1. Articles from R. Theodore Smith

    1-12 of 12
    1. Classification of healthy and diseased retina using SD-OCT imaging and Random Forest algorithm

      Classification of healthy and diseased retina using SD-OCT imaging and Random Forest algorithm

      In this paper, we propose a novel classification model for automatically identifying individuals with age-related macular degeneration (AMD) or Diabetic Macular Edema (DME) using retinal features from Spectral Domain Optical Coherence Tomography (SD-OCT) images. Our classification method uses retinal features such as the thickness of the retina and the thickness of the individual retinal layers, and the volume of the pathologies such as drusen and hyper-reflective intra-retinal spots. We extract automatically, ten clinically important retinal features by segmenting individual SD-OCT images for classification purposes. The effectiveness of the extracted features is evaluated using several classification methods such as Random Forrest ...

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    2. A pilot study assessing retinal pathology in psychosis using optical coherence tomography: choroidal and macular thickness

      A pilot study assessing retinal pathology in psychosis using optical coherence tomography: choroidal and macular thickness

      Mounting evidence supports a genetic-vascular-inflammatory etiology of schizophrenia. The retina provides an indirect assessment of inflammation and degeneration in the brain. In particular, the use of spectral domain optical coherence tomography (SD-OCT) has emerged as a powerful tool for examining single retinal nerve cell layers and the choroid, the vascular layer supplying the outer retina. In this study, choroidal and macular thicknesses were measured in six patients with psychosis with either schizophrenia or bipolar disorder, and in 18 age- and sex-matched healthy controls. Mean choroidal thickness was reduced in psychosis, though not significantly so. There was a statistically significant decrease ...

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    3. An Automated Method for Choroidal Thickness Measurement from Enhanced Depth Imaging Optical Coherence Tomography Images

      An Automated Method for Choroidal Thickness Measurement from Enhanced Depth Imaging Optical Coherence Tomography Images

      The choroid is vascular tissue located underneath the retina and supplies oxygen to the outer retina; any damage to this tissue can be a precursor to retinal diseases. This paper presents an automated method of choroidal segmentation from enhanced depth imaging optical coherence tomography (EDI-OCT) images. The Dijkstra shortest path algorithm is used to segment the choroid-sclera interface (CSI), the outermost border of the choroid. A novel intensity-normalisation technique that is based on the depth of the choroid is used to equalise the intensity of all non-vessel pixels in the choroid region. The outer boundary of choroidal vessel and CSI ...

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    4. Automatic Identification of Pathology-Distorted Retinal Layer Boundaries Using SD-OCT Imaging

      Automatic Identification of Pathology-Distorted Retinal Layer Boundaries Using SD-OCT Imaging

      Objective: We propose an effective automatic method for identification of four retinal layer boundaries from the spectral domain optical coherence tomography images in the presence and absence of pathologies and morphological changes due to disease. Methods: The approach first finds an approximate location of three reference layers and then uses these to bound the search space for the actual layers, which is achieved by modeling the problem as a graph and applying Dijkstra's shortest path algorithm. The edge weight between nodes is determined using pixel distance, slope similarity to a reference, and nonassociativity of the layers, which is designed ...

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    5. Choroidal Osteoma Deossification Visualized by Enhanced Depth Imaging Spectral-Domain Optical Coherence Tomography

      Choroidal Osteoma Deossification Visualized by Enhanced Depth Imaging Spectral-Domain Optical Coherence Tomography

      Choroidal osteoma (CO) is a rare, benign ossifying lesion of the choroid found in otherwise healthy patients. Although associated with good visual prognosis, tumor deossification in choroidal osteoma has been linked with vision loss, presumably due to overlying photoreceptor degeneration. Here the authors present a case of CO in an elderly male demonstrating tumor deossification and photoreceptor atrophy during a 3-year follow-up using enhanced depth imaging optical coherence tomography (EDI-OCT). Visual acuity was maintained due to the tumor's noncentral location. Patients with CO should undergo regular imaging with EDI-OCT to screen for tumor deossification and impending vision loss.

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    6. The Project MACULA retinal pigment epithelium grading system for histology and optical coherence tomography in age-related macular degeneration

      The Project MACULA retinal pigment epithelium grading system for histology and optical coherence tomography in age-related macular degeneration

      Purpose: To seek pathways of retinal pigment epithelium (RPE) fate in age-related macular degeneration via a morphology grading system ; provide nomenclature, visualization targets, and metrics for cl in ical imag in g and model system s. Methods: Donor eyes with geographic atrophy (GA) or choroidal neovascularization (CNV) and one GA eye with previous cl in ical spectral doma in optical coherence tomography (SDOCT) imag in g were processed for histology , photodocumented, and annotated at pre-def in ed locations. RPE cells conta in ed sp in dle-shaped melanosomes, apposed a basal lam in a or basal lam in ar deposit (BLamD ...

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    7. Quantitative Fundus Autofluorescence and Optical Coherence Tomography in Best Vitelliform Macular Dystrophy

      Quantitative Fundus Autofluorescence and Optical Coherence Tomography in Best Vitelliform Macular Dystrophy

      Purpose: Quantitative fundus autofluorescence (qAF), spectral domain optical coherence tomography (SD-OCT) segmentation and multimodal imaging were performed to elucidate the pathogenesis of Best vitelliform macular dystrophy (BVMD) and to identify abnormalities in lesion versus non-lesion fundus areas. Methods: 16 patients with a clinical diagnosis of BVMD were studied. AF images (30°, 488 nm excitation) were acquired with a confocal scanning laser ophthalmoscope equipped with an internal fluorescent reference to account for variable laser power and detector sensitivity. The grey levels (GLs) of each image were calibrated to the reference, zero GL, magnification, and normative optical media density, to yield qAF ...

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    8. Disruption in Bruch membrane in patients with Stargardt disease

      Disruption in Bruch membrane in patients with Stargardt disease
      Purpose: To describe the spectral domain-optical coherence tomography (SD-OCT) findings of two patients with complete defects in the retinal pigment epithelium (RPE) with disruptions in Bruch membrane in Stargardt disease (STGD1). Methods: Two patients with STGD1 were referred to our clinic for further evaluation. Fundus autofluorescence (FAF), spectral domain optical coherence tomography (SD-OCT), electroretinography (ERG) and Microperimetry (MP-1) were performed to assess the retinal anatomy and function. Screening for mutations in the ABCA4 gene was carried out and detected mutations were confirmed by direct sequencing. Results: Both patients had bilateral macular geographic atrophy (GA) and yellowish subretinal pisciform flecks and ...
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    9. Image Registration and Multimodal Imaging of Reticular Pseudodrusen

      Image Registration and Multimodal Imaging of Reticular Pseudodrusen
      Purpose. To characterize reticular pseudodrusen (RPD) by using a point-to-point comparison of the reticular pattern on infrared reflectance (IR), autofluorescence (AF), and red-free (RF) images registered with en face sections of the choroid from spectral domain optical coherence tomography (SD-OCT) scans. Methods. A cross-sectional, retrospective study of all patients with the diagnosis of AMD who presented to the Doheny Retina Institute between December 2007 and November 2009 was conducted to identify patients with RPD. IR, AF, and RF images were obtained using confocal scanning laser ophthalmoscopy and were manually registered to OCT choroidal sections to study the location of RPD ...
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    10. Image Registration and Multimodal Imaging of Reticular Pseudodrusen

      Image Registration and Multimodal Imaging of Reticular Pseudodrusen
      Purpose: To characterize reticular pseudodrusen (RPD) by utilizing a point-to-point comparison of the reticular pattern on infrared reflectance (IR), autofluorescence (AF), and red-free (RF) images registered with en face sections of the choroid from spectral domain optical coherence tomography (SD-OCT) scans. Methods: A cross-sectional, retrospective study of all patients with the diagnosis of age-related macular degeneration (AMD), who presented to the Doheny Retina Institute from 12/2007 to 11/2009 was conducted to identify patients with RPD. IR, AF, and RF images were obtained using confocal scanning laser ophthalmoscopy and were manually registered to OCT choroidal sections to study the ...
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    11. Quantitative Comparison of Drusen Segmented on SD OCT versus Drusen Delineated on Color Fundus Photographs

      Purpose. Spectral domain optical coherence tomography (SD OCT) may be useful for efficient measurement of drusen in patients with age-related macular degeneration (AMD). We evaluated areas identified as drusen from semi-automated segmentation of drusen on SD OCT versus those identified from review of digital color fundus photographs (CFP). Methods. Twelve eyes with non-neovascular AMD were prospectively imaged with digital CFP and SD OCT. For each eye, areas on CFP in which at least 2 of 3 retina specialists agreed upon drusen presence produced the composite CFP drusen map. Automated image analysis produced another CFP map. Areas identified as drusen by ...
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    12. A Comparison of Fundus Autofluorescence and Retinal Structure in Patients with Stargardt Disease

      Purpose: To improve our understanding of Stargardt disease by comparing structural changes seen on spectral domain optical coherence tomography (SD-OCT) to those visible on fundus autofluorescence (FAF). Methods: FAF and SD-OCT were obtained on 22 eyes of 11 patients with Stargardt disease. SD-OCT images were obtained at the fovea and at the eccentric preferred retinal locus (PRL). The diameters of "absent" (hypo-autofluorescent) and "abnormal" FAF areas were measured. The extent of the transverse defect of the junction between the inner and outer segments of the photoreceptors (IS-OS) was measured in the foveal area. The PRL was evaluated with fundus photography ...
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    1-12 of 12
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    1. (5 articles) Columbia University
    2. (2 articles) University of Melbourne
    3. (2 articles) University of Southern California
    4. (2 articles) Duke University
    5. (2 articles) Srinivas R. Sadda
    6. (2 articles) Joel S. Schuman
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    Image Registration and Multimodal Imaging of Reticular Pseudodrusen Image Registration and Multimodal Imaging of Reticular Pseudodrusen Disruption in Bruch membrane in patients with Stargardt disease Quantitative Fundus Autofluorescence and Optical Coherence Tomography in Best Vitelliform Macular Dystrophy The Project MACULA retinal pigment epithelium grading system for histology and optical coherence tomography in age-related macular degeneration Choroidal Osteoma Deossification Visualized by Enhanced Depth Imaging Spectral-Domain Optical Coherence Tomography An Automated Method for Choroidal Thickness Measurement from Enhanced Depth Imaging Optical Coherence Tomography Images A pilot study assessing retinal pathology in psychosis using optical coherence tomography: choroidal and macular thickness In-stent restenosis and longitudinal stent deformation: a case report Microvascular Features of Treated Retinoblastoma Tumors in Children Assessed Using OCTA OCTA characterisation of microvascular retinal alterations in patients with central serous chorioretinopathy Comparative study of the influence of linear and branched alkyltrichlorosilanes on the removal efficiency of polyethylene and polypropylene-based microplastic particles from water