1. Articles from Ireneusz Grulkowski

    1-24 of 43 1 2 »
    1. Air-Puff-Induced Dynamics of Ocular Components Measured with Optical Biometry

      Air-Puff-Induced Dynamics of Ocular Components Measured with Optical Biometry

      Purpose : To analyze the dynamics of all optical components of the eye and the behavior of the eyeball under air-puff conditions in vivo. To determine the impact of the intraocular pressure (IOP) on the air-puff-induced deformation of the eye. Methods : Twenty eyes of 20 healthy subjects were included in this study. The dynamics of the ocular components, such as the cornea, the crystalline lens, and the retina, was measured by a prototype swept source optical coherence tomography biometer integrated with the air-puff system. The system allows to acquire a series of axial scans at the same location as a function ...

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    2. Assessment of the influence of viscoelasticity of cornea in animal ex vivo model using air‐puff optical coherence tomography and corneal hysteresis

      Assessment of the influence of viscoelasticity of cornea in animal ex vivo model using air‐puff optical coherence tomography and corneal hysteresis

      Application of the air‐puff swept source OCT (SS‐OCT) instrument to determine the influence of viscoelasticity on the relation between overall the air‐puff force and corneal apex displacement of porcine corneas ex vivo is demonstrated. Simultaneous recording of time‐evolution of the tissue displacement and air pulse stimulus allows obtaining valuable information related in part to the mechanical properties of the cornea. A novel approach based on quantitative analysis of the corneal hysteresis of OCT data is presented. The corneal response to the air pulse is assessed for different well‐controlled IOP levels and for the progression of ...

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    3. Post-doctoral Research Fellow Position and 2 PhD Studentships in Ophthalmic Imaging at the Nicolaus Copernicus University, Torun, Poland

      Post-doctoral Research Fellow Position and 2 PhD Studentships in Ophthalmic Imaging at the Nicolaus Copernicus University, Torun, Poland

      The Bio-Optics & Optical Engineering Lab at the Nicolaus Copernicus University invites applications for the positions in a project entitled Lenticular and vitreal light scattering and refraction for tomorrow's eye diagnostics financed by the Foundation for Polish Science (Programme TEAM) from the Smart Growth Operational Programme funds (PO IR) in 2014-2020. We are seeking young researchers for the following positions: Post-doctoral Research Fellow, and PhD students (2x). The project aims at the development and clinical validation of novel imaging-based tools to extract spatially resolved information on the light scattering and refraction in the ocular structures and media. The project addresses ...

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    4. Volumetric macro- and micro-scale assessment of crystalline lens opacities in cataract patients using long-depth-range swept source optical coherence tomography

      Volumetric macro- and micro-scale assessment of crystalline lens opacities in cataract patients using long-depth-range swept source optical coherence tomography

      We demonstrate an optimized optical platform for the three-dimensional (3-D) visualization of crystalline lens opacities in vivo in the eyes of patients with different types and grades of cataracts. We developed a prototype long-depth-range swept source optical coherence tomography (SS-OCT) instrument operating at the speed of 50 kA-scans/second and at the central wavelength of 1 μm to perform high-resolution imaging of the whole anterior segment of the eye. Volumetric data sets of cataractous eyes were acquired and processed to obtain contrast-enhanced high-resolution images of lenticular structures and opacifications. The results showed lens micro- and macro-scale features related to possible ...

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    5. Three-Dimensional Cataract Crystalline Lens Imaging With Swept-Source Optical Coherence Tomography | IOVS

      Three-Dimensional Cataract Crystalline Lens Imaging With Swept-Source Optical Coherence Tomography | IOVS

      Purpose : To image, describe, and characterize different features visible in the crystalline lens of older adults with and without cataract when imaged three-dimensionally with a swept-source optical coherence tomography (SS-OCT) system. Methods : We used a new SS-OCT laboratory prototype designed to enhance the visualization of the crystalline lens and imaged the entire anterior segment of both eyes in two groups of participants: patients scheduled to undergo cataract surgery, n = 17, age range 36 to 91 years old, and volunteers without visual complains, n = 14, age range 20 to 81 years old. Pre–cataract surgery patients were also clinically graded according ...

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    6. Swept source optical coherence tomography and tunable lens technology for comprehensive imaging and biometry of the whole eye

      Swept source optical coherence tomography and tunable lens technology for comprehensive imaging and biometry of the whole eye

      Standard optical systems in ophthalmology are strictly dedicated either to retinal or to anterior segment imaging due to the refractive properties of the eye. We demonstrate a swept source optical coherence tomography platform with an electrically tunable lens (ETL) for versatile 3D in vivo imaging of both the eye’s anterior segment and the retina. The optimized optical setup with adaptive operational states of the ETL permits focusing on the retina and on the anterior segment. Dynamic control of the optical beam focus allows for OCT image enhancement, leading to the visualization of the vitreous details at both the vitreo-lenticular ...

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    7. Non-contact investigation of the corneal biomechanics with air-puff swept source optical coherence tomography

      Non-contact investigation of the corneal biomechanics with air-puff swept source optical coherence tomography

      In this paper, we use swept source optical coherence tomography combined with air-puff module (air-puff SS-OCT) to investigate the properties of the cornea. During OCT measurement the cornea was stimulated by short, air pulse, and corneal response was recorded. In this preliminary study, the air-puff SS-OCT instrument was applied to measure behavior of the porcine corneas under varied, well-controlled intraocular pressure conditions. Additionally, the biomechanical response of the corneal tissue before, during and after crosslinking procedure (CXL) was assessed. Air-puff swept source OCT is a promising tool to extract information about corneal behavior as well as to monitor and assess ...

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    8. Optical Coherence Tomography of the Labial Salivary Glands Reveals Age-Related Differences in Women

      Optical Coherence Tomography of the Labial Salivary Glands Reveals Age-Related Differences in Women

      The labial minor salivary glands (LSGs) play a role in medical research and practice due to their superficial location and involvement in both systemic and localized diseases. Swept-source optical coherence tomography (OCT) is a noninvasive modality that enables in vivo , micrometer resolution, wide-field three-dimensional imaging in seconds. A purpose-built swept-source OCT instrument was employed to acquire three-dimensional datasets covering the area of 2.43 cm 2 of the mucosa of the lower lip to the depth of 3.4 mm in young ( n = 14; mean age ± SD: 27 ± 3 years; body mass index [BMI] 20.4 ± 2.3 kg/m ...

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    9. Optical Coherence Tomography Identifies Lower Labial Salivary Gland Surface Density in Cystic Fibrosis

      Optical Coherence Tomography Identifies Lower Labial Salivary Gland Surface Density in Cystic Fibrosis

      The labial minor salivary glands (LSGs) are easily accessible mucus-secreting structures of the alimentary tract that may provide new information on the basis of gastrointestinal complications of cystic fibrosis (CF). It was shown that they are destructed in the course of cystic fibrosis. We employed wide-field, micrometer resolution in vivo optical coherence tomography to assess the surface density of LSGs in 18 patients with CF and 18 healthy subjects. The median LSGs’ surface densities in CF patients, and in the control group were 4.32 glands/cm2 and 6.58 glands/cm2, respectively (p = 0.006; Mann-Whitney U test). A ...

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    10. Optical Coherence Tomography Identifies Lower Labial Salivary Gland Surface Density in Cystic Fibrosis

      Optical Coherence Tomography Identifies Lower Labial Salivary Gland Surface Density in Cystic Fibrosis

      The labial minor salivary glands (LSGs) are easily accessible mucus-secreting structures of the alimentary tract that may provide new information on the basis of gastrointestinal complications of cystic fibrosis (CF). It was shown that they are destructed in the course of cystic fibrosis. We employed wide-field, micrometer resolution in vivo optical coherence tomography to assess the surface density of LSGs in 18 patients with CF and 18 healthy subjects. The median LSGs’ surface densities in CF patients, and in the control group were 4.32 glands/cm 2 and 6.58 glands/cm 2 , respectively (p = 0.006; Mann-Whitney U ...

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    11. Microscopic OCT imaging with focus extension by ultrahigh-speed acousto-optic tunable lens and stroboscopic illumination

      Microscopic OCT imaging with focus extension by ultrahigh-speed acousto-optic tunable lens and stroboscopic illumination

      We develop high-resolution optical coherence tomography (OCT) system with high-speed acousto-optic tunable lens. Stroboscopic pulsed illumination is used for the first time to perform time-resolved OCT imaging with acousto-optic tunable focusing. The operation of ultrahigh-speed tunable acousto-optic lens is demonstrated theoretically and experimentally. Focal position tuning at MHz frequency range is experimentally shown in the imaging system leading to OCT images with extended depth of focus. Imaging with active optical elements is helpful for improvement of photon collection efficiency, depth of focus and enhancement of the image quality.

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    12. Quantitative optical inspection of contact lenses immersed in wet cell using swept source OCT

      Quantitative optical inspection of contact lenses immersed in wet cell using swept source OCT

      We demonstrate swept source optical coherence tomography (OCT) imaging of contact lenses (CLs) in a wet cell and comprehensive quantitative characterization of CLs from volumetric OCT datasets. The approach is based on a technique developed for lens autopositioning and autoleveling enabled by lateral capillary interactions between the wet cell wall and the lens floating on the liquid surface. The demonstrated OCT imaging has enhanced contrast due to the application of a scattering medium and it improves visualization of both CL interfaces and edges. We also present precise and accurate three-dimensional metrology of soft and rigid CLs based on the OCT ...

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    13. Enhanced Vitreous Imaging in Healthy Eyes Using Swept Source Optical Coherence Tomography

      Enhanced Vitreous Imaging in Healthy Eyes Using Swept Source Optical Coherence Tomography

      Purpose To describe enhanced vitreous imaging for visualization of anatomic features and microstructures within the posterior vitreous and vitreoretinal interface in healthy eyes using swept-source optical coherence tomography (SS-OCT). The study hypothesis was that long-wavelength, high-speed, volumetric SS-OCT with software registration motion correction and vitreous window display or high-dynamic-range (HDR) display improves detection sensitivity of posterior vitreous and vitreoretinal features compared to standard OCT logarithmic scale display. Design Observational prospective cross-sectional study. Methods Multiple wide-field three-dimensional SS-OCT scans (500×500A-scans over 12×12 mm 2 ) were obtained using a prototype instrument in 22 eyes of 22 healthy volunteers. A registration ...

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    14. Reproducibility of In-Vivo OCT Measured Three-Dimensional Human Lamina Cribrosa Microarchitecture

      Reproducibility of In-Vivo OCT Measured Three-Dimensional Human Lamina Cribrosa Microarchitecture

      Purpose To determine the reproducibility of automated segmentation of the three-dimensional (3D) lamina cribrosa (LC) microarchitecture scanned in-vivo using optical coherence tomography (OCT). Methods Thirty-nine eyes (8 healthy, 19 glaucoma suspects and 12 glaucoma) from 49 subjects were scanned twice using swept-source (SS−) OCT in a 3.5×3.5×3.64 mm (400×400×896 pixels) volume centered on the optic nerve head, with the focus readjusted after each scan. The LC was automatically segmented and analyzed for microarchitectural parameters, including pore diameter, pore diameter standard deviation (SD), pore aspect ratio, pore area, beam thickness, beam thickness SD, and ...

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    15. Feature Of The Week 2/16/14: En Face Enhanced-Depth Swept-Source Optical Coherence Tomography Features of Chronic Central Serous Chorioretinopath

      Feature Of The Week 2/16/14: En Face Enhanced-Depth Swept-Source Optical Coherence Tomography Features of Chronic Central Serous Chorioretinopath

      We characterized en face features of the retinal pigment epithelium (RPE) and choroid in eyes with chronic central serous chorioretinopathy (CSCR) using a high-speed, enhanced tissue penetration, swept-source optical coherence tomography (SS-OCT) prototype. Fifteen eyes of 13 consecutive patients with the clinical diagnosis of CSCR were prospectively examined with SS-OCT. Three-dimensional 6x6mm macular cube raster scans were obtained with SS-OCT operating at 1050nm wavelength and 100,000 A-lines/sec with 6µm axial resolution. Segmentation of the RPE generated a reference surface; en face SS-OCT images of the RPE and choroid were extracted at varying depths every 3.5 µm ...

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    16. Quantitative assessment of oral mucosa and labial minor salivary glands in patients with Sjögren’s syndrome using swept source OCT

      Quantitative assessment of oral mucosa and labial minor salivary glands in patients with Sjögren’s syndrome using swept source OCT

      Three-dimensional imaging of the mucosa of the lower lip and labial minor salivary glands is demonstrated in vivo using swept source optical coherence tomography (OCT) system at 1310 nm with modified interface. Volumetric data sets of the inner surface of the lower lip covering ~230 mm 2 field are obtained from patients with Sjögren’s syndrome and a control group. OCT enables high-resolution visualization of mucosal architecture using cross-sectional images as well as en-face projection images. Comprehensive morphometry of the labial minor salivary glands is performed, and statistical significance is assessed. Statistically significant differences in morphometric parameters are found ...

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    17. In Vivo Lamina Cribrosa Micro-Architecture in Healthy and Glaucomatous Eyes as Assessed by Optical Coherence Tomography

      In Vivo Lamina Cribrosa Micro-Architecture in Healthy and Glaucomatous Eyes as Assessed by Optical Coherence Tomography

      Purpose. The lamina cribrosa (LC) is a prime location of glaucomatous damage. The purpose of this study was to compare LC 3-dimensional micro-architecture between healthy and glaucomatous eyes in vivo by using optical coherence tomography (OCT). Methods. Sixty-eight eyes (19 healthy and 49 glaucomatous) from 47 subjects were scanned in a 3.5 × 3.5 × 3.64-mm volume (400 × 400 × 896 pixels) at the optic nerve head by using swept-source OCT. The LC micro-architecture parameters were measured on the visible LC by an automated segmentation algorithm. The LC parameters were compared to diagnosis and visual field mean deviation (VF MD ...

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    18. In-Vivo Lamina Cribrosa Microarchitecture in Healthy and Glaucomatous Eyes as Assessed by Optical Coherence Tomography

      In-Vivo Lamina Cribrosa Microarchitecture in Healthy and Glaucomatous Eyes as Assessed by Optical Coherence Tomography

      Purpose: Lamina cribrosa (LC) is a leading location of glaucomatous damage. The purpose of this study is to compare LC 3-dimensional microarchitecture between healthy and glaucomatous eyes in-vivo using optical coherence tomography (OCT). Methods: Sixty-eight eyes (19 healthy and 49 glaucomatous) from 47 subjects were scanned in a 3.5x3.5x3.64mm volume (400x400x896 pixels) at the optic nerve head using swept-source OCT. The LC microarchitecture parameters were measured on the visible LC by an automated segmentation algorithm. The LC parameters were compared to diagnosis and visual field mean deviation (MD) using a linear mixed effects model accounting for age ...

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    19. Enhanced Visualization of the Choroido-Scleral Interface Using Swept-Source OCT

      Enhanced Visualization of the Choroido-Scleral Interface Using Swept-Source OCT

      An accurate analysis of the thickness and volume of choroid using optical coherence tomography (OCT) requires precise visualization of the choroido-scleral interface. Results of studies that use spectral-domain OCT (SD-OCT) to look at the percent visualization of the choroido-scleral interface for accurate analysis of choroidal thickness show varying success rates. This study assessed the visualization of choroido-scleral interface in 19 healthy participants (19 eyes) prospectively recruited for consecutive high-definition raster scanning with an SD-OCT system with and without enhanced depth imaging (EDI) and a prototype long-wavelength swept-source OCT (SS-OCT) system. Choroido-scleral interface was visualized in all eyes imaged on SS-OCT ...

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    20. En Face Enhanced-Depth Swept-Source Optical Coherence Tomography Features of Chronic Central Serous Chorioretinopathy

      En Face Enhanced-Depth Swept-Source Optical Coherence Tomography Features of Chronic Central Serous Chorioretinopathy

      Objective To characterize en face features of the retinal pigment epithelium (RPE) and choroid in eyes with chronic central serous chorioretinopathy (CSCR) using a high-speed, enhanced-depth swept-source optical coherence tomography (SS-OCT) prototype. Design Consecutive patients with chronic CSCR were prospectively examined with SS-OCT. Participants Fifteen eyes of 13 patients. Methods Three-dimensional 6×6 mm macular cube raster scans were obtained with SS-OCT operating at 1050 nm wavelength and 100 000 A-lines/sec with 6 μm axial resolution. Segmentation of the RPE generated a reference surface; en face SS-OCT images of the RPE and choroid were extracted at varying depths every ...

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    21. Automated lamina cribrosa microstructural segmentation in optical coherence tomography scans of healthy and glaucomatous eyes

      Automated lamina cribrosa microstructural segmentation in optical coherence tomography scans of healthy and glaucomatous eyes

      We demonstrate an automated segmentation method for in-vivo 3D optical coherence tomography (OCT) imaging of the lamina cribrosa (LC). Manual segmentations of coronal slices of the LC were used as a gold standard in parameter selection and evaluation of the automated technique. The method was validated using two prototype OCT devices; each had a subject cohort including both healthy and glaucomatous eyes. Automated segmentation of in-vivo 3D LC OCT microstructure performed comparably to manual segmentation and is useful for investigative research and in clinical quantification of the LC.

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    22. Swept source optical coherence microscopy using a 1310 nm VCSEL light source

      Swept source optical coherence microscopy using a 1310 nm VCSEL light source

      We demonstrate high speed, swept source optical coherence microscopy (OCM) using a MEMS tunable vertical cavity surface-emitting laser (VCSEL) light source. The light source had a sweep rate of 280 kHz, providing a bidirectional axial scan rate of 560 kHz. The sweep bandwidth was 117 nm centered at 1310 nm, corresponding to an axial resolution of 13.1 µm in air, corresponding to 8.1 µm (9.6 µm spectrally shaped) in tissue. Dispersion mismatch from different objectives was compensated numerically, enabling magnification and field of view to be easily changed. OCM images were acquired with transverse resolutions between 0 ...

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    23. 4D dynamic imaging of the eye using ultrahigh speed SS-OCT

      4D dynamic imaging of the eye using ultrahigh speed SS-OCT

      Recent advances in swept-source / Fourier domain optical coherence tomography (SS-OCT) technology enable in vivo ultrahigh speed imaging, offering a promising technique for four-dimensional (4-D) imaging of the eye. Using an ultrahigh speed tunable vertical cavity surface emitting laser (VCSEL) light source based SS-OCT prototype system, we performed imaging of human eye dynamics in four different imaging modes: 1) Pupillary reaction to light at 200,000 axial scans per second and 9 μm resolution in tissue. 2) Anterior eye focusing dynamics at 100,000 axial scans per second and 9 μm resolution in tissue. 3) Tear film break up at 50 ...

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    1-24 of 43 1 2 »
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    1. (43 articles) Ireneusz Grulkowski
    2. (26 articles) Nicolaus Copernicus University
    3. (22 articles) Maciej Wojtkowski
    4. (17 articles) Massachusetts Institute of Technology
    5. (17 articles) James G. Fujimoto
    6. (15 articles) Jonathan J. Liu
    7. (10 articles) University of Erlangen
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    Anterior segment imaging with Spectral OCT system using a high-speed CMOS camera Four-dimensional visualization with optical coherence tomography Scanning protocols dedicated to smart velocity ranging in Spectral OCT Optical distortion correction in Optical Coherence Tomography for quantitative ocular anterior segment by three-dimensional imaging Real-time bulk motion insensitive flow segmentation algorithm for doppler spectral optical coherence tomography High-speed optical coherence imaging: towards the structure and the physiology of living tissue 1065nm and 1310nm MEMS tunable VCSEL light source technology for OCT imaging Feature Of The Week 2/16/14: En Face Enhanced-Depth Swept-Source Optical Coherence Tomography Features of Chronic Central Serous Chorioretinopath Post-doctoral Research Fellow Position and 2 PhD Studentships in Ophthalmic Imaging at the Nicolaus Copernicus University, Torun, Poland IMAGING TECHNIQUE FROM BECKMAN LAB NAMED TOP 10 MICROSCOPY INNOVATION Optical coherence refraction tomography University of Southern California Receives NIH Grant for Imaging Cerebral and Retinal Microvasculature in Cerebral Small Vessel Disease