measurements is important for longitudinal, OCTA-based studies of disease progression, and treatment response.
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24
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Chu Z, Zhang Q, Gregori G, Rosenfeld PJ, Wang RK. Guidelines for Imaging the Choriocapillaris Using OCT Angiography. Am J Ophthalmol 2021; 222:92-101. [PMID: 32891694 DOI: 10.1016/j.ajo.2020.08.045] [Citation(s) in RCA: 71] [Impact Index Per Article: 23.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Revised: 08/12/2020] [Accepted: 08/28/2020] [Indexed: 01/23/2023]
Abstract
PURPOSE To provide guidance on how to appropriately quantitate various choriocapillaris (CC) parameters with optical coherence tomography angiography (OCTA). DESIGN Evidence-based perspective. METHODS Review of literature and experience of authors. RESULTS Accurate and reliable quantification of CC using OCTA requires that CC can be visualized and that the measurements of various CC parameters are validated. For accurate visualization, the selected CC slab must be physiologically sound, must produce images consistent with histology, and must yield qualitatively similar images when viewing repeats of the same scan or scans of different sizes. For accurate quantification, the measured intercapillary distances (ICDs) should be consistent with known measurements using histology and adaptive optics and/or OCTA, the selected CC parameters must be physiologically and physically meaningful based on the resolution of the instrument and the density of the scans, the selected algorithm for CC binarization must be appropriate and generate meaningful results, and the CC measurements calculated from multiple scans of the same and different sizes should be quantitatively similar. If the Phansalkar local thresholding method is used, then its parameters must be optimized for CC based on the OCTA instrument and scan patterns used. It is recommended that the window radius used in the Phansalkar method should be related to the expected average ICD in normal eyes. CONCLUSIONS Quantitative analysis of CC using commercially available OCTA instruments is complicated, and researchers need to tailor their strategies based on the instrument, scan patterns, anatomy, and thresholding strategies to achieve accurate and reliable measurements.
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Schottenhamml J, Moult EM, Ploner SB, Chen S, Novais E, Husvogt L, Duker JS, Waheed NK, Fujimoto JG, Maier AK. OCT-OCTA segmentation: combining structural and blood flow information to segment Bruch's membrane. BIOMEDICAL OPTICS EXPRESS 2021; 12:84-99. [PMID: 33520378 PMCID: PMC7818963 DOI: 10.1364/boe.398222] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/21/2020] [Revised: 10/28/2020] [Accepted: 11/11/2020] [Indexed: 05/13/2023]
Abstract
In this paper we present a fully automated graph-based segmentation algorithm that jointly uses optical coherence tomography (OCT) and OCT angiography (OCTA) data to segment Bruch's membrane (BM). This is especially valuable in cases where the spatial correlation between BM, which is usually not visible on OCT scans, and the retinal pigment epithelium (RPE), which is often used as a surrogate for segmenting BM, is distorted by pathology. We validated the performance of our proposed algorithm against manual segmentation in a total of 18 eyes from healthy controls and patients with diabetic retinopathy (DR), non-exudative age-related macular degeneration (AMD) (early/intermediate AMD, nascent geographic atrophy (nGA) and drusen-associated geographic atrophy (DAGA) and geographic atrophy (GA)), and choroidal neovascularization (CNV) with a mean absolute error of ∼0.91 pixel (∼4.1 μm). This paper suggests that OCT-OCTA segmentation may be a useful framework to complement the growing usage of OCTA in ophthalmic research and clinical communities.
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Affiliation(s)
- Julia Schottenhamml
- Pattern Recognition Lab, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, 91058, Germany
| | - Eric M. Moult
- Department of Electrical Engineering and Computer Science, Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Stefan B. Ploner
- Pattern Recognition Lab, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, 91058, Germany
| | - Siyu Chen
- Department of Electrical Engineering and Computer Science, Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Eduardo Novais
- New England Eye Center, Tufts Medical Center, Boston, MA 02116, USA
- Federal University of São Paulo, School of Medicine, São Paulo - SP, 04021-001, Brazil
| | - Lennart Husvogt
- Pattern Recognition Lab, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, 91058, Germany
- Department of Electrical Engineering and Computer Science, Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Jay S. Duker
- New England Eye Center, Tufts Medical Center, Boston, MA 02116, USA
| | - Nadia K. Waheed
- New England Eye Center, Tufts Medical Center, Boston, MA 02116, USA
| | - James G. Fujimoto
- Department of Electrical Engineering and Computer Science, Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Andreas K. Maier
- Pattern Recognition Lab, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, 91058, Germany
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26
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Hormel TT, Jia Y, Jian Y, Hwang TS, Bailey ST, Pennesi ME, Wilson DJ, Morrison JC, Huang D. Plexus-specific retinal vascular anatomy and pathologies as seen by projection-resolved optical coherence tomographic angiography. Prog Retin Eye Res 2021; 80:100878. [PMID: 32712135 PMCID: PMC7855241 DOI: 10.1016/j.preteyeres.2020.100878] [Citation(s) in RCA: 60] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2019] [Revised: 05/13/2020] [Accepted: 05/18/2020] [Indexed: 12/22/2022]
Abstract
Optical coherence tomographic angiography (OCTA) is a novel technology capable of imaging retinal vasculature three-dimensionally at capillary scale without the need to inject any extrinsic dye contrast. However, projection artifacts cause superficial retinal vascular patterns to be duplicated in deeper layers, thus interfering with the clean visualization of some retinal plexuses and vascular pathologies. Projection-resolved OCTA (PR-OCTA) uses post-processing algorithms to reduce projection artifacts. With PR-OCTA, it is now possible to resolve up to 4 distinct retinal vascular plexuses in the living human eye. The technology also allows us to detect and distinguish between various retinal and optic nerve diseases. For example, optic nerve diseases such as glaucoma primarily reduces the capillary density in the superficial vascular complex, which comprises the nerve fiber layer plexus and the ganglion cell layer plexus. Outer retinal diseases such as retinitis pigmentosa primarily reduce the capillary density in the deep vascular complex, which comprises the intermediate capillary plexus and the deep capillary plexus. Retinal vascular diseases such as diabetic retinopathy and vein occlusion affect all plexuses, but with different patterns of capillary loss and vascular malformations. PR-OCTA is also useful in distinguishing various types of choroidal neovascularization and monitoring their response to anti-angiogenic medications. In retinal angiomatous proliferation and macular telangiectasia type 2, PR-OCTA can trace the pathologic vascular extension into deeper layers as the disease progress through stages. Plexus-specific visualization and measurement of retinal vascular changes are improving our ability to diagnose, stage, monitor, and assess treatment response in a wide variety of optic nerve and retinal diseases. These applications will be further enhanced with the continuing improvement of the speed and resolution of the OCT platforms, as well as the development of software algorithms to reduce artifacts, improve image quality, and make quantitative measurements.
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Affiliation(s)
- Tristan T Hormel
- Casey Eye Institute, Oregon Health & Science University, Portland, OR, 97239, USA
| | - Yali Jia
- 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
| | - Thomas S Hwang
- Casey Eye Institute, Oregon Health & Science University, Portland, OR, 97239, USA
| | - Steven T Bailey
- Casey Eye Institute, Oregon Health & Science University, Portland, OR, 97239, USA
| | - Mark E Pennesi
- Casey Eye Institute, Oregon Health & Science University, Portland, OR, 97239, USA
| | - David J Wilson
- Casey Eye Institute, Oregon Health & Science University, Portland, OR, 97239, USA
| | - John C Morrison
- Casey Eye Institute, Oregon Health & Science University, Portland, OR, 97239, USA
| | - David Huang
- Casey Eye Institute, Oregon Health & Science University, Portland, OR, 97239, USA.
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27
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Shi Y, Chu Z, Wang L, Zhang Q, Feuer W, de Sisternes L, Durbin MK, Gregori G, Wang RK, Rosenfeld PJ. Validation of a Compensation Strategy Used to Detect Choriocapillaris Flow Deficits Under Drusen With Swept Source OCT Angiography. Am J Ophthalmol 2020; 220:115-127. [PMID: 32621895 DOI: 10.1016/j.ajo.2020.06.033] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2020] [Revised: 06/14/2020] [Accepted: 06/19/2020] [Indexed: 12/19/2022]
Abstract
PURPOSE A compensation strategy that was developed to measure the choriocapillaris (CC) flow deficits (FDs) under drusen was tested in eyes with large drusen from age-related macular degeneration (AMD) before and after the drusen spontaneously resolved without evidence of disease progression. DESIGN Prospective, observational consecutive case series. METHODS Patients with AMD were enrolled in a prospective swept-source optical coherence tomography (SS-OCT) imaging study. Consecutive eyes with large drusen were followed, and eyes that underwent spontaneous collapse of drusen without evidence of disease progression were identified retrospectively. The drusen-resolved regions were manually outlined. CC FDs were measured using a previously published compensation strategy that adjusted for the decreased signal intensity underlying drusen. Both the percentage of FDs (FD%) and the mean FD sizes (MFDSs) were measured before and after drusen resolution. RESULTS Resolution of drusen was identified in 8 eyes from 8 patients. The average interval between the 2 visits was 7.8 months. The average drusen volumes measured between visits were 0.23 and 0.04 mm3, respectively. After the drusen resolved, the average follow-up time without evidence of disease progression was 10.1 months. When the 2 visits were compared, there were no statistically significant differences in any of the CC parameters within the drusen resolved regions once the compensation strategy was applied (all P values >.22). CONCLUSIONS In this naturally occurring experiment in which drusen collapsed without evidence of disease progression, the CC parameters were similar once our compensation strategy was applied both before and after the drusen resolved.
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Affiliation(s)
- Yingying Shi
- Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, Florida, USA
| | - Zhongdi Chu
- Department of Bioengineering, University of Washington, Seattle, Washington, USA
| | - Liang Wang
- Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, Florida, USA
| | - Qinqin Zhang
- Department of Bioengineering, University of Washington, Seattle, Washington, USA
| | - William Feuer
- Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, Florida, USA
| | - Luis de Sisternes
- Research and Development, Carl Zeiss Meditec, Inc, Dublin, California, USA
| | - Mary K Durbin
- Research and Development, Carl Zeiss Meditec, Inc, Dublin, California, USA
| | - Giovanni Gregori
- Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, Florida, USA
| | - Ruikang K Wang
- Department of Bioengineering, University of Washington, Seattle, Washington, USA
| | - Philip J Rosenfeld
- Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, Florida, USA.
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Optimizing the Repeatability of Choriocapillaris Flow Deficit Measurement From Optical Coherence Tomography Angiography. Am J Ophthalmol 2020; 219:21-32. [PMID: 32454035 DOI: 10.1016/j.ajo.2020.05.027] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2019] [Revised: 05/15/2020] [Accepted: 05/18/2020] [Indexed: 11/20/2022]
Abstract
PURPOSE To evaluate the impact of processing technique and slab selection on the repeatability of choriocapillaris (CC) flow deficit (FD) measurements as assessed using optical coherence tomography angiography (OCTA) DESIGN: Prospective, cross-sectional study. METHODS Healthy subjects were imaged with 4 consecutive 3 × 3-mm OCTA using a swept-source OCT (PLEX elite 9000; Carl Zeiss Meditec). OCTA images were generated using the Max projection, and three 10-μm-thick slabs starting 11, 21, and 31 μm posterior to the automatically segmented retinal pigment epithelial band. The resultant images were binarized using the Phansalkar method with a 43.94-μm radius and then the CCFD% was computed. The intraclass correlation coefficient (ICC) and coefficient of variation (CV) were computed for the 4 acquisitions to assess the repeatability of the CCFD%. This entire analysis was repeated after separately modulating several parameters: (1) Sum instead of the Max projection, (2) retinal pigment epithelial fit instead of the retinal pigment epithelial band as the offset reference, (3) 14.65 and 87.88 μm radius values instead of 43.94 μm. RESULTS Twenty-four healthy eyes (mean age; 36.4 years) were enrolled. The CCFD% in the 11-21-, 21-31-, and 31-41-μm slabs generated by the Max algorithm and the retinal pigment epithelial band showed high repeatability values (ICCs = 0.963, 0.975, and 911; CVs = 0.05, 0.05, and 0.05, respectively). As most of the cases were confounded with the hypointense region when the 11-21-μm slab was used, however, this slab could not be included in the subsequent analyses. Those values in the 21-31- and 31-41-μm slabs were higher than those of the corresponding slabs by the Sum algorithm (ICC = 0.916 and 0.776; CV = 0.15 and 0.19, respectively) or by the retinal pigment epithelial fit (ICC = 0.907 and 0.802; CV = 0.06 and 0.06, respectively). The Phansalkar radius of 43.94 μm had the highest ICC numerically, but this was not statistically significantly greater than for a radius of 14.65 μm (ICC = 0.960 and 0.911, respectively) or a radius of 87.88 μm (ICC = 0.958 and 0.897, respectively). Regardless of which parameter was modulated, the 21-31-μm slab was the most repeatable. CONCLUSIONS In normal eyes, en face CC OCTA images generated using the Max projection and a 10-μm-thick slab offset of 21 μm below the instrument-generated retinal pigment epithelial band yielded the most repeatable CCFD%. These findings have implications for the design of standardized processing algorithms for quantitative CC assessment.
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29
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Corvi F, Corradetti G, Parrulli S, Pace L, Staurenghi G, Sadda SR. Comparison and Repeatability of High Resolution and High Speed Scans from Spectralis Optical Coherence Tomography Angiography. Transl Vis Sci Technol 2020; 9:29. [PMID: 33062392 PMCID: PMC7533739 DOI: 10.1167/tvst.9.10.29] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Accepted: 08/24/2020] [Indexed: 12/25/2022] Open
Abstract
Purpose The purpose of this study was to evaluate and compare the repeatability of optical coherence tomography angiography (OCTA) derived retinal vascular quantitative metrics using high resolution (HR) versus high speed (HS) acquisition modes. Methods Macular 4.4 × 2.9-mm OCTA images from normal, healthy volunteers were captured using both HR (768 A-scans × 256 B-scans) and HS (384 A-scans × 256 B-scans) acquisition protocols. Vessel density and vessel length density of the superficial capillary plexus and deep capillary plexus, as well as choriocapillaris flow deficit were computed. In a subset of eyes, the OCTA scans were repeated twice 2 days later and the same metrics were recomputed to assess repeatability, using intraclass correlation coefficients and coefficient of variation (CV). Results Comparison of measurements between HR and HS acquisitions in 41 healthy eyes showed statistically significant differences for all quantitative metrics (P < 0.01). However, no significant differences were observed among the three repeated scans (one on day 1 and two on day 3) obtained with each of the acquisition modes. The CVs ranged from 0.01 to 0.03 with the HR mode and 0.01 to 0.04 with the HS mode. The intraclass correlation coefficients (ICCs) among measurements were similar and high for both HR and HS modes, ranging from 0.844 to 0.949. Conclusions HR and HS OCTA acquisition modes both yielded repeatable quantitative metrics for the retinal circulation and the choriocapillaris. However, despite a similar field, the HR and HS derived measurements differed significantly. Translational Relevance To establish OCTA imaging in clinical and research practice, standardized and repeatability image analysis are necessary.
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Affiliation(s)
- Federico Corvi
- Doheny Image Reading Center, Doheny Eye Institute, Los Angeles, CA, USA
| | - Giulia Corradetti
- Doheny Image Reading Center, Doheny Eye Institute, Los Angeles, CA, USA.,Department of Ophthalmology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
| | - Salvatore Parrulli
- Eye Clinic, Department of Biomedical and Clinical Science "Luigi Sacco," Sacco Hospital, University of Milan, Milan, Italy
| | - Lucia Pace
- Eye Clinic, Department of Biomedical and Clinical Science "Luigi Sacco," Sacco Hospital, University of Milan, Milan, Italy
| | - Giovanni Staurenghi
- Eye Clinic, Department of Biomedical and Clinical Science "Luigi Sacco," Sacco Hospital, University of Milan, Milan, Italy
| | - SriniVas R Sadda
- Doheny Image Reading Center, Doheny Eye Institute, Los Angeles, CA, USA.,Department of Ophthalmology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
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30
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Mehta N, Braun PX, Gendelman I, Alibhai AY, Arya M, Duker JS, Waheed NK. Repeatability of binarization thresholding methods for optical coherence tomography angiography image quantification. Sci Rep 2020; 10:15368. [PMID: 32958813 PMCID: PMC7505834 DOI: 10.1038/s41598-020-72358-z] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2019] [Accepted: 08/25/2020] [Indexed: 02/06/2023] Open
Abstract
Binarization is a critical step in analysis of retinal optical coherence tomography angiography (OCTA) images, but the repeatability of metrics produced from various binarization methods has not been fully assessed. This study set out to examine the repeatability of OCTA quantification metrics produced using different binarization thresholding methods, all of which have been applied in previous studies, across multiple devices and plexuses. Successive 3 × 3 mm foveal OCTA images of 13 healthy eyes were obtained on three different devices. For each image, contrast adjustments, 3 image processing techniques (linear registration, histogram normalization, and contrast-limited adaptive histogram equalization), and 11 binarization thresholding methods were independently applied. Vessel area density (VAD) and vessel length were calculated for retinal vascular images. Choriocapillaris (CC) images were quantified for VAD and flow deficit metrics. Repeatability, measured using the intra-class correlation coefficient, was inconsistent and generally not high (ICC < 0.8) across binarization thresholds, devices, and plexuses. In retinal vascular images, local thresholds tended to incorrectly binarize the foveal avascular zone as white (i.e., wrongly indicating flow). No image processing technique analyzed consistently resulted in highly repeatable metrics. Across contrast changes, retinal vascular images showed the lowest repeatability and CC images showed the highest.
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Affiliation(s)
- Nihaal Mehta
- Department of Ophthalmology, New England Eye Center, Tufts Medical Center, 800 Washington Street, Box 450, Boston, MA, 02111, USA.,Department of Ophthalmology, University of Colorado, Denver, CO, USA
| | - Phillip X Braun
- Department of Ophthalmology, New England Eye Center, Tufts Medical Center, 800 Washington Street, Box 450, Boston, MA, 02111, USA.,Flaum Eye Institute, University of Rochester Medical Center, Rochester, NY, USA
| | - Isaac Gendelman
- Department of Ophthalmology, New England Eye Center, Tufts Medical Center, 800 Washington Street, Box 450, Boston, MA, 02111, USA.,Department of Surgery, Tufts Medical Center, Boston, MA, USA
| | - A Yasin Alibhai
- Department of Ophthalmology, New England Eye Center, Tufts Medical Center, 800 Washington Street, Box 450, Boston, MA, 02111, USA
| | - Malvika Arya
- Department of Ophthalmology, New England Eye Center, Tufts Medical Center, 800 Washington Street, Box 450, Boston, MA, 02111, USA
| | - Jay S Duker
- Department of Ophthalmology, New England Eye Center, Tufts Medical Center, 800 Washington Street, Box 450, Boston, MA, 02111, USA
| | - Nadia K Waheed
- Department of Ophthalmology, New England Eye Center, Tufts Medical Center, 800 Washington Street, Box 450, Boston, MA, 02111, USA.
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31
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Miller DT, Kurokawa K. Cellular-Scale Imaging of Transparent Retinal Structures and Processes Using Adaptive Optics Optical Coherence Tomography. Annu Rev Vis Sci 2020; 6:115-148. [PMID: 32609578 PMCID: PMC7864592 DOI: 10.1146/annurev-vision-030320-041255] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
High-resolution retinal imaging is revolutionizing how scientists and clinicians study the retina on the cellular scale. Its exquisite sensitivity enables time-lapse optical biopsies that capture minute changes in the structure and physiological processes of cells in the living eye. This information is increasingly used to detect disease onset and monitor disease progression during early stages, raising the possibility of personalized eye care. Powerful high-resolution imaging tools have been in development for more than two decades; one that has garnered considerable interest in recent years is optical coherence tomography enhanced with adaptive optics. State-of-the-art adaptive optics optical coherence tomography (AO-OCT) makes it possible to visualize even highly transparent cells and measure some of their internal processes at all depths within the retina, permitting reconstruction of a 3D view of the living microscopic retina. In this review, we report current AO-OCT performance and its success in visualizing and quantifying these once-invisible cells in human eyes.
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Affiliation(s)
- Donald T Miller
- School of Optometry, Indiana University, Bloomington, Indiana 47405, USA; ,
| | - Kazuhiro Kurokawa
- School of Optometry, Indiana University, Bloomington, Indiana 47405, USA; ,
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32
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Tan B, Sim R, Chua J, Wong DWK, Yao X, Garhöfer G, Schmidl D, Werkmeister RM, Schmetterer L. Approaches to quantify optical coherence tomography angiography metrics. ANNALS OF TRANSLATIONAL MEDICINE 2020; 8:1205. [PMID: 33241054 PMCID: PMC7576021 DOI: 10.21037/atm-20-3246] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Optical coherence tomography (OCT) has revolutionized the field of ophthalmology in the last three decades. As an OCT extension, OCT angiography (OCTA) utilizes a fast OCT system to detect motion contrast in ocular tissue and provides a three-dimensional representation of the ocular vasculature in a non-invasive, dye-free manner. The first OCT machine equipped with OCTA function was approved by U.S. Food and Drug Administration in 2016 and now it is widely applied in clinics. To date, numerous methods have been developed to aid OCTA interpretation and quantification. In this review, we focused on the workflow of OCTA-based interpretation, beginning from the generation of the OCTA images using signal decorrelation, which we divided into intensity-based, phase-based and phasor-based methods. We further discussed methods used to address image artifacts that are commonly observed in clinical settings, to the algorithms for image enhancement, binarization, and OCTA metrics extraction. We believe a better grasp of these technical aspects of OCTA will enhance the understanding of the technology and its potential application in disease diagnosis and management. Moreover, future studies will also explore the use of ocular OCTA as a window to link ocular vasculature to the function of other organs such as the kidney and brain.
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Affiliation(s)
- Bingyao Tan
- Institute for Health Technologies, Nanyang Technological University, Singapore, Singapore.,Singapore Eye Research Institute, Singapore National Eye Centre, Singapore, Singapore.,SERI-NTU Advanced Ocular Engineering (STANCE) Program, Nanyang Technological University, Singapore, Singapore
| | - Ralene Sim
- Singapore Eye Research Institute, Singapore National Eye Centre, Singapore, Singapore
| | - Jacqueline Chua
- Singapore Eye Research Institute, Singapore National Eye Centre, Singapore, Singapore.,Academic Clinical Program, Duke-NUS Medical School, Singapore, Singapore
| | - Damon W K Wong
- Institute for Health Technologies, Nanyang Technological University, Singapore, Singapore.,Singapore Eye Research Institute, Singapore National Eye Centre, Singapore, Singapore.,SERI-NTU Advanced Ocular Engineering (STANCE) Program, Nanyang Technological University, Singapore, Singapore
| | - Xinwen Yao
- Institute for Health Technologies, Nanyang Technological University, Singapore, Singapore.,Singapore Eye Research Institute, Singapore National Eye Centre, Singapore, Singapore.,SERI-NTU Advanced Ocular Engineering (STANCE) Program, Nanyang Technological University, Singapore, Singapore
| | - Gerhard Garhöfer
- Department of Clinical Pharmacology, Medical University of Vienna, Vienna, Austria
| | - Doreen Schmidl
- Department of Clinical Pharmacology, Medical University of Vienna, Vienna, Austria
| | - René M Werkmeister
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria
| | - Leopold Schmetterer
- Singapore Eye Research Institute, Singapore National Eye Centre, Singapore, Singapore.,SERI-NTU Advanced Ocular Engineering (STANCE) Program, Nanyang Technological University, Singapore, Singapore.,Academic Clinical Program, Duke-NUS Medical School, Singapore, Singapore.,Department of Clinical Pharmacology, Medical University of Vienna, Vienna, Austria.,Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria.,Yong Loo Lin School of Medicine, National University of Singapore and National University Health System, Singapore, Singapore.,Department of Ophthalmology, Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore, Singapore.,Institute of Molecular and Clinical Ophthalmology, Basel, Switzerland
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33
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Singh SR, Chhablani J. Imaging the Choroid. Vision (Basel) 2020; 4:vision4030038. [PMID: 32824300 PMCID: PMC7558177 DOI: 10.3390/vision4030038] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2020] [Revised: 08/07/2020] [Accepted: 08/11/2020] [Indexed: 11/25/2022] Open
Affiliation(s)
- Sumit Randhir Singh
- Jacobs Retina Center at Shiley Eye Institute, University of California, San Diego, La Jolla, CA 92093-0021, USA;
| | - Jay Chhablani
- Department of Ophthalmology, University of Pittsburgh Eye and Ear Institute, Pittsburgh, PA 15213, USA
- Correspondence: ; Tel.: +1-412-377-1943
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34
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Janpongsri W, Huang J, Ng R, Wahl DJ, Sarunic MV, Jian Y. Pseudo-real-time retinal layer segmentation for high-resolution adaptive optics optical coherence tomography. JOURNAL OF BIOPHOTONICS 2020; 13:e202000042. [PMID: 32421890 DOI: 10.1002/jbio.202000042] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/13/2020] [Revised: 04/04/2020] [Accepted: 04/28/2020] [Indexed: 06/11/2023]
Abstract
We present a pseudo-real-time retinal layer segmentation for high-resolution Sensorless Adaptive Optics-Optical Coherence Tomography (SAO-OCT). Our pseudo-real-time segmentation method is based on Dijkstra's algorithm that uses the intensity of pixels and the vertical gradient of the image to find the minimum cost in a geometric graph formulation within a limited search region. It segments six retinal layer boundaries in an iterative process according to their order of prominence. The segmentation time is strongly correlated to the number of retinal layers to be segmented. Our program permits en face images to be extracted during data acquisition to guide the depth specific focus control and depth dependent aberration correction for high-resolution SAO-OCT systems. The average processing times for our entire pipeline for segmenting six layers in a retinal B-scan of 496 × 400 and 240 × 400 pixels are around 25.60 and 13.76 ms, respectively. When reducing the number of layers segmented to only two layers, the time required for a 240 × 400 pixel image is 8.26 ms.
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Affiliation(s)
- Worawee Janpongsri
- Biomedical Optics Research Group, School of Engineering Science, Simon Fraser University, Burnaby, British Columbia, Canada
| | - Joey Huang
- Biomedical Optics Research Group, School of Engineering Science, Simon Fraser University, Burnaby, British Columbia, Canada
| | - Ringo Ng
- Biomedical Optics Research Group, School of Engineering Science, Simon Fraser University, Burnaby, British Columbia, Canada
| | - Daniel J Wahl
- Biomedical Optics Research Group, School of Engineering Science, Simon Fraser University, Burnaby, British Columbia, Canada
| | - Marinko V Sarunic
- Biomedical Optics Research Group, School of Engineering Science, Simon Fraser University, Burnaby, British Columbia, Canada
| | - Yifan Jian
- Casey Eye Institute, Oregon Health & Science University, Portland, OR, USA
- Department of Biomedical Engineering, Oregon Health & Science University, Portland, Oregon, USA
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Camino A, Zang P, Athwal A, Ni S, Jia Y, Huang D, Jian Y. Sensorless adaptive-optics optical coherence tomographic angiography. BIOMEDICAL OPTICS EXPRESS 2020; 11:3952-3967. [PMID: 33014578 PMCID: PMC7510908 DOI: 10.1364/boe.396829] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Revised: 06/15/2020] [Accepted: 06/16/2020] [Indexed: 05/18/2023]
Abstract
Optical coherence tomographic angiography (OCTA) can image the retinal blood flow but visualization of the capillary caliber is limited by the low lateral resolution. Adaptive optics (AO) can be used to compensate ocular aberrations when using high numerical aperture (NA), and thus improve image resolution. However, previously reported AO-OCTA instruments were large and complex, and have a small sub-millimeter field of view (FOV) that hinders the extraction of biomarkers with clinical relevance. In this manuscript, we developed a sensorless AO-OCTA prototype with an intermediate numerical aperture to produce depth-resolved angiograms with high resolution and signal-to-noise ratio over a 2 × 2 mm FOV, with a focal spot diameter of 6 µm, which is about 3 times finer than typical commercial OCT systems. We believe these parameters may represent a better tradeoff between resolution and FOV compared to large-NA AO systems, since the spot size matches better that of capillaries. The prototype corrects defocus, astigmatism, and coma using a figure of merit based on the mean reflectance projection of a slab defined with real-time segmentation of retinal layers. AO correction with the ability to optimize focusing in arbitrary retinal depths - particularly the plexuses in the inner retina - could be achieved in 1.35 seconds. The AO-OCTA images showed greater flow signal, signal-to-noise ratio, and finer capillary caliber compared to commercial OCTA. Projection artifacts were also reduced in the intermediate and deep capillary plexuses. The instrument reported here improves OCTA image quality without excessive sacrifice in FOV and device complexity, and thus may have potential for clinical translation.
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Affiliation(s)
- Acner Camino
- Casey Eye Institute, Oregon Health & Science University, Portland, OR 27239, USA
| | - Pengxiao Zang
- Casey Eye Institute, Oregon Health & Science University, Portland, OR 27239, USA
| | - Arman Athwal
- Department of Engineering Science, Simon Fraser University, Burnaby, Canada
| | - Shuibin Ni
- Casey Eye Institute, Oregon Health & Science University, Portland, OR 27239, USA
| | - Yali Jia
- Casey Eye Institute, Oregon Health & Science University, Portland, OR 27239, USA
- Department of Biomedical Engineering, Oregon Health & Science University, Portland, OR 97239, USA
| | - David Huang
- Casey Eye Institute, Oregon Health & Science University, Portland, OR 27239, USA
| | - Yifan Jian
- Casey Eye Institute, Oregon Health & Science University, Portland, OR 27239, USA
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Chu Z, Cheng Y, Zhang Q, Zhou H, Dai Y, Shi Y, Gregori G, Rosenfeld PJ, Wang RK. Quantification of Choriocapillaris with Phansalkar Local Thresholding: Pitfalls to Avoid. Am J Ophthalmol 2020; 213:161-176. [PMID: 32059979 DOI: 10.1016/j.ajo.2020.02.003] [Citation(s) in RCA: 72] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2019] [Revised: 01/31/2020] [Accepted: 02/01/2020] [Indexed: 01/01/2023]
Abstract
PURPOSE To demonstrate the proper use of the Phansalkar local thresholding method (Phansalkar method) in choriocapillaris (CC) quantification with optical coherence tomography angiography (OCTA). DESIGN Retrospective, observational case series. METHODS Swept source OCTA imaging was performed using 3×3 mm and 6×6 mm scanning patterns. The CC slab was extracted after semiautomatic segmentation of the retinal pigment epithelium/Bruch membrane complex. Retinal projection artifacts were removed before further analysis, and CC OCTA images from drusen eyes were compensated using a previously published strategy. CC flow deficits (FDs) were segmented with 2 previously published algorithms: the fuzzy C-means approach (FCM method) and the Phansalkar method. With the Phansalkar method, different parameters were tested and a local window radius of 1 to 15 pixels was used. FD density, mean FD size, and FD number were calculated for comparison. RESULTS Six normal eyes from 6 subjects and 6 eyes with drusen secondary to age-related macular degeneration from 6 subjects were analyzed. With both 3×3 mm and 6×6 mm scans from all eyes, the FD metrics were highly dependent on the selection of the local window radius when using the Phansalkar method. Larger window radii resulted in higher FD density values. FD number increased with the increase in the window radius but then decreased, with an inflection point at about 1 to 2 intercapillary distances. Mean FD size decreased then increased with increasing window radii. CONCLUSIONS Multiple parameters, especially the local window radius, should be optimized before using the Phansalkar method for the quantification of CC FDs with OCTA imaging. It is recommended that the proper use of the Phansalkar method should include the selection of the window radius that is related to the expected intercapillary distance in normal eyes.
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Affiliation(s)
- Zhongdi Chu
- Department of Bioengineering, University of Washington, Seattle, Washington, USA
| | - Yuxuan Cheng
- Department of Bioengineering, University of Washington, Seattle, Washington, USA
| | - Qinqin Zhang
- Department of Bioengineering, University of Washington, Seattle, Washington, USA
| | - Hao Zhou
- Department of Bioengineering, University of Washington, Seattle, Washington, USA
| | - Yining Dai
- Department of Bioengineering, University of Washington, Seattle, Washington, USA
| | - Yingying Shi
- Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, Florida, USA
| | - Giovanni Gregori
- Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, Florida, USA
| | - Philip J Rosenfeld
- Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, Florida, USA
| | - Ruikang K Wang
- Department of Bioengineering, University of Washington, Seattle, Washington, USA; Department of Ophthalmology, University of Washington, Seattle, Washington, USA.
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Zhou H, Dai Y, Gregori G, Rosenfeld PR, Duncan JL, Schwartz DM, Wang RK. Automated morphometric measurement of the retinal pigment epithelium complex and choriocapillaris using swept source OCT. BIOMEDICAL OPTICS EXPRESS 2020; 11:1834-1850. [PMID: 32341851 PMCID: PMC7173887 DOI: 10.1364/boe.385113] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/04/2019] [Revised: 03/01/2020] [Accepted: 03/02/2020] [Indexed: 05/25/2023]
Abstract
We report the development of an automated method to measure morphological features of the retinal pigment epithelium (RPE), Bruch's membrane (BM) and choriocapillaris (CC) using a commercially available swept source OCT (SS-OCT) system. The locations of the inner segment/outer segment (IS/OS), RPE and CC were determined by optical coherence tomography (OCT) and OCT angiography (OCTA) A-scan intensity profiles, which were used to calculate the mean IS/OS-to-RPE distance, mean RPE-to-CC distance, mean RPE-to-CC outer boundary distance, mean RPE thickness and mean CC thickness across the entire scan volume. The automated method was tested on two groups of normal subjects: younger age group (n=20, 30.3 ± 5.72 years, axial length = 24.2 ± 0.96 mm) and older age group (n=20, 80.8 ± 4.12 years, axial length = 23.5 ± 0.93 mm). The 6×6 mm macular scans were acquired from one eye of each subject. Repeatability of the measurements showed a coefficient of variance < 5% for all the cases. CC locations were confirmed qualitatively with pixel-by-pixel moving of the en face OCT/OCTA images. Relative distance and thickness maps of the RPE-BM-CC complex were generated for visualization of regional changes. We observed thinner CC, thinner RPE and increased RPE-to-CC distance in the older age group. Correlation between CC thickness and choroid thickness suggests that the CC thins with the overall thinning of the choroid. These metrics should be useful to reveal more morphological details of RPE-BM-CC complex, provide a better understanding of the CC in three dimensions, and further investigate potential functional relationships between RPE, BM and CC, and their involvement in age-related ocular diseases.
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Affiliation(s)
- Hao Zhou
- Department of Bioengineering, University of Washington, Seattle, WA 98105, USA
| | - Yining Dai
- Department of Bioengineering, University of Washington, Seattle, WA 98105, USA
| | - Giovanni Gregori
- Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Philip R. Rosenfeld
- Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Jacque L. Duncan
- Department of Ophthalmology, University of California, San Francisco, CA 94143, USA
| | - Daniel M. Schwartz
- Department of Ophthalmology, University of California, San Francisco, CA 94143, USA
| | - Ruikang K. Wang
- Department of Bioengineering, University of Washington, Seattle, WA 98105, USA
- Department of Ophthalmology, University of Washington, Seattle, WA 98105, USA
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Hessler M, Nelis P, Ertmer C, Alnawaiseh M, Lehmann F, Schmidt C, Kampmeier TG, Rehberg SW, Arnemann PH, Rovas A. Optical coherence tomography angiography as a novel approach to contactless evaluation of sublingual microcirculation: A proof of principle study. Sci Rep 2020; 10:5408. [PMID: 32214141 PMCID: PMC7096522 DOI: 10.1038/s41598-020-62128-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2019] [Accepted: 03/03/2020] [Indexed: 01/06/2023] Open
Abstract
Microcirculatory disorders are crucial in pathophysiology of organ dysfunction in critical illness. Evaluation of sublingual microcirculation is not routinely conducted in daily practice due to time-consuming analysis and susceptibility to artifacts. We investigated the suitability of optical coherence tomography angiography (OCTA) for contactless evaluation of sublingual microcirculation. Sublingual microcirculation was imaged in 10 healthy volunteers, using an OCTA device and an incident dark field (IDF) illumination microscopy (current gold standard). OCTA images were analyzed with regard to flow density and perfused vessel density (PVDbyOCTA). IDF videos were analyzed following current recommendations. Flow density was automatically extracted from OCTA images (whole en face 48.9% [43.2; 54.5]; central ring 52.6% [43.6; 60.6]). PVDbyOCTA did not differ from the PVD calculated from IDF videos (PVDbyOCTA 18.6 mm/mm² [18.0; 21.7]) vs. PVDbyIDF 21.0 mm/mm² [17.5; 22.9]; p = 0.430). Analysis according to Bland-Altman revealed a mean bias of 0.95 mm/mm² (95% Confidence interval −1.34 to 3.25) between PVDbyOCTA and PVDbyIDF with limits of agreement of −5.34 to 7.24 mm/mm². This study is the first to demonstrate the suitability of OCTA for evaluating sublingual microcirculation. Comparison of the perfused vessel density between methods showed a plausible level of agreement.
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Affiliation(s)
- Michael Hessler
- Department of Anesthesiology, Intensive Care, and Pain Therapy, University Hospital Muenster, Albert-Schweitzer-Campus 1, Building A1, Muenster, Germany
| | - Pieter Nelis
- Department of Ophthalmology, University Hospital Muenster, Domagkstraße 15, Muenster, Germany.,Department of Ophthalmology, University of Brussels (VUB), Laarbeeklaan 101, Jette, Belgium
| | - Christian Ertmer
- Department of Anesthesiology, Intensive Care, and Pain Therapy, University Hospital Muenster, Albert-Schweitzer-Campus 1, Building A1, Muenster, Germany.
| | - Maged Alnawaiseh
- Department of Ophthalmology, University Hospital Muenster, Domagkstraße 15, Muenster, Germany
| | - Florian Lehmann
- Department of Anesthesiology, Intensive Care, and Pain Therapy, University Hospital Muenster, Albert-Schweitzer-Campus 1, Building A1, Muenster, Germany
| | - Christina Schmidt
- Department of Anesthesiology, Intensive Care, and Pain Therapy, University Hospital Muenster, Albert-Schweitzer-Campus 1, Building A1, Muenster, Germany
| | - Tim-Gerald Kampmeier
- Department of Anesthesiology, Intensive Care, and Pain Therapy, University Hospital Muenster, Albert-Schweitzer-Campus 1, Building A1, Muenster, Germany
| | - Sebastian Willy Rehberg
- Department of Anesthesiology, Intensive Care, Emergency Medicine, Transfusion Medicine and Pain Therapy, Protestant Hospital of the Bethel Foundation, Burgsteig, Bielefeld, Germany
| | - Philip-Helge Arnemann
- Department of Anesthesiology, Intensive Care, and Pain Therapy, University Hospital Muenster, Albert-Schweitzer-Campus 1, Building A1, Muenster, Germany
| | - Alexandros Rovas
- Department of Medicine D, Division of General Internal Medicine, Nephrology, and Rheumatology, University Hospital Muenster, Albert-Schweitzer-Campus 1, Muenster, Germany
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Shi Y, Zhang Q, Zheng F, Russell JF, Motulsky EH, Banta JT, Chu Z, Zhou H, Patel NA, de Sisternes L, Durbin MK, Feuer W, Gregori G, Wang RK, Rosenfeld PJ. Correlations Between Different Choriocapillaris Flow Deficit Parameters in Normal Eyes Using Swept Source OCT Angiography. Am J Ophthalmol 2020; 209:18-26. [PMID: 31562858 PMCID: PMC7017580 DOI: 10.1016/j.ajo.2019.09.017] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2019] [Revised: 09/16/2019] [Accepted: 09/17/2019] [Indexed: 11/24/2022]
Abstract
PURPOSE Choriocapillaris (CC) imaging of normal eyes with swept-source optical coherence tomographic angiography (SS-OCTA) was performed, and the percentage of CC flow deficits (FD%) and the average area of CC flow deficits (FDa) were compared within the given macular regions. DESIGN A prospective, cross-sectional study. METHODS Subjects with normal eyes ranging in age from their 20s through their 80s were imaged with SS-OCTA (PLEX Elite 9000; Carl Zeiss Meditec, Dublin, California, USA) using both 3×3-mm and 6×6-mm macular scan patterns. The CC images were generated using a previously published and validated algorithm. In both 3×3-mm and 6×6-mm scans, the CC FD% and FDa were measured in circular regions centered on the fovea with diameters as 1 mm and 2.5 mm (C1 and C2.5). In 6×6-mm scans, the FD% and FDa were measured within an additional circular region with diameter as 5 mm (C5). The correlations between FD% and FDa from each region were analyzed with Pearson correlation coefficients. RESULTS A total of 164 eyes were analyzed. There was excellent correlation between CC FDa and FD% measurements from each region. In the 3×3-mm scans, the correlations in the C1 and C2.5 regions were 0.83 and 0.90, respectively. In the 6×6-mm scans, the correlations in C1, C2.5, and C5 regions were 0.90, 0.89, and 0.89, respectively. CONCLUSIONS When measuring CC FDs, we found excellent correlations between FDa and FD% in regions from 3×3-mm and 6×6-mm scans. Further studies are needed to determine if one parameter is more useful when studying diseased eyes.
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Affiliation(s)
- Yingying Shi
- Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, Florida, USA
| | - Qinqin Zhang
- Department of Bioengineering, University of Washington, Seattle, Washington, USA
| | - Fang Zheng
- Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, Florida, USA
| | - Jonathan F Russell
- Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, Florida, USA
| | - Elie H Motulsky
- Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, Florida, USA
| | - James T Banta
- Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, Florida, USA
| | - Zhongdi Chu
- Department of Bioengineering, University of Washington, Seattle, Washington, USA
| | - Hao Zhou
- Department of Bioengineering, University of Washington, Seattle, Washington, USA
| | - Nimesh A Patel
- Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, Florida, USA
| | - Luis de Sisternes
- Research and Development, Carl Zeiss Meditec, Inc, Dublin, California, USA
| | - Mary K Durbin
- Research and Development, Carl Zeiss Meditec, Inc, Dublin, California, USA
| | - William Feuer
- Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, Florida, USA
| | - Giovanni Gregori
- Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, Florida, USA
| | - Ruikang K Wang
- Department of Bioengineering, University of Washington, Seattle, Washington, USA
| | - Philip J Rosenfeld
- Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, Florida, USA.
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40
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Chu Z, Gregori G, Rosenfeld PJ, Wang RK. Quantification of Choriocapillaris with Optical Coherence Tomography Angiography: A Comparison Study. Am J Ophthalmol 2019; 208:111-123. [PMID: 31323202 DOI: 10.1016/j.ajo.2019.07.003] [Citation(s) in RCA: 56] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2019] [Revised: 06/19/2019] [Accepted: 07/11/2019] [Indexed: 12/19/2022]
Abstract
PURPOSE To demonstrate the variation in quantitative choriocapillaris (CC) metrics with various binarization approaches using optical coherence tomography angiography (OCTA). DESIGN Retrospective, observational, cross-sectional case series. METHODS Macular OCTA scans, 3- × 3-mm and 6- × 6-mm, were obtained from normal eyes and from eyes with drusen secondary to age-related macular degeneration (AMD). The CC slab was extracted, and the CC flow deficits (FDs) were segmented with 2 previously published algorithms: the fuzzy C-means approach (FCM method) and Phansalkar's local thresholding (Phansalkar method). Four different values for the radius were used in order to investigate the effect on the FD segmentation when using the Phansalkar method. FD density (FDD), mean FD size (MFDS), FD number (FDN), FD area (FDA) and intercapillary distance (ICD) were calculated for comparison. Repeatability was assessed as coefficient of variation (CV), and Pearson's correlation analysis was conducted. RESULTS Six eyes from 6 subjects with normal eyes and 6 eyes from 6 subjects with drusen secondary to AMD were scanned. The 3- × 3-mm scans resulted in higher repeatability than the 6- × 6-mm scans. For the Phansalkar method, larger values of the radius resulted in higher repeatability. ANOVA tests resulted in significant differences (P < 0.001) among the FCM method and the Phansalkar method with different radius options for all CC metrics and scan sizes investigated. In 3- × 3-mm scans, significant correlation was found between the FCM method and the Phansalkar method for all quantitative CC metrics other than FDN (all P < 0.001; 0.90 < r <0.99). CONCLUSIONS Quantitative CC analysis with commercially available OCTA is complicated and researchers need to pay close attention to how they conduct such analyses.
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Affiliation(s)
- Zhongdi Chu
- Department of Bioengineering, University of Washington, Seattle, Washington
| | - Giovanni Gregori
- Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, Florida, USA
| | - Philip J Rosenfeld
- Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, Florida, USA
| | - Ruikang K Wang
- Department of Bioengineering, University of Washington, Seattle, Washington; Department of Ophthalmology, University of Washington, Seattle, Washington.
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Lipecz A, Miller L, Kovacs I, Czakó C, Csipo T, Baffi J, Csiszar A, Tarantini S, Ungvari Z, Yabluchanskiy A, Conley S. Microvascular contributions to age-related macular degeneration (AMD): from mechanisms of choriocapillaris aging to novel interventions. GeroScience 2019; 41:813-845. [PMID: 31797238 PMCID: PMC6925092 DOI: 10.1007/s11357-019-00138-3] [Citation(s) in RCA: 43] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2019] [Accepted: 11/12/2019] [Indexed: 12/13/2022] Open
Abstract
Aging of the microcirculatory network plays a central role in the pathogenesis of a wide range of age-related diseases, from heart failure to Alzheimer's disease. In the eye, changes in the choroid and choroidal microcirculation (choriocapillaris) also occur with age, and these changes can play a critical role in the pathogenesis of age-related macular degeneration (AMD). In order to develop novel treatments for amelioration of choriocapillaris aging and prevention of AMD, it is essential to understand the cellular and functional changes that occur in the choroid and choriocapillaris during aging. In this review, recent advances in in vivo analysis of choroidal structure and function in AMD patients and patients at risk for AMD are discussed. The pathophysiological roles of fundamental cellular and molecular mechanisms of aging including oxidative stress, mitochondrial dysfunction, and impaired resistance to molecular stressors in the choriocapillaris are also considered in terms of their contribution to the pathogenesis of AMD. The pathogenic roles of cardiovascular risk factors that exacerbate microvascular aging processes, such as smoking, hypertension, and obesity as they relate to AMD and choroid and choriocapillaris changes in patients with these cardiovascular risk factors, are also discussed. Finally, future directions and opportunities to develop novel interventions to prevent/delay AMD by targeting fundamental cellular and molecular aging processes are presented.
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Affiliation(s)
- Agnes Lipecz
- Translational Geroscience Laboratory, Center for Geroscience and Healthy Brain Aging/Reynolds Oklahoma Center on Aging, Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
- Vascular Cognitive Impairment and Neurodegeneration Program, Center for Geroscience and Healthy Brain Aging/Reynolds Oklahoma Center on Aging, Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
- Department of Ophthalmology, Josa Andras Hospital, Nyiregyhaza, Hungary
- International Training Program in Geroscience, Doctoral School of Basic and Translational Medicine/Department of Public Health, Semmelweis University, Budapest, Hungary
- Department of Ophthalmology, Semmelweis University, Budapest, Hungary
| | - Lauren Miller
- Vascular Cognitive Impairment and Neurodegeneration Program, Center for Geroscience and Healthy Brain Aging/Reynolds Oklahoma Center on Aging, Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
- Department of Cell Biology, University of Oklahoma Health Sciences Center, 940 Stanton L. Young Blvd. BMSB553, Oklahoma City, OK, 73104, USA
| | - Illes Kovacs
- Vascular Cognitive Impairment and Neurodegeneration Program, Center for Geroscience and Healthy Brain Aging/Reynolds Oklahoma Center on Aging, Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
- Department of Ophthalmology, Semmelweis University, Budapest, Hungary
- Department of Ophthalmology, Weill Cornell Medical College, New York City, NY, USA
| | - Cecília Czakó
- Department of Ophthalmology, Semmelweis University, Budapest, Hungary
| | - Tamas Csipo
- Translational Geroscience Laboratory, Center for Geroscience and Healthy Brain Aging/Reynolds Oklahoma Center on Aging, Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
- Vascular Cognitive Impairment and Neurodegeneration Program, Center for Geroscience and Healthy Brain Aging/Reynolds Oklahoma Center on Aging, Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
- International Training Program in Geroscience, Doctoral School of Basic and Translational Medicine/Department of Public Health, Semmelweis University, Budapest, Hungary
- International Training Program in Geroscience, Division of Clinical Physiology, Department of Cardiology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Judit Baffi
- Vascular Cognitive Impairment and Neurodegeneration Program, Center for Geroscience and Healthy Brain Aging/Reynolds Oklahoma Center on Aging, Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Anna Csiszar
- Translational Geroscience Laboratory, Center for Geroscience and Healthy Brain Aging/Reynolds Oklahoma Center on Aging, Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
- Vascular Cognitive Impairment and Neurodegeneration Program, Center for Geroscience and Healthy Brain Aging/Reynolds Oklahoma Center on Aging, Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
- International Training Program in Geroscience, Doctoral School of Basic and Translational Medicine/Department of Public Health, Semmelweis University, Budapest, Hungary
- International Training Program in Geroscience, Theoretical Medicine Doctoral School, University of Szeged, Szeged, Hungary
| | - Stefano Tarantini
- Translational Geroscience Laboratory, Center for Geroscience and Healthy Brain Aging/Reynolds Oklahoma Center on Aging, Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
- Vascular Cognitive Impairment and Neurodegeneration Program, Center for Geroscience and Healthy Brain Aging/Reynolds Oklahoma Center on Aging, Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
- International Training Program in Geroscience, Doctoral School of Basic and Translational Medicine/Department of Public Health, Semmelweis University, Budapest, Hungary
- International Training Program in Geroscience, Theoretical Medicine Doctoral School, University of Szeged, Szeged, Hungary
| | - Zoltan Ungvari
- Translational Geroscience Laboratory, Center for Geroscience and Healthy Brain Aging/Reynolds Oklahoma Center on Aging, Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
- Vascular Cognitive Impairment and Neurodegeneration Program, Center for Geroscience and Healthy Brain Aging/Reynolds Oklahoma Center on Aging, Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
- International Training Program in Geroscience, Doctoral School of Basic and Translational Medicine/Department of Public Health, Semmelweis University, Budapest, Hungary
- International Training Program in Geroscience, Theoretical Medicine Doctoral School, University of Szeged, Szeged, Hungary
- Department of Health Promotion Sciences, College of Public Health, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Andriy Yabluchanskiy
- Translational Geroscience Laboratory, Center for Geroscience and Healthy Brain Aging/Reynolds Oklahoma Center on Aging, Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
- Vascular Cognitive Impairment and Neurodegeneration Program, Center for Geroscience and Healthy Brain Aging/Reynolds Oklahoma Center on Aging, Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Shannon Conley
- Vascular Cognitive Impairment and Neurodegeneration Program, Center for Geroscience and Healthy Brain Aging/Reynolds Oklahoma Center on Aging, Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA.
- Department of Cell Biology, University of Oklahoma Health Sciences Center, 940 Stanton L. Young Blvd. BMSB553, Oklahoma City, OK, 73104, USA.
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Zhang P, Miller EB, Manna SK, Meleppat RK, Pugh EN, Zawadzki RJ. Temporal speckle-averaging of optical coherence tomography volumes for in-vivo cellular resolution neuronal and vascular retinal imaging. NEUROPHOTONICS 2019; 6:041105. [PMID: 31528657 PMCID: PMC6732665 DOI: 10.1117/1.nph.6.4.041105] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2019] [Accepted: 07/31/2019] [Indexed: 05/08/2023]
Abstract
It has been recently demonstrated that structures corresponding to the cell bodies of highly transparent cells in the retinal ganglion cell layer could be visualized noninvasively in the living human eye by optical coherence tomography (OCT) via temporal averaging. Inspired by this development, we explored the application of volumetric temporal averaging in mice, which are important models for studying human retinal diseases and therapeutic interventions. A general framework of temporal speckle-averaging (TSA) of OCT and optical coherence tomography angiography (OCTA) is presented and applied to mouse retinal volumetric data. Based on the image analysis, the eyes of mice under anesthesia exhibit only minor motions, corresponding to lateral displacements of a few micrometers and rotations of a fraction of 1 deg. Moreover, due to reduced eye movements under anesthesia, there is a negligible amount of motion artifacts within the volumes that need to be corrected to achieve volume coregistration. In addition, the relatively good optical quality of the mouse ocular media allows for cellular-resolution imaging without adaptive optics (AO), greatly simplifying the experimental system, making the proposed framework feasible for large studies. The TSA OCT and TSA OCTA results provide rich information about new structures previously not visualized in living mice with non-AO-OCT. The mechanism of TSA relies on improving signal-to-noise ratio as well as efficient suppression of speckle contrast due to temporal decorrelation of the speckle patterns, enabling full utilization of the high volumetric resolution offered by OCT and OCTA.
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Affiliation(s)
- Pengfei Zhang
- University of California Davis, Department of Cell Biology and Human Anatomy, UC Davis Eye-Pod Small Animal Ocular Imaging Laboratory, Davis, California, United States
| | - Eric B. Miller
- University of California Davis, Center for Neuroscience, Davis, California, United States
| | - Suman K. Manna
- University of California Davis, Department of Cell Biology and Human Anatomy, UC Davis Eye-Pod Small Animal Ocular Imaging Laboratory, Davis, California, United States
| | - Ratheesh K. Meleppat
- University of California Davis, Department of Cell Biology and Human Anatomy, UC Davis Eye-Pod Small Animal Ocular Imaging Laboratory, Davis, California, United States
| | - Edward N. Pugh
- University of California Davis, Department of Cell Biology and Human Anatomy, UC Davis Eye-Pod Small Animal Ocular Imaging Laboratory, Davis, California, United States
- University of California Davis, Department of Ophthalmology and Vision Science, Vision Science and Advanced Retinal Imaging Laboratory, Sacramento, California, United States
| | - Robert J. Zawadzki
- University of California Davis, Department of Cell Biology and Human Anatomy, UC Davis Eye-Pod Small Animal Ocular Imaging Laboratory, Davis, California, United States
- University of California Davis, Department of Ophthalmology and Vision Science, Vision Science and Advanced Retinal Imaging Laboratory, Sacramento, California, United States
- University of California Davis, UC Davis Eye Center, Department of Ophthalmology and Vision Science, Sacramento, California, United States
- Address all correspondence to Robert J. Zawadzki, E-mail:
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Camino A, Guo Y, You Q, Wang J, Huang D, Bailey ST, Jia Y. Detecting and measuring areas of choriocapillaris low perfusion in intermediate, non-neovascular age-related macular degeneration. NEUROPHOTONICS 2019; 6:041108. [PMID: 31528658 PMCID: PMC6739623 DOI: 10.1117/1.nph.6.4.041108] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/08/2019] [Accepted: 08/16/2019] [Indexed: 05/06/2023]
Abstract
Age-related macular degeneration (AMD) is a vision-threatening disease that affects the outer retina and choroid of elderly adults. Because photoreceptors are found in the outer retina and rely primarily on the trophic support of the underlying choriocapillaris, imaging of flow or lack thereof in choriocapillaris by optical coherence tomography angiography (OCTA) has great clinical potential in AMD assessment. We introduce a metric using OCTA, named "focal perfusion loss" (FPL) to describe the effects of age and non-neovascular AMD on choriocapillaris flow. Because OCTA imaging of choriocapillaris is vulnerable to artifacts-namely motion, projections, segmentation errors, and shadows-they are removed by postprocessing software. The shadow detection software is a machine learning algorithm recently developed for the evaluation of the retinal circulation and here adapted for choriocapillaris analysis. It aims to exclude areas with unreliable flow signal due to blocking of the OCT beam by objects anterior to the choriocapillaris (e.g., drusen, retinal vessels, vitreous floaters, and iris). We found that both the FPL and the capillary density were able to detect changes in the choriocapillaris of AMD and healthy age-matched subjects with respect to young controls. The dominant cause of shadowing in AMD is drusen, and the shadow exclusion algorithm helps determine which areas under drusen retain sufficient signal for perfusion evaluation and which areas must be excluded. Such analysis allowed us to determine unambiguously that choriocapillaris density under drusen is indeed reduced.
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Affiliation(s)
- Acner Camino
- Oregon Health and Science University, Casey Eye Institute, Portland, Oregon, United States
| | - Yukun Guo
- Oregon Health and Science University, Casey Eye Institute, Portland, Oregon, United States
| | - Qisheng You
- Oregon Health and Science University, Casey Eye Institute, Portland, Oregon, United States
| | - Jie Wang
- Oregon Health and Science University, Casey Eye Institute, Portland, Oregon, United States
| | - David Huang
- Oregon Health and Science University, Casey Eye Institute, Portland, Oregon, United States
| | - Steven T. Bailey
- Oregon Health and Science University, Casey Eye Institute, Portland, Oregon, United States
| | - Yali Jia
- Oregon Health and Science University, Casey Eye Institute, Portland, Oregon, United States
- Address all correspondence to Yali Jia, E-mail:
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Chen M, Dai W, Shao Q, Wang H, Liu Z, Niu L, Zhang X, Wang H, Xie C. Optical properties of electrically controlled arc-electrode liquid-crystal microlens array for wavefront measurement and adjustment. APPLIED OPTICS 2019; 58:6611-6617. [PMID: 31503592 DOI: 10.1364/ao.58.006611] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2019] [Accepted: 07/22/2019] [Indexed: 06/10/2023]
Abstract
An electrically controlled arc-electrode liquid-crystal microlens array (AE-LCMLA), with tuning and swing focus, is proposed, which can be utilized to replace the traditional mechanically controlled microlenses and also cooperate with photosensitive arrays to solve the problems of measuring and further adjusting a strong distortion wavefront. The top patterned electrode of a single LC microlens is composed of three arc-electrodes distributed symmetrically around a central microhole for constructing the key controlling structures of the LC cavity in the AE-LCMLA. All the arc-electrodes are individually controlled, and then the focal spot of each microlens can be moved freely in a three-dimensional fashion including along the optical axial direction and over the focal plane by simply adjusting the driving signal voltage applied over each arc-electrode, independently. The featured performances of the AE-LCMLA in a wavelength range of ∼501-561 nm are the driving signal voltage being relatively low (less than ∼11 Vrms), the focal length tuning range being from ∼2.54 mm to ∼3.50 mm, the maximum focus swing distance being ∼52.92 μm, and the focus swing ratio K being ∼20‰.
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Zhou K, Song S, Zhang Q, Chu Z, Huang Z, Wang RK. Visualizing choriocapillaris using swept-source optical coherence tomography angiography with various probe beam sizes. BIOMEDICAL OPTICS EXPRESS 2019; 10:2847-2860. [PMID: 31259055 PMCID: PMC6583358 DOI: 10.1364/boe.10.002847] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2019] [Revised: 04/02/2019] [Accepted: 05/09/2019] [Indexed: 05/29/2023]
Abstract
Imaging choriocapillaris (CC) is a long-term challenge for commercial OCT angiography (OCTA) systems due to limited transverse resolution. Effects of transverse resolution on the visualization of a CC microvascular network are explored and demonstrated in this paper. We use three probe beams with sizes of ~1.12 mm, ~2.51 mm and ~3.50 mm at the pupil plane, which deliver an estimated transverse resolution at the retina of 17.5 µm, 8.8 µm and 7.0 µm, respectively, to investigate the ability of OCTA to resolve the CC capillary vessels. The complex optical microangiography algorithm is applied to extract blood flow in the CC slab. Mean retinal pigment epithelium (RPE) to CC (RPE-CC) distance, mean CC inter-vascular spacing and the magnitude in the radially-averaged power spectrum are quantified. We demonstrate that a clearer CC lobular capillary network is resolved in the angiograms provided by a larger beam size. The image contrast of the CC angiogram with a large beam size of 3.50 mm is 114% higher than that with a small beam size of 1.12 mm. While the measurements of the mean RPE-CC distance and CC inter-vascular spacing are almost consistent regardless of the beam sizes, they are more reliable and stable with the larger beam size of 3.50 mm. We conclude that the beam size is a key parameter for CC angiography if the purpose of the investigation is to visualize the individual CC capillaries.
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Affiliation(s)
- Kanheng Zhou
- School of Science and Engineering, University of Dundee, Dundee DD1 4HN, UK
- Department of Bioengineering, University of Washington, Seattle, WA 98195, USA
| | - Shaozhen Song
- Department of Bioengineering, University of Washington, Seattle, WA 98195, USA
| | - Qinqin Zhang
- Department of Bioengineering, University of Washington, Seattle, WA 98195, USA
| | - Zhongdi Chu
- Department of Bioengineering, University of Washington, Seattle, WA 98195, USA
| | - Zhihong Huang
- School of Science and Engineering, University of Dundee, Dundee DD1 4HN, UK
| | - Ruikang K. Wang
- Department of Bioengineering, University of Washington, Seattle, WA 98195, USA
- Department of Ophthalmology, University of Washington, Seattle, WA 98195, USA
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Thulliez M, Zhang Q, Shi Y, Zhou H, Chu Z, de Sisternes L, Durbin MK, Feuer W, Gregori G, Wang RK, Rosenfeld PJ. Correlations between Choriocapillaris Flow Deficits around Geographic Atrophy and Enlargement Rates Based on Swept-Source OCT Imaging. Ophthalmol Retina 2019; 3:478-488. [PMID: 31174669 DOI: 10.1016/j.oret.2019.01.024] [Citation(s) in RCA: 81] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2018] [Revised: 12/08/2018] [Accepted: 01/30/2019] [Indexed: 01/12/2023]
Abstract
PURPOSE To determine the possible correlation between the annual enlargement rates (ERs) of geographic atrophy (GA) with the percentage and size of the choriocapillaris (CC) flow deficits (FDs) surrounding GA, measured with swept-source OCT angiography (SS-OCTA) images. DESIGN Prospective, observational case series. PARTICIPANTS Patients with GA secondary to nonexudative AMD. METHODS Patients were imaged with a 100-kHz SS-OCTA instrument (PLEX Elite 9000, Carl Zeiss Meditec, Dublin, CA) using a 6×6-mm field of view scan pattern. The GA area measurements were obtained from en face SS-OCT sub-retinal pigment epithelium (RPE) slab images. Visualization of the CC and quantification of FDs were performed using a previously published validated algorithm based on a 20-μm thickness slab with the inner boundary located beneath Bruch's membrane. The percentage of CC FDs (FD%) and the average FD area measurements were calculated in different regions around the GA. MAIN OUTCOME MEASURES The correlation between the CC FDs and the ERs of GA. RESULTS Twenty-two eyes from 15 patients were eligible for the analysis. The annual square root ERs for GA ranged from 0.07 to 0.75 mm/year. The CC FD% and average FD area measurements were highly correlated with each other (P < 0.001), with the highest FD values found in the region closest to the margin of GA. The ERs correlated best with the average CC FD area measurements in the total scan area minus the area of GA (Pearson r = 0.747; P < 0.001) than those in the regions immediately surrounding the GA (r = 0.544; P = 0.009). CONCLUSIONS Contrary to expectations, the global CC FD measurements had a better correlation with the ERs of GA than those in the regions immediately around the GA. The most likely explanation for this outcome is that normal age-related increases in FDs within the central macula confound the correlations between the ERs of GA and FDs, whereas the regions furthest away from the margins of GA are less affected by normal age-related changes and reflect FD alterations related to AMD severity.
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Affiliation(s)
- Marie Thulliez
- Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, Florida
| | - Qinqin Zhang
- Department of Bioengineering, University of Washington, Seattle, Washington
| | - Yingying Shi
- Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, Florida
| | - Hao Zhou
- Department of Bioengineering, University of Washington, Seattle, Washington
| | - Zhongdi Chu
- Department of Bioengineering, University of Washington, Seattle, Washington
| | - Luis de Sisternes
- Research and Development, Carl Zeiss Meditec, Inc, Dublin, California
| | - Mary K Durbin
- Research and Development, Carl Zeiss Meditec, Inc, Dublin, California
| | - William Feuer
- Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, Florida
| | - Giovanni Gregori
- Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, Florida
| | - Ruikang K Wang
- Department of Bioengineering, University of Washington, Seattle, Washington
| | - Philip J Rosenfeld
- Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, Florida.
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Cone photoreceptor classification in the living human eye from photostimulation-induced phase dynamics. Proc Natl Acad Sci U S A 2019; 116:7951-7956. [PMID: 30944223 PMCID: PMC6475411 DOI: 10.1073/pnas.1816360116] [Citation(s) in RCA: 76] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
The three spectral types of cone photoreceptors underlie color perception and are largely responsible for inherited and acquired color vision anomalies. In vivo mapping of the trichromatic cone mosaic by imaging provides the most direct and quantitative means to assess the role of photoreceptors in color vision, but remains challenging because cone reflections only weakly differentiate cone types. Here, we show a noninvasive light microscopy modality that reveals the cell’s spectral type, using the optical phase change that arises within the cell when stimulated with light. Our procedure is orders of magnitude faster and more accurate than prior approaches and makes in vivo cone classification promising for a much wider range of color vision applications. Human color vision is achieved by mixing neural signals from cone photoreceptors sensitive to different wavelengths of light. The spatial arrangement and proportion of these spectral types in the retina set fundamental limits on color perception, and abnormal or missing types are responsible for color vision loss. Imaging provides the most direct and quantitative means to study these photoreceptor properties at the cellular scale in the living human retina, but remains challenging. Current methods rely on retinal densitometry to distinguish cone types, a prohibitively slow process. Here, we show that photostimulation-induced optical phase changes occur in cone cells and carry substantial information about spectral type, enabling cones to be differentiated with unprecedented accuracy and efficiency. Moreover, these phase dynamics arise from physiological activity occurring on dramatically different timescales (from milliseconds to seconds) inside the cone outer segment, thus exposing the phototransduction cascade and subsequent downstream effects. We captured these dynamics in cones of subjects with normal color vision and a deuteranope, and at different macular locations by: (i) marrying adaptive optics to phase-sensitive optical coherence tomography to avoid optical blurring of the eye, (ii) acquiring images at high speed that samples phase dynamics at up to 3 KHz, and (iii) localizing phase changes to the cone outer segment, where photoactivation occurs. Our method should have broad appeal for color vision applications in which the underlying neural processing of photoreceptors is sought and for investigations of retinal diseases that affect cone function.
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Zheng F, Zhang Q, Shi Y, Russell JF, Motulsky EH, Banta JT, Chu Z, Zhou H, Patel NA, de Sisternes L, Durbin MK, Feuer W, Gregori G, Wang R, Rosenfeld PJ. Age-dependent Changes in the Macular Choriocapillaris of Normal Eyes Imaged With Swept-Source Optical Coherence Tomography Angiography. Am J Ophthalmol 2019; 200:110-122. [PMID: 30639367 DOI: 10.1016/j.ajo.2018.12.025] [Citation(s) in RCA: 102] [Impact Index Per Article: 20.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2018] [Revised: 12/30/2018] [Accepted: 12/31/2018] [Indexed: 12/31/2022]
Abstract
PURPOSE Swept-source optical coherence tomography angiography (SS-OCTA) was used to measure the age-dependent changes in macular choriocapillaris (CC) flow deficits (FDs) in normal eyes. DESIGN A prospective, cross-sectional study. METHODS Subjects with normal eyes ranging in age from their 20s to their 80s were imaged using a 100-kHz SS-OCTA instrument (PLEX Elite 9000, Carl Zeiss Meditec, Dublin, California, USA). Both 3 × 3-mm and 6 × 6-mm scans were used to image the macular CC. Visualization of the CC and quantification of FDs were performed using a previously validated algorithm. The percentage of FDs (FD%) in the central 1-mm circle (C1), 1.5-mm rim (R1.5), and 2.5-mm circle (C2.5) from the 3 × 3-mm and 6 × 6-mm scans and FD% in the 2.5-mm rim (R2.5) and 5-mm circle (C5) from the 6 × 6-mm scans were measured and correlated with age and axial length. RESULTS A total of 164 subjects were enrolled, with at least 10 subjects from each decade of life. No meaningful correlations were found between FD% and axial length (|r| < 0.30). FD% in all fields increased with increasing age (all r > 0.50; all P < .001); however, the greatest increases were found in the central macula C1 regions and the smallest increases in the peripheral macula R2.5 regions. CONCLUSIONS In normal aging, the FD% increased with age across the central 5 mm of the macula, but the greatest increase was found in the central 1-mm region of the macula.
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Puyo L, Paques M, Fink M, Sahel JA, Atlan M. Choroidal vasculature imaging with laser Doppler holography. BIOMEDICAL OPTICS EXPRESS 2019; 10:995-1012. [PMID: 30800528 PMCID: PMC6377881 DOI: 10.1364/boe.10.000995] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2018] [Revised: 01/09/2019] [Accepted: 01/10/2019] [Indexed: 05/18/2023]
Abstract
The choroid is a highly vascularized tissue supplying the retinal pigment epithelium and photoreceptors. Its implication in retinal diseases is gaining increasing interest. However, investigating the anatomy and flow of the choroid remains challenging. Here we show that laser Doppler holography provides high-contrast imaging of choroidal vessels in humans, with a spatial resolution comparable to state-of-the-art indocyanine green angiography and optical coherence tomography. Additionally, laser Doppler holography contributes to sort out choroidal arteries and veins by using a power Doppler spectral analysis. We thus demonstrate the potential of laser Doppler holography to improve our understanding of the anatomy and flow of the choroidal vascular network.
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Affiliation(s)
- Léo Puyo
- Institut Langevin, Centre National de la Recherche Scientifique (CNRS), Paris Sciences & Lettres (PSL University), École Supérieure de Physique et de Chimie Industrielles (ESPCI Paris), 1 rue Jussieu, 75005 Paris,
France
- Paris Adaptive Optics, Retinal Imaging, and Surgery, (PARIS) Group,
France
| | - Michel Paques
- Paris Adaptive Optics, Retinal Imaging, and Surgery, (PARIS) Group,
France
- Centre Hospitalier National d’Ophtalmologie des Quinze-Vingts, INSERM-DHOS CIC 1423, 28 rue de Charenton, 75012 Paris,
France
- Institut de la Vision-Sorbonne Universités, 17 rue Moreau, 75012 Paris,
France
| | - Mathias Fink
- Institut Langevin, Centre National de la Recherche Scientifique (CNRS), Paris Sciences & Lettres (PSL University), École Supérieure de Physique et de Chimie Industrielles (ESPCI Paris), 1 rue Jussieu, 75005 Paris,
France
- Paris Adaptive Optics, Retinal Imaging, and Surgery, (PARIS) Group,
France
| | - José-Alain Sahel
- Paris Adaptive Optics, Retinal Imaging, and Surgery, (PARIS) Group,
France
- Centre Hospitalier National d’Ophtalmologie des Quinze-Vingts, INSERM-DHOS CIC 1423, 28 rue de Charenton, 75012 Paris,
France
- Institut de la Vision-Sorbonne Universités, 17 rue Moreau, 75012 Paris,
France
| | - Michael Atlan
- Institut Langevin, Centre National de la Recherche Scientifique (CNRS), Paris Sciences & Lettres (PSL University), École Supérieure de Physique et de Chimie Industrielles (ESPCI Paris), 1 rue Jussieu, 75005 Paris,
France
- Paris Adaptive Optics, Retinal Imaging, and Surgery, (PARIS) Group,
France
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Chlebiej M, Gorczynska I, Rutkowski A, Kluczewski J, Grzona T, Pijewska E, Sikorski BL, Szkulmowska A, Szkulmowski M. Quality improvement of OCT angiograms with elliptical directional filtering. BIOMEDICAL OPTICS EXPRESS 2019; 10:1013-1031. [PMID: 30800529 PMCID: PMC6377873 DOI: 10.1364/boe.10.001013] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/28/2018] [Revised: 01/09/2019] [Accepted: 01/09/2019] [Indexed: 05/06/2023]
Abstract
We present a method of OCT angiography (OCTA) data filtering for noise suppression and improved visualization of the retinal vascular networks in en face projection images. In our approach, we use a set of filters applied in three orthogonal axes in the three-dimensional (3-D) data sets. Minimization of artifacts generated in B-scan-wise data processing is accomplished by filtering the cross-sections along the slow scanning axis. A-scans are de-noised by axial filtering. The core of the method is the application of directional filtering to the C-scans, i.e. one-pixel thick sections of the 3-D data set, perpendicular to the direction of the scanning OCT beam. The method uses a concept of structuring, directional kernels of shapes matching the geometry of the image features. We use rotating ellipses to find the most likely local orientation of the vessels and use the best matching ellipses for median filtering of the C-scans. We demonstrate our approach in the imaging of a normal human eye with laboratory-grade spectral-domain OCT setup. The "field performance" is demonstrated in imaging of diabetic retinopathy cases with a commercial OCT device. The absolute complex differences method is used for the generation of OCTA images from the data collected in the most noise-wise unfavorable OCTA scanning regime-two frame scanning.
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Affiliation(s)
- Michał Chlebiej
- Faculty of Mathematics and Computer Science, Nicolaus Copernicus University in Torun, Chopina 12/18, 87-100 Torun, Poland
- AM2M Ltd. L.P., Mickiewicza 7/17, 87-100 Torun, Poland
| | | | - Andrzej Rutkowski
- Faculty of Mathematics and Computer Science, Nicolaus Copernicus University in Torun, Chopina 12/18, 87-100 Torun, Poland
- AM2M Ltd. L.P., Mickiewicza 7/17, 87-100 Torun, Poland
| | - Jakub Kluczewski
- Faculty of Mathematics and Computer Science, Nicolaus Copernicus University in Torun, Chopina 12/18, 87-100 Torun, Poland
- AM2M Ltd. L.P., Mickiewicza 7/17, 87-100 Torun, Poland
| | - Tomasz Grzona
- Faculty of Mathematics and Computer Science, Nicolaus Copernicus University in Torun, Chopina 12/18, 87-100 Torun, Poland
- AM2M Ltd. L.P., Mickiewicza 7/17, 87-100 Torun, Poland
| | - Ewelina Pijewska
- Institute of Physics, Faculty of Physics, Astronomy and Informatics, Nicolaus Copernicus University in Torun, Grudziadzka 5, 87-100 Torun, Poland
| | - Bartosz L. Sikorski
- Department of Ophthalmology, Nicolaus Copernicus University in Torun, 9 M. Sklodowskiej-Curie St., Bydgoszcz, Poland
- Oculomedica Eye Centre, 9 Broniewskiego St. Bydgoszcz, Poland
| | | | - Maciej Szkulmowski
- Institute of Physics, Faculty of Physics, Astronomy and Informatics, Nicolaus Copernicus University in Torun, Grudziadzka 5, 87-100 Torun, Poland
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