1. Articles from Francesco LaRocca

    1-7 of 7
    1. Wide-field retinal optical coherence tomography with wavefront sensorless adaptive optics for enhanced imaging of targeted regions

      Wide-field retinal optical coherence tomography with wavefront sensorless adaptive optics for enhanced imaging of targeted regions

      The peripheral retina of the human eye offers a unique opportunity for assessment and monitoring of ocular diseases. We have developed a novel wide-field (>70°) optical coherence tomography system (WF-OCT) equipped with wavefront sensorless adaptive optics (WSAO) for enhancing the visualization of smaller (<25°) targeted regions in the peripheral retina. We iterated the WSAO algorithm at the speed of individual OCT B-scans (~20 ms) by using raw spectral interferograms to calculate the optimization metric. Our WSAO approach with a 3 mm beam diameter permitted primarily low- but also high- order peripheral wavefront correction in less than 10 seconds. In preliminary ...

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    2. Handheld, rapidly switchable, anterior/posterior segment swept source optical coherence tomography probe

      Handheld, rapidly switchable, anterior/posterior segment swept source optical coherence tomography probe

      We describe the first handheld, swept source optical coherence tomography (SSOCT) system capable of imaging both the anterior and posterior segments of the eye in rapid succession. A single 2D microelectromechanical systems (MEMS) scanner was utilized for both imaging modes, and the optical paths for each imaging mode were optimized for their respective application using a combination of commercial and custom optics. The system has a working distance of 26.1 mm and a measured axial resolution of 8 μm (in air). In posterior segment mode, the design has a lateral resolution of 9 μm, 7.4 mm imaging depth ...

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    3. True color scanning laser ophthalmoscopy and optical coherence tomography handheld probe

      True color scanning laser ophthalmoscopy and optical coherence tomography handheld probe

      Scanning laser ophthalmoscopes (SLOs) are able to achieve superior contrast and axial sectioning capability compared to fundus photography. However, SLOs typically use monochromatic illumination and are thus unable to extract color information of the retina. Previous color SLO imaging techniques utilized multiple lasers or narrow band sources for illumination, which allowed for multiple color but not “true color” imaging as done in fundus photography. We describe the first “true color” SLO, handheld color SLO, and combined color SLO integrated with a spectral domain optical coherence tomography (OCT) system. To achieve accurate color imaging, the SLO was calibrated with a color ...

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    4. Handheld simultaneous scanning laser ophthalmoscopy and optical coherence tomography system

      Handheld simultaneous scanning laser ophthalmoscopy and optical coherence tomography system

      Scanning laser ophthalmoscopy (SLO) and optical coherence tomography (OCT) are widely used retinal imaging modalities that can assist in the diagnosis of retinal pathologies. The combination of SLO and OCT provides a more comprehensive imaging system and a method to register OCT images to produce motion corrected retinal volumes. While high quality, bench-top SLO-OCT systems have been discussed in the literature and are available commercially, there are currently no handheld designs. We describe the first design and fabrication of a handheld SLO/spectral domain OCT probe. SLO and OCT images were acquired simultaneously with a combined power under the ANSI ...

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    5. Distributed scanning volumetric SDOCT for motion corrected corneal biometry

      Distributed scanning volumetric SDOCT for motion corrected corneal biometry

      We present a method, termed distributed scanning OCT (DSOCT), which reduces the effects of patient motion on corneal biometry utilizing current-generation clinically available spectral domain optical coherence tomography (SDOCT) systems. We first performed a pilot study of the power spectrum of normal patient axial eye motion based on repeated (M-mode) SDOCT. Using DSOCT to reduce the effects of patient motion, we conducted a preliminary patient study comparing the measured anterior and posterior corneal curvatures and the calculated corneal power to both corneal topography and Scheimpflug photography in normal subjects. The repeatability for the measured radius of curvature of both anterior ...

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    6. Corneal biometry from volumetric SDOCT and comparison with existing clinical modalities

      Corneal biometry from volumetric SDOCT and comparison with existing clinical modalities

      We present a comparison of corneal biometric values from dense volumetric spectral domain optical coherence tomography (SDOCT) scans to reference values in both phantoms and clinical subjects. We also present a new optically based “keratometric equivalent power” formula for SDOCT that eliminates previously described discrepancies between corneal power form SDOCT and existing clinical modalities. Phantom objects of varying radii of curvature and corneas of normal subjects were imaged with a clinical SDOCT system. The optically corrected three-dimensional surfaces were used to recover radii of curvature and power as appropriate. These were then compared to the manufacturer’s reference values in ...

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    7. Robust automatic segmentation of corneal layer boundaries in SDOCT images using graph theory and dynamic programming

      Robust automatic segmentation of corneal layer boundaries in SDOCT images using graph theory and dynamic programming

      Segmentation of anatomical structures in corneal images is crucial for the diagnosis and study of anterior segment diseases. However, manual segmentation is a time-consuming and subjective process. This paper presents an automatic approach for segmenting corneal layer boundaries in Spectral Domain Optical Coherence Tomography images using graph theory and dynamic programming. Our approach is robust to the low-SNR and different artifact types that can appear in clinical corneal images. We show that our method segments three corneal layer boundaries in normal adult eyes more accurately compared to an expert grader than a second grader—even in the presence of significant ...

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    1-7 of 7
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  2. Topics in the News

    1. (7 articles) Duke University
    2. (7 articles) Joseph A. Izatt
    3. (6 articles) Sina Farsiu
    4. (4 articles) Anthony N. Kuo
    5. (1 articles) Stephanie J. Chiu
    6. (1 articles) Oscar Carrasco-Zevallos
    7. (1 articles) Mingtao Zhao
    8. (1 articles) Wakayama Medical University
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    Robust automatic segmentation of corneal layer boundaries in SDOCT images using graph theory and dynamic programming Corneal biometry from volumetric SDOCT and comparison with existing clinical modalities Distributed scanning volumetric SDOCT for motion corrected corneal biometry Handheld simultaneous scanning laser ophthalmoscopy and optical coherence tomography system True color scanning laser ophthalmoscopy and optical coherence tomography handheld probe Handheld, rapidly switchable, anterior/posterior segment swept source optical coherence tomography probe Wide-field retinal optical coherence tomography with wavefront sensorless adaptive optics for enhanced imaging of targeted regions The Macular Choriocapillaris Flow in Glaucoma and Within-Day Fluctuations: An Optical Coherence Tomography Angiography Study Impact of Optical Coherence Tomography Imaging on Decision-Making During Percutaneous Coronary Intervention in Patients Presented With Acute Coronary Syndromes Time course of collateral vessel formation after retinal vein occlusion visualized by OCTA and elucidation of factors in their formation Peripapillary Retinal Nerve Fiber Layer and Ganglion Cell-Inner Plexiform Layer Changes on Optical Coherence Tomography in Patients with Unilateral Hypertensive Cytomegalovirus Anterior Uveitis Utility of spectral domain OCT in differentiating optic disc drusen from papilledema in children