1. Articles from Florian Beer

    1-5 of 5
    1. Investigating spontaneous retinal venous pulsation using Doppler optical coherence tomography

      Investigating spontaneous retinal venous pulsation using Doppler optical coherence tomography

      We demonstrate the advantages of optical coherence tomography (OCT) imaging for investigation of spontaneous retinal venous pulsation (SRVP). The pulsatile changes in venous vessel caliber are analyzed qualitatively and quantitatively using conventional intensity-based OCT as well as the functional extension Doppler OCT (DOCT). Single-channel and double-channel line scanning protocols of our multi-channel OCT prototype are employed to investigate venous pulsatile caliber oscillations as well as venous flow pulsatility in the eyes of healthy volunteers. A comparison to recordings of scanning laser ophthalmoscopy (SLO) – a standard en-face imaging modality for evaluation of SRVP – is provided, emphasizing the advantages of tomographic image ...

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    2. Mapping of Corneal Layer Thicknesses With Polarization-Sensitive Optical Coherence Tomography Using a Conical Scan Pattern

      Mapping of Corneal Layer Thicknesses With Polarization-Sensitive Optical Coherence Tomography Using a Conical Scan Pattern

      Purpose : We demonstrate segmentation and mapping of corneal layers (epithelium, Bowman's layer, and stroma) across the entire cornea (limbus to limbus), using additional contrast provided by polarization-sensitive optical coherence tomography (PS-OCT) and analyze the reproducibility of the procedure. Methods : A custom built PS-OCT system operating at 1045 nm central wavelength with conical scanning was used for image acquisition. Conical scanning allows for almost perpendicular beam incidence on the corneal surface and provides good signal quality over the entire field of view. Epithelium, Bowman's layer, and stroma were segmented using the additional contrast provided by PS-OCT. Thickness maps were ...

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    3. Adaptable switching schemes for time-encoded multichannel optical coherence tomography

      Adaptable switching schemes for time-encoded multichannel optical coherence tomography

      We introduce the approach of variable time encoding for multichannel optical coherence tomography (OCT). High-speed fiber optical switches are applied for sequential sample arm switching to enable quasisimultaneous image acquisition from three different orientation angles. In comparison with previous multichannel OCT (using simultaneous sample illumination), time-encoded multichannel OCT has no need for division of illumination power among the respective channels to satisfy laser safety requirements. Especially for ophthalmic applications—in particular retinal imaging, which the presented prototype was developed for—this advantage strongly influences image quality through an enhanced sensitivity. Nevertheless, time encoding comes at the cost of a decrease ...

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    4. Multi-directional optical coherence tomography for retinal imaging

      Multi-directional optical coherence tomography for retinal imaging

      We introduce multi-directional optical coherence tomography (OCT), a technique for investigation of the scattering properties of directionally reflective tissue samples. By combining the concepts of multi-channel and directional OCT, this approach enables simultaneous acquisition of multiple reflectivity depth-scans probing a mutual sample location from differing angular orientations. The application of multi-directional OCT in retinal imaging allows for in-depth investigations on the directional reflectivity of the retinal nerve fiber layer, Henle’s fiber layer and the photoreceptor layer. Major ophthalmic diseases (such as glaucoma or age-related macular degeneration) have been reported to alter the directional reflectivity properties of these retinal layers ...

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    5. Conical scan pattern for enhanced visualization of the human cornea using polarization-sensitive OCT

      Conical scan pattern for enhanced visualization of the human cornea using polarization-sensitive OCT

      Conventional imaging of the human cornea with optical coherence tomography (OCT) relies on telecentric scanning optics with sampling beams that are parallel to the optical axis of the eye. Because of the shape of the cornea, the beams have in some areas considerable inclination to the corneal surface which is accompanied by low signal intensities in these areas and thus an inhomogeneous appearance of corneal structures. In addition, alterations in the polarization state of the probing light depend on the angle between the imaging beam and the birefringent axis of the sample. Therefore, changes in the polarization state observed with ...

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    1-5 of 5
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  2. Topics in the News

    1. (5 articles) Medical University of Vienna
    2. (5 articles) Bernhard Baumann
    3. (5 articles) Christoph K. Hitzenberger
    4. (5 articles) Michael Pircher
    5. (1 articles) Stanford University
    6. (1 articles) University of Lübeck
    7. (1 articles) Peking University
    8. (1 articles) Devers Eye Institute
    9. (1 articles) Chinese Academy of Sciences
    10. (1 articles) UC Riverside
    11. (1 articles) University of Heidelberg
    12. (1 articles) Yalin Zheng
    13. (1 articles) Jeffrey M. Liebmann
    14. (1 articles) Yi Wang
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    Conical scan pattern for enhanced visualization of the human cornea using polarization-sensitive OCT Multi-directional optical coherence tomography for retinal imaging Adaptable switching schemes for time-encoded multichannel optical coherence tomography Mapping of Corneal Layer Thicknesses With Polarization-Sensitive Optical Coherence Tomography Using a Conical Scan Pattern Investigating spontaneous retinal venous pulsation using Doppler optical coherence tomography Chalcogenide-glass polarization-maintaining photonic crystal fiber for mid-infrared supercontinuum generation Supervised machine learning based multi-task artificial intelligence classification of retinopathies OCT-Detected Optic Nerve Head Neural Canal Direction, Obliqueness and Minimum Cross-Sectional Area in Healthy Eyes Combined intracoronary assessment and treatment of a patient with coronary plaque rapid progression prior to acute myocardial infarction A case report Quantifying microstructural changes in retinitis pigmentosa using spectral domain – optical coherence tomography Photothermal Optical Coherence Tomography of Anti-Angiogenic Treatment in the Mouse Retina Using Gold Nanorods as Contrast Agents Simple and robust calibration procedure for k-linearization and dispersion compensation in optical coherence tomography