1. Articles from Martin Glösmann

    1-10 of 10
    1. Three-dimensional visualization of opacifications in the murine crystalline lens by in vivo optical coherence tomography

      Three-dimensional visualization of opacifications in the murine crystalline lens by in vivo optical coherence tomography

      Diagnostic classification techniques used to diagnose cataracts, the world’s leading cause of blindness, are currently based on subjective methods. Here, we present optical coherence tomography as a noninvasive tool for volumetric visualization of lesions formed in the crystalline lens. A custom-made swept-source optical coherence tomography (SS-OCT) system was utilized to investigate the murine crystalline lens. In addition to imaging cataractous lesions in aged wildtype mice, we studied the structure and shape of cataracts in a mouse model of Alzheimer’s disease. Hyperscattering opacifications in the crystalline lens were observed in both groups. Post mortem histological analysis were performed to ...

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    2. Optical Coherence Tomography Findings in the Retinas of SOD1 Knockout Mice

      Optical Coherence Tomography Findings in the Retinas of SOD1 Knockout Mice

      Purpose : The retinal phenotype of popular mouse models mimicking ophthalmic diseases, such as the superoxide dismutase 1 (SOD1) knockout (KO) mouse model, has mainly been assessed by ex vivo histology and in vivo fundus photography. We used multifunctional optical coherence tomography (OCT) to characterize the retinas of SOD1 KO mice in vivo. Methods : The custom-made ophthalmoscope featured a combination of conventional OCT, polarization-sensitive OCT, and OCT angiography. Seven SOD1 KO mice and nine age-matched controls were imaged between 6 and 17 months of age. A postprocessing framework was used to analyze total and outer retinal thickness changes. Drusenlike lesions were ...

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    3. In Vivo Characterization of Spontaneous Retinal Neovascularization in the Mouse Eye by Multifunctional Optical Coherence Tomography

      In Vivo Characterization of Spontaneous Retinal Neovascularization in the Mouse Eye by Multifunctional Optical Coherence Tomography

      Purpose : To investigate the early development of spontaneous retinal neovascularization in the murine retina by a multifunctional optical coherence tomography approach. To characterize involved tissue changes in vivo and describe structural and functional changes over time. Methods : A multifunctional optical coherence tomography (OCT) system providing 3-fold contrast comprising reflectivity, polarization sensitivity, and OCT angiography (OCTA) was utilized to image very-low-density lipoprotein receptor (VLDLR) knockout mice. Baseline measurements were acquired as early as postnatal day 14 and a follow-up of neovascularization development was performed until the age of 3 months. Control mice were imaged accordingly and a multiparametric image analysis was ...

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    4. White light polarization sensitive optical coherence tomography for sub-micron axial resolution and spectroscopic contrast in the murine retina

      White light polarization sensitive optical coherence tomography for sub-micron axial resolution and spectroscopic contrast in the murine retina

      A white light polarization sensitive optical coherence tomography system has been developed, using a supercontinuum laser as the light source. By detecting backscattered light from 400–700 nm, an axial resolution of 1.0 µm in air was achieved. The system consists of a free-space interferometer and two homemade spectrometers that detect orthogonal polarization states. Following system specifications, images of a healthy murine retina as acquired by this non-contact system are presented, showing high resolution reflectivity images as well as spectroscopic and polarization sensitive contrast. Additional images of the very-low-density-lipoprotein-receptor (VLDLR) knockout mouse model were acquired. The high resolution allows ...

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    5. Posterior rat eye during acute intraocular pressure elevation studied using polarization sensitive optical coherence tomography

      Posterior rat eye during acute intraocular pressure elevation studied using polarization sensitive optical coherence tomography

      Polarization sensitive optical coherence tomography (PS-OCT) operating at 840 nm with axial resolution of 3.8 µm in tissue was used for investigating the posterior rat eye during an acute intraocular pressure (IOP) increase experiment. IOP was elevated in the eyes of anesthetized Sprague Dawley rats by cannulation of the anterior chamber. Three dimensional PS-OCT data sets were acquired at IOP levels between 14 mmHg and 105 mmHg. Maps of scleral birefringence, retinal nerve fiber layer (RNFL) retardation and relative RNFL/retina reflectivity were generated in the peripapillary area and quantitatively analyzed. All investigated parameters showed a substantial correlation with ...

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    6. Multi-Functional OCT Enables Longitudinal Study of Retinal Changes in a VLDLR Knockout Mouse Model

      Multi-Functional OCT Enables Longitudinal Study of Retinal Changes in a VLDLR Knockout Mouse Model

      We present a multi-functional optical coherence tomography (OCT) imaging approach to study retinal changes in the very-low-density-lipoprotein-receptor (VLDLR) knockout mouse model with a threefold contrast. In the retinas of VLDLR knockout mice spontaneous retinal-chorodoidal neovascularizations form, having an appearance similar to choroidal and retinal neovascularizations (CNV and RNV) in neovascular age-related macular degeneration (AMD) or retinal angiomatous proliferation (RAP). For this longitudinal study, the mice were imaged every 4 to 6 weeks starting with an age of 4 weeks and following up to the age of 11 months. Significant retinal changes were identified by the multi-functional imaging approach offering a ...

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    7. Polarization properties of single layers in the posterior eyes of mice and rats investigated using high resolution polarization sensitive optical coherence tomography

      Polarization properties of single layers in the posterior eyes of mice and rats investigated using high resolution polarization sensitive optical coherence tomography

      We present a high resolution polarization sensitive optical coherence tomography (PS-OCT) system for ocular imaging in rodents. The system operates at 840 nm and uses a broadband superluminescent diode providing an axial resolution of 5.1 µm in air. PS-OCT data was acquired at 83 kHz A-scan rate by two identical custom-made spectrometers for orthogonal polarization states. Pigmented (Brown Norway, Long Evans) and non-pigmented (Sprague Dawley) rats as well as pigmented mice (C57BL/6) were imaged. Melanin pigment related depolarization was analyzed in the retinal pigment epithelium (RPE) and choroid of these animals using the degree of polarization uniformity (DOPU ...

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    8. Spectral degree of polarization uniformity for polarization-sensitive OCT

      Spectral degree of polarization uniformity for polarization-sensitive OCT

      Depolarization of light can be measured by polarization-sensitive optical coherence tomography (PS-OCT) and has been used to improve tissue discrimination as well as segmentation of pigmented structures. Most approaches to depolarization assessment for PS-OCT – such as the degree of polarization uniformity (DOPU) – rely on measuring the uniformity of polarization states using spatial evaluation kernels. In this article, we present a different approach which exploits the spectral dimension. We introduce the spectral DOPU for the pixelwise analysis of polarization state variations between sub-bands of the broadband light source spectrum. Alongside a comparison with conventional spatial and temporal DOPU algorithms, we demonstrate ...

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    9. Melanin Pigmentation in Rat Eyes: In Vivo Imaging by Polarization-Sensitive Optical Coherence Tomography and Comparison to Histology

      Melanin Pigmentation in Rat Eyes: In Vivo Imaging by Polarization-Sensitive Optical Coherence Tomography and Comparison to Histology

      Purpose : The purpose of this study was to demonstrate polarization-sensitive optical coherence tomography (PS-OCT) for imaging pigmented structures in the posterior eye segments of albino and pigmented rats and to correlate depolarization contrast of the retinal pigment epithelium (RPE) and choroid in in vivo PS-OCT to melanin pigmentation detected in postmortem histologic serial sections. Methods : In vivo three-dimensional PS-OCT imaging was performed in adult albino and pigmented rat eyes at 70-kHz A-line rate. Degree of polarization uniformity (DOPU) fundus maps and radial DOPU profiles were generated. Postmortem histomorphologic analysis was performed in order to investigate melanin pigmentation of the RPE ...

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    10. Peripapillary rat sclera investigated in vivo with polarization sensitive optical coherence tomography

      Peripapillary rat sclera investigated in vivo with polarization sensitive optical coherence tomography

      Purpose: To demonstrate polarization sensitive (PS) optical coherence tomography (OCT) for non-invasive, volumetric, and quantitative imaging of the birefringent properties of the peripapillary rat sclera. To compare the findings in PS-OCT images to state-of-the-art histomorphometric analysis of the same tissues. Methods: A high-speed PS-OCT prototype operating at 840 nm was modified for imaging the rat eye. Densely sampled PS-OCT raster scans covering an area of ~1.5 mm × 1.5 mm centered at the papilla were acquired in the eyes of anesthetized, male Sprague Dawley rats. Cross-sectional PS-OCT images were computed and fundus maps displaying the birefringent properties of the ...

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    1-10 of 10
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    1. (10 articles) Medical University of Vienna
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    Peripapillary rat sclera investigated in vivo with polarization sensitive optical coherence tomography Melanin Pigmentation in Rat Eyes: In Vivo Imaging by Polarization-Sensitive Optical Coherence Tomography and Comparison to Histology Spectral degree of polarization uniformity for polarization-sensitive OCT Polarization properties of single layers in the posterior eyes of mice and rats investigated using high resolution polarization sensitive optical coherence tomography Multi-Functional OCT Enables Longitudinal Study of Retinal Changes in a VLDLR Knockout Mouse Model Posterior rat eye during acute intraocular pressure elevation studied using polarization sensitive optical coherence tomography White light polarization sensitive optical coherence tomography for sub-micron axial resolution and spectroscopic contrast in the murine retina In Vivo Characterization of Spontaneous Retinal Neovascularization in the Mouse Eye by Multifunctional Optical Coherence Tomography Optical Coherence Tomography Findings in the Retinas of SOD1 Knockout Mice Three-dimensional visualization of opacifications in the murine crystalline lens by in vivo optical coherence tomography Optical coherence tomography features of neovascularization in proliferative diabetic retinopathy: a systematic review Retinal microvascular metrics in untreated essential hypertensives using optical coherence tomography angiography