1. Articles from Christian Y. Mardin

    1-15 of 15
    1. OCT-Angiography: Mydriatic phenylephrine and tropicamide do not influence retinal microvasculature in macula and peripapillary region

      OCT-Angiography: Mydriatic phenylephrine and tropicamide do not influence retinal microvasculature in macula and peripapillary region

      Purpose Optical coherence tomography angiography (OCT-A) enables visualization of retinal microcirculation. As a potential influence of mydriatic eye drops on retinal vessel density (VD) was proposed, the purpose of the present study was to investigate an influence of 5% phenylephrine and 0.5% tropicamide on macula and peripapillary VD. Methods 30 eyes of 30 healthy persons were measured by en face OCT-A (Spectralis OCT II, Heidelberg Engineering, Heidelberg). Scans of the macula (12 sectors, region of interest, ROI: 6.10 mm 2 ) and peripapillary region (4 sectors, ROI: 2.67 mm 2 ) were performed before (-) and 30 minutes after application ...

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    2. OCT-Detected Optic Nerve Head Neural Canal Direction, Obliqueness and Minimum Cross-Sectional Area in Healthy Eyes

      OCT-Detected Optic Nerve Head Neural Canal Direction, Obliqueness and Minimum Cross-Sectional Area in Healthy Eyes

      Purpose To assess anterior scleral canal opening (ASCO) offset relative to Bruch’s membrane opening (BMO) (ASCO/BMO offset) so as to determine neural canal direction, obliqueness, and minimum cross-sectional area (NCMCA) in 362 healthy eyes. Design Cross-sectional study Methods After OCT optic nerve head (ONH) and retinal nerve fiber layer thickness (RNFLT) imaging, BMO and ASCO were manually segmented and planes, centroids, size and shape were calculated. Neural canal direction was defined by projecting the neural canal axis vector (connecting BMO and ASCO centroids) onto the BMO plane. Neural canal obliqueness was defined by the angle between the neural ...

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    3. Factors Influencing Optical Coherence Tomography Peripapillary Choroidal Thickness: A Multicenter Study

      Factors Influencing Optical Coherence Tomography Peripapillary Choroidal Thickness: A Multicenter Study

      Purpose : To quantify peripapillary choroidal thickness (PCT) and the factors that influence it in healthy participants who represent the racial and ethnic composition of the U.S. population. Methods : A total of 362 healthy participants underwent optical coherence tomography (OCT) enhanced depth imaging of the optic nerve head with a 24 radial B-scan pattern aligned to the fovea to Bruch's membrane opening axis. Bruch's membrane, anterior scleral canal opening (ASCO), and the anterior scleral surface were manually segmented. PCT was measured at 100, 300, 500, 700, 900, and 1100 μm from the ASCO globally and within 12 clock-hour ...

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    4. Precision of Optic Nerve Head and Retinal Nerve Fiber Layer Parameter Measurements by Spectral-domain Optical Coherence Tomography

      Precision of Optic Nerve Head and Retinal Nerve Fiber Layer Parameter Measurements by Spectral-domain Optical Coherence Tomography

      Purpose: The aim of this study was to assess the repeatability and reproducibility (R&R) of Bruch’s Membrane Opening – based on Minimum Rim Width (BMO-MRW), Minimum Rim Area (BMO-MRA) and peripapillary retinal nerve fiber layer thickness (RNFLT) with the Spectralis OCT (Heidelberg Engineering) for normal and glaucoma subjects. Precise measurement of these parameters can support detection of structural glaucomatous damage and progression. Methods: This cross-sectional study included 16 healthy controls and 16 patients with glaucoma. One eye was randomly selected and included in this study. Subjects underwent 1 baseline and 3 follow-up measurements, using three different Spectralis OCT devices ...

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    5. Predicted and Measured Retinal Nerve Fiber Layer Thickness From Time-Domain Optical Coherence Tomography Compared With Spectral-Domain Optical Coherence Tomography

      Predicted and Measured Retinal Nerve Fiber Layer Thickness From Time-Domain Optical Coherence Tomography Compared With Spectral-Domain Optical Coherence Tomography

      Importance New methods are needed to compare peripapillary retinal nerve fiber layer thickness (pRNFLT) measurements taken from time-domain optical coherence tomography (TD-OCT) and spectral-domain OCT (SD-OCT). Objective To compare the agreement of measured and predicted pRNFLT using different equations based on pRNFLT measurements obtained by TD-OCT and SD-OCT. Design, Setting, and Participants Cross-sectional single-center study that took place at the Department of Ophthalmology, University of Erlangen–Nuremberg from November 16, 2005, to June 3, 2015, and included 138 eyes of control participants, 126 eyes of patients with ocular hypertension, 128 eyes of patients with preperimetric glaucoma, and 160 eyes of ...

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    6. RETINOPATHY IN A PATIENT WITH ACUTE EPSTEIN-BARR VIRUS INFECTION: FOLLOW-UP ANALYSIS USING SPECTRAL DOMAIN OPTICAL COHERENCE TOMOGRAPHY

      RETINOPATHY IN A PATIENT WITH ACUTE EPSTEIN-BARR VIRUS INFECTION: FOLLOW-UP ANALYSIS USING SPECTRAL DOMAIN OPTICAL COHERENCE TOMOGRAPHY

      Purpose: To describe the clinical findings, diagnostics, and differential diagnosis in a patient with retinopathy in acute systemic Epstein-Barr virus (EBV) infection. Methods: Description of the clinical course of the EBV retinopathy was based on the medical record, photographs, and visual fields of the patient. Retinal morphology was visualized using spectral domain optical coherence tomography (Heidelberg Engineering), and fluorescein angiography. Multiple serologic tests were performed to exclude different infectious agents. A 30-year-old male patient presented with a focal scotoma in his right visual field. One week ago, he suffered from high fever, joint pain, neck stiffness, and hepatitis; 2 weeks ...

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    7. Longitudinal analysis of progression in glaucoma using spectral-domain optical coherence tomography

      Longitudinal analysis of progression in glaucoma using spectral-domain optical coherence tomography

      Purpose. To compare the longitudinal loss of RNFL thickness measurements by SD-OCT in normals and glaucoma patients with or without progression concerning optic disc morphology. Methods. 62 eyes, comprising 38 glaucomatous eyes with open angle glaucoma and 24 healthy controls, were included in the study (Erlangen Glaucoma Registry, NTC00494923). All patients were investigated annually over a period of three years by Spectralis SD-OCT measuring peripapillary RNFL thickness. By masked comparative analysis of photographs the eyes were classified into non-progressive and progressive glaucoma cases. Longitudinal loss of RNFL thickness was compared to morphological changes of optic disc morphology. Results. Mixed model ...

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    8. Wavelet denoising of multiframe optical coherence tomography data

      Wavelet denoising of multiframe optical coherence tomography data

      We introduce a novel speckle noise reduction algorithm for OCT images. Contrary to present approaches, the algorithm does not rely on simple averaging of multiple image frames or denoising on the final averaged image. Instead it uses wavelet decompositions of the single frames for a local noise and structure estimation. Based on this analysis, the wavelet detail coefficients are weighted, averaged and reconstructed. At a signal-to-noise gain at about 100% we observe only a minor sharpness decrease, as measured by a full-width-half-maximum reduction of 10.5%. While a similar signal-to-noise gain would require averaging of 29 frames, we achieve this ...

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    9. Retinal Nerve Fiber Layer Segmentation on FD-OCT Scans of Normal Subjects and Glaucoma Patients

      Retinal Nerve Fiber Layer Segmentation on FD-OCT Scans of Normal Subjects and Glaucoma Patients

      Automated measurements of the retinal nerve fiber layer thickness on circular OCT B-Scans provide physicians additional parameters for glaucoma diagnosis. We propose a novel retinal nerve fiber layer segmentation algorithm for frequency domain data that can be applied on scans from both normal healthy subjects, as well as glaucoma patients, using the same set of parameters. In addition, the algorithm remains almost unaffected by image quality. The main part of the segmentation process is based on the minimization of an energy function consisting of gradient and local smoothing terms. A quantitative evaluation comparing the automated segmentation results to manually corrected ...

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    10. Retinal Nerve Fiber Layer Thickness in Normals Measured by Spectral Domain OCT

      Purpose: To determine normal values for peripapillary retinal nerve fiber layer thickness (RNFL) measured by spectral domain Optical Coherence Tomography (SOCT) in healthy white adults and to examine the relationship of RNFL with age, gender, and clinical variables. Patients and Methods: The peripapillary RNFL of 170 healthy patients (96 males and 74 females, age 20 to 78 y) was imaged with a high-resolution SOCT (Spectralis HRA+OCT, Heidelberg Engineering) in an observational cross-sectional study. RNFL thickness was measured around the optic nerve head using 16 automatically averaged, consecutive circular B-scans with 3.4-mm diameter. The automatically segmented RNFL thickness was ...
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    11. Vitreal Seeding From Uveal Melanoma Detected by High-Resolution Spectral-Domain Optical Coherence Tomography

      High-resolution spectral-domain optical coherence tomography (SD-OCT) is a new exciting technology for visualization of microstructural alterations in retinal diseases.1 We investigated the applicability of this noninvasive method to detect in vivo early vitreous seeding of a histologically proven choroidal melanoma with transretinal tumor extension (Knapp-Rønne melanoma). Report of a Case A 68-year-old man had blurred vision and inferotemporal visual field defect of the right eye for 4 months. His visual acuity was 20/30 OD and 20/20 OS. On funduscopy, a large pigmented choroidal mass with overlying hemorrhages was observed in the superonasal quadrant (Figure, A). Subretinal fluid ...
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    12. Correlation between Local Glaucomatous Visual Field Defects and Loss of Nerve Fiber Layer Thickness Measured with Polarimetry and Spectral Domain OCT

      PURPOSE. To study the correlation between local perimetric field defects and glaucoma-induced thickness reduction of the nerve layer measured in the peripapillary area with scanning laser polarimetry (SLP) and spectral domain optical coherence tomography (SOCT) and to compare the results with those of a theoretical model. METHODS. The thickness of the retinal nerve fiber layer was determined in 32 sectors (11.25° each) by using SLP with variable cornea compensation (GDxVCC; Laser Diagnostics, San Diego, CA) and the newly introduced high-resolution SOCT (Spectralis; Heidelberg Engineering, Heidelberg, Germany). Eighty-eight healthy subjects served as control subjects, to determine the thickness deviation in ...
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    13. Comparison of Scanning Laser Polarimetry and Optical Coherence Tomography in Quantitative Retinal Nerve Fiber Assessment

      Purpose: To investigate the relationship between retinal nerve fiber layer (RNFL) measurements in corresponding areas obtained with scanning laser polarimetry and optical coherence tomography and to compare their discriminating ability in the diagnosis of preperimetric and perimetric glaucoma. Patients and Methods: Three hundred eighty-six subjects-57 healthy controls, 145 ocular hypertensive patients, 89 with preperimetric glaucoma, and 95 with perimetric glaucoma-were recruited from the Erlangen Glaucoma Registry. Perimetry, 24-hours intraocular pressure profile, stereographic optic disc slides, optical coherence tomography StratusOCT, and scanning laser polarimetry GDx VCC (Carl Zeiss Meditec, Inc, Dublin, CA) were performed in all patients. Receiver operating characteristic (ROC ...
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    14. Correlation between Local Glaucomatous Visual Field Defects and Loss of Nerve Fiber Layer Thickness measured with Scanning Laser Polarimetry and Spectral Domain Optical Coherence Tomograpy

      Purpose: To study the correlation between local perimetric field defects and glaucoma induced thickness reduction of the nerve layer measured peripapillary with scanning laser polarimetry (SLP) and spectral domain optical coherence tomography (SOCT) and to compare the results with a theoretical model. Method: Thickness values of the retinal nerve fiber layer were determined in 32 sectors (11.25° each) using SLP with variable cornea compensation (GDxVCC, Zeiss-Humphrey) and a newly introduced high resolution SOCT (Spectralis, Heidelberg Engineering). 88 healthy subjects served as controls to determine the thickness deviation in glaucoma patients. Relationship between glaucomatous nerve fiber reduction and visual field ...
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    15. Visualization of Changes of the Iris Configuration After Peripheral Laser Iridotomy in Primary Melanin Dispersion Syndrome Using Optical Coherence Tomography.

      Pigment or melanin dispersion syndrome is characterized by radial iris transillumination defects, retrocorneal Krukenberg spindle, and dense trabecular pigmentation. Reverse pupillary block has been presumed as one possible pathogenetic mechanism for backward bowing of the iris leading to iris-zonular rubbing and distribution of melanin granules in the anterior chamber. Laser iridotomy is recommended as a treatment to prevent further melanin dispersion and development of pigmentary glaucoma. The effect of Nd:YAG laser iridotomy as a prophylactic and potentially causal treatment in melanin dispersion syndrome can be easily visualized by optical coherence tomography as a fast and noncontact procedure.
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    1-15 of 15
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    1. (6 articles) University of Erlangen
    2. (6 articles) Heidelberg Engineering
    3. (3 articles) University of Heidelberg
    4. (2 articles) Johns Hopkins University
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    6. (2 articles) University of Alabama
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    Retinal Nerve Fiber Layer Segmentation on FD-OCT Scans of Normal Subjects and Glaucoma Patients Wavelet denoising of multiframe optical coherence tomography data Longitudinal analysis of progression in glaucoma using spectral-domain optical coherence tomography Predicted and Measured Retinal Nerve Fiber Layer Thickness From Time-Domain Optical Coherence Tomography Compared With Spectral-Domain Optical Coherence Tomography Customized Slab-Segmentation Method for Projection-Artifact Elimination in Best Vitelliform Macular Dystrophy: A Swept-Source Optical Coherence Tomography Angiography Study Corneal Epithelial Thickness Profile in Healthy Portuguese Children by High-Definition Optical Coherence Tomography Prediction model for best focus, power, and spherical aberration of the cornea: Raytracing on a large dataset of OCT data Classification of pachychoroid on optical coherence tomography using deep learning Noninvasive Evaluation of HepaRG Aggregates during Drug‐Induced Intrahepatic Cholestasis Using Optical Coherence Tomography Online measurement of floc size, viscosity, and consistency of cellulose microfibril suspensions with optical coherence tomography A Joint Model for Macular Edema Analysis in Optical Coherence Tomography Images Based on Image Enhancement and Segmentation Choroidal Thickness by Handheld Swept-Source Optical Coherence Tomography in Term Newborns