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Lee S, Choi SS, Meleppat RK, Zawadzki RJ, Doble N. High-speed, phase contrast retinal and blood flow imaging using an adaptive optics partially confocal multi-line ophthalmoscope. BIOMEDICAL OPTICS EXPRESS 2024; 15:1815-1830. [PMID: 38495707 PMCID: PMC10942708 DOI: 10.1364/boe.507449] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/17/2023] [Revised: 12/18/2023] [Accepted: 01/14/2024] [Indexed: 03/19/2024]
Abstract
High-speed, phase contrast retinal and blood flow imaging using an adaptive optics partially confocal multi-line ophthalmosocope (AO-pcMLO) is described. It allows for simultaneous confocal and phase contrast imaging with various directional multi-line illumination by using a single 2D camera and a digital micromirror device (DMD). Both vertical and horizontal line illumination directions were tested, for photoreceptor and vascular imaging. The phase contrast imaging provided improved visualization of retinal structures such as cone inner segments, vessel walls and red blood cells with images being acquired at frame rates up to 500 Hz. Blood flow velocities of small vessels (<40 µm in diameter) were measured using kymographs for capillaries and cross-correlation between subsequent images for arterioles or venules. Cardiac-related pulsatile patterns were observed with normal resting heart-beat rate, and instantaneous blood flow velocities from 0.7 to 20 mm/s were measured.
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Affiliation(s)
- Soohyun Lee
- College of Optometry, The Ohio State University, 338 West 10th Avenue, Columbus, Ohio 43210, USA
| | - Stacey S. Choi
- College of Optometry, The Ohio State University, 338 West 10th Avenue, Columbus, Ohio 43210, USA
- Department of Ophthalmology and Visual Sciences, Havener Eye Institute, The Ohio State University, 915 Olentangy River Road, Suite 5000, Ohio 43212, USA
| | - Ratheesh K. Meleppat
- UC Davis Eye Center, Department of Ophthalmology and Vision Science, University of California, Davis, 4860 Y Street, Suite 2400, Sacramento, California 95817, USA
- UC Davis EyePod Small Animal Ocular Imaging Laboratory, Department of Cell Biology and Human Anatomy, University of California, Davis, 4320 Tupper Hall, Davis, California 95616, USA
| | - Robert J. Zawadzki
- UC Davis Eye Center, Department of Ophthalmology and Vision Science, University of California, Davis, 4860 Y Street, Suite 2400, Sacramento, California 95817, USA
- UC Davis EyePod Small Animal Ocular Imaging Laboratory, Department of Cell Biology and Human Anatomy, University of California, Davis, 4320 Tupper Hall, Davis, California 95616, USA
| | - Nathan Doble
- College of Optometry, The Ohio State University, 338 West 10th Avenue, Columbus, Ohio 43210, USA
- Department of Ophthalmology and Visual Sciences, Havener Eye Institute, The Ohio State University, 915 Olentangy River Road, Suite 5000, Ohio 43212, USA
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Krafft L, Senée P, Gofas E, Thouvenin O, Atlan M, Paques M, Meimon S, Mecê P. Multimodal high-resolution retinal imaging using a camera-based DMD-integrated adaptive optics flood-illumination ophthalmoscope. OPTICS LETTERS 2023; 48:3785-3788. [PMID: 37450750 DOI: 10.1364/ol.495515] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2023] [Accepted: 06/28/2023] [Indexed: 07/18/2023]
Abstract
We demonstrate the feasibility of a multimodal adaptive optics flood-illumination ophthalmoscope, able to provide both bright-field and dark-field images (such as phase contrast). The multimodality was made possible by integrating a digital micromirror device (DMD) at the illumination path to project a sequence of complementary high-resolution patterns into the retina. Through a versatile post-processing method that digitally selects backscattered or multiply scattered photons, we were able: (1) to achieve up to four-fold contrast increase of bright-field images when imaging the photoreceptor mosaic and nerve fibers; and (2) to visualize translucent retinal features such as capillaries, red blood cells, vessel walls, ganglion cells, and photoreceptor inner segments through phase contrast.
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Abstract
The human retina is amenable to direct, noninvasive visualization using a wide array of imaging modalities. In the ∼140 years since the publication of the first image of the living human retina, there has been a continued evolution of retinal imaging technology. Advances in image acquisition and processing speed now allow real-time visualization of retinal structure, which has revolutionized the diagnosis and management of eye disease. Enormous advances have come in image resolution, with adaptive optics (AO)-based systems capable of imaging the retina with single-cell resolution. In addition, newer functional imaging techniques provide the ability to assess function with exquisite spatial and temporal resolution. These imaging advances have had an especially profound impact on the field of inherited retinal disease research. Here we will review some of the advances and applications of AO retinal imaging in patients with inherited retinal disease.
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Affiliation(s)
- Jacque L Duncan
- Department of Ophthalmology, University of California, San Francisco, California 94143-4081, USA
| | - Joseph Carroll
- Department of Ophthalmology & Visual Sciences, Medical College of Wisconsin Eye Institute, Milwaukee, Wisconsin 53226, USA
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Ackermann J, Stegemann J, Smola T, Reger E, Jung S, Schmitz A, Herbertz S, Erpenbeck L, Seidl K, Kruss S. High Sensitivity Near-Infrared Imaging of Fluorescent Nanosensors. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2023; 19:e2206856. [PMID: 36610045 DOI: 10.1002/smll.202206856] [Citation(s) in RCA: 14] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/06/2022] [Revised: 11/27/2022] [Indexed: 06/17/2023]
Abstract
Biochemical processes are fast and occur on small-length scales, which makes them difficult to measure. Optical nanosensors based on single-wall carbon nanotubes (SWCNTs) are able to capture such dynamics. They fluoresce in the near-infrared (NIR, 850-1700 nm) tissue transparency window and the emission wavelength depends on their chirality. However, NIR imaging requires specialized indium gallium arsenide (InGaAs) cameras with a typically low resolution because the quantum yield of normal Si-based cameras rapidly decreases in the NIR. Here, an efficient one-step phase separation approach to isolate monochiral (6,4)-SWCNTs (880 nm emission) from mixed SWCNT samples is developed. It enables imaging them in the NIR with high-resolution standard Si-based cameras (>50× more pixels). (6,4)-SWCNTs modified with (GT)10 -ssDNA become highly sensitive to the important neurotransmitter dopamine. These sensors are 1.7× brighter and 7.5× more sensitive and allow fast imaging (<50 ms). They enable high-resolution imaging of dopamine release from cells. Thus, the assembly of biosensors from (6,4)-SWCNTs combines the advantages of nanosensors working in the NIR with the sensitivity of (Si-based) cameras and enables broad usage of these nanomaterials.
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Affiliation(s)
- Julia Ackermann
- Fraunhofer Institute for Microelectronic Circuits and Systems, Finkenstrasse 61, 47057, Duisburg, Germany
- Department EBS, University Duisburg-Essen, Bismarkstrasse 81, 47057, Duisburg, Germany
| | - Jan Stegemann
- Fraunhofer Institute for Microelectronic Circuits and Systems, Finkenstrasse 61, 47057, Duisburg, Germany
- Department of Chemistry, Ruhr-University Bochum, Universitätsstrasse 150, 44801, Bochum, Germany
| | - Tim Smola
- Fraunhofer Institute for Microelectronic Circuits and Systems, Finkenstrasse 61, 47057, Duisburg, Germany
- Department EBS, University Duisburg-Essen, Bismarkstrasse 81, 47057, Duisburg, Germany
| | - Eline Reger
- Fraunhofer Institute for Microelectronic Circuits and Systems, Finkenstrasse 61, 47057, Duisburg, Germany
- Department EBS, University Duisburg-Essen, Bismarkstrasse 81, 47057, Duisburg, Germany
| | - Sebastian Jung
- ZEMOS Center for Solvation Science, Ruhr-University Bochum, Universitätsstrasse 150, 44801, Bochum, Germany
| | - Anne Schmitz
- Department of Dermatology, University Hospital Münster, Von-Esmarch-Strasse 58, 48149, Münster, Germany
| | - Svenja Herbertz
- Fraunhofer Institute for Microelectronic Circuits and Systems, Finkenstrasse 61, 47057, Duisburg, Germany
| | - Luise Erpenbeck
- Department of Dermatology, University Hospital Münster, Von-Esmarch-Strasse 58, 48149, Münster, Germany
| | - Karsten Seidl
- Fraunhofer Institute for Microelectronic Circuits and Systems, Finkenstrasse 61, 47057, Duisburg, Germany
- Department EBS, University Duisburg-Essen, Bismarkstrasse 81, 47057, Duisburg, Germany
- Center for Nanointegration Duisburg-Essen (CENIDE), Carl-Benz-Strasse 199, 47057, Duisburg, Germany
| | - Sebastian Kruss
- Fraunhofer Institute for Microelectronic Circuits and Systems, Finkenstrasse 61, 47057, Duisburg, Germany
- Department of Chemistry, Ruhr-University Bochum, Universitätsstrasse 150, 44801, Bochum, Germany
- Center for Nanointegration Duisburg-Essen (CENIDE), Carl-Benz-Strasse 199, 47057, Duisburg, Germany
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Gu B, Zhang Y. Adaptive optics wavefront correction using a damped transpose matrix of the influence function. PHOTONICS RESEARCH 2022; 10:1777-1786. [PMID: 37153536 PMCID: PMC10162714 DOI: 10.1364/prj.452364] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
To assess the performance of adaptive optics and predict an optimal wavefront correction, we built a wavefront reconstructor with a damped transpose matrix of the influence function. Using an integral control strategy, we tested this reconstructor with four deformable mirrors in an experimental system, an adaptive optics scanning laser ophthalmoscope, and an adaptive optics near-confocal ophthalmoscope. Testing results proved that this reconstructor could ensure a stable and precise correction for wavefront aberration compared to a conventional optimal reconstructor formed by the inverse matrix of the influence function. This method may provide a helpful tool for testing, evaluating, and optimizing adaptive optics systems.
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Affiliation(s)
- Boyu Gu
- Doheny Eye Institute, 150 N Orange Grove Boulevard, Pasadena, California 91103, USA
- Department of Ophthalmology, University of California - Los Angeles, 100 Stein Plaza Driveway, Los Angeles, CA 90095, USA
| | - Yuhua Zhang
- Doheny Eye Institute, 150 N Orange Grove Boulevard, Pasadena, California 91103, USA
- Department of Ophthalmology, University of California - Los Angeles, 100 Stein Plaza Driveway, Los Angeles, CA 90095, USA
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Kowalski B, Huang X, Steven S, Dubra A. Hybrid FPGA-CPU pupil tracker. BIOMEDICAL OPTICS EXPRESS 2021; 12:6496-6513. [PMID: 34745752 PMCID: PMC8548015 DOI: 10.1364/boe.433766] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/11/2021] [Revised: 08/17/2021] [Accepted: 09/11/2021] [Indexed: 06/13/2023]
Abstract
An off-axis monocular pupil tracker designed for eventual integration in ophthalmoscopes for eye movement stabilization is described and demonstrated. The instrument consists of light-emitting diodes, a camera, a field-programmable gate array (FPGA) and a central processing unit (CPU). The raw camera image undergoes background subtraction, field-flattening, 1-dimensional low-pass filtering, thresholding and robust pupil edge detection on an FPGA pixel stream, followed by least-squares fitting of the pupil edge pixel coordinates to an ellipse in the CPU. Experimental data suggest that the proposed algorithms require raw images with a minimum of ∼32 gray levels to achieve sub-pixel pupil center accuracy. Tests with two different cameras operating at 575, 1250 and 5400 frames per second trained on a model pupil achieved 0.5-1.5 μm pupil center estimation precision with 0.6-2.1 ms combined image download, FPGA and CPU processing latency. Pupil tracking data from a fixating human subject show that the tracker operation only requires the adjustment of a single parameter, namely an image intensity threshold. The latency of the proposed pupil tracker is limited by camera download time (latency) and sensitivity (precision).
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Affiliation(s)
| | - Xiaojing Huang
- Department of Ophthalmology, Stanford University, Palo Alto, CA 94303, USA
- Institute of Optics, University of Rochester, Rochester, NY 14620, USA
| | - Samuel Steven
- Department of Ophthalmology, Stanford University, Palo Alto, CA 94303, USA
- Institute of Optics, University of Rochester, Rochester, NY 14620, USA
| | - Alfredo Dubra
- Department of Ophthalmology, Stanford University, Palo Alto, CA 94303, USA
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Litts KM, Woertz EN, Wynne N, Brooks BP, Chacon A, Connor TB, Costakos D, Dumitrescu A, Drack AV, Fishman GA, Hauswirth WW, Kay CN, Lam BL, Michaelides M, Pennesi ME, Stepien KE, Strul S, Summers CG, Carroll J. Examining Whether AOSLO-Based Foveal Cone Metrics in Achromatopsia and Albinism Are Representative of Foveal Cone Structure. Transl Vis Sci Technol 2021; 10:22. [PMID: 34111268 PMCID: PMC8132001 DOI: 10.1167/tvst.10.6.22] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose Adaptive optics scanning light ophthalmoscopy (AOSLO) imaging in patients with achromatopsia (ACHM) and albinism is not always successful. Here, we tested whether optical coherence tomography (OCT) measures of foveal structure differed between patients for whom AOSLO images were either quantifiable or unquantifiable. Methods The study included 166 subjects (84 with ACHM; 82 with albinism) with previously acquired OCT scans, AOSLO images, and best-corrected visual acuity (BCVA, if available). Foveal OCT scans were assessed for outer retinal structure, outer nuclear layer thickness, and hypoplasia. AOSLO images were graded as quantifiable if a peak cone density could be measured and/or usable if the location of peak density could be identified and the parafoveal mosaic was quantifiable. Results Forty-nine percent of subjects with ACHM and 57% of subjects with albinism had quantifiable AOSLO images. Older age and better BCVA were found in subjects with quantifiable AOSLO images for both ACHM (P = 0.0214 and P = 0.0276, respectively) and albinism (P = 0.0073 and P < 0.0004, respectively). There was a significant trend between ellipsoid zone appearance and ability to quantify AOSLO (P = 0.0028). In albinism, OCT metrics of cone structure did not differ between groups. Conclusions Previously reported AOSLO-based cone density measures in ACHM may not necessarily reflect the degree of remnant cone structure in these patients. Translational Relevance Until AOSLO is successful in all patients with ACHM and albinism, the possibility of the reported data from a particular cohort not being representative of the entire population remains an important issue to consider when interpreting results from AOSLO studies.
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Affiliation(s)
- Katie M Litts
- Department of Ophthalmology & Visual Sciences, Medical College of Wisconsin, Milwaukee, WI, USA
| | - Erica N Woertz
- Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, Milwaukee, WI, USA.,School of Medicine, Medical College of Wisconsin, Milwaukee, WI, USA
| | - Niamh Wynne
- Department of Ophthalmology & Visual Sciences, Medical College of Wisconsin, Milwaukee, WI, USA
| | | | - Alicia Chacon
- Department of Ophthalmology & Visual Sciences, Medical College of Wisconsin, Milwaukee, WI, USA
| | - Thomas B Connor
- Department of Ophthalmology & Visual Sciences, Medical College of Wisconsin, Milwaukee, WI, USA
| | - Deborah Costakos
- Department of Ophthalmology & Visual Sciences, Medical College of Wisconsin, Milwaukee, WI, USA
| | - Alina Dumitrescu
- Department of Ophthalmology and Visual Sciences, University of Iowa Hospitals and Clinics, Iowa City, IA, USA
| | - Arlene V Drack
- Department of Ophthalmology and Visual Sciences, University of Iowa Hospitals and Clinics, Iowa City, IA, USA
| | - Gerald A Fishman
- Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago, Chicago, IL, USA
| | | | | | - Byron L Lam
- Bascom Palmer Eye Institute, University of Miami, Miami, FL, USA
| | - Michel Michaelides
- UCL Institute of Ophthalmology, University College London, London, UK.,Moorfields Eye Hospital NHS Foundation Trust, London, UK
| | - Mark E Pennesi
- Casey Eye Institute, Oregon Health & Science University, Portland, OR, USA
| | - Kimberly E Stepien
- Department of Ophthalmology and Visual Sciences, University of Wisconsin-Madison, Madison, WI, USA
| | - Sasha Strul
- Department of Ophthalmology & Visual Neurosciences, University of Minnesota, Minneapolis, MN, USA
| | - C Gail Summers
- Department of Ophthalmology & Visual Neurosciences, University of Minnesota, Minneapolis, MN, USA
| | - Joseph Carroll
- Department of Ophthalmology & Visual Sciences, Medical College of Wisconsin, Milwaukee, WI, USA.,Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, Milwaukee, WI, USA
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Lu Y, Son T, Kim TH, Le D, Yao X. Virtually structured detection enables super-resolution ophthalmoscopy of rod and cone photoreceptors in human retina. Quant Imaging Med Surg 2021; 11:1060-1069. [PMID: 33654677 PMCID: PMC7829177 DOI: 10.21037/qims-20-542] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2020] [Accepted: 08/26/2020] [Indexed: 11/06/2022]
Abstract
BACKGROUND High resolution imaging is desirable for advanced study and clinical management of retinal diseases. However, spatial resolution of retinal imaging has been limited due to available numerical aperture and optical aberration of the ocular optics. This study is to develop and validate virtually structured detection (VSD) to surpass diffraction limit for resolution improvement in in vivo retinal imaging of awake human. METHODS A rapid line scanning laser ophthalmoscope (SLO) was constructed for in vivo retinal imaging. A high speed (25,000 kHz) camera was used for recording the two-dimensional (2D) light reflectance profile, corresponding to each focused line illumination. VSD was implemented to the 2D light reflectance profiles for super-resolution reconstruction. Because each 2D light reflectance profile was recorded within 40 μs, the intra-frame blur due to eye movements can be ignored. Digital registration was implemented to further compensate for inter-frame eye movements, before the VSD processing. Based on digital processing, the modulation transfer function (MTF) of the imaging system was derived for objective identification of the cut-off frequency of ocular optics, which is essential for robust VSD processing to ensure reliable super-resolution imaging. Dynamic motility analysis of the super-resolution images was implemented to further enhance the imaging contrast of retinal rod and cone photoreceptors. RESULTS The VSD based super-resolution SLO significantly improved image quality compared with equivalent wide-field imaging. In vivo observation of individual retinal photoreceptors has been demonstrated unambiguously. Dynamic motility analysis of the super-resolution images enhanced the contrast of retinal rod and cone photoreceptors, and revealed sub-cellular structures in cone photoreceptors. CONCLUSIONS In conjunction with rapid line-scan imaging and digital registration to minimize the effect of eye movements, VSD enabled resolution improvement to observe individual retinal photoreceptors without the involvement of adaptive optics (AO). An objective method has been developed to identify MTF to enable quantitative estimation of the cut-off frequency required for robust VSD processing.
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Affiliation(s)
- 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
| | - Tae-Hoon Kim
- Department of Bioengineering, University of Illinois at Chicago, Chicago, IL, USA
| | - David Le
- 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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Luo T, Warner RL, Sapoznik KA, Walker BR, Burns SA. Template free eye motion correction for scanning systems. OPTICS LETTERS 2021; 46:753-756. [PMID: 33577506 PMCID: PMC8447858 DOI: 10.1364/ol.415285] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Accepted: 12/31/2020] [Indexed: 05/18/2023]
Abstract
Scanning imaging systems are susceptible to image warping in the presence of target motion occurring within the time required to acquire an individual image frame. In this Letter, we introduce the use of a dual raster scanning approach to correct for motion distortion without the need for prior knowledge of the undistorted image. In the dual scanning approach, the target is imaged simultaneously with two imaging beams from the same imaging system. The two imaging beams share a common pupil but have a spatial shift between the beams on the imaging plane. The spatial shift can be used to measure high speed events, because it measures an identical region at two different times within the time required for acquisition of a single frame. In addition, it provides accurate spatial information, since two different regions on the target are imaged simultaneously, providing an undistorted estimate of the spatial relation between regions. These spatial and temporal relations accurately measure target motion. Data from adaptive optics scanning laser ophthalmoscope (AOSLO) imaging of the human retina are used to demonstrate this technique. We apply the technique to correct the shearing of retinal images produced by eye motion. Three control subjects were measured while imaging different retinal layers and retinal locations to qualify the effectiveness of the algorithm. Since the time shift between channels is readily adjustable, this method can be tuned to match different imaging situations. The major requirement is the need to separate the two images; in our case, we used different near infrared spectral regions and dichroic filters.
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Affiliation(s)
- Ting Luo
- Optometry School, Indiana University Bloomington, 800 Atwater Ave., Bloomington, IN 47045
| | - Raymond L. Warner
- Optometry School, Indiana University Bloomington, 800 Atwater Ave., Bloomington, IN 47045
| | - Kaitlyn A Sapoznik
- Optometry School, Indiana University Bloomington, 800 Atwater Ave., Bloomington, IN 47045
| | - Brittany R. Walker
- Optometry School, Indiana University Bloomington, 800 Atwater Ave., Bloomington, IN 47045
| | - Stephen A. Burns
- Optometry School, Indiana University Bloomington, 800 Atwater Ave., Bloomington, IN 47045
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Litts KM, Woertz EN, Georgiou M, Patterson EJ, Lam BL, Fishman GA, Pennesi ME, Kay CN, Hauswirth WW, Michaelides M, Carroll J. Optical Coherence Tomography Artifacts Are Associated With Adaptive Optics Scanning Light Ophthalmoscopy Success in Achromatopsia. Transl Vis Sci Technol 2021; 10:11. [PMID: 33510950 PMCID: PMC7804582 DOI: 10.1167/tvst.10.1.11] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2020] [Accepted: 12/04/2020] [Indexed: 12/22/2022] Open
Abstract
Purpose To determine whether artifacts in optical coherence tomography (OCT) images are associated with the success or failure of adaptive optics scanning light ophthalmoscopy (AOSLO) imaging in subjects with achromatopsia (ACHM). Methods Previously acquired OCT and non-confocal, split-detector AOSLO images from one eye of 66 subjects with genetically confirmed achromatopsia (15 CNGA3 and 51 CNGB3) were reviewed along with best-corrected visual acuity (BCVA) and axial length. OCT artifacts in interpolated vertical volumes from CIRRUS macular cubes were divided into four categories: (1) none or minimal, (2) clear and low frequency, (3) low amplitude and high frequency, and (4) high amplitude and high frequency. Each vertical volume was assessed once by two observers. AOSLO success was defined as sufficient image quality in split-detector images at the fovea to assess cone quantity. Results There was excellent agreement between the two observers for assessing OCT artifact severity category (weighted kappa = 0.88). Overall, AOSLO success was 47%. For subjects with OCT artifact severity category 1, AOSLO success was 65%; for category 2, 47%; for category 3, 11%; and for category 4, 0%. There was a significant association between OCT artifact severity category and AOSLO success (P = 0.0002). Neither BCVA nor axial length was associated with AOSLO success (P = 0.07 and P = 0.75, respectively). Conclusions Artifacts in OCT volumes are associated with AOSLO success in ACHM. Subjects with less severe OCT artifacts are more likely to be good candidates for AOSLO imaging, whereas AOSLO was successful in only 7% of subjects with category 3 or 4 OCT artifacts. These results may be useful in guiding patient selection for AOSLO imaging. Translational Relevance Using OCT to prescreen patients could be a valuable tool for clinical trials that utilize AOSLO to reduce costs and decrease patient testing burden.
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Affiliation(s)
- Katie M. Litts
- Department of Ophthalmology & Visual Sciences, Medical College of Wisconsin, Milwaukee, WI, USA
| | - Erica N. Woertz
- Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, Milwaukee, WI, USA
| | - Michalis Georgiou
- UCL Institute of Ophthalmology, University College London, London, UK
- Moorfields Eye Hospital NHS Foundation Trust, London, UK
| | - Emily J. Patterson
- Department of Ophthalmology & Visual Sciences, Medical College of Wisconsin, Milwaukee, WI, USA
| | - Byron L. Lam
- Bascom Palmer Eye Institute, University of Miami, Miami, FL, USA
| | - Gerald A. Fishman
- Pangere Center for Inherited Retinal Diseases, The Chicago Lighthouse, Chicago, IL, USA
| | - Mark E. Pennesi
- Casey Eye Institute, Oregon Health & Science University, Portland, OR, USA
| | | | | | - Michel Michaelides
- UCL Institute of Ophthalmology, University College London, London, UK
- Moorfields Eye Hospital NHS Foundation Trust, London, UK
| | - Joseph Carroll
- Department of Ophthalmology & Visual Sciences, Medical College of Wisconsin, Milwaukee, WI, USA
- Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, Milwaukee, WI, USA
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Li Z, Pandiyan VP, Maloney-Bertelli A, Jiang X, Li X, Sabesan R. Correcting intra-volume distortion for AO-OCT using 3D correlation based registration. OPTICS EXPRESS 2020; 28:38390-38409. [PMID: 33379652 PMCID: PMC7771894 DOI: 10.1364/oe.410374] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/17/2020] [Revised: 11/15/2020] [Accepted: 11/19/2020] [Indexed: 05/18/2023]
Abstract
Adaptive optics (AO) based ophthalmic imagers, such as scanning laser ophthalmoscopes (SLO) and optical coherence tomography (OCT), are used to evaluate the structure and function of the retina with high contrast and resolution. Fixational eye movements during a raster-scanned image acquisition lead to intra-frame and intra-volume distortion, resulting in an inaccurate reproduction of the underlying retinal structure. For three-dimensional (3D) AO-OCT, segmentation-based and 3D correlation based registration methods have been applied to correct eye motion and achieve a high signal-to-noise ratio registered volume. This involves first selecting a reference volume, either manually or automatically, and registering the image/volume stream against the reference using correlation methods. However, even within the chosen reference volume, involuntary eye motion persists and affects the accuracy with which the 3D retinal structure is finally rendered. In this article, we introduced reference volume distortion correction for AO-OCT using 3D correlation based registration and demonstrate a significant improvement in registration performance via a few metrics. Conceptually, the general paradigm follows that developed previously for intra-frame distortion correction for 2D raster-scanned images, as in an AOSLO, but extended here across all three spatial dimensions via 3D correlation analyses. We performed a frequency analysis of eye motion traces before and after intra-volume correction and revealed how periodic artifacts in eye motion estimates are effectively reduced upon correction. Further, we quantified how the intra-volume distortions and periodic artifacts in the eye motion traces, in general, decrease with increasing AO-OCT acquisition speed. Overall, 3D correlation based registration with intra-volume correction significantly improved the visualization of retinal structure and estimation of fixational eye movements.
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Affiliation(s)
- Zhenghan Li
- Key Laboratory on Adaptive Optics, Chinese Academy of Sciences, Chengdu, Sichuan 610209, China
- Institute of Optics and Electronics, Chinese Academy of Sciences, Chengdu, Sichuan 610209, China
- University of Chinese Academy of Sciences, Beijing 100049, China
- Department of Ophthalmology, University of Washington, Seattle, Washington 98109, USA
- These authors contributed equally to this work
| | - Vimal Prabhu Pandiyan
- Department of Ophthalmology, University of Washington, Seattle, Washington 98109, USA
- These authors contributed equally to this work
| | | | - Xiaoyun Jiang
- Department of Ophthalmology, University of Washington, Seattle, Washington 98109, USA
| | - Xinyang Li
- Key Laboratory on Adaptive Optics, Chinese Academy of Sciences, Chengdu, Sichuan 610209, China
- Institute of Optics and Electronics, Chinese Academy of Sciences, Chengdu, Sichuan 610209, China
| | - Ramkumar Sabesan
- Department of Ophthalmology, University of Washington, Seattle, Washington 98109, USA
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12
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Phung MC, Rouse AR, Pangilinan J, Bell RC, Bracamonte ER, Mashi S, Gmitro AF, Lee BR. Investigation of confocal microscopy for differentiation of renal cell carcinoma versus benign tissue. Can an optical biopsy be performed? Asian J Urol 2019; 7:363-368. [PMID: 32995282 PMCID: PMC7498942 DOI: 10.1016/j.ajur.2019.12.008] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2018] [Revised: 02/12/2019] [Accepted: 07/17/2019] [Indexed: 01/20/2023] Open
Abstract
Objective Novel optical imaging modalities are under development with the goal of obtaining an “optical biopsy” to efficiently provide pathologic details. One such modality is confocal microscopy which allows in situ visualization of cells within a layer of tissue and imaging of cellular-level structures. The goal of this study is to validate the ability of confocal microscopy to quickly and accurately differentiate between normal renal tissue and cancer. Methods Specimens were obtained from patients who underwent robotic partial nephrectomy for renal mass. Samples of suspected normal and tumor tissue were extracted from the excised portion of the kidney and stained with acridine orange. The stained samples were imaged on a Nikon E600 C1 Confocal Microscope. The samples were then submitted for hematoxylin and eosin processing and read by an expert pathologist to provide a gold-standard diagnosis that can later be compared to the confocal images. Results This study included 11 patients, 17 tissue samples, and 118 confocal images. Of the 17 tissue samples, 10 had a gold-standard diagnosis of cancer and seven were benign. Of 118 confocal images, 66 had a gold-standard diagnosis of cancer and 52 were benign. Six confocal images were used as a training set to train eight observers. The observers were asked to rate the test images on a six point scale and the results were analyzed using a web based receiver operating characteristic curve calculator. The average accuracy, sensitivity, specificity, and area under the empirical receiver operating characteristic curve for this study were 91%, 98%, 81%, and 0.94 respectively. Conclusion This preliminary study suggest that confocal microscopy can be used to distinguish cancer from normal tissue with high sensitivity and specificity. The observers in this study were trained quickly and on only six images. We expect even higher performance as observers become more familiar with the confocal images.
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Affiliation(s)
- Michael C Phung
- Department of Urology, University of Arizona College of Medicine, Arizona, USA
| | - Andrew R Rouse
- Department of Medical Imaging, University of Arizona College of Medicine, Arizona, USA
| | - Jayce Pangilinan
- Department of Pathology, University of Arizona College of Medicine, Arizona, USA
| | - Robert C Bell
- Department of Pathology, University of Arizona College of Medicine, Arizona, USA
| | - Erika R Bracamonte
- Department of Pathology, University of Arizona College of Medicine, Arizona, USA
| | - Sharfuddeen Mashi
- Ringgold Standard Institution, Aminu Kano Teaching Hospital, Kano, Nigeria
| | - Arthur F Gmitro
- Biomedical Engineering, University of Arizona College of Medicine, Arizona, USA
| | - Benjamin R Lee
- Department of Urology, University of Arizona College of Medicine, Arizona, USA
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13
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Song W, Zhou L, Yi J. Volumetric fluorescein angiography (vFA) by oblique scanning laser ophthalmoscopy in mouse retina at 200 B-scans per second. BIOMEDICAL OPTICS EXPRESS 2019; 10:4907-4918. [PMID: 31565534 PMCID: PMC6757486 DOI: 10.1364/boe.10.004907] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/01/2019] [Revised: 08/26/2019] [Accepted: 08/26/2019] [Indexed: 05/25/2023]
Abstract
Oblique scanning laser ophthalmoscopy (oSLO) is a recently developed technique to provide three-dimensional volumetric fluorescence imaging in retinas over a large field of view, without the need for depth sectioning. In this study, we present volumetric fluorescein angiography (vFA) at 200 B-scans per second in mouse retina in vivo by oSLO. By using a low-cost industrial CMOS camera, imaging speed was improved to 2 volumes per second, ∼10 times more than our previous results. Enabled by the volumetric imaging, we visualized hemodynamics at single capillary level in a depth-dependent manner, and provided methods to quantify capillary hematocrit, absolute capillary blood flow speed, and detection of capillary flow stagnancy and stalling at different vascular layers. The quantitative metrics for capillary hemodynamics enhanced by volumetric imaging can offer valuable insight into vision science and retinal pathologies.
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Affiliation(s)
- Weiye Song
- Department of Medicine, Boston University School of Medicine, Boston Medical Center, Boston MA 02118, USA
| | - Libo Zhou
- Department of Medicine, Boston University School of Medicine, Boston Medical Center, Boston MA 02118, USA
| | - Ji Yi
- Department of Medicine, Boston University School of Medicine, Boston Medical Center, Boston MA 02118, USA
- Department of Biomedical Engineering, Boston University, Boston MA 02118, USA
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14
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Gofas-Salas E, Mecê P, Mugnier L, Bonnefois AM, Petit C, Grieve K, Sahel J, Paques M, Meimon S. Near infrared adaptive optics flood illumination retinal angiography. BIOMEDICAL OPTICS EXPRESS 2019; 10:2730-2743. [PMID: 31259047 PMCID: PMC6583347 DOI: 10.1364/boe.10.002730] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/14/2018] [Revised: 12/06/2018] [Accepted: 12/22/2018] [Indexed: 05/06/2023]
Abstract
Image-based angiography is a well-adapted technique to characterize vasculature, and has been used in retinal neurovascular studies. Because the microvasculature is of particular interest, being the site of exchange between blood and tissue, a high spatio-temporal resolution is required, implying the use of adaptive optics ophthalmoscopes with a high frame rate. Creating the opportunity for decoupled stimulation and imaging of the retina makes the use of near infrared (NIR) imaging light desirable, while the need for a large field of view and a lack of distortion implies the use of a flood illumination-based setup. However, flood-illumination NIR video sequences of erythrocytes, or red blood cells (RBC), have a limited contrast compared to scanning systems and visible light. As a result, they cannot be processed via existing image-based angiography methods. We have therefore developed a new computational method relying on a spatio-temporal filtering of the sequence to isolate blood flow from noise in low-contrast sequences. Applying this computational approach enabled us to perform angiography with an adaptive optics flood illumination ophthalmoscope (AO-FIO) using NIR light, both in bright-field and dark-field modalities. Finally, we demonstrate the capabilities of our system to differentiate blood flow velocity on a retinal capillary network in vivo.
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Affiliation(s)
- Elena Gofas-Salas
- DOTA, ONERA, Université Paris Saclay, F-91123 Palaiseau,
France
- Institut de la Vision, 17 rue Moreau, Sorbonne Universités, UPMC Univ Paris 06, INSERM, CNRS, 75012 Paris,
France
- PARIS Group - Paris Adaptive-Optics for Retinal Imaging and Surgery, Paris,
France
| | - Pedro Mecê
- DOTA, ONERA, Université Paris Saclay, F-91123 Palaiseau,
France
- PARIS Group - Paris Adaptive-Optics for Retinal Imaging and Surgery, Paris,
France
- Quantel Medical, Cournon d’Auvergne,
France
| | - Laurent Mugnier
- DOTA, ONERA, Université Paris Saclay, F-91123 Palaiseau,
France
| | | | - Cyril Petit
- DOTA, ONERA, Université Paris Saclay, F-91123 Palaiseau,
France
- PARIS Group - Paris Adaptive-Optics for Retinal Imaging and Surgery, Paris,
France
| | - Kate Grieve
- Institut de la Vision, 17 rue Moreau, Sorbonne Universités, UPMC Univ Paris 06, INSERM, CNRS, 75012 Paris,
France
- PARIS Group - Paris Adaptive-Optics for Retinal Imaging and Surgery, Paris,
France
- CIC 1423, INSERM, Quinze-Vingts Hospital, Paris,
France
| | - José Sahel
- Institut de la Vision, 17 rue Moreau, Sorbonne Universités, UPMC Univ Paris 06, INSERM, CNRS, 75012 Paris,
France
- Quantel Medical, Cournon d’Auvergne,
France
- CIC 1423, INSERM, Quinze-Vingts Hospital, Paris,
France
- Department of Ophthalmology, The University of Pittsburgh School of Medicine, Pittsburgh, PA,
USA
| | - Michel Paques
- Institut de la Vision, 17 rue Moreau, Sorbonne Universités, UPMC Univ Paris 06, INSERM, CNRS, 75012 Paris,
France
- PARIS Group - Paris Adaptive-Optics for Retinal Imaging and Surgery, Paris,
France
- CIC 1423, INSERM, Quinze-Vingts Hospital, Paris,
France
| | - Serge Meimon
- DOTA, ONERA, Université Paris Saclay, F-91123 Palaiseau,
France
- PARIS Group - Paris Adaptive-Optics for Retinal Imaging and Surgery, Paris,
France
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15
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Gu B, Wang X, Twa MD, Tam J, Girkin CA, Zhang Y. Noninvasive in vivo characterization of erythrocyte motion in human retinal capillaries using high-speed adaptive optics near-confocal imaging. BIOMEDICAL OPTICS EXPRESS 2018; 9:3653-3677. [PMID: 30338146 PMCID: PMC6191635 DOI: 10.1364/boe.9.003653] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2018] [Revised: 07/02/2018] [Accepted: 07/02/2018] [Indexed: 05/18/2023]
Abstract
The flow of erythrocytes in parafoveal capillaries was imaged in the living human eye with an adaptive optics near-confocal ophthalmoscope at a frame rate of 800 Hz with a low coherence near-infrared (NIR) light source. Spatiotemporal traces of the erythrocyte movement were extracted from consecutive images. Erythrocyte velocity was measured using custom software based on the Radon transform. The impact of imaging speed on velocity measurement was estimated using images of frame rates of 200, 400, and 800 Hz. The NIR light allowed for long imaging periods without visually stimulating the retina and disturbing the natural rheological state. High speed near-confocal imaging enabled direct and accurate measurement of erythrocyte velocity, and revealed a distinctively cardiac-dependent pulsatile velocity waveform of the erythrocyte flow in retinal capillaries, disclosed the impact of the leukocytes on erythrocyte motion, and provided new metrics for precise assessment of erythrocyte movement. The approach may facilitate new investigations on the pathophysiology of retinal microcirculation with applications for ocular and systemic diseases.
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Affiliation(s)
- Boyu Gu
- Department of Ophthalmology and Visual Sciences, School of Medicine, University of Alabama at Birmingham, 1670 University Boulevard, Birmingham, AL 35294, USA
| | - Xiaolin Wang
- Department of Ophthalmology and Visual Sciences, School of Medicine, University of Alabama at Birmingham, 1670 University Boulevard, Birmingham, AL 35294, USA
| | - Michael D. Twa
- Department of Optometry and Vision Science, School of Optometry, University of Alabama at Birmingham, 1716 University Boulevard, Birmingham, AL 35294, USA
| | - Johnny Tam
- National Eye Institute, National Institutes of Health, 10 Center Drive, Bethesda, MD 20892, USA
| | - Christopher A. Girkin
- Department of Ophthalmology and Visual Sciences, School of Medicine, University of Alabama at Birmingham, 1670 University Boulevard, Birmingham, AL 35294, USA
| | - Yuhua Zhang
- Department of Ophthalmology and Visual Sciences, School of Medicine, University of Alabama at Birmingham, 1670 University Boulevard, Birmingham, AL 35294, USA
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16
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Gofas-Salas E, Mecê P, Petit C, Jarosz J, Mugnier LM, Montmerle Bonnefois A, Grieve K, Sahel J, Paques M, Meimon S. High loop rate adaptive optics flood illumination ophthalmoscope with structured illumination capability. APPLIED OPTICS 2018; 57:5635-5642. [PMID: 30118075 DOI: 10.1364/ao.57.005635] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
The design and performance of an adaptive optics flood illumination ophthalmoscope (AO-FIO) platform, based on eye motion and dynamic aberrations experimental analysis, are described. The system incorporates a custom-built real-time controller, enabling up to 70 Hz loop rate without jitter, and an AO-corrected illumination capable of projecting high-resolution features in the retina. Wide-field (2.7°×5.4°) and distortionless images from vessel walls, capillaries, and the lamina cribrosa are obtained with an enhanced contrast and signal-to-noise ratio, thanks to careful control of AO parameters. The high spatial and temporal resolution (image acquisition up to 200 Hz) performance achieved by this platform enables the visualization of vessel deformation and blood flow. This system opens up the prospect of a return to favor of flood illumination adaptive optics systems provided that its high pixel rate and structured illumination capabilities are exploited.
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17
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Lu J, Gu B, Wang X, Zhang Y. High speed adaptive optics ophthalmoscopy with an anamorphic point spread function. OPTICS EXPRESS 2018; 26:14356-14374. [PMID: 29877476 PMCID: PMC6005671 DOI: 10.1364/oe.26.014356] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/08/2018] [Accepted: 05/11/2018] [Indexed: 05/04/2023]
Abstract
Retinal imaging working with a line scan mechanism and a line camera has the potential to image the eye with a near-confocal performance at the high frame rate, but this regime has difficulty to collect sufficient imaging light while adequately digitize the optical resolution in adaptive optics imaging. To meet this challenge, we have developed an adaptive optics line scan ophthalmoscope with an anamorphic point spread function. The instrument uses a high-speed line camera to acquire the retinal image and act as a confocal gate. Meanwhile, it employs a digital micro-mirror device to modulate the imaging light into a line of point sources illuminating the retina. The anamorphic mechanism ensures adequate digitization of the optical resolution and increases light collecting efficiency. We demonstrate imaging of the living human retina with cellular level resolution at a frame rate of 200 frames/second (FPS) with a digitization of 512 × 512 pixels over a field of view of 1.2° × 1.2°. We have assessed cone photoreceptor structure in images acquired at 100, 200, and 800 FPS in 2 normal human subjects, and confirmed that retinal images acquired at high speed rendered macular cone mosaic with improved measurement repeatability.
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18
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Zhang B, Li N, Kang J, He Y, Chen XM. Adaptive optics scanning laser ophthalmoscopy in fundus imaging, a review and update. Int J Ophthalmol 2017; 10:1751-1758. [PMID: 29181321 DOI: 10.18240/ijo.2017.11.18] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2016] [Accepted: 09/04/2017] [Indexed: 02/05/2023] Open
Abstract
Adaptive optics scanning laser ophthalmoscopy (AO-SLO) has been a promising technique in funds imaging with growing popularity. This review firstly gives a brief history of adaptive optics (AO) and AO-SLO. Then it compares AO-SLO with conventional imaging methods (fundus fluorescein angiography, fundus autofluorescence, indocyanine green angiography and optical coherence tomography) and other AO techniques (adaptive optics flood-illumination ophthalmoscopy and adaptive optics optical coherence tomography). Furthermore, an update of current research situation in AO-SLO is made based on different fundus structures as photoreceptors (cones and rods), fundus vessels, retinal pigment epithelium layer, retinal nerve fiber layer, ganglion cell layer and lamina cribrosa. Finally, this review indicates possible research directions of AO-SLO in future.
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Affiliation(s)
- Bing Zhang
- Department of Ophthalmology, West China Hospital, Sichuan University, Chengdu 610041, Sichuan Province, China
| | - Ni Li
- Department of Ophthalmology, West China Hospital, Sichuan University, Chengdu 610041, Sichuan Province, China
| | - Jie Kang
- Department of Ophthalmology, West China Hospital, Sichuan University, Chengdu 610041, Sichuan Province, China
| | - Yi He
- Institute of Optics and Electronics, Chinese Academy of Sciences, Chengdu 610209, Sichuan Province, China
| | - Xiao-Ming Chen
- Department of Ophthalmology, West China Hospital, Sichuan University, Chengdu 610041, Sichuan Province, China
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19
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Litts KM, Cooper RF, Duncan JL, Carroll J. Photoreceptor-Based Biomarkers in AOSLO Retinal Imaging. Invest Ophthalmol Vis Sci 2017; 58:BIO255-BIO267. [PMID: 28873135 PMCID: PMC5584616 DOI: 10.1167/iovs.17-21868] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2017] [Accepted: 07/28/2017] [Indexed: 01/08/2023] Open
Abstract
Improved understanding of the mechanisms underlying inherited retinal degenerations has created the possibility of developing much needed treatments for these relentless, blinding diseases. However, standard clinical indicators of retinal health (such as visual acuity and visual field sensitivity) are insensitive measures of photoreceptor survival. In many retinal degenerations, significant photoreceptor loss must occur before measurable differences in visual function are observed. Thus, there is a recognized need for more sensitive outcome measures to assess therapeutic efficacy as numerous clinical trials are getting underway. Adaptive optics (AO) retinal imaging techniques correct for the monochromatic aberrations of the eye and can be used to provide nearly diffraction-limited images of the retina. Many groups routinely are using AO imaging tools to obtain in vivo images of the rod and cone photoreceptor mosaic, and it now is possible to monitor photoreceptor structure over time with single cell resolution. Highlighting recent work using AO scanning light ophthalmoscopy (AOSLO) across a range of patient populations, we review the development of photoreceptor-based metrics (e.g., density/geometry, reflectivity, and size) as candidate biomarkers. Going forward, there is a need for further development of automated tools and normative databases, with the latter facilitating the comparison of data sets across research groups and devices. Ongoing and future clinical trials for inherited retinal diseases will benefit from the improved resolution and sensitivity that multimodal AO retinal imaging affords to evaluate safety and efficacy of emerging therapies.
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Affiliation(s)
- Katie M. Litts
- Department of Ophthalmology & Visual Sciences, Medical College of Wisconsin, Milwaukee, Wisconsin, United States
| | - Robert F. Cooper
- Department of Psychology, University of Pennsylvania, Philadelphia, Pennsylvania, United States
- Department of Ophthalmology, University of Pennsylvania, Philadelphia, Pennsylvania, United States
| | - Jacque L. Duncan
- Department of Ophthalmology, University of California, San Francisco, California, United States
| | - Joseph Carroll
- Department of Ophthalmology & Visual Sciences, Medical College of Wisconsin, Milwaukee, Wisconsin, United States
- Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, Milwaukee, Wisconsin, United States
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