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Kim TH, Ma G, Son T, Yao X. Functional Optical Coherence Tomography for Intrinsic Signal Optoretinography: Recent Developments and Deployment Challenges. Front Med (Lausanne) 2022; 9:864824. [PMID: 35445037 PMCID: PMC9013890 DOI: 10.3389/fmed.2022.864824] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2022] [Accepted: 03/16/2022] [Indexed: 11/13/2022] Open
Abstract
Intrinsic optical signal (IOS) imaging of the retina, also termed as optoretinogram or optoretinography (ORG), promises a non-invasive method for the objective assessment of retinal function. By providing the unparalleled capability to differentiate individual retinal layers, functional optical coherence tomography (OCT) has been actively investigated for intrinsic signal ORG measurements. However, clinical deployment of functional OCT for quantitative ORG is still challenging due to the lack of a standardized imaging protocol and the complication of IOS sources and mechanisms. This article aims to summarize recent developments of functional OCT for ORG measurement, OCT intensity- and phase-based IOS processing. Technical challenges and perspectives of quantitative IOS analysis and ORG interpretations are discussed.
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Affiliation(s)
- Tae-Hoon Kim
- Richard and Loan Hill Department of Biomedical Engineering, University of Illinois at Chicago, Chicago, IL, United States
| | - Guangying Ma
- Richard and Loan Hill Department of Biomedical Engineering, University of Illinois at Chicago, Chicago, IL, United States
| | - Taeyoon Son
- Richard and Loan Hill Department of Biomedical Engineering, University of Illinois at Chicago, Chicago, IL, United States
| | - Xincheng Yao
- Richard and Loan Hill Department of Biomedical Engineering, University of Illinois at Chicago, Chicago, IL, United States
- Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago, Chicago, IL, United States
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2
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Pijewska E, Zhang P, Meina M, Meleppat RK, Szkulmowski M, Zawadzki RJ. Extraction of phase-based optoretinograms (ORG) from serial B-scans acquired over tens of seconds by mouse retinal raster scanning OCT system. BIOMEDICAL OPTICS EXPRESS 2021; 12:7849-7871. [PMID: 35003871 PMCID: PMC8713677 DOI: 10.1364/boe.439900] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Revised: 11/01/2021] [Accepted: 11/08/2021] [Indexed: 06/14/2023]
Abstract
Several specialized retinal optical coherence tomography (OCT) acquisition and processing methods have been recently developed to allow in vivo probing of light-evoked photoreceptors function, focusing on measurements in individual photoreceptors (rods and cones). Recent OCT investigations in humans and experimental animals have shown that the outer segments in dark-adapted rods and cones elongate in response to the visible optical stimuli that bleach fractions of their visual photopigment. We have previously successfully contributed to these developments by implementing OCT intensity-based "optoretinograms" (ORG), the paradigm of using near-infrared OCT (NIR OCT) to measure bleaching-induced back-scattering and/or elongation changes of photoreceptors in the eye in vivo. In parallel, several groups have successfully implemented phase-based ORGs, mainly in human studies, exploiting changes in the phases of back-scattered light. This allowed more sensitive observations of tiny alterations of photoreceptors structures. Applications of the phase-based ORG have been implemented primarily in high speed and cellular resolution AO-OCT systems that can visualize photoreceptor mosaic, allowing phase measurements of path length changes in outer segments of individual photoreceptors. The phase-based ORG in standard resolution OCT systems is much more demanding to implement and has not been explored extensively. This manuscript describes our efforts to implement a phase analysis framework to retinal images acquired with a standard resolution and raster scanning OCT system, which offers much lower phase stability than line-field or full-field OCT detection schemes due to the relatively slower acquisition speed. Our initial results showcase the successful extraction of phase-based ORG signal from the B-scans acquired at ∼100 Hz rate and its favorable comparison with intensity-based ORG signal extracted from the same data sets. We implemented the calculation of phase-based ORG signals using Knox-Thompson paths and modified signal recovery by adding decorrelation weights. The phase-sensitive ORG signal analysis developed here for mouse retinal raster scanning OCT systems could be in principle extended to clinical retinal raster scanning OCT systems, potentially opening doors for clinically friendly ORG probing.
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Affiliation(s)
- Ewelina Pijewska
- Institute of Physics, Faculty of Physics, Astronomy and Informatics, Nicolaus Copernicus University in Toruń, Grudziądzka 5, 87-100 Torun, Poland
| | - Pengfei Zhang
- UC Davis Eyepod Imaging Laboratory, Dept. of Cell Biology and Human Anatomy, University of California Davis, 4320 Tupper Hall, Davis, CA 95616, USA
- School of Optoelectronic Engineering and Instrumentation Science, Dalian University of Technology, No. 2 Linggong Road, Ganjingzi District, Dalian City, Liaoning Province 116024, China
| | - Michał Meina
- Institute of Physics, Faculty of Physics, Astronomy and Informatics, Nicolaus Copernicus University in Toruń, Grudziądzka 5, 87-100 Torun, Poland
| | - Ratheesh K. Meleppat
- UC Davis Eyepod Imaging Laboratory, Dept. of Cell Biology and Human Anatomy, University of California Davis, 4320 Tupper Hall, Davis, CA 95616, USA
| | - Maciej Szkulmowski
- Institute of Physics, Faculty of Physics, Astronomy and Informatics, Nicolaus Copernicus University in Toruń, Grudziądzka 5, 87-100 Torun, Poland
| | - Robert J. Zawadzki
- UC Davis Eyepod Imaging Laboratory, Dept. of Cell Biology and Human Anatomy, University of California Davis, 4320 Tupper Hall, Davis, CA 95616, USA
- Department of Ophthalmology & Vision Science, University of California Davis, 4860 Y Street Suite 2400 Sacramento, CA 95817, USA
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3
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Su X, Zheng H, Li Q, Sun P, Zhou M, Li H, Guo J, Chai X, Zhou C. Retinal neurovascular responses to transcorneal electrical stimulation measured with optical coherence tomography. Exp Biol Med (Maywood) 2020; 245:289-300. [PMID: 31958987 DOI: 10.1177/1535370219900495] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Noninvasive transcorneal electrical stimulation (TES) has emerged as a potential strategy to facilitate visual restoration and promote retinal cell survival for certain retinal and optic nerve diseases owing to its neuroprotective effects. However, the neurovascular responses of retinal neurons evoked by TES have not been completely determined. To investigate this issue, we utilized a custom-designed spectral-domain optical coherence tomography (SD-OCT) to record the retinal neural and vascular responses under TES in vivo simultaneously. Significant increases of both positive and negative intrinsic optical signal (IOS) changes were recorded in all three segmented retinal layers, which mainly related to neural activities. However, the changes of TES-induced retinal vascular responses, including blood velocity, cross-sectional area of vessel, and blood flow, were not significant. It suggests that TES mainly elicited neural responses in retina, while no significant vascular responses were evoked. Our results provide experimental evidence to the mechanism of retinal neurovascular coupling under TES. Additionally, the present study also suggests that SD-OCT could be utilized as a promoting method to explore neurovascular responses under retinal stimulation in clinical treatment and technology. Impact statement Noninvasive transcorneal electrical stimulation (TES) has emerged as an effective treatment for certain retinal and optic nerve diseases owing to its neuroprotective effects. However, the retinal neurovascular responses evoked by TES have not been completely determined. To investigate this issue, we utilized a custom-designed spectral-domain optical coherence tomography (SD-OCT) to record the retinal neural and vascular responses evoked by TES in vivo simultaneously. The present study suggested that TES mainly elicited neural responses in retina, while no significant vascular responses were evoked. Our results provide experimental evidence to the mechanism of retinal neurovascular coupling evoked by TES. Additionally, the present study also suggests that SD-OCT could be utilized as a promoting method to explore neurovascular responses under retinal electrical stimulation.
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Affiliation(s)
- Xiaofan Su
- School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Hao Zheng
- School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Qian Li
- School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai 200240, China.,Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna 1090, Austria
| | - Pengcheng Sun
- School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Meixuan Zhou
- School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Heng Li
- School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Jiahui Guo
- School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Xinyu Chai
- School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Chuanqing Zhou
- School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai 200240, China.,Institute of Biomedical Engineering, Shenzhen Bay Laboratory, Shenzhen 518055, China
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4
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Sun P, Li Q, Li H, Di L, Su X, Chen J, Zheng H, Chen Y, Zhou C, Chai X. Depth-Resolved Physiological Response of Retina to Transcorneal Electrical Stimulation Measured With Optical Coherence Tomography. IEEE Trans Neural Syst Rehabil Eng 2019; 27:905-915. [PMID: 31021770 DOI: 10.1109/tnsre.2019.2912168] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Transcorneal electrical stimulation (TES) has become an effective strategy to modulate retinal neural activities and partially restore visual function in ophthalmic diseases. However, the exact responses in different retinal layers still need to be clarified. This paper's goal was to evaluate the depth-resolved retinal physiological responses evoked by TES by using optical coherence tomography (OCT). A custom-built spectral-domain OCT system was used to record the intrinsic optical signals (IOSs) in different retinal layers. TES and flickers were used to stimulate the retina electrically and visually. Tetrodotoxin was used to inhibit the retinal neural activity for confirming the origin of TES-induced IOSs. We found both positive and negative IOSs could be evoked by TES in three segmented retinal layers, especially in the inner retina and subretinal space. The TES-induced IOSs correlated with the TES intensity. After tetrodotoxin injection, the IOSs evoked by TES were significantly declined, peculiarly in the inner retina. The IOSs elicited by flickers kept increasing during the stimulation, while those evoked by TES kept at a stable level. In conclusion, TES could elicit IOSs that originated from retinal neural activity in all segmented layers. The TES-induced IOSs were highly synchronized to the electrical field in the retina.
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5
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Tan B, MacLellan B, Mason E, Bizheva K. Structural, functional and blood perfusion changes in the rat retina associated with elevated intraocular pressure, measured simultaneously with a combined OCT+ERG system. PLoS One 2018; 13:e0193592. [PMID: 29509807 PMCID: PMC5839563 DOI: 10.1371/journal.pone.0193592] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2017] [Accepted: 02/14/2018] [Indexed: 02/07/2023] Open
Abstract
Acute elevation of intraocular pressure (IOP) to ischemic and non-ischemic levels can cause temporary or permanent changes in the retinal morphology, function and blood flow/blood perfusion. Previously, such changes in the retina were assessed separately with different methods in clinical studies and animal models. In this study, we used a combined OCT+ ERG system in combination with Doppler OCT and OCT angiography (OCTA) imaging protocols, in order to evaluate simultaneously and correlate changes in the retinal morphology, the retinal functional response to visual stimulation, and the retinal blood flow/blood perfusion, associated with IOP elevation to ischemic and non-ischemic levels in rats. Results from this study suggest that the inner retina responds faster to IOP elevation to levels greater than 30 mmHg with significant reduction of the total retinal blood flow (TRBF), decrease of the capillaries’ perfusion and reduction of the ON bipolar cells contribution to the ERG traces. Furthermore, this study showed that ischemic levels of IOP elevation cause an additional significant decrease in the ERG photoreceptor response in the posterior retina. Thirty minutes after IOP normalization, retinal morphology, blood flow and blood perfusion recovered to baseline values, while retinal function did not recover completely.
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Affiliation(s)
- Bingyao Tan
- Department of Physics and Astronomy, University of Waterloo, Waterloo, Ontario, Canada
| | - Benjamin MacLellan
- Department of Physics and Astronomy, University of Waterloo, Waterloo, Ontario, Canada
| | - Erik Mason
- Department of Physics and Astronomy, University of Waterloo, Waterloo, Ontario, Canada
| | - Kostadinka Bizheva
- Department of Physics and Astronomy, University of Waterloo, Waterloo, Ontario, Canada
- School of Optometry and Vision Science, University of Waterloo, Waterloo, Ontario, Canada
- Department of System Design Engineering, University of Waterloo, Waterloo, Ontario, Canada
- * E-mail:
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6
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Erchova I, Tumlinson AR, Fergusson J, White N, Drexler W, Sengpiel F, Morgan JE. Optophysiological Characterisation of Inner Retina Responses with High-Resolution Optical Coherence Tomography. Sci Rep 2018; 8:1813. [PMID: 29379036 PMCID: PMC5788978 DOI: 10.1038/s41598-018-19975-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2017] [Accepted: 01/03/2018] [Indexed: 11/18/2022] Open
Abstract
Low coherence laser interferometry has revolutionised quantitative biomedical imaging of optically transparent structures at cellular resolutions. We report the first optical recording of neuronal excitation at cellular resolution in the inner retina by quantifying optically recorded stimulus-evoked responses from the retinal ganglion cell layer and comparing them with an electrophysiological standard. We imaged anaesthetised paralysed tree shrews, gated image acquisition, and used numerical filters to eliminate noise arising from retinal movements during respiratory and cardiac cycles. We observed increases in contrast variability in the retinal ganglion cell layer and nerve fibre layer with flash stimuli and gratings. Regions of interest were subdivided into three-dimensional patches (up to 5–15 μm in diameter) based on response similarity. We hypothesise that these patches correspond to individual cells, or segments of blood vessels within the inner retina. We observed a close correlation between the patch optical responses and mean electrical activity of the visual neurons in afferent pathway. While our data suggest that optical imaging of retinal activity is possible with high resolution OCT, the technical challenges are not trivial.
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Affiliation(s)
- Irina Erchova
- School of Optometry and Visual Sciences, Cardiff University, Cardiff, United Kingdom
| | - Alexandre R Tumlinson
- School of Optometry and Visual Sciences, Cardiff University, Cardiff, United Kingdom.,Zeiss Meditec, Dublin, California, USA
| | - James Fergusson
- School of Optometry and Visual Sciences, Cardiff University, Cardiff, United Kingdom
| | - Nick White
- School of Optometry and Visual Sciences, Cardiff University, Cardiff, United Kingdom
| | - Wolfgang Drexler
- Center for Medical Physics & Biom Eng, Medical University Vienna, Vienna, Austria
| | - Frank Sengpiel
- School of Biosciences, Cardiff University, Cardiff, United Kingdom
| | - James E Morgan
- School of Optometry and Visual Sciences, Cardiff University, Cardiff, United Kingdom. .,Ophthalmology, University Hospital of Wales, Cardiff, United Kingdom.
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7
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Tan B, Hosseinaee Z, Bizheva K. Dense concentric circle scanning protocol for measuring pulsatile retinal blood flow in rats with Doppler optical coherence tomography. JOURNAL OF BIOMEDICAL OPTICS 2017; 22:1-4. [PMID: 29110446 DOI: 10.1117/1.jbo.22.11.110501] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/12/2017] [Accepted: 10/16/2017] [Indexed: 05/22/2023]
Abstract
The variability in the spatial orientation of retinal blood vessels near the optic nerve head (ONH) results in imprecision of the measured Doppler angle and therefore the pulsatile blood flow (BF), when those parameters are evaluated using Doppler OCT imaging protocols based on dual-concentric circular scans. Here, we utilized a dense concentric circle scanning protocol and evaluated its precision for measuring pulsatile retinal BF in rats for different numbers of the circular scans. An spectral domain optical coherence tomography (SD-OCT) system operating in the 1060-nm spectral range with image acquisition rate of 47,000 A-scans/s was used to acquire concentric circular scans centered at the rat's ONH, with diameters ranging from 0.8 to 1.0 mm. A custom, automatic blood vessel segmentation algorithm was used to track the spatial orientation of the retinal blood vessels in three dimensions, evaluate the spatially dependent Doppler angle and calculate more accurately the axial BF for each major retinal blood vessel. Metrics such as retinal BF, pulsatility index, and resistance index were evaluated for each and all of the major retinal blood vessels. The performance of the proposed dense concentric circle scanning protocols was compared with that of the dual-circle scanning protocol. Results showed a 3.8±2.2 deg difference in the Doppler angle calculation between the two approaches, which resulted in ∼7% difference in the calculated retinal BF.
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Affiliation(s)
- Bingyao Tan
- University of Waterloo, Department of Physics and Astronomy, Waterloo, Ontario, Canada
| | - Zohreh Hosseinaee
- University of Waterloo, Department of System Design Engineering, Waterloo, Ontario, Canada
| | - Kostadinka Bizheva
- University of Waterloo, Department of Physics and Astronomy, Waterloo, Ontario, Canada
- University of Waterloo, Department of System Design Engineering, Waterloo, Ontario, Canada
- University of Waterloo, School of Optometry, Waterloo, Ontario, Canada
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8
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Thapa D, Wang B, Lu Y, Son T, Yao X. Enhancement of intrinsic optical signal recording with split spectrum optical coherence tomography. JOURNAL OF MODERN OPTICS 2017; 64:1800-1807. [PMID: 29129961 PMCID: PMC5679439 DOI: 10.1080/09500340.2017.1318966] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Functional optical coherence tomography (OCT) of stimulus-evoked intrinsic optical signal (IOS) promises to be a new methodology for high-resolution mapping of retinal neural dysfunctions. However, its practical applications for non-invasive examination of retinal function have been hindered by the low signal-to-noise ratio (SNR) and small magnitude of IOSs. Split spectrum amplitude-decorrelation has been demonstrated to improve the image quality of OCT angiography. In this study, we exploited split spectrum strategy to improve the sensitivity of IOS recording. The full OCT spectrum was split into multiple spectral bands and IOSs from each sub-band were calculated separately and then combined to generate a single IOS image sequence. The algorithm was tested on in vivo images of frog retinas. It significantly improved both IOS magnitude and SNR, which are essential for practical applications of functional IOS imaging.
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Affiliation(s)
- Damber Thapa
- Department of Bioengineering, University of Illinois at Chicago, Chicago, IL, USA
| | - Benquan Wang
- Department of Bioengineering, University of Illinois at Chicago, Chicago, IL, USA
| | - Yiming Lu
- Department of Bioengineering, University of Illinois at Chicago, Chicago, IL, USA
| | - Taeyoon Son
- Department of Bioengineering, University of Illinois at Chicago, Chicago, IL, USA
| | - Xincheng Yao
- Department of Bioengineering, University of Illinois at Chicago, Chicago, IL, USA
- Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago, Chicago, IL, USA
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9
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Tong MQ, Hasan MM, Lee SS, Haque MR, Kim DH, Islam MS, Adams ME, Park BH. OCT intensity and phase fluctuations correlated with activity-dependent neuronal calcium dynamics in the Drosophila CNS [Invited]. BIOMEDICAL OPTICS EXPRESS 2017; 8:726-735. [PMID: 28270979 PMCID: PMC5330578 DOI: 10.1364/boe.8.000726] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/17/2016] [Revised: 01/04/2017] [Accepted: 01/06/2017] [Indexed: 05/09/2023]
Abstract
Phase-resolved OCT and fluorescence microscopy were used simultaneously to examine stereotypic patterns of neural activity in the isolated Drosophila central nervous system. Both imaging modalities were focused on individually identified bursicon neurons known to be involved in a fixed action pattern initiated by ecdysis-triggering hormone. We observed clear correspondence of OCT intensity, phase fluctuations, and activity-dependent calcium-induced fluorescence.
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Affiliation(s)
- Minh Q. Tong
- Graduate Program in Neuroscience, University of California, Riverside, CA 92521, USA
| | - Md. Monirul Hasan
- Department of Bioengineering, University of California, 900 University Ave, Riverside, CA 92521, USA
| | - Sang Soo Lee
- Graduate Program in Neuroscience, University of California, Riverside, CA 92521, USA
| | - Md. Rezuanul Haque
- Department of Bioengineering, University of California, 900 University Ave, Riverside, CA 92521, USA
| | - Do-Hyoung Kim
- Department of Entomology, University of California, 900 University Ave, Riverside, CA 92521, USA
- Current Affiliation Department of Biological Sciences, Korea Advanced Institute of Science and Technology, 291 Daehak-ro, Yuseong-gu, Daejeon, 34141, South Korea
| | - Md. Shahidul Islam
- Department of Bioengineering, University of California, 900 University Ave, Riverside, CA 92521, USA
| | - Michael E. Adams
- Graduate Program in Neuroscience, University of California, Riverside, CA 92521, USA
- Department of Entomology, University of California, 900 University Ave, Riverside, CA 92521, USA
- Department of Cell Biology & Neuroscience, University of California, 900 University Ave, Riverside, CA 92521, USA
| | - B. Hyle Park
- Department of Bioengineering, University of California, 900 University Ave, Riverside, CA 92521, USA
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10
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Wang B, Lu Y, Yao X. In vivo optical coherence tomography of stimulus-evoked intrinsic optical signals in mouse retinas. JOURNAL OF BIOMEDICAL OPTICS 2016; 21:96010. [PMID: 27653936 PMCID: PMC5030472 DOI: 10.1117/1.jbo.21.9.096010] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/16/2016] [Accepted: 08/26/2016] [Indexed: 05/22/2023]
Abstract
Intrinsic optical signal (IOS) imaging promises a noninvasive method for advanced study and diagnosis of eye diseases. Before pursuing clinical applications, it is essential to understand anatomic and physiological sources of retinal IOSs and to establish the relationship between IOS distortions and eye diseases. The purpose of this study was designed to demonstrate the feasibility of <italic<in vivo</italic< IOS imaging of mouse models. A high spatiotemporal resolution spectral domain optical coherence tomography (SD-OCT) was employed for depth-resolved retinal imaging. A custom-designed animal holder equipped with ear bar and bite bar was used to minimize eye movements. Dynamic OCT imaging revealed rapid IOS from the photoreceptor’s outer segment immediately after the stimulation delivery, and slow IOS changes were observed from inner retinal layers. Comparative photoreceptor IOS and electroretinography recordings suggested that the fast photoreceptor IOS may be attributed to the early stage of phototransduction before the hyperpolarization of retinal photoreceptor.
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Affiliation(s)
- Benquan Wang
- University of Illinois at Chicago, Department of Bioengineering, 851 South Morgan Street, Chicago, Illinois 60607, United States
| | - Yiming Lu
- University of Illinois at Chicago, Department of Bioengineering, 851 South Morgan Street, Chicago, Illinois 60607, United States
| | - Xincheng Yao
- University of Illinois at Chicago, Department of Bioengineering, 851 South Morgan Street, Chicago, Illinois 60607, United States
- University of Illinois at Chicago, Department of Ophthalmology and Visual Sciences, 1855 West Taylor Street, Chicago, Illinois 60612, United States
- Address all correspondence to: Xincheng Yao, E-mail:
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11
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Wang B, Yao X. In vivo intrinsic optical signal imaging of mouse retinas. PROCEEDINGS OF SPIE--THE INTERNATIONAL SOCIETY FOR OPTICAL ENGINEERING 2016; 9693:96930H. [PMID: 28163346 PMCID: PMC5289717 DOI: 10.1117/12.2212810] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
Intrinsic optical signal (IOS) imaging is a promising noninvasive method for advanced study and diagnosis of eye diseases. Before pursuing clinical applications, more IOS studies employing animal models are necessary to establish the relationship between IOS distortions and eye diseases. Ample mouse models are available for investigating the relationship between IOS distortions and eye diseases. However, in vivo IOS imaging of mouse retinas is challenging due to the small ocular lens (compared to frog eyes) and inevitable eye movements. We report here in vivo IOS imaging of mouse retinas using a custom-designed functional OCT. The OCT system provided high resolution (3 μm) and high speed (up to 500 frames/s) imaging of mouse retinas. An animal holder equipped with a custom designed ear bar and bite bar was used to minimize eye movement due to breathing and heartbeats. Residual eye movement in OCT images was further compensated by accurate image registration. Dynamic OCT imaging revealed rapid IOSs from photoreceptor outer segments immediately (<10 ms) after the stimulation delivery, and unambiguous IOS changes were also observed from inner retinal layers with delayed time courses compared to that of photoreceptor IOSs.
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Affiliation(s)
- Benquan Wang
- Department of Bioengineering, University of Illinois at Chicago, Chicago, IL 60607, USA
| | - Xincheng Yao
- Department of Bioengineering, University of Illinois at Chicago, Chicago, IL 60607, USA
- Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago, Chicago, IL 60612, USA
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12
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Yao X, Wang B. Intrinsic optical signal imaging of retinal physiology: a review. JOURNAL OF BIOMEDICAL OPTICS 2015; 20:090901. [PMID: 26405819 PMCID: PMC4689108 DOI: 10.1117/1.jbo.20.9.090901] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/23/2015] [Accepted: 08/31/2015] [Indexed: 05/09/2023]
Abstract
Intrinsic optical signal (IOS) imaging promises to be a noninvasive method for high-resolution examination of retinal physiology, which can advance the study and diagnosis of eye diseases. While specialized optical instruments are desirable for functional IOS imaging of retinal physiology, in depth understanding of multiple IOS sources in the complex retinal neural network is essential for optimizing instrument designs. We provide a brief overview of IOS studies and relationships in rod outer segment suspensions, isolated retinas, and intact eyes. Recent developments of line-scan confocal and functional optical coherence tomography (OCT) instruments have allowed in vivo IOS mapping of photoreceptor physiology. Further improvements of the line-scan confocal and functional OCT systems may provide a feasible solution to pursue functional IOS mapping of human photoreceptors. Some interesting IOSs have already been detected in inner retinal layers, but better development of the IOS instruments and software algorithms is required to achieve optimal physiological assessment of inner retinal neurons.
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Affiliation(s)
- Xincheng Yao
- University of Illinois at Chicago, Department of Bioengineering, Chicago, Illinois 60607, United States
- University of Illinois at Chicago, Department of Ophthalmology and Visual Sciences, Chicago, Illinois 60612, United States
| | - Benquan Wang
- University of Illinois at Chicago, Department of Bioengineering, Chicago, Illinois 60607, United States
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Yeh YJ, Black AJ, Landowne D, Akkin T. Optical coherence tomography for cross-sectional imaging of neural activity. NEUROPHOTONICS 2015. [PMID: 26217674 PMCID: PMC4509668 DOI: 10.1117/1.nph.2.3.035001] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
We report a functional optical coherence tomography cross-sectional scanner to detect neural activity using unmyelinated nerves dissected from squid. The nerves, unstained or stained with a voltage-sensitive dye, were imaged in a nerve chamber. Transient phase changes from backscattered light were detected during action potential propagation. The results show that the scanner can provide high spatiotemporal resolution cross-sectional images of neural activity ([Formula: see text]; [Formula: see text]; [Formula: see text] in [Formula: see text]). The advantage of this method compared to monitoring a single depth profile [Formula: see text] is a dramatic increase in the number of available sites that can be measured in two spatial dimensions [Formula: see text] with lateral scanning; therefore, the study demonstrates that two-dimensional monitoring of small-scale functional activity would also be feasible.
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Affiliation(s)
- Yi-Jou Yeh
- University of Minnesota, Department of Electrical and Computer Engineering, Minneapolis, Minnesota 55455, United States
- University of Minnesota, Department of Biomedical Engineering, 312 Church Street S.E., Minneapolis, Minnesota 55455, United States
| | - Adam J. Black
- University of Minnesota, Department of Biomedical Engineering, 312 Church Street S.E., Minneapolis, Minnesota 55455, United States
| | - David Landowne
- University of Miami, Department of Physiology and Biophysics, Miami, Florida 33101, United States
| | - Taner Akkin
- University of Minnesota, Department of Biomedical Engineering, 312 Church Street S.E., Minneapolis, Minnesota 55455, United States
- Address all correspondence to: Taner Akkin, E-mail:
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Teussink MM, Cense B, van Grinsven MJ, Klevering BJ, Hoyng CB, Theelen T. Impact of motion-associated noise on intrinsic optical signal imaging in humans with optical coherence tomography. BIOMEDICAL OPTICS EXPRESS 2015; 6:1632-47. [PMID: 26137369 PMCID: PMC4467722 DOI: 10.1364/boe.6.001632] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2014] [Revised: 04/04/2015] [Accepted: 04/04/2015] [Indexed: 06/04/2023]
Abstract
A growing body of evidence suggests that phototransduction can be studied in the human eye in vivo by imaging of fast intrinsic optical signals (IOS). There is consensus concerning the limiting influence of motion-associated imaging noise on the reproducibility of IOS-measurements, especially in those employing spectral-domain optical coherence tomography (SD-OCT). However, no study to date has conducted a comprehensive analysis of this noise in the context of IOS-imaging. In this study, we discuss biophysical correlates of IOS, and we address motion-associated imaging noise by providing correctional post-processing methods. In order to avoid cross-talk of adjacent IOS of opposite signal polarity, cellular resolution and stability of imaging to the level of individual cones is likely needed. The optical Stiles-Crawford effect can be a source of significant IOS-imaging noise if alignment with the peak of the Stiles-Crawford function cannot be maintained. Therefore, complete head stabilization by implementation of a bite-bar may be critical to maintain a constant pupil entry position of the OCT beam. Due to depth-dependent sensitivity fall-off, heartbeat and breathing associated axial movements can cause tissue reflectivity to vary by 29% over time, although known methods can be implemented to null these effects. Substantial variations in reflectivity can be caused by variable illumination due to changes in the beam pupil entry position and angle, which can be reduced by an adaptive algorithm based on slope-fitting of optical attenuation in the choriocapillary lamina.
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Affiliation(s)
- Michel M. Teussink
- Department of Ophthalmology, Radboud University Medical Center, Nijmegen, P.O. Box 6500 HB,
The Netherlands
| | - Barry Cense
- Center for Optical Research and Education, Utsunomiya University, Utsunomiya, Tochigi, 321-8585,
Japan
| | - Mark J.J.P. van Grinsven
- Diagnostic Image Analysis Group, Department of Radiology and Nuclear Medicine, Radboud University Medical Center, Nijmegen, P.O. Box 6500 HB,
The Netherlands
| | - B. Jeroen Klevering
- Department of Ophthalmology, Radboud University Medical Center, Nijmegen, P.O. Box 6500 HB,
The Netherlands
| | - Carel B. Hoyng
- Department of Ophthalmology, Radboud University Medical Center, Nijmegen, P.O. Box 6500 HB,
The Netherlands
| | - Thomas Theelen
- Department of Ophthalmology, Radboud University Medical Center, Nijmegen, P.O. Box 6500 HB,
The Netherlands
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Zhang Q, Lu R, Wang B, Messinger JD, Curcio CA, Yao X. Functional optical coherence tomography enables in vivo physiological assessment of retinal rod and cone photoreceptors. Sci Rep 2015; 5:9595. [PMID: 25901915 PMCID: PMC4894434 DOI: 10.1038/srep09595] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2014] [Accepted: 03/05/2015] [Indexed: 11/09/2022] Open
Abstract
Transient intrinsic optical signal (IOS) changes have been observed in retinal photoreceptors, suggesting a unique biomarker for eye disease detection. However, clinical deployment of IOS imaging is challenging due to unclear IOS sources and limited signal-to-noise ratios (SNRs). Here, by developing high spatiotemporal resolution optical coherence tomography (OCT) and applying an adaptive algorithm for IOS processing, we were able to record robust IOSs from single-pass measurements. Transient IOSs, which might reflect an early stage of light phototransduction, are consistently observed in the photoreceptor outer segment almost immediately (<4 ms) after retinal stimulation. Comparative studies of dark- and light-adapted retinas have demonstrated the feasibility of functional OCT mapping of rod and cone photoreceptors, promising a new method for early disease detection and improved treatment of diseases such as age-related macular degeneration (AMD) and other eye diseases that can cause photoreceptor damage.
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Affiliation(s)
- Qiuxiang Zhang
- Department of Biomedical Engineering, University of Alabama at Birmingham, Birmingham, AL 35294
| | - Rongwen Lu
- Department of Biomedical Engineering, University of Alabama at Birmingham, Birmingham, AL 35294
| | - Benquan Wang
- Department of Biomedical Engineering, University of Alabama at Birmingham, Birmingham, AL 35294
| | - Jeffrey D. Messinger
- Department of Ophthalmology, University of Alabama at Birmingham, Birmingham, AL 35294
| | - Christine A. Curcio
- Department of Ophthalmology, University of Alabama at Birmingham, Birmingham, AL 35294
| | - Xincheng Yao
- Department of Biomedical Engineering, University of Alabama at Birmingham, Birmingham, AL 35294
- Department of Ophthalmology, University of Alabama at Birmingham, Birmingham, AL 35294
- Department of Bioengineering, University of Illinois at Chicago, Chicago, IL 60607
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Akhlagh Moayed A, Hariri S, Choh V, Bizheva K. Correlation of visually evoked intrinsic optical signals and electroretinograms recorded from chicken retina with a combined functional optical coherence tomography and electroretinography system. JOURNAL OF BIOMEDICAL OPTICS 2012; 17:016011. [PMID: 22352661 DOI: 10.1117/1.jbo.17.1.016011] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
Visually evoked fast intrinsic optical signals (IOSs) were recorded for the first time in vivo from all layers of healthy chicken retina by using a combined functional optical coherence tomography (fOCT) and electroretinography (ERG) system. The fast IOSs were observed to develop within ∼5 ms from the on-set of the visual stimulus, whereas slow IOSs were measured up to 1 s later. The visually evoked IOSs and ERG traces were recorded simultaneously, and a clear correlation was observed between them. The ability to measure visually evoked fast IOSs non-invasively and in vivo from individual retinal layers could significantly improve the understanding of the complex communication between different retinal cell types in healthy and diseased retinas.
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Affiliation(s)
- Alireza Akhlagh Moayed
- University of Waterloo, Department of Physics and Astronomy, 200 University Avenue West, Waterloo, Ontario N2L3G1, Canada
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