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Martínez-Ojeda RM, Prieto-Bonete G, Perez-Cárceles MD, Bueno JM. Structural changes in the crystalline lens as a function of the postmortem interval assessed with two-photon imaging microscopy. BIOMEDICAL OPTICS EXPRESS 2024; 15:4318-4329. [PMID: 39022534 PMCID: PMC11249687 DOI: 10.1364/boe.524380] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/21/2024] [Revised: 05/28/2024] [Accepted: 06/03/2024] [Indexed: 07/20/2024]
Abstract
The properties and structure of the crystalline lens change as time after death passes. Some experiments have suggested that these might be used to estimate the postmortem interval (PMI). In this study, the organization and texture of the rabbit lens were objectively evaluated as a function of the PMI using two-photon excitation fluorescence (TPEF) imaging microscopy. Between 24 h and 72 h, the lens presented a highly organized structure, although the fiber delineation was progressively vanishing. At 96 h, this turned into a homogeneous pattern where fibers were hardly observed. This behaviour was similar for parameters providing information on tissue texture. On the other hand, the fiber density of the lens is linearly reduced with the PMI. On average, density at 24 h was approximately two-fold when compared to 96 h after death. The present results show that TPEF microscopy combined with different quantitative tools can be used to objectively monitor temporal changes in the lens fiber organization after death. This might help to estimate the PMI, which is one of the most complex problems in forensic science.
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Affiliation(s)
- Rosa M. Martínez-Ojeda
- Laboratorio de Óptica, Instituto Universitario de Investigación en Óptica y Nanofísica, Universidad de Murcia, Campus de Espinardo (Ed. 34), 30100 Murcia, Spain
| | - Gemma Prieto-Bonete
- Servicio de Protección de la Naturaleza (SEPRONA), Guardia Civil, Ministerio del Interior, Spain
| | - María D. Perez-Cárceles
- Departamento de Medicina Legal y Forense, IMIB-Arrixaca, Facultad de Medicina, Universidad de Murcia, 30100 Murcia, Spain
| | - Juan M. Bueno
- Laboratorio de Óptica, Instituto Universitario de Investigación en Óptica y Nanofísica, Universidad de Murcia, Campus de Espinardo (Ed. 34), 30100 Murcia, Spain
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2
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Sioufi K, Zheleznyak L, MacRae S, Rocha KM. Femtosecond Lasers in Cornea & Refractive Surgery. Exp Eye Res 2021; 205:108477. [PMID: 33516763 DOI: 10.1016/j.exer.2021.108477] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2020] [Revised: 01/20/2021] [Accepted: 01/22/2021] [Indexed: 11/18/2022]
Abstract
Since the introduction of femtosecond laser (FS) systems for corneal flap creation in laser-assisted in-situ keratomileusis there have been numerous applications for FS laser in corneal surgery. This manuscript details the utility of FS lasers in corneal surgical procedures including refractive laser surgeries, intracorneal ring segment tunnels, presbyopic treatments, and FS-assisted keratoplasty. We also review the role of FS lasers in diagnostic procedures such as two photon excitation fluorescence and second harmonic generation.
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Affiliation(s)
- Kareem Sioufi
- Storm Eye Institute, Medical University of South Carolina, Charleston, SC, USA
| | | | - Scott MacRae
- Flaum Eye Institute and the Institute of Optics, University of Rochester, Rochester, NY, USA
| | - Karolinne M Rocha
- Storm Eye Institute, Medical University of South Carolina, Charleston, SC, USA.
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3
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Bueno JM, Cruz-Castillo R, Avilés-Trigueros M, Bautista-Elivar N. Arrangement of the photoreceptor mosaic in a diabetic rat model imaged with multiphoton microscopy. BIOMEDICAL OPTICS EXPRESS 2020; 11:4901-4914. [PMID: 33014589 PMCID: PMC7510868 DOI: 10.1364/boe.399835] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/08/2020] [Revised: 07/23/2020] [Accepted: 07/24/2020] [Indexed: 06/11/2023]
Abstract
Diabetic retinopathy (DR) is defined as a microvascular pathology. However, some data have suggested that the retinal photoreceptors (PRs) might be important in the pathogenesis of this ocular disease. In this study the organization of the PRs in control and diabetic-induced rats was compared using multiphoton microscopy. The PR mosaic was imaged at different locations in non-stained retinas. The density of PRs was directly quantified from cell counting. The spatially resolved density presents a double-slope pattern (from the central retina towards the periphery) in both healthy and pathological samples, although the values for the latter were significantly lower all across the retina. Moreover, Voronoi analysis was performed to explore changes in PR topography. In control specimens a hexagonally packed structure was dominant. However, despite the non-controlled effects of the disease in retinal structures, this PR regularity was fairly maintained in diabetic retinas.
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Affiliation(s)
- Juan M. Bueno
- Laboratorio de Óptica, Instituto Universitario de Investigación en Óptica y Nanofísica, Universidad de Murcia, Murcia, Spain
| | - Ricardo Cruz-Castillo
- Área Académica de Matemáticas y Física, Instituto de Ciencias Básicas e Ingeniería, Universidad Autónoma del Estado de Hidalgo, Hidalgo, Mexico
| | - Marcelino Avilés-Trigueros
- Departamento de Oftalmología, Facultad de Medicina, Universidad de Murcia e Instituto Murciano de Investigación Biosanitaria Virgen de la Arrixaca, “Campus Mare Nostrum” de Excelencia International, Murcia, Spain
| | - Nazario Bautista-Elivar
- Departamento de Ingeniería Eléctrica, Tecnológico Nacional de México, Instituto Tecnológico de Pachuca, Hidalgo, Mexico
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4
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Abstract
Two-photon (2P) microscopy is a powerful tool for imaging and exploring label-free biological tissues at high resolution. Although this type of microscopy has been demonstrated in ex vivo ocular tissues of both humans and animal models, imaging the human eye in vivo has always been challenging. This work presents a novel compact 2P microscope for non-contact imaging of the anterior part of the living human eye. The performance of the instrument was tested and the maximum permissible exposure to protect ocular tissues established. To the best of our knowledge, 2P images of the in vivo human cornea, the sclera and the trabecular meshwork are shown for the very first time. Acquired images are of enough quality to visualize collagen arrangement and morphological features of clinical interest. Future implementations of this technique may constitute a potential tool for early diagnosis of ocular diseases at submicron scale.
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5
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Batista A, Breunig HG, König A, Morgado AM, König K. Assessment of the metabolism and morphology of the porcine cornea, lens and retina by 2-photon imaging. JOURNAL OF BIOPHOTONICS 2018; 11:e201700324. [PMID: 29575612 DOI: 10.1002/jbio.201700324] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2017] [Accepted: 03/21/2018] [Indexed: 06/08/2023]
Abstract
Two-photon imaging is a noninvasive imaging technique with increasing importance in the biological and medical fields since it allows intratissue cell imaging with high resolution. We demonstrate the feasibility of using a single 2-photon instrument to evaluate the cornea, the crystalline lens and the retina based on their autofluorescence (AF). Image acquisition was performed using a custom-built 2-photon microscope for 5-dimensional microscopy with a near infrared broadband sub-15 femtosecond laser centered at 800 nanometers. Signals were detected using a spectral photomultiplier tube. The spectral ranges for the analysis of each tissue/layer AF were determined based on the spectra of each tissue as well as of pure endogenous fluorophores. The cornea, lens and retina are characterized at multiple depths with subcellular resolution based on their morphology and AF lifetime. Additionally, the AF lifetime of NAD(P)H was used to assess the metabolic activity of the cornea epithelium, endothelium and keratocytes. The feasibility to evaluate the metabolic activity of lens epithelial cells was also demonstrated, which may be used to further investigate the pathogenesis of cataracts. The results illustrate the potential of multimodal multiphoton imaging as a novel ophthalmologic technique as well as its potential as a diagnostic tool.
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Affiliation(s)
- Ana Batista
- Biophotonics and Laser Technology, Saarland University, Saarbrücken, Germany
- JenLab GmbH, Saarbrücken, Germany
| | - Hans G Breunig
- Biophotonics and Laser Technology, Saarland University, Saarbrücken, Germany
- JenLab GmbH, Saarbrücken, Germany
| | - Aisada König
- Biophotonics and Laser Technology, Saarland University, Saarbrücken, Germany
- JenLab GmbH, Saarbrücken, Germany
| | - António M Morgado
- Department of Physics, University of Coimbra, Coimbra, Portugal
- Coimbra Institute for Biomedical Imaging and Translational Research/Institute of Nuclear Sciences Applied to Heath (CIBIT/ICNAS), University of Coimbra, Coimbra, Portugal
| | - Karsten König
- Biophotonics and Laser Technology, Saarland University, Saarbrücken, Germany
- JenLab GmbH, Saarbrücken, Germany
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Alonso B, Pérez-Vizcaíno J, Mínguez-Vega G, Sola ÍJ. Tailoring the spatio-temporal distribution of diffractive focused ultrashort pulses through pulse shaping. OPTICS EXPRESS 2018; 26:10762-10772. [PMID: 29716008 DOI: 10.1364/oe.26.010762] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2018] [Accepted: 04/09/2018] [Indexed: 06/08/2023]
Abstract
Focusing control of ultrashort pulsed beams is an important research topic, due to its impact to subsequent interaction with matter. In this work, we study the propagation near the focus of ultrashort laser pulses of ~25 fs duration under diffractive focusing. We perform the spatio-spectral and spatio-temporal measurements of their amplitude and phase, complemented by the corresponding simulations. With them, we demonstrate that pulse shaping allows modifying in a controlled way not only the spatio-temporal distribution of the light irradiance in the focal region, but also the way it propagates as well as the frequency distribution within the pulse (temporal chirp). To gain a further intuitive insight, the role of diverse added spectral phase components is analyzed, showing the symmetries that arise for each case. In particular, we compare the effects, similarities and differences of the second and third order dispersion cases.
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Imaging and quantifying ganglion cells and other transparent neurons in the living human retina. Proc Natl Acad Sci U S A 2017; 114:12803-12808. [PMID: 29138314 PMCID: PMC5715765 DOI: 10.1073/pnas.1711734114] [Citation(s) in RCA: 139] [Impact Index Per Article: 19.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Ganglion cells (GCs) are fundamental to retinal neural circuitry, processing photoreceptor signals for transmission to the brain via their axons. However, much remains unknown about their role in vision and their vulnerability to disease leading to blindness. A major bottleneck has been our inability to observe GCs and their degeneration in the living human eye. Despite two decades of development of optical technologies to image cells in the living human retina, GCs remain elusive due to their high optical translucency. Failure of conventional imaging-using predominately singly scattered light-to reveal GCs has led to a focus on multiply-scattered, fluorescence, two-photon, and phase imaging techniques to enhance GC contrast. Here, we show that singly scattered light actually carries substantial information that reveals GC somas, axons, and other retinal neurons and permits their quantitative analysis. We perform morphometry on GC layer somas, including projection of GCs onto photoreceptors and identification of the primary GC subtypes, even beneath nerve fibers. We obtained singly scattered images by: (i) marrying adaptive optics to optical coherence tomography to avoid optical blurring of the eye; (ii) performing 3D subcellular image registration to avoid motion blur; and (iii) using organelle motility inside somas as an intrinsic contrast agent. Moreover, through-focus imaging offers the potential to spatially map individual GCs to underlying amacrine, bipolar, horizontal, photoreceptor, and retinal pigment epithelium cells, thus exposing the anatomical substrate for neural processing of visual information. This imaging modality is also a tool for improving clinical diagnosis and assessing treatment of retinal disease.
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Marcos S, Werner JS, Burns SA, Merigan WH, Artal P, Atchison DA, Hampson KM, Legras R, Lundstrom L, Yoon G, Carroll J, Choi SS, Doble N, Dubis AM, Dubra A, Elsner A, Jonnal R, Miller DT, Paques M, Smithson HE, Young LK, Zhang Y, Campbell M, Hunter J, Metha A, Palczewska G, Schallek J, Sincich LC. Vision science and adaptive optics, the state of the field. Vision Res 2017; 132:3-33. [PMID: 28212982 PMCID: PMC5437977 DOI: 10.1016/j.visres.2017.01.006] [Citation(s) in RCA: 78] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2016] [Revised: 01/24/2017] [Accepted: 01/25/2017] [Indexed: 12/27/2022]
Abstract
Adaptive optics is a relatively new field, yet it is spreading rapidly and allows new questions to be asked about how the visual system is organized. The editors of this feature issue have posed a series of question to scientists involved in using adaptive optics in vision science. The questions are focused on three main areas. In the first we investigate the use of adaptive optics for psychophysical measurements of visual system function and for improving the optics of the eye. In the second, we look at the applications and impact of adaptive optics on retinal imaging and its promise for basic and applied research. In the third, we explore how adaptive optics is being used to improve our understanding of the neurophysiology of the visual system.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | - Yuhua Zhang
- University of Alabama at Birmingham, Birmingham, USA
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9
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Imaging individual neurons in the retinal ganglion cell layer of the living eye. Proc Natl Acad Sci U S A 2017; 114:586-591. [PMID: 28049835 DOI: 10.1073/pnas.1613445114] [Citation(s) in RCA: 129] [Impact Index Per Article: 18.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Although imaging of the living retina with adaptive optics scanning light ophthalmoscopy (AOSLO) provides microscopic access to individual cells, such as photoreceptors, retinal pigment epithelial cells, and blood cells in the retinal vasculature, other important cell classes, such as retinal ganglion cells, have proven much more challenging to image. The near transparency of inner retinal cells is advantageous for vision, as light must pass through them to reach the photoreceptors, but it has prevented them from being directly imaged in vivo. Here we show that the individual somas of neurons within the retinal ganglion cell (RGC) layer can be imaged with a modification of confocal AOSLO, in both monkeys and humans. Human images of RGC layer neurons did not match the quality of monkey images for several reasons, including safety concerns that limited the light levels permissible for human imaging. We also show that the same technique applied to the photoreceptor layer can resolve ambiguity about cone survival in age-related macular degeneration. The capability to noninvasively image RGC layer neurons in the living eye may one day allow for a better understanding of diseases, such as glaucoma, and accelerate the development of therapeutic strategies that aim to protect these cells. This method may also prove useful for imaging other structures, such as neurons in the brain.
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Sharma R, Williams DR, Palczewska G, Palczewski K, Hunter JJ. Two-Photon Autofluorescence Imaging Reveals Cellular Structures Throughout the Retina of the Living Primate Eye. Invest Ophthalmol Vis Sci 2016; 57:632-46. [PMID: 26903224 PMCID: PMC4771181 DOI: 10.1167/iovs.15-17961] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2015] [Accepted: 12/30/2015] [Indexed: 11/24/2022] Open
Abstract
PURPOSE Although extrinsic fluorophores can be introduced to label specific cell types in the retina, endogenous fluorophores, such as NAD(P)H, FAD, collagen, and others, are present in all retinal layers. These molecules are a potential source of optical contrast and can enable noninvasive visualization of all cellular layers. We used a two-photon fluorescence adaptive optics scanning light ophthalmoscope (TPF-AOSLO) to explore the native autofluorescence of various cell classes spanning several layers in the unlabeled retina of a living primate eye. METHODS Three macaques were imaged on separate occasions using a custom TPF-AOSLO. Two-photon fluorescence was evoked by pulsed light at 730 and 920 nm excitation wavelengths, while fluorescence emission was collected in the visible range from several retinal layers and different locations. Backscattered light was recorded simultaneously in confocal modality and images were postprocessed to remove eye motion. RESULTS All retinal layers yielded two-photon signals and the heterogeneous distribution of fluorophores provided optical contrast. Several structural features were observed, such as autofluorescence from vessel walls, Müller cell processes in the nerve fibers, mosaics of cells in the ganglion cell and other nuclear layers of the inner retina, as well as photoreceptor and RPE layers in the outer retina. CONCLUSIONS This in vivo survey of two-photon autofluorescence throughout the primate retina demonstrates a wider variety of structural detail in the living eye than is available through conventional imaging methods, and broadens the use of two-photon imaging of normal and diseased eyes.
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Affiliation(s)
- Robin Sharma
- The Institute of Optics, University of Rochester, Rochester, New York, United States
- Center for Visual Science, University of Rochester, Rochester, New York, United States
| | - David R. Williams
- The Institute of Optics, University of Rochester, Rochester, New York, United States
- Center for Visual Science, University of Rochester, Rochester, New York, United States
- Flaum Eye Institute, University of Rochester, Rochester, New York, United States
| | | | - Krzysztof Palczewski
- Department of Pharmacology, Cleveland Center for Membrane and Structural Biology, School of Medicine, Case Western Reserve University, Cleveland, Ohio, United States
| | - Jennifer J. Hunter
- Center for Visual Science, University of Rochester, Rochester, New York, United States
- Flaum Eye Institute, University of Rochester, Rochester, New York, United States
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11
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Bar-Noam AS, Farah N, Shoham S. Correction-free remotely scanned two-photon in vivo mouse retinal imaging. LIGHT, SCIENCE & APPLICATIONS 2016; 5:e16007. [PMID: 30167112 PMCID: PMC6059848 DOI: 10.1038/lsa.2016.7] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/07/2015] [Revised: 08/14/2015] [Accepted: 08/17/2015] [Indexed: 05/16/2023]
Abstract
Non-invasive fluorescence retinal imaging in small animals is an important requirement for an array of translational vision applications. The in vivo two-photon imaging of the mouse retina may enable the long-term investigation of the structure and function of healthy and diseased retinal tissue. However, to date, this has only been possible using relatively complex adaptive-optics systems. Here, the optical modeling of the murine eye and of the imaging system is used to achieve correction-free two-photon microscopy through the pupil of a mouse eye to yield high-quality, optically sectioned fundus images. By remotely scanning the focus using an electronically tunable lens, high-resolution three-dimensional fluorescein angiograms and cellular-scale images are acquired, thus introducing a correction-free baseline performance level for two-photon in vivo retinal imaging. Moreover, the system enables functional calcium imaging of repeated retinal responses to light stimulation using the genetically encoded indicator, GCaMP6s. These results and the simplicity of the new add-on optics are an important step toward several structural, functional, and multimodal imaging applications that will benefit from the tight optical sectioning and the use of near-infrared light.
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Affiliation(s)
- Adi Schejter Bar-Noam
- />Faculty of Biomedical Engineering, Technion – Israel Institute of Technology, Kiryat HaTechnion, Haifa 32000, Israel
| | - Nairouz Farah
- />Faculty of Biomedical Engineering, Technion – Israel Institute of Technology, Kiryat HaTechnion, Haifa 32000, Israel
| | - Shy Shoham
- />Faculty of Biomedical Engineering, Technion – Israel Institute of Technology, Kiryat HaTechnion, Haifa 32000, Israel
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Stremplewski P, Komar K, Palczewski K, Wojtkowski M, Palczewska G. Periscope for noninvasive two-photon imaging of murine retina in vivo. BIOMEDICAL OPTICS EXPRESS 2015; 6:3352-61. [PMID: 26417507 PMCID: PMC4574663 DOI: 10.1364/boe.6.003352] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/03/2015] [Revised: 08/01/2015] [Accepted: 08/02/2015] [Indexed: 05/18/2023]
Abstract
Two-photon microscopy allows visualization of subcellular structures in the living animal retina. In previously reported experiments it was necessary to apply a contact lens to each subject. Extending this technology to larger animals would require fitting a custom contact lens to each animal and cumbersome placement of the living animal head on microscope stage. Here we demonstrate a new device, periscope, for coupling light energy into mouse eye and capturing emitted fluorescence. Using this periscope we obtained images of the RPE and their subcellular organelles, retinosomes, with larger field of view than previously reported. This periscope provides an interface with a commercial microscope, does not require contact lens and its design could be modified to image retina in larger animals.
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Affiliation(s)
- Patrycjusz Stremplewski
- Institute of Physics, Faculty of Physics, Astronomy and Informatics, Nicolaus Copernicus University in Torun, Grudziadzka 5, 87-100 Torun, Poland
| | - Katarzyna Komar
- Institute of Physics, Faculty of Physics, Astronomy and Informatics, Nicolaus Copernicus University in Torun, Grudziadzka 5, 87-100 Torun, Poland
| | - Krzysztof Palczewski
- Department of Pharmacology, Cleveland Center for Membrane and Structural Biology, School of Medicine, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Maciej Wojtkowski
- Institute of Physics, Faculty of Physics, Astronomy and Informatics, Nicolaus Copernicus University in Torun, Grudziadzka 5, 87-100 Torun, Poland
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Bueno JM, Palacios R, Pennos A, Artal P. Second-harmonic generation microscopy of photocurable polymer intrastromal implants in ex-vivo corneas. BIOMEDICAL OPTICS EXPRESS 2015; 6:2211-9. [PMID: 26114039 PMCID: PMC4473754 DOI: 10.1364/boe.6.002211] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/17/2015] [Revised: 05/14/2015] [Accepted: 05/14/2015] [Indexed: 05/25/2023]
Abstract
A custom adaptive-optics (AO) multiphoton microscope was used to visualize the corneal stroma after the insertion of a photocurable polymer material. A lamellar pocket was created and a certain amount of polymer in liquid form was injected. This turned into a rigid film after UV irradiation. Intact eyes were used as control. Tomographic and regular second harmonic generation (SHG) microscopy images were recorded from both control and corneas with polymer implants. In control corneas, the SHG signal decreased uniformly with depth. However, treated corneas exhibited an abrupt loss of SHG signal at the implant location. The use of AO increased the SHG levels and improved the visualization of the stroma, not only at deeper corneal layers but also beneath the implant. Moreover, the absence of SHG signal from the implant allowed its geometrical characterization (thickness and location). This technique offers a potential tool for non-invasive analysis of morphological changes in the cornea after surgery or treatment, and might be useful in future clinical environments.
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Palczewska G, Golczak M, Williams DR, Hunter JJ, Palczewski K. Endogenous fluorophores enable two-photon imaging of the primate eye. Invest Ophthalmol Vis Sci 2014; 55:4438-47. [PMID: 24970255 DOI: 10.1167/iovs.14-14395] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
PURPOSE Noninvasive two-photon imaging of a living mammalian eye can reveal details of molecular processes in the retina and RPE. Retinyl esters and all-trans-retinal condensation products are two types of retinoid fluorophores present in these tissues. We measured the content of these two types of retinoids in monkey and human eyes to validate the potential of two-photon imaging for monitoring retinoid changes in human eyes. METHODS Two-photon microscopy (TPM) was used to visualize excised retina from monkey eyes. Retinoid composition and content in human and monkey eyes were quantified by HPLC and mass spectrometry (MS). RESULTS Clear images of inner and outer segments of rods and cones were obtained in primate eyes at different eccentricities. Fluorescence spectra from outer segments revealed a maximum emission at 480 nm indicative of retinols and their esters. In cynomolgus monkey and human retinal extracts, retinyl esters existed predominantly in the 11-cis configuration along with notable levels of 11-cis-retinol, a characteristic of cone-enriched retinas. Average amounts of di-retinoid-pyridinium-ethanolamine (A2E) in primate and human eyes were 160 and 225 pmol/eye, respectively. CONCLUSIONS These data show that human retina contains sufficient amounts of retinoids for two-photon excitation imaging. Greater amounts of 11-cis-retinyl esters relative to rodent retinas contribute to the fluorescence signal from both monkey and human eyes. These observations indicate that TPM imaging found effective in mice could detect early age- and disease-related changes in human retina.
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Affiliation(s)
| | - Marcin Golczak
- Department of Pharmacology, Case Western Reserve University, Cleveland, Ohio, United States
| | - David R Williams
- Center for Visual Science, University of Rochester, Rochester, New York, United States The Institute of Optics, University of Rochester, Rochester, New York, United States
| | - Jennifer J Hunter
- Center for Visual Science, University of Rochester, Rochester, New York, United States Flaum Eye Institute, University of Rochester, Rochester, New York, United States Department of Biomedical Engineering, University of Rochester, Rochester, New York, United States
| | - Krzysztof Palczewski
- Department of Pharmacology, Case Western Reserve University, Cleveland, Ohio, United States
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Bueno JM, Palacios R, Giakoumaki A, Gualda EJ, Schaeffel F, Artal P. Retinal cell imaging in myopic chickens using adaptive optics multiphoton microscopy. BIOMEDICAL OPTICS EXPRESS 2014; 5:664-674. [PMID: 24688804 PMCID: PMC3959843 DOI: 10.1364/boe.5.000664] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2013] [Revised: 01/30/2014] [Accepted: 01/31/2014] [Indexed: 06/03/2023]
Abstract
Abnormal eye growth induced by visual deprivation can modify the structure and density of the retinal cells. We have used an adaptive optics multiphoton microscope to image photoreceptors (PRs) and ganglion cells (GCs) at different retinal locations in unstained retinas of chicken eyes with about 10D of myopia and their normal-sighted fellow eyes. In all samples, the local averaged inter-PR distance increased with eccentricity. No significant differences in PR density were found between control and myopic eyes. GC density declined in myopic eyes compared to control eyes and the inter-cell distance increased. In normal eyes, the size of the GC cell bodies increased approximately two-fold between the area centralis and the peripheral retina. In myopic eyes, this trend was preserved but the GC bodies were larger at each retinal location, compared to control eyes. Obviously, GC morphology is changing when the retinal area is enlarged in myopic eyes.
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Affiliation(s)
- Juan M. Bueno
- Laboratorio de Óptica, Instituto Universitario de Investigación en Óptica y Nanofísica, Universidad de Murcia, Campus de Espinardo (Ed.34), 30100 Murcia, Spain
| | | | - Anastasia Giakoumaki
- Laboratorio de Óptica, Instituto Universitario de Investigación en Óptica y Nanofísica, Universidad de Murcia, Campus de Espinardo (Ed.34), 30100 Murcia, Spain
| | - Emilio J. Gualda
- Laboratorio de Óptica, Instituto Universitario de Investigación en Óptica y Nanofísica, Universidad de Murcia, Campus de Espinardo (Ed.34), 30100 Murcia, Spain
| | - Frank Schaeffel
- Section of Neurobiology of the Eye, Ophthalmic Research Institute, Calwerstrasse 7/1, 72076 Tuebingen, Germany
| | - Pablo Artal
- Laboratorio de Óptica, Instituto Universitario de Investigación en Óptica y Nanofísica, Universidad de Murcia, Campus de Espinardo (Ed.34), 30100 Murcia, Spain
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Sharma R, Yin L, Geng Y, Merigan WH, Palczewska G, Palczewski K, Williams DR, Hunter JJ. In vivo two-photon imaging of the mouse retina. BIOMEDICAL OPTICS EXPRESS 2013; 4:1285-93. [PMID: 24009992 PMCID: PMC3756587 DOI: 10.1364/boe.4.001285] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/04/2013] [Revised: 05/06/2013] [Accepted: 06/17/2013] [Indexed: 05/18/2023]
Abstract
Though in vivo two-photon imaging has been demonstrated in non-human primates, improvements in the signal-to-noise ratio (SNR) would greatly improve its scientific utility. In this study, extrinsic fluorophores, expressed in otherwise transparent retinal ganglion cells, were imaged in the living mouse eye using a two-photon fluorescence adaptive optics scanning laser ophthalmoscope. We recorded two orders of magnitude greater signal levels from extrinsically labeled cells relative to previous work done in two-photon autofluorescence imaging of primates. Features as small as single dendrites in various layers of the retina could be resolved and predictions are made about the feasibility of measuring functional response from cells. In the future, two-photon imaging in the intact eye may allow us to monitor the function of retinal cell classes with infrared light that minimally excites the visual response.
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Affiliation(s)
- Robin Sharma
- Center for Visual Science, University of Rochester, Rochester, New York 14627, USA
- The Institute of Optics, University of Rochester, Rochester, New York 14620, USA
| | - Lu Yin
- Center for Visual Science, University of Rochester, Rochester, New York 14627, USA
| | - Ying Geng
- Center for Visual Science, University of Rochester, Rochester, New York 14627, USA
- The Institute of Optics, University of Rochester, Rochester, New York 14620, USA
- Currently at: Corning Incorporated, One Riverfront Plaza, Corning, New York 14831, USA
| | - William H. Merigan
- Center for Visual Science, University of Rochester, Rochester, New York 14627, USA
- Flaum Eye Institute, University of Rochester, Rochester, New York 14642, USA
| | - Grazyna Palczewska
- Polgenix, Inc., 11000 Cedar Avenue, Suite 260, Cleveland, Ohio 44106, USA
| | - Krzysztof Palczewski
- Department of Pharmacology, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, Ohio 44106, USA
| | - David R. Williams
- Center for Visual Science, University of Rochester, Rochester, New York 14627, USA
- The Institute of Optics, University of Rochester, Rochester, New York 14620, USA
- Flaum Eye Institute, University of Rochester, Rochester, New York 14642, USA
| | - Jennifer J. Hunter
- Center for Visual Science, University of Rochester, Rochester, New York 14627, USA
- Flaum Eye Institute, University of Rochester, Rochester, New York 14642, USA
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Gualda EJ, Vázquez de Aldana JR, Martínez-García MC, Moreno P, Hernández-Toro J, Roso L, Artal P, Bueno JM. Femtosecond infrared intrastromal ablation and backscattering-mode adaptive-optics multiphoton microscopy in chicken corneas. BIOMEDICAL OPTICS EXPRESS 2011; 2:2950-60. [PMID: 22076258 PMCID: PMC3207366 DOI: 10.1364/boe.2.002950] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2011] [Revised: 09/27/2011] [Accepted: 09/27/2011] [Indexed: 05/07/2023]
Abstract
The performance of femtosecond (fs) laser intrastromal ablation was evaluated with backscattering-mode adaptive-optics multiphoton microscopy in ex vivo chicken corneas. The pulse energy of the fs source used for ablation was set to generate two different ablation patterns within the corneal stroma at a certain depth. Intrastromal patterns were imaged with a custom adaptive-optics multiphoton microscope to determine the accuracy of the procedure and verify the outcomes. This study demonstrates the potential of using fs pulses as surgical and monitoring techniques to systematically investigate intratissue ablation. Further refinement of the experimental system by combining both functions into a single fs laser system would be the basis to establish new techniques capable of monitoring corneal surgery without labeling in real-time. Since the backscattering configuration has also been optimized, future in vivo implementations would also be of interest in clinical environments involving corneal ablation procedures.
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Affiliation(s)
- Emilio J. Gualda
- Laboratorio de Óptica, Centro de Investigación en Óptica y Nanofísica, Universidad de Murcia, Campus de Espinardo (Edificio 34), 30100 Murcia, Spain
| | - Javier R. Vázquez de Aldana
- Grupo de Investigación en Microprocesado de Materiales con Láser,Plaza de la Merced s/n, 37008 Salamanca, Spain
| | - M. Carmen Martínez-García
- Departamento Biología Celular, Histología y Farmacología,Facultad de Medicina, Universidad de Valladolid, Valladolid, Spain
| | - Pablo Moreno
- Grupo de Investigación en Microprocesado de Materiales con Láser,Plaza de la Merced s/n, 37008 Salamanca, Spain
| | - Juan Hernández-Toro
- Grupo de Investigación en Microprocesado de Materiales con Láser,Plaza de la Merced s/n, 37008 Salamanca, Spain
| | - Luis Roso
- Centro de Láseres Pulsados Ultracortos y Ultraintensos (CLPU), Plaza de la Merced s/n, 37008 Salamanca, Spain
| | - Pablo Artal
- Laboratorio de Óptica, Centro de Investigación en Óptica y Nanofísica, Universidad de Murcia, Campus de Espinardo (Edificio 34), 30100 Murcia, Spain
| | - Juan M. Bueno
- Laboratorio de Óptica, Centro de Investigación en Óptica y Nanofísica, Universidad de Murcia, Campus de Espinardo (Edificio 34), 30100 Murcia, Spain
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Abstract
PURPOSE To investigate the organization of stromal collagen in healthy ex vivo corneas of different species from second harmonic generation (SHG) microscopy images. METHODS A custom backscattered nonlinear microscope has been used to study the corneal structure of different species: porcine, bovine, rabbit, rat, chicken, and humans. The instrument uses a femtosecond laser for illumination, a scanning unit, and a photon-counting detection device. It also includes a wavefront aberration control module. SHG signals produced by collagen within the cornea were acquired. A motorized stage allowed optical sectioning across the entire corneal thickness. Samples were neither fixed nor stained, and they were fully scanned. RESULTS SHG images revealed the microscopic organization of the lamellae of collagen fibers. Despite absorption, for all corneal depths, images could be analyzed. The anterior stroma was similar in all samples, showing interwoven short bands of collagen randomly distributed. The lamellae at the central and posterior stroma were densely packed and often presented longer bundles lying predominantly parallel to the corneal surface with characteristic spatial distributions for each species. In particular, collagen bundles in bovine and porcine corneas were interweaved. In the chick cornea, the stromal arrangement had an orientation changing regularly with depth. In human corneas, lamellae were longer and had similar orientation than their neighbors. CONCLUSIONS Using a unique wavefront aberration-controlled backscattered nonlinear microscope, changes in corneal morphology as a function of depth were characterized for different species (including humans). This allowed a direct comparison among species, which might help to establish the basis of collagen distribution in animal models or to understand diseased corneas.
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Bueno JM, Giakoumaki A, Gualda EJ, Schaeffel F, Artal P. Analysis of the chicken retina with an adaptive optics multiphoton microscope. BIOMEDICAL OPTICS EXPRESS 2011; 2:1637-48. [PMID: 21698025 PMCID: PMC3114230 DOI: 10.1364/boe.2.001637] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/07/2011] [Revised: 05/13/2011] [Accepted: 05/13/2011] [Indexed: 05/23/2023]
Abstract
The structure and organization of the chicken retina has been investigated with an adaptive optics multiphoton imaging microscope in a backward configuration. Non-stained flat-mounted retinal tissues were imaged at different depths, from the retinal nerve fiber layer to the outer segment, by detecting the intrinsic nonlinear fluorescent signal. From the stacks of images corresponding to the different retinal layers, volume renderings of the entire retina were reconstructed. The density of photoreceptors and ganglion cells layer were directly estimated from the images as a function of the retinal eccentricity. The maximum anatomical resolving power at different retinal eccentricities was also calculated. This technique could be used for a better characterization of retinal alterations during myopia development, and may be useful for visualization of retinal pathologies and intoxication during pharmacological studies.
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Affiliation(s)
- Juan M. Bueno
- Laboratorio de Óptica, Centro de Investigación en Óptica y Nanofísica, Universidad de Murcia, Campus de Espinardo (Edificio 34), 30100 Murcia, Spain
| | - Anastasia Giakoumaki
- Laboratorio de Óptica, Centro de Investigación en Óptica y Nanofísica, Universidad de Murcia, Campus de Espinardo (Edificio 34), 30100 Murcia, Spain
| | - Emilio J. Gualda
- Laboratorio de Óptica, Centro de Investigación en Óptica y Nanofísica, Universidad de Murcia, Campus de Espinardo (Edificio 34), 30100 Murcia, Spain
| | - Frank Schaeffel
- Section of Neurobiology of the Eye, Ophthalmic Research Institute, Calwerstrasse 7/1, 72076 Tuebingen, Germany
| | - Pablo Artal
- Laboratorio de Óptica, Centro de Investigación en Óptica y Nanofísica, Universidad de Murcia, Campus de Espinardo (Edificio 34), 30100 Murcia, Spain
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Lu RW, Li YC, Ye T, Strang C, Keyser K, Curcio CA, Yao XC. Two-photon excited autofluorescence imaging of freshly isolated frog retinas. BIOMEDICAL OPTICS EXPRESS 2011; 2:1494-503. [PMID: 21698013 PMCID: PMC3114218 DOI: 10.1364/boe.2.001494] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/03/2011] [Revised: 05/07/2011] [Accepted: 05/07/2011] [Indexed: 05/07/2023]
Abstract
The purpose of this study was to investigate cellular sources of autofluorescence signals in freshly isolated frog (Rana pipiens) retinas. Equipped with an ultrafast laser, a laser scanning two-photon excitation fluorescence microscope was employed for sub-cellular resolution examination of both sliced and flat-mounted retinas. Two-photon imaging of retinal slices revealed autofluorescence signals over multiple functional layers, including the photoreceptor layer (PRL), outer nuclear layer (ONL), outer plexiform layer (OPL), inner nuclear layer (INL), inner plexiform layer (IPL), and ganglion cell layer (GCL). Using flat-mounted retinas, depth-resolved imaging of individual retinal layers further confirmed multiple sources of autofluorescence signals. Cellular structures were clearly observed at the PRL, ONL, INL, and GCL. At the PRL, the autofluorescence was dominantly recorded from the intracellular compartment of the photoreceptors; while mixed intracellular and extracellular autofluorescence signals were observed at the ONL, INL, and GCL. High resolution autofluorescence imaging clearly revealed mosaic organization of rod and cone photoreceptors; and sub-cellular bright autofluorescence spots, which might relate to connecting cilium, was observed in the cone photoreceptors only. Moreover, single-cone and double-cone outer segments could be directly differentiated.
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Affiliation(s)
- Rong-Wen Lu
- Department of Biomedical Engineering, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Yi-Chao Li
- Department of Biomedical Engineering, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Tong Ye
- Department of Neurobiology, University of Alabama at Birmingham, Birmingham, AL 35294
| | - Christianne Strang
- Department of Vision Sciences, University of Alabama at Birmingham, Birmingham, AL 35294
| | - Kent Keyser
- Department of Vision Sciences, University of Alabama at Birmingham, Birmingham, AL 35294
| | - Christine A. Curcio
- Department of Ophthalmology, University of Alabama at Birmingham, Birmingham, AL 35294
| | - Xin-Cheng Yao
- Department of Biomedical Engineering, University of Alabama at Birmingham, Birmingham, AL 35294, USA
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Multiphoton microscopy for ophthalmic imaging. J Ophthalmol 2011; 2011:870879. [PMID: 21274261 PMCID: PMC3022205 DOI: 10.1155/2011/870879] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2010] [Revised: 09/06/2010] [Accepted: 10/26/2010] [Indexed: 12/02/2022] Open
Abstract
We review multiphoton microscopy (MPM) including two-photon autofluorescence (2PAF), second harmonic generation (SHG), third harmonic generation (THG), fluorescence lifetime (FLIM), and coherent anti-Stokes Raman Scattering (CARS) with relevance to clinical applications in ophthalmology. The different imaging modalities are discussed highlighting the particular strength that each has for functional tissue imaging. MPM is compared with current clinical ophthalmological imaging techniques such as reflectance confocal microscopy, optical coherence tomography, and fluorescence imaging. In addition, we discuss the future prospects for MPM in disease detection and clinical monitoring of disease progression, understanding fundamental disease mechanisms, and real-time monitoring of drug delivery.
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Hunter JJ, Masella B, Dubra A, Sharma R, Yin L, Merigan WH, Palczewska G, Palczewski K, Williams DR. Images of photoreceptors in living primate eyes using adaptive optics two-photon ophthalmoscopy. BIOMEDICAL OPTICS EXPRESS 2010; 2:139-48. [PMID: 21326644 PMCID: PMC3028489 DOI: 10.1364/boe.2.000139] [Citation(s) in RCA: 74] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/08/2010] [Revised: 12/14/2010] [Accepted: 12/14/2010] [Indexed: 05/18/2023]
Abstract
In vivo two-photon imaging through the pupil of the primate eye has the potential to become a useful tool for functional imaging of the retina. Two-photon excited fluorescence images of the macaque cone mosaic were obtained using a fluorescence adaptive optics scanning laser ophthalmoscope, overcoming the challenges of a low numerical aperture, imperfect optics of the eye, high required light levels, and eye motion. Although the specific fluorophores are as yet unknown, strong in vivo intrinsic fluorescence allowed images of the cone mosaic. Imaging intact ex vivo retina revealed that the strongest two-photon excited fluorescence signal comes from the cone inner segments. The fluorescence response increased following light stimulation, which could provide a functional measure of the effects of light on photoreceptors.
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Affiliation(s)
- Jennifer J. Hunter
- Flaum Eye Institute, University of Rochester, 601 Elmwood Avenue, Rochester, NY, 14642, USA
- Center for Visual Science, University of Rochester, 601 Elmwood Avenue, Rochester, NY, 14642, USA
| | - Benjamin Masella
- Institute of Optics, University of Rochester, 601 Elmwood Avenue, Rochester, NY, 14642, USA
- Center for Visual Science, University of Rochester, 601 Elmwood Avenue, Rochester, NY, 14642, USA
| | - Alfredo Dubra
- Flaum Eye Institute, University of Rochester, 601 Elmwood Avenue, Rochester, NY, 14642, USA
- Center for Visual Science, University of Rochester, 601 Elmwood Avenue, Rochester, NY, 14642, USA
| | - Robin Sharma
- Institute of Optics, University of Rochester, 601 Elmwood Avenue, Rochester, NY, 14642, USA
- Center for Visual Science, University of Rochester, 601 Elmwood Avenue, Rochester, NY, 14642, USA
| | - Lu Yin
- Center for Visual Science, University of Rochester, 601 Elmwood Avenue, Rochester, NY, 14642, USA
| | - William H. Merigan
- Flaum Eye Institute, University of Rochester, 601 Elmwood Avenue, Rochester, NY, 14642, USA
- Center for Visual Science, University of Rochester, 601 Elmwood Avenue, Rochester, NY, 14642, USA
| | - Grazyna Palczewska
- Polgenix, Inc., 11000 Cedar Avenue, Suite 260, Cleveland, OH, 44106, USA
| | - Krzysztof Palczewski
- Polgenix, Inc., 11000 Cedar Avenue, Suite 260, Cleveland, OH, 44106, USA
- Department of Pharmacology, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH, 44106, USA
| | - David R. Williams
- Flaum Eye Institute, University of Rochester, 601 Elmwood Avenue, Rochester, NY, 14642, USA
- Institute of Optics, University of Rochester, 601 Elmwood Avenue, Rochester, NY, 14642, USA
- Center for Visual Science, University of Rochester, 601 Elmwood Avenue, Rochester, NY, 14642, USA
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Bueno JM, Gualda EJ, Artal P. Adaptive optics multiphoton microscopy to study ex vivo ocular tissues. JOURNAL OF BIOMEDICAL OPTICS 2010; 15:066004. [PMID: 21198178 DOI: 10.1117/1.3505018] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
We develop an adaptive optics (AO) multiphoton microscope by incorporating a deformable mirror and a Hartmann-Shack wavefront sensor. The AO module operating in closed-loop is used to correct for the aberrations of the illumination laser beam. This increases the efficiency of the nonlinear processes in reducing tissue photodamage, improves contrast, and enhances lateral resolution in images of nonstained ocular tissues. In particular, the use of AO in the multiphoton microscope provides a better visualization of ocular structures, which are relevant in ophthalmology. This instrument might be useful to explore the possible connections between changes in ocular structures and the associated pathologies.
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Affiliation(s)
- Juan M Bueno
- Universidad de Murcia, Laboratorio de Óptica, Campus de Espinardo, Murcia, 30100 Spain.
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