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The Role of Medical Image Modalities and AI in the Early Detection, Diagnosis and Grading of Retinal Diseases: A Survey. Bioengineering (Basel) 2022; 9:bioengineering9080366. [PMID: 36004891 PMCID: PMC9405367 DOI: 10.3390/bioengineering9080366] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2022] [Revised: 07/28/2022] [Accepted: 08/01/2022] [Indexed: 11/16/2022] Open
Abstract
Traditional dilated ophthalmoscopy can reveal diseases, such as age-related macular degeneration (AMD), diabetic retinopathy (DR), diabetic macular edema (DME), retinal tear, epiretinal membrane, macular hole, retinal detachment, retinitis pigmentosa, retinal vein occlusion (RVO), and retinal artery occlusion (RAO). Among these diseases, AMD and DR are the major causes of progressive vision loss, while the latter is recognized as a world-wide epidemic. Advances in retinal imaging have improved the diagnosis and management of DR and AMD. In this review article, we focus on the variable imaging modalities for accurate diagnosis, early detection, and staging of both AMD and DR. In addition, the role of artificial intelligence (AI) in providing automated detection, diagnosis, and staging of these diseases will be surveyed. Furthermore, current works are summarized and discussed. Finally, projected future trends are outlined. The work done on this survey indicates the effective role of AI in the early detection, diagnosis, and staging of DR and/or AMD. In the future, more AI solutions will be presented that hold promise for clinical applications.
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Yao X, Lu R, Wang B, Lu Y, Kim TH. Super-resolution ophthalmoscopy: Virtually structured detection for resolution improvement in retinal imaging. Exp Biol Med (Maywood) 2021; 246:249-259. [PMID: 33243006 PMCID: PMC7876641 DOI: 10.1177/1535370220970533] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Quantitative retinal imaging is essential for advanced study and clinical management of eye diseases. However, spatial resolution of retinal imaging has been limited due to available numerical aperture and optical aberration of the ocular optics. Structured illumination microscopy has been established to break the diffraction-limit resolution in conventional light microscopy. However, practical implementation of structured illumination microscopy for in vivo ophthalmoscopy of the retina is challenging due to inevitable eye movements that can produce phase artifacts. Recently, we have demonstrated the feasibility of using virtually structured detection as one alternative to structured illumination microscopy for super-resolution imaging. By providing the flexibility of digital compensation of eye movements, the virtually structured detection provides a feasible, phase-artifact-free strategy to achieve super-resolution ophthalmoscopy. In this article, we summarize the technical rationale of virtually structured detection, and its implementations for super-resolution imaging of freshly isolated retinas, intact animals, and awake human subjects.
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Affiliation(s)
- 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
| | - Rongwen Lu
- National Eye Institute, National Institutes of Health, Bethesda, MD 20814, USA
| | - Benquan Wang
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA 20147, USA
| | - Yiming Lu
- Department of Bioengineering, University of Washington, Seattle, WA 98105, USA
| | - Tae-Hoon Kim
- Department of Bioengineering, University of Illinois at Chicago, Chicago, IL 60607, USA
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3
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Yao X, Kim TH. Fast intrinsic optical signal correlates with activation phase of phototransduction in retinal photoreceptors. Exp Biol Med (Maywood) 2020; 245:1087-1095. [PMID: 32558598 PMCID: PMC7400727 DOI: 10.1177/1535370220935406] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
IMPACT STATEMENT As the center of phototransduction, retinal photoreceptors are responsible for capturing and converting photon energy to bioelectric signals for following visual information processing in the retina. This article summarizes experimental observation and discusses biophysical mechanism of fast photoreceptor-intrinsic optical signal (IOS) correlated with early phase of phototransduction. Quantitative imaging of fast photoreceptor-IOS may provide objective optoretinography to advance the study and diagnosis of age-related macular degeneration, retinitis pigmentosa, diabetic retinopathy, and other eye diseases that can cause photoreceptor dysfunctions.
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Affiliation(s)
- 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
| | - Tae-Hoon Kim
- Department of Bioengineering, University of Illinois at Chicago, Chicago, IL 60607, USA
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4
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Lu Y, Benedetti J, Yao X. Light-Induced Length Shrinkage of Rod Photoreceptor Outer Segments. Transl Vis Sci Technol 2018; 7:29. [PMID: 30619649 PMCID: PMC6314056 DOI: 10.1167/tvst.7.6.29] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2018] [Accepted: 10/23/2018] [Indexed: 12/20/2022] Open
Abstract
Purpose This study was designed to verify light-induced outer segment (OS) length shrinkage of rod photoreceptors and to characterize its anatomic source at disc-level resolution. Methods Frog (Rana pipiens) retinas were used for this study. Time-lapse light microscopy of freshly isolated OSs was employed to test transient rod OS changes at 10 ms temporal resolution. Histological light microscopy of dark- and light-adapted retinas was used to confirm light-induced rod OS length changes; and transmission electron microscopy (TEM) was used to quantify light-driven structural perturbation of rod OSs at disc level resolution. Results Time-lapse light microscopy images verified transient length shrinking responses in freshly isolated rod OSs. Histological light microscopy images confirmed reduced rod OS lengths in light-adapted retinas, compared to that of dark-adapted retinas. TEM images disclosed shortened inter-disc distances in light-adapted retinas compared to dark-adapted retinas. Conclusions Light-induced rod OS length shrinkage was confirmed using time-lapse light microscopy of isolated rod OSs and histological light microscopy of dark- and light-adapted retinas. TEM revealed that the rod OS length shrinkage was correlated to the light-driven decrease of the space between individual discs, not the disc thickness itself. Translational Relevance Light-induced transient rod response promises a noninvasive biomarker for early diagnosis of age-related macular degeneration and retinitis pigmentosa, in which the rod photoreceptors are known to be more vulnerable than cone photoreceptors.
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Affiliation(s)
- Yiming Lu
- Department of Bioengineering, University of Illinois at Chicago, Chicago, IL, USA
| | - Jacopo Benedetti
- 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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5
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Son T, Alam M, Toslak D, Wang B, Lu Y, Yao X. Functional optical coherence tomography of neurovascular coupling interactions in the retina. JOURNAL OF BIOPHOTONICS 2018; 11:e201800089. [PMID: 29770594 PMCID: PMC6239985 DOI: 10.1002/jbio.201800089] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/16/2018] [Accepted: 05/15/2018] [Indexed: 05/19/2023]
Abstract
Quantitative evaluation of retinal neurovascular coupling is essential for a better understanding of visual function and early detection of eye diseases. However, there is no established method to monitor coherent interactions between stimulus-evoked neural activity and hemodynamic responses at high resolution. Here, we report a multimodal functional optical coherence tomography (OCT) imaging methodology to enable concurrent intrinsic optical signal (IOS) imaging of stimulus-evoked neural activity and hemodynamic responses at capillary resolution. OCT angiography guided IOS analysis was used to separate neural-IOS and hemodynamic-IOS changes in the same retinal image sequence. Frequency flicker stimuli evoked neural-IOS changes in the outer retina; that is, photoreceptor layer, first and then in the inner retina, including outer plexus layer (OPL), inner plexiform layer (IPL), and ganglion cell layer (GCL), which were followed by hemodynamic-IOS changes primarily in the inner retina; that is, OPL, IPL, and GCL. Different time courses and signal magnitudes of hemodynamic-IOS responses were observed in blood vessels with various diameters.
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Affiliation(s)
- Taeyoon Son
- Department of Bioengineering, University of Illinois at Chicago, Chicago, IL 60607, USA
| | - Minhaj Alam
- Department of Bioengineering, University of Illinois at Chicago, Chicago, IL 60607, USA
| | - Devrim Toslak
- Department of Bioengineering, University of Illinois at Chicago, Chicago, IL 60607, USA
- Department of Ophthalmology, Antalya Training and Research Hospital, Antalya, Turkey
| | - Benquan Wang
- Department of Bioengineering, University of Illinois at Chicago, Chicago, IL 60607, USA
| | - Yiming Lu
- 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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6
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Yao X, Son T, Kim TH, Lu Y. Functional optical coherence tomography of retinal photoreceptors. Exp Biol Med (Maywood) 2018; 243:1256-1264. [PMID: 30482040 DOI: 10.1177/1535370218816517] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
IMPACT STATEMENT Retinal photoreceptors are the primary target of age-related macular degeneration (AMD) which is the leading cause of severe vision loss and legal blindness. An objective method for functional assessment of photoreceptor physiology can benefit early detection and better treatment evaluation of AMD and other eye diseases that are known to cause photoreceptor dysfunctions. This article summarizes in vitro study of IOS mechanisms and in vivo demonstration of IOS imaging of intact animals. Further development of the functional IOS imaging may provide a revolutionary solution to achieve objective assessment of human photoreceptors.
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Affiliation(s)
- Xincheng Yao
- 1 Department of Bioengineering, University of Illinois at Chicago, Chicago, IL 60607, USA.,2 Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago, Chicago, IL 60612, USA
| | - Taeyoon Son
- 1 Department of Bioengineering, University of Illinois at Chicago, Chicago, IL 60607, USA
| | - Tae-Hoon Kim
- 1 Department of Bioengineering, University of Illinois at Chicago, Chicago, IL 60607, USA
| | - Yiming Lu
- 1 Department of Bioengineering, University of Illinois at Chicago, Chicago, IL 60607, USA
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Lu Y, Liu C, Yao X. In vivo super-resolution imaging of transient retinal phototropism evoked by oblique light stimulation. JOURNAL OF BIOMEDICAL OPTICS 2018; 23:1-4. [PMID: 29752801 PMCID: PMC5946809 DOI: 10.1117/1.jbo.23.5.050502] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2018] [Accepted: 04/19/2018] [Indexed: 05/28/2023]
Abstract
Rod-dominated transient retinal phototropism (TRP) has been observed in freshly isolated retinas, promising a noninvasive biomarker for objective assessment of retinal physiology. However, in vivo mapping of TRP is challenging due to its subcellular signal magnitude and fast time course. We report here a virtually structured detection-based super-resolution ophthalmoscope to achieve subcellular spatial resolution and millisecond temporal resolution for in vivo imaging of TRP. Spatiotemporal properties of in vivo TRP were characterized corresponding to variable light intensity stimuli, confirming that TRP is tightly correlated with early stages of phototransduction.
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Affiliation(s)
- Yiming Lu
- University of Illinois at Chicago, Department of Bioengineering, Chicago, Illinois, United States
| | - Changgeng Liu
- University of Illinois at Chicago, Department of Bioengineering, Chicago, Illinois, United States
| | - Xincheng Yao
- University of Illinois at Chicago, Department of Bioengineering, Chicago, Illinois, United States
- University of Illinois at Chicago, Department of Ophthalmology and Visual Sciences, Chicago, Illinois, United States
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Lu Y, Liu C, Yao X. In vivo observation of transient photoreceptor movement correlated with oblique light stimulation. PROCEEDINGS OF SPIE--THE INTERNATIONAL SOCIETY FOR OPTICAL ENGINEERING 2018; 10497:104971M. [PMID: 29950751 PMCID: PMC6016829 DOI: 10.1117/12.2287262] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Rod-dominated transient retinal phototropism (TRP) has been observed in freshly isolated retinas, promising a noninvasive biomarker for high resolution assessment of retinal physiology. However, in vivo mapping of TRP is challenging due to its fast time course and sub-cellular signal magnitude. By developing a line-scanning and virtually structured detection based super-resolution ophthalmoscope, we report here in vivo observation of TRP in frog retina. In vivo characterization of TRP time course and magnitude were implemented by using variable light stimulus intensities.
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Affiliation(s)
- Yiming Lu
- Department of Bioengineering, University of Illinois at Chicago, Chicago, IL 60607, USA
| | - Changgeng Liu
- 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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Abstract
Zebrafish (Danio rerio) provide many advantages as a model organism for studying ocular disease and development, and there is great interest in the ability to non-invasively assess their photoreceptor mosaic. Despite recent applications of scanning light ophthalmoscopy, fundus photography, and gonioscopy to in vivo imaging of the adult zebrafish eye, current techniques either lack accurate scaling information (limiting quantitative analyses) or require euthanizing the fish (precluding longitudinal analyses). Here we describe improved methods for imaging the adult zebrafish retina using spectral domain optical coherence tomography (OCT). Transgenic fli1:eGFP zebrafish were imaged using the Bioptigen Envisu R2200 broadband source OCT with a 12-mm telecentric probe to measure axial length and a mouse retina probe to acquire retinal volume scans subtending 1.2 × 1.2 mm nominally. En face summed volume projections were generated from the volume scans using custom software that allows the user to create contours tailored to specific retinal layer(s) of interest. Following imaging, the eyes were dissected for ex vivo fluorescence microscopy, and measurements of blood vessel branch points were compared to those made from the en face OCT images to determine the OCT lateral scale as a function of axial length. Using this scaling model, we imaged the photoreceptor layer of five wild-type zebrafish and quantified the density and packing geometry of the UV cone submosaic. Our in vivo cone density measurements agreed with measurements from previously published histology values. The method presented here allows accurate, quantitative assessment of cone structure in vivo and will be useful for longitudinal studies of the zebrafish cone mosaics.
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Son T, Wang B, Lu Y, Chen Y, Cao D, Yao X. Concurrent OCT imaging of stimulus evoked retinal neural activation and hemodynamic responses. PROCEEDINGS OF SPIE--THE INTERNATIONAL SOCIETY FOR OPTICAL ENGINEERING 2017; 10045. [PMID: 29225397 DOI: 10.1117/12.2252480] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
It is well established that major retinal diseases involve distortions of the retinal neural physiology and blood vascular structures. However, the details of distortions in retinal neurovascular coupling associated with major eye diseases are not well understood. In this study, a multi-modal optical coherence tomography (OCT) imaging system was developed to enable concurrent imaging of retinal neural activity and vascular hemodynamics. Flicker light stimulation was applied to mouse retinas to evoke retinal neural responses and hemodynamic changes. The OCT images were acquired continuously during the pre-stimulation, light-stimulation, and post-stimulation phases. Stimulus-evoked intrinsic optical signals (IOSs) and hemodynamic changes were observed over time in blood-free and blood regions, respectively. Rapid IOSs change occurred almost immediately after stimulation. Both positive and negative signals were observed in adjacent retinal areas. The hemodynamic changes showed time delays after stimulation. The signal magnitudes induced by light stimulation were observed in blood regions and did not show significant changes in blood-free regions. These differences may arise from different mechanisms in blood vessels and neural tissues in response to light stimulation. These characteristics agreed well with our previous observations in mouse retinas. Further development of the multi-modal OCT may provide a new imaging method for studying how retinal structures and metabolic and neural functions are affected by age-related macular degeneration (AMD), glaucoma, diabetic retinopathy (DR), and other diseases, which promises novel noninvasive biomarkers for early disease detection and reliable treatment evaluations of eye diseases.
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Affiliation(s)
- Taeyoon Son
- Department of Bioengineering, University of Illinois at Chicago, Chicago, IL 60607, USA
| | - Benquan Wang
- Department of Bioengineering, University of Illinois at Chicago, Chicago, IL 60607, USA
| | - Yiming Lu
- Department of Bioengineering, University of Illinois at Chicago, Chicago, IL 60607, USA
| | - Yanjun Chen
- Department of Bioengineering, University of Illinois at Chicago, Chicago, IL 60607, USA
| | - Dingcai Cao
- Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago, Chicago, IL 60612, 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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11
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Lu Y, Wang B, Yao X. Comparative investigation of stimulus-evoked rod outer segment movement and retinal electrophysiological activity. PROCEEDINGS OF SPIE--THE INTERNATIONAL SOCIETY FOR OPTICAL ENGINEERING 2017; 10068. [PMID: 28867866 DOI: 10.1117/12.2249548] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
Transient retinal phototropism (TRP) has been observed in rod photoreceptors activated by oblique visible light flashes. Time-lapse confocal microscopy and optical coherence tomography (OCT) revealed rod outer segment (ROS) movements as the physical source of TRP. However, the physiological source of TRP is still not well understood. In this study, concurrent TRP and electroretinogram (ERG) measurements disclosed a remarkably earlier onset time of the ROS movements (≤10 ms) than that (∼38 ms) of the ERG a-wave. Furthermore, low sodium treatment reversibly blocked the photoreceptor ERG a-wave, which is known to reflect hyperpolarization of retinal photoreceptors, but preserved the TRP associated rod OS movements well. Our experimental results and theoretical analysis suggested that the physiological source of TRP might be attributed to early stages of phototransduction, before the hyperpolarization of retinal photoreceptors.
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Affiliation(s)
- Yiming Lu
- Department of Bioengineering, University of Illinois at Chicago, Chicago, IL 60607, USA
| | - 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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Lu Y, Wang B, Pepperberg DR, Yao X. Stimulus-evoked outer segment changes occur before the hyperpolarization of retinal photoreceptors. BIOMEDICAL OPTICS EXPRESS 2017; 8:38-47. [PMID: 28101399 PMCID: PMC5231306 DOI: 10.1364/boe.8.000038] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/16/2016] [Revised: 11/02/2016] [Accepted: 11/09/2016] [Indexed: 05/22/2023]
Abstract
Transient retinal phototropism (TRP) has been predominantly observed in rod photoreceptors activated by oblique visible light stimulation. Dynamic confocal microscopy and optical coherence tomography (OCT) have revealed rod outer segment (ROS) movement as the physical source of TRP. However, the physiological source of ROS movement is still not well understood. In this study, concurrent near-infrared imaging of TRP and electroretinogram (ERG) measurement of retinal electrophysiology revealed that ROS movement occurs before the onset of the ERG a-wave, which is known to reflect the hyperpolarization of retinal photoreceptors. Moreover, substitution of normal superfusing medium with low-sodium medium reversibly blocked the photoreceptor ERG a-wave, but largely preserved the stimulus-evoked ROS movements. Our experimental results and theoretical analysis indicate that early, disc-based stages of the phototransduction cascade, which occur before the hyperpolarization of retinal photoreceptors, contribute to the TRP associated ROS movement.
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Affiliation(s)
- Yiming Lu
- Department of Bioengineering, University of Illinois at Chicago, Chicago, IL 60607, USA
| | - Benquan Wang
- Department of Bioengineering, University of Illinois at Chicago, Chicago, IL 60607, USA
| | - David R. Pepperberg
- Lions of Illinois Eye Research Institute, Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago, Chicago, IL 60612, USA
| | - Xincheng Yao
- Department of Bioengineering, University of Illinois at Chicago, Chicago, IL 60607, USA
- Lions of Illinois Eye Research Institute, Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago, Chicago, IL 60612, USA
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Liu C, Zhi Y, Wang B, Thapa D, Chen Y, Alam M, Lu Y, Yao X. In vivo super-resolution retinal imaging through virtually structured detection. JOURNAL OF BIOMEDICAL OPTICS 2016; 21:120502. [PMID: 27992630 PMCID: PMC5167560 DOI: 10.1117/1.jbo.21.12.120502] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2016] [Accepted: 11/28/2016] [Indexed: 06/01/2023]
Abstract
High resolution is important for sensitive detection of subtle distortions of retinal morphology at an early stage of eye diseases. We demonstrate virtually structured detection (VSD) as a feasible method to achieve in vivo super-resolution ophthalmoscopy. A line-scanning strategy was employed to achieve a super-resolution imaging speed up to 127 ?? frames / s with a frame size of 512 × 512 ?? pixels . The proof-of-concept experiment was performed on anesthetized frogs. VSD-based super-resolution images reveal individual photoreceptors and nerve fiber bundles unambiguously. Both image contrast and signal-to-noise ratio are significantly improved due to the VSD implementation.
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Affiliation(s)
- Changgeng Liu
- University of Illinois at Chicago, Department of Bioengineering, 851 South Morgen Street, Chicago, Illinois 60607, United States
| | - Yanan Zhi
- University of Illinois at Chicago, Department of Bioengineering, 851 South Morgen Street, Chicago, Illinois 60607, United States
| | - Benquan Wang
- University of Illinois at Chicago, Department of Bioengineering, 851 South Morgen Street, Chicago, Illinois 60607, United States
| | - Damber Thapa
- University of Illinois at Chicago, Department of Bioengineering, 851 South Morgen Street, Chicago, Illinois 60607, United States
| | - Yanjun Chen
- University of Illinois at Chicago, Department of Bioengineering, 851 South Morgen Street, Chicago, Illinois 60607, United States
| | - Minhaj Alam
- University of Illinois at Chicago, Department of Bioengineering, 851 South Morgen Street, Chicago, Illinois 60607, United States
| | - Yiming Lu
- University of Illinois at Chicago, Department of Bioengineering, 851 South Morgen Street, Chicago, Illinois 60607, United States
| | - Xincheng Yao
- University of Illinois at Chicago, Department of Bioengineering, 851 South Morgen Street, Chicago, Illinois 60607, United States
- University of Illinois at Chicago, Department of Ophthalmology and Visual Sciences, 1905 West Taylor Street, Chicago, Illinois 60612, United States
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14
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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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15
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Zhao X, Thapa D, Wang B, Lu Y, Gai S, Yao X. Stimulus-evoked outer segment changes in rod photoreceptors. JOURNAL OF BIOMEDICAL OPTICS 2016; 21:65006. [PMID: 27334933 PMCID: PMC4917604 DOI: 10.1117/1.jbo.21.6.065006] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/23/2016] [Accepted: 06/01/2016] [Indexed: 05/21/2023]
Abstract
Rod-dominated transient retinal phototropism (TRP) has been recently observed in freshly isolated mouse and frog retinas. Comparative confocal microscopy and optical coherence tomography revealed that the TRP was predominantly elicited from the rod outer segment (OS). However, the biophysical mechanism of rod OS dynamics is still unknown. Mouse and frog retinal slices, which displayed a cross-section of retinal photoreceptors and other functional layers, were used to test the effect of light stimulation on rod OSs. Time-lapse microscopy revealed stimulus-evoked conformational changes of rod OSs. In the center of the stimulated region, the length of the rod OS shrunk, while in the peripheral region, the rod OS swung toward the center region. Our experimental observation and theoretical analysis suggest that the TRP may reflect unbalanced rod disc-shape changes due to localized visible light stimulation.
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Affiliation(s)
- Xiaohui Zhao
- Hebei University, College of Physics Science and Technology, Hebei Key Lab of Optic-Electronic Information Materials, Baoding 071002, China
- University of Illinois at Chicago, Department of Bioengineering, Chicago, Illinois 60607, United States
| | - Damber Thapa
- University of Illinois at Chicago, Department of Bioengineering, Chicago, Illinois 60607, United States
| | - Benquan Wang
- University of Illinois at Chicago, Department of Bioengineering, Chicago, Illinois 60607, United States
| | - Yiming Lu
- University of Illinois at Chicago, Department of Bioengineering, Chicago, Illinois 60607, United States
| | - Shaoyan Gai
- University of Illinois at Chicago, Department of Bioengineering, Chicago, Illinois 60607, United States
| | - Xincheng Yao
- Hebei University, College of Physics Science and Technology, Hebei Key Lab of Optic-Electronic Information Materials, Baoding 071002, China
- 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
- Address all correspondence to: Xincheng Yao, E-mail:
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Zhao X, Thapa D, Wang B, Gai S, Yao X. Biophysical mechanism of transient retinal phototropism in rod photoreceptors. PROCEEDINGS OF SPIE--THE INTERNATIONAL SOCIETY FOR OPTICAL ENGINEERING 2016; 9706:97061O. [PMID: 28163347 PMCID: PMC5289741 DOI: 10.1117/12.2209144] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Oblique light stimulation evoked transient retinal phototropism (TRP) has been recently detected in frog and mouse retinas. High resolution microscopy of freshly isolated retinas indicated that the TRP is predominated by rod photoreceptors. Comparative confocal microscopy and optical coherence tomography (OCT) revealed that the TRP predominantly occurred from the photoreceptor outer segment (OS). However, biophysical mechanism of rod OS change is still unknown. In this study, frog retinal slices, which open a cross section of retinal photoreceptor and other functional layers, were used to test the effect of light stimulation on rod OS. Near infrared light microscopy was employed to monitor photoreceptor changes in retinal slices stimulated by a rectangular-shaped visible light flash. Rapid rod OS length change was observed after the stimulation delivery. The magnitude and direction of the rod OS change varied with the position of the rods within the stimulated area. In the center of stimulated region the length of the rod OS shrunk, while in the peripheral region the rod OS tip swung towards center region in the plane perpendicular to the incident stimulus light. Our experimental result and theoretical analysis suggest that the observed TRP may reflect unbalanced disc-shape change due to localized pigment bleaching. Further investigation is required to understand biochemical mechanism of the observed rod OS kinetics. Better study of the TRP may provide a noninvasive biomarker to enable early detection of age-related macular degeneration (AMD) and other diseases that are known to produce retinal photoreceptor dysfunctions.
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Affiliation(s)
- Xiaohui Zhao
- College of Physics Science and Technology, Hebei University, Baoding, China 071002
- Department of Bioengineering, University of Illinois at Chicago, Chicago, IL USA 60607
| | - Damber Thapa
- Department of Bioengineering, University of Illinois at Chicago, Chicago, IL USA 60607
| | - Benquan Wang
- Department of Bioengineering, University of Illinois at Chicago, Chicago, IL USA 60607
| | - Shaoyan Gai
- Department of Bioengineering, University of Illinois at Chicago, Chicago, IL USA 60607
| | - Xincheng Yao
- Department of Bioengineering, University of Illinois at Chicago, Chicago, IL USA 60607
- Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago, Chicago, IL USA 60612
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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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Kusnyerik A, Rozsa B, Veress M, Szabo A, Nemeth J, Maak P. Modeling of in vivo acousto-optic two-photon imaging of the retina in the human eye. OPTICS EXPRESS 2015; 23:23436-23449. [PMID: 26368444 DOI: 10.1364/oe.23.023436] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Our aim is to establish a novel combined acousto-optical method for in vivo imaging of the human retina with the two-photon microscope. In this paper we present modeling results based on eye model samples constructed with parameters measured on patients. We used effectively the potential of the electronic compensation offered by the acousto-optic lenses to avoid the use of adaptive optical correction. Simulation predicted lateral resolution between 1.6 µm and 3 µm on the retina. This technology allows the visualization of single cells and promises real time measuring of neural activity in individual neurons, neural segments and cell assemblies with 30-100 µs temporal and subcellular spatial resolution.
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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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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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Abstract
Light microscopy plays a key role in biological studies and medical diagnosis. The spatial resolution of conventional optical microscopes is limited to approximately half the wavelength of the illumination light as a result of the diffraction limit. Several approaches-including confocal microscopy, stimulated emission depletion microscopy, stochastic optical reconstruction microscopy, photoactivated localization microscopy, and structured illumination microscopy-have been established to achieve super-resolution imaging. However, none of these methods is suitable for the super-resolution ophthalmoscopy of retinal structures because of laser safety issues and inevitable eye movements. We recently experimentally validated virtually structured detection (VSD) as an alternative strategy to extend the diffraction limit. Without the complexity of structured illumination, VSD provides an easy, low-cost, and phase artifact-free strategy to achieve super-resolution in scanning laser microscopy. In this article we summarize the basic principles of the VSD method, review our demonstrated single-point and line-scan super-resolution systems, and discuss both technical challenges and the potential of VSD-based instrumentation for super-resolution ophthalmoscopy of the retina.
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Affiliation(s)
- Yanan Zhi
- Department of Bioengineering, University of Illinois at Chicago, Chicago, IL
| | - Benquan Wang
- Department of Bioengineering, University of Illinois at Chicago, Chicago, IL
| | - Xincheng Yao
- Department of Bioengineering, University of Illinois at Chicago, Chicago, IL
- Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago, Chicago, IL
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Zhang QX, Lu RW, Messinger JD, Curcio CA, Guarcello V, Yao XC. In vivo optical coherence tomography of light-driven melanosome translocation in retinal pigment epithelium. Sci Rep 2014; 3:2644. [PMID: 24025778 PMCID: PMC3770963 DOI: 10.1038/srep02644] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2013] [Accepted: 08/27/2013] [Indexed: 01/23/2023] Open
Abstract
Optical coherence tomography (OCT) may revolutionize fundamental investigation and clinical management of age-related macular degeneration and other eye diseases. However, quantitative OCT interpretation is hampered due to uncertain sub-cellular correlates of reflectivity in the retinal pigment epithelium (RPE) and photoreceptor. The purpose of this study was twofold: 1) to test OCT correlates in the RPE, and 2) to demonstrate the feasibility of longitudinal OCT monitoring of sub-cellular RPE dynamics. A high resolution OCT was constructed to achieve dynamic imaging of frog eyes, in which light-driven translocation of RPE melanosomes occurred within the RPE cell body and apical processes. Comparative histological examination of dark- and light-adapted eyes indicated that the RPE melanin granule, i.e., melanosome, was a primary OCT correlate. In vivo OCT imaging of RPE melanosomes opens the opportunity for quantitative assessment of RPE abnormalities associated with disease, and enables longitudinal investigation of RPE kinetics correlated with visual function.
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Affiliation(s)
- Qiu-Xiang Zhang
- Department of Biomedical Engineering, University of Alabama at Birmingham, Birmingham, AL 35294
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Bao L, Zhao J, Dai X, Wang Y, Ma R, Su Y, Cui H, Niu J, Bai S, Xiao Z, Yuan H, Yang Z, Li C, Cheng R, Ren X. Correlation between miR-23a and onset of hepatocellular carcinoma. Clin Res Hepatol Gastroenterol 2014; 38:318-30. [PMID: 24417970 DOI: 10.1016/j.clinre.2013.12.002] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/21/2013] [Revised: 10/28/2013] [Accepted: 12/10/2013] [Indexed: 02/04/2023]
Abstract
BACKGROUND AND AIMS To clarify the role of miR-23a in the onset and development of hepatocarcinoma on the cellular, genetic and molecular levels. PATIENTS AND METHODS Seventy-eight patients were included after hepatectomy. Relationships between the clinical pathological factors of tumor and paracancerous tissues were analyzed. Risk factors of overall and recurrence-free survival rates were subject to multi-variable analysis. Tissues were sequenced by digital miRNA expression profiling, and new miRNA was subject to target gene prediction. RESULTS miR-23a expression was correlated with the stage of the TNM Classification of Malignant Tumours most significantly, followed by tumor size (P=0.041 and 0.047). High miR-23a, vascular invasion, tumor size≥7cm, tumor capsule and late pathological stage were the risk factors of overall survival rate, and those of recurrence-free survival rate also included alpha-fetoprotein level≥200μg/L and multiple tumors. Compared with normal hepatic cell line L-02, the miR-23a expression levels in tumor cell lines SMMC-7721 and HepG2 were up-regulated and down-regulated respectively. Transfecting miR-23a inhibitor suppressed cell growth. Apoptotic rates of the control and those transfected with inhibitor-NC and miR-23a inhibitor for 48h were similar. CONCLUSION High miR-23a expression is the independent prognostic factor of overall and recurrence-free survival rates, and miR-23a may be involved in the onset of hepatocarcinoma as an oncogene.
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Affiliation(s)
- Lidao Bao
- Department of Pharmacy, Affiliated Hospital of Inner Mongolia Medical University, 010059 Hohhot, PR China.
| | - Jianfen Zhao
- Department of Health Care for Cadres, Binzhou People's Hospital, 256610 Binzhou, PR China
| | - Xiaoxia Dai
- Department of Respiratory Medicine, Binzhou People's Hospital, 256610 Binzhou, PR China
| | - Yi Wang
- Department of Pharmacy, Affiliated Hospital of Inner Mongolia Medical University, 010059 Hohhot, PR China
| | - Ruilian Ma
- Department of Pharmacy, Affiliated Hospital of Inner Mongolia Medical University, 010059 Hohhot, PR China
| | - Yila Su
- Molecular Biotechnology Center of Inner Mongolia Medical University, 010059 Hohhot, PR China
| | - Hongwei Cui
- Molecular Biotechnology Center of Inner Mongolia Medical University, 010059 Hohhot, PR China
| | - Jianxiang Niu
- Department of Hepatobiliary Surgery, Inner Mongolia Medical University, 010059 Hohhot, PR China
| | - Shiming Bai
- Kitami Institute of Technology, 090-8507 Kitami, Japan
| | - Zhiying Xiao
- College of Chemistry and Chemical Engineering, Inner Mongolia University for Nationalities, 028043 Tongliao, PR China
| | - Hongwei Yuan
- Department of Pathology, Inner Mongolia Medical University, 010059 Hohhot, PR China
| | - Zhou Yang
- Department of Imaging, Affiliated Hospital of Inner Mongolia Medical University, 010059 Hohhot, PR China
| | - Changqing Li
- Department of Geriatrics, Affiliated Hospital of Inner Mongolia Medical University, 010059 Hohhot, PR China
| | - Rui Cheng
- Department of Pharmacy, Affiliated Hospital of Inner Mongolia Medical University, 010059 Hohhot, PR China
| | - Xianhua Ren
- Department of Pharmacy, Affiliated Hospital of Inner Mongolia Medical University, 010059 Hohhot, PR China.
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Wang B, Lu R, Zhang Q, Jiang Y, Yao X. En face optical coherence tomography of transient light response at photoreceptor outer segments in living frog eyecup. OPTICS LETTERS 2013; 38:4526-9. [PMID: 24322065 PMCID: PMC4428569 DOI: 10.1364/ol.38.004526] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
This study was designed to test the feasibility of en face mapping of the transient intrinsic optical signal (IOS) response at photoreceptor outer segments and to assess the effect of spatial resolution on functional IOS imaging of retinal photoreceptors. A line-scan optical coherence tomography (LS-OCT) was constructed to achieve depth-resolved functional IOS imaging of living frog eyecups. Rapid en face OCT revealed transient IOS almost immediately (<3 ms) after the onset of visible light flashes at photoreceptor outer segments. Quantitative analysis indicated that the IOS kinetics may reflect dynamics of G-protein binding and releasing in early phases of visual transduction, and high resolution is essential to differentiate positive and negative IOS changes in adjacent locations.
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Affiliation(s)
- Benquan Wang
- Department of Biomedical Engineering, University of Alabama at Birmingham, Birmingham, Alabama 35294, USA
| | - Rongwen Lu
- Department of Biomedical Engineering, University of Alabama at Birmingham, Birmingham, Alabama 35294, USA
| | - Qiuxiang Zhang
- Department of Biomedical Engineering, University of Alabama at Birmingham, Birmingham, Alabama 35294, USA
| | - Yuqiang Jiang
- Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
| | - Xincheng Yao
- Department of Biomedical Engineering, University of Alabama at Birmingham, Birmingham, Alabama 35294, USA
- Vision Science Research Center, University of Alabama at Birmingham, Birmingham, Alabama 35294, USA
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Lu R, Levy AM, Zhang Q, Pittler SJ, Yao X. Dynamic near-infrared imaging reveals transient phototropic change in retinal rod photoreceptors. JOURNAL OF BIOMEDICAL OPTICS 2013; 18:106013. [PMID: 24165739 PMCID: PMC3809571 DOI: 10.1117/1.jbo.18.10.106013] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2013] [Accepted: 10/03/2013] [Indexed: 05/05/2023]
Abstract
Stiles-Crawford effect (SCE) is exclusively observed in cone photoreceptors, but why the SCE is absent in rod photoreceptors is still a mystery. In this study, we employed dynamic near infrared light imaging to monitor photoreceptor kinetics in freshly isolated frog and mouse retinas stimulated by oblique visible light flashes. It was observed that retinal rods could rapidly (onset: ∼10 ms for frog and 5 ms for mouse; time-to-peak: ∼200 ms for frog and 30 ms for mouse) shift toward the direction of the visible light, which might quickly compensate for the loss of luminous efficiency due to oblique illumination. In contrast, such directional movement was negligible in retinal cones. Moreover, transient rod phototropism could contribute to characteristic intrinsic optical signal (IOS). We anticipate that further study of the transient rod phototropism may not only provide insight into better understanding of the nature of vision but also promise an IOS biomarker for functional mapping of rod physiology at high resolution.
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Affiliation(s)
- Rongwen Lu
- University of Alabama at Birmingham, Department of Biomedical Engineering, Birmingham, Alabama 35294
| | - Alexander M. Levy
- University of Alabama at Birmingham, Department of Biomedical Engineering, Birmingham, Alabama 35294
| | - Qiuxiang Zhang
- University of Alabama at Birmingham, Department of Biomedical Engineering, Birmingham, Alabama 35294
| | - Steven J. Pittler
- University of Alabama at Birmingham, Department of Vision Sciences, Birmingham, Alabama 35294
| | - Xincheng Yao
- University of Alabama at Birmingham, Department of Biomedical Engineering, Birmingham, Alabama 35294
- University of Alabama at Birmingham, Department of Vision Sciences, Birmingham, Alabama 35294
- Address all correspondence to: Xincheng Yao, University of Alabama at Birmingham, Department of Biomedical Engineering, Birmingham, Alabama 35294. Tel: (205) 996-7459; Fax: (205) 934-3425; E-mail:
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Lu RW, Wang BQ, Zhang QX, Yao XC. Super-resolution scanning laser microscopy through virtually structured detection. BIOMEDICAL OPTICS EXPRESS 2013; 4:1673-82. [PMID: 24049688 PMCID: PMC3771838 DOI: 10.1364/boe.4.001673] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/17/2013] [Revised: 08/12/2013] [Accepted: 08/14/2013] [Indexed: 05/07/2023]
Abstract
High resolution microscopy is essential for advanced study of biological structures and accurate diagnosis of medical diseases. The spatial resolution of conventional microscopes is light diffraction limited. Structured illumination has been extensively explored to break the diffraction limit in wide field light microscopy. However, deployable application of the structured illumination in scanning laser microscopy is challenging due to the complexity of the illumination system and possible phase errors in sequential illumination patterns required for super-resolution reconstruction. We report here a super-resolution scanning laser imaging system which employs virtually structured detection (VSD) to break the diffraction limit. Without the complexity of structured illumination, VSD provides an easy, low-cost and phase-artifact free strategy to achieve super-resolution in scanning laser microscopy.
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Affiliation(s)
- Rong-Wen Lu
- Department of Biomedical Engineering, University of Alabama at Birmingham, Birmingham, AL 35294, USA
- These authors contributed equally to this work
| | - Ben-Quan Wang
- Department of Biomedical Engineering, University of Alabama at Birmingham, Birmingham, AL 35294, USA
- These authors contributed equally to this work
| | - Qiu-Xiang Zhang
- Department of Biomedical Engineering, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Xin-Cheng Yao
- Department of Biomedical Engineering, University of Alabama at Birmingham, Birmingham, AL 35294, USA
- Department of Vision Sciences, University of Alabama at Birmingham, Birmingham, AL 35294, USA
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