1. Articles from fred k. chen

    1-17 of 17
    1. Branch Retinal Vein Occlusion Secondary To A Retinal Arteriolar Macroaneurysm: A Novel Mechanism Supported By Multimodal Imaging

      Branch Retinal Vein Occlusion Secondary To A Retinal Arteriolar Macroaneurysm: A Novel Mechanism Supported By Multimodal Imaging

      Background/Purpose: To report a case of a branch retinal vein occlusion secondary to a retinal arteriolar macroaneurysm (RAM). Methods: Retrospective case report describing examination findings, treatment outcome and unique multimodal imaging features demonstrated on fluorescein angiography, optical coherence tomography, optical coherence tomography angiography and adaptive optics photography of the retinal vessels and RAM. Results: A 61-year-old man presented with 20/200 vision in the right eye because of a branch retinal vein occlusion secondary to a RAM. After sector panretinal photocoagulation and a course of 24 intravitreal antivascular endothelial growth factor injections over 4 years, visual acuity improved to ...

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    2. Posterior Choroidal Stroma Reduces Accuracy of Automated Segmentation of Outer Choroidal Boundary in Swept Source Optical Coherence Tomography

      Posterior Choroidal Stroma Reduces Accuracy of Automated Segmentation of Outer Choroidal Boundary in Swept Source Optical Coherence Tomography

      Purpose : To determine the influence of choroidal boundary morphology on the accuracy of automated measurements of subfoveal choroidal thickness (SFCT) in swept source optical coherence tomography (SSOCT). Methods : A retrospective image analysis of foveal-centered horizontal line scans from normal and diseased eyes using the Topcon DRI OCT-1 Atlantis SSOCT was conducted. Subfoveal choroid-scleral junction (CSJ) and retina-choroidal junction (RCJ) morphologies were graded by two observers. Automated SFCT (A-SFCT) was compared with manual SFCT (M-SFCT) measurements from Bruch's membrane to the posterior limits of choroidal vessel, hyperreflective stroma, and hyporeflective lamina fusca. Agreement in boundary grading was assessed by Cohen ...

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    3. Axial Length Variation Impacts on Superficial Retinal Vessel Density and Foveal Avascular Zone Area Measurements Using Optical Coherence Tomography Angiography

      Axial Length Variation Impacts on Superficial Retinal Vessel Density and Foveal Avascular Zone Area Measurements Using Optical Coherence Tomography Angiography

      Purpose : To evaluate the impact of image magnification correction on superficial retinal vessel density (SRVD) and foveal avascular zone area (FAZA) measurements using optical coherence tomography angiography (OCTA). Methods : Participants with healthy retinas were recruited for ocular biometry, refraction, and RTVue XR Avanti OCTA imaging with the 3 × 3-mm protocol. The foveal and parafoveal SRVD and FAZA were quantified with custom software before and after correction for magnification error using the Littman and the modified Bennett formulae. Relative changes between corrected and uncorrected SRVD and FAZA were calculated. Results : Forty subjects were enrolled and the median (range) age of the ...

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    4. Enhanced Visualization of Subtle Outer Retinal Pathology by En Face Optical Coherence Tomography and Correlation with Multi-Modal Imaging

      Enhanced Visualization of Subtle Outer Retinal Pathology by En Face Optical Coherence Tomography and Correlation with Multi-Modal Imaging

      Purpose To present en face optical coherence tomography (OCT) images generated by graph-search theory algorithm-based custom software and examine correlation with other imaging modalities. Methods En face OCT images derived from high density OCT volumetric scans of 3 healthy subjects and 4 patients using a custom algorithm (graph-search theory) and commercial software (Heidelberg Eye Explorer software (Heidelberg Engineering)) were compared and correlated with near infrared reflectance, fundus autofluorescence, adaptive optics flood-illumination ophthalmoscopy (AO-FIO) and microperimetry. Results Commercial software was unable to generate accurate en face OCT images in eyes with retinal pigment epithelium (RPE) pathology due to segmentation error at ...

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    5. Impact of retinal pigment epithelium pathology on spectral-domain optical coherence tomography-derived macular thickness and volume metrics and their intersession repeatability

      Impact of retinal pigment epithelium pathology on spectral-domain optical coherence tomography-derived macular thickness and volume metrics and their intersession repeatability

      Background To determine the impact of retinal pigment epithelium (RPE) pathology on intersession repeatability of retinal thickness and volume metrics derived from Spectralis spectral-domain optical coherence tomography (SD-OCT). Design Prospective cross-sectional single centre study. Participants 56 eyes of 56 subjects were divided into 3 groups: (A) normal RPE band (25 eyes), (B) RPE elevation: macular soft drusen (13 eyes) and (C) RPE attenuation: geographic atrophy or inherited retinal diseases (18 eyes). Methods Each subject underwent three consecutive follow-up macular raster scans (61 B-scans at 119 micron separation) at 1-month intervals. Main outcome measures Retinal thicknesses and volumes for each zone ...

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    6. Classification of image artefacts in optical coherence tomography angiography of the choroid in macular diseases

      Classification of image artefacts in optical coherence tomography angiography of the choroid in macular diseases

      Background To evaluate and classify image artefacts in optical coherence tomography (OCT) angiography (OCTA) of the choroid in a group of patients with macular diseases. Design Retrospective observational study. Participants 5 patients with age-related macular degeneration, 3 with central serous retinopathy, 1 with polypoidal choroidal vasculopathy and 1 with multiple evanescent white dot syndrome. Methods OCTA and OCT reflectivity (OCTR) maps were reviewed along with their fluorescein angiography and indocyanine green angiography. 60 OCTA images (20 outer retina, 20 Sattler and 20 Haller layers) were graded for image artefacts by 2 examiners independently. Main Outcome Measures OCTA artefacts and their ...

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    7. Repeatability of retinal thickness and volume metrics in neovascular age-related macular degeneration using the topcon 3DOCT-1000

      Repeatability of retinal thickness and volume metrics in neovascular age-related macular degeneration using the topcon 3DOCT-1000

      Optical coherence tomography (OCT) is a commonly used imaging modality that provides detailed cross-sectional retinal images. This has revolutionised management of neovascular age-related macular degeneration. The need for repeated anti-vascular endothelial growth factor injections has led to therapy being delivered using OCT-guided retreatment strategies with both qualitative OCT features of disease activity (e.g. macular fluid) and changes in retinal thickness as triggers for retreatment The purpose of this study is to determine the intra-session repeatability of retinal thickness and volume measurements using the Topcon 3DOCT-1000 spectral-domain optical coherence tomography (SDOCT) device in patients with neovascular age-related macular degeneration (nAMD ...

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    8. Novel optical coherence tomography classification of torpedo maculopathy

      Novel optical coherence tomography classification of torpedo maculopathy

      Background Torpedo maculopathy is a rare condition with a twofold clinical significance. Firstly, it is a differential of atypical congenital hypertrophy of the retinal pigment epithelium. Secondly, visual field loss has been reported. We demonstrate the spectrum of structural abnormality of torpedo maculopathy as seen on optical coherence tomography, and correlate this with age of presentation, fundus autofluorescence, retinal sensitivity loss and visual field abnormality. Design A retrospective, observational case series. Participants Five Australian patients seen between 2008 and 2013. Methods Fundus photography, optical coherence tomography, fundus autofluorescence and visual field analysis. One patient underwent fluorescein angiography. Main Outcome Measures ...

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    9. Zero delay switch technique in optical coherence tomography for duo enhanced vitreoretinal and choroidoscleral imaging in highly myopic eyes

      Zero delay switch technique in optical coherence tomography for duo enhanced vitreoretinal and choroidoscleral imaging in highly myopic eyes

      Posterior staphyloma is a concave depression of the posterior shell of the eye globe that is frequently observed in highly myopic eyes. As hallmark lesion, it is seen in 90% of patients with high myopia and increases in prevalence with age.1 Highly myopic eyes with posterior staphylomata have a higher probability of visual disturbances; the stretching of the posterior fundus results in various lesions such as chorioretinal atrophy, choroidal neovascularization, lacquer cracks, foveoschisis, macular holes and serous macular detachments. 2 It has been observed that with age, posterior staphylomata tend to deepen and their morphological characteristics can change accompanied ...

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    10. Topographic variation and interocular symmetry of macular choroidal thickness using enhanced depth imaging optical coherence tomography

      Topographic variation and interocular symmetry of macular choroidal thickness using enhanced depth imaging optical coherence tomography

      Purpose: To report and analyse factors influencing topographical and interocular variations of choroidal thickness (CT) in healthy adult population. Methods: 100 eyes of 50 healthy subjects underwent visual acuity and axial length measurements and optical coherence tomography with enhanced depth imaging using the Heidelberg Spectralis HRA+OCT. CT at the fovea, and 3 mm nasal, temporal, superior and inferior to the fovea were measured manually. Topographic variation, relative interocular differences in CT and predictors of CT were analysed. The relationship between interocular differences in CT, age and interocular axial length differences was explored. Results: The mean (SD) foveal CT in ...

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    11. Repeatability of manual subfoveal choroidal thickness measurements in healthy subjects using the technique of enhanced depth imaging optical coherence tomography

      Repeatability of manual subfoveal choroidal thickness measurements in healthy subjects using the technique of enhanced depth imaging optical coherence tomography

      Purpose- The aim of this study was to investigate the repeatability of manual measurements of choroidal thickness in normal subjects imaged on spectral domain optical coherence tomography (OCT) using the enhanced depth imaging (EDI) technique. Methods- Fifty consecutive, healthy, young, adult volunteers with no known eye disease were enrolled prospectively. Two good quality, horizontal and vertical line scans through the fovea were obtained for each eye. Using the manual callipers provided by the software of the proprietary device, two experienced OCT readers measured the subfoveal choroidal thickness (SFCT) of the horizontal and vertical line scans for all eyes. The readers ...

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    12. Intrasession repeatability of optical coherence tomography measures in active neovascular age-related macular degeneration

      Objectives: To determine the repeatability of Stratus optical coherence tomography fast macular thickness map analysis in patients with active neovascular age-related macular degeneration (nAMD).Methods: Consecutive pairs of scans from 112 eyes of 112 consecutive patients with active nAMD were analyzed. The Bland[ndash]Altman coefficient of repeatability (CR) was calculated for each retinal thickness or volume measure.Results: The CR for the central 1 mm macular subfield was 59 [mu]m (18% of retinal thickness) and did not exceed 69 [mu]m in any subfield. There was much poorer repeatability for the center-point thickness (CPT) measure (CR of 78 ...

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    13. Intersession repeatability of optical coherence tomography measures of retinal thickness in early age-related macular degeneration

      Purpose: To determine the intersession repeatability of Stratus optical coherence tomography (OCT) measures of retinal thickness in patients with age-related macular degeneration (AMD).Methods: Measurement of retinal thickness was performed over four sessions over 12 weeks using a standardized OCT protocol with the fast macular thickness map in 67 non-treated eyes of 67 patients with AMD enrolled in a clinical trial. The intrapatient standard deviation (Sw) and 95% coefficient of repeatability (CR) (), expressed in [mu]m and as a percentage of mean retinal thickness, were calculated to estimate intersession repeatability.Results: The CR was 32 [mu]m for the average ...

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    14. Interobserver agreement for the detection of optical coherence tomography features of neovascular age-related macular degeneration

      Purpose. To investigate the inter-observer agreement for the detection of optical coherence tomography (OCT) features of disease activity in patients with neovascular age-related macular degeneration (nAMD). Method. A cross-sectional agreement study with grading of OCT line scans from patients with nAMD prior to receiving treatment conducted by 2 retinal specialists. Scans were graded for the presence of features of nAMD disease activity (intra-retinal cysts, IRC; subretinal fluid, SRF; diffuse retinal edema, DRE; retinal pigment epithelial detachment, PED and sub-retinal tissue, SRT). Results. Though scans from 78 patients were available for analysis, 5 patients were excluded due to a mean signal ...
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    15. Segmentation Error in Stratus Optical Coherence Tomography for Neovascular Age-Related Macular Degeneration

      This study reports the rate of segmentation error, the effect of these errors on the accuracy of retinal thickness measurements and the impact of repeat scanning on segmentation error in Stratus OCT scans of patients undergoing anti-VEGF therapy for neovascular AMD.

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    16. Evidence of Retinal Function Using Microperimetry following Autologous Retinal Pigment Epithelium-Choroid Graft in Macular Dystrophy

      purpose. To describe the outcomes of autologous retinal pigment epithelium (RPE)-choroid graft in macular dystrophy. methods. In this prospective interventional case series, five patients with macular dystrophy were enrolled to undergo autologous RPE-choroid patch graft between August 2005 and January 2007. All patients received preoperative and postoperative evaluations including visual acuity, contrast sensitivity, reading ability, microperimetry, fluorescein angiography, indocyanine green angiography, fundus autofluorescence (AF) imaging, and optical coherence tomography (OCT). results. Patients were followed up for an average of 13.4 (9–23) months. Two patients gained reading acuity but only one regained visual task function after graft. This ...

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      Mentions: Fred K. Chen
    17. Repeatability of Stratus Optical Coherence Tomography Measures in Neovascular Age-Related Macular Degeneration

      purpose. To determine the repeatability of Stratus optical coherence tomography (OCT) measures of retinal thickness and volume in patients with neovascular age-related macular degeneration (nAMD) method. Fifty-one eyes of 51 consecutive patients with nAMD underwent an OCT imaging session in which two fast macular thickness map (FMTM) protocol scans sets were acquired by a single experienced operator certified for clinical trials work. Coefficients of repeatability for each of nine Early Treatment of Diabetic Retinopathy Study (ETDRS)-like regions, foveolar center-point retinal thickness (CPT) and total macular volume (TMV), were calculated. Scans were analyzed retrospectively for errors in retinal boundary placement ...

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    1-17 of 17
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    1. (16 articles) Fred K. Chen
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    Repeatability of manual subfoveal choroidal thickness measurements in healthy subjects using the technique of enhanced depth imaging optical coherence tomography Topographic variation and interocular symmetry of macular choroidal thickness using enhanced depth imaging optical coherence tomography Zero delay switch technique in optical coherence tomography for duo enhanced vitreoretinal and choroidoscleral imaging in highly myopic eyes Novel optical coherence tomography classification of torpedo maculopathy Perimeter Medical Imaging Closes Oversubscribed $C4.4M Financing Time-domain optical coherence tomography system based on moving-optical-wedge interferometer ML and AI: At the Forefront of Ophthalmology Automated 3D Optical Coherence Tomography to Elucidate Biofilm Morphogenesis Over Large ... 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 Columbia University Receives NIH Grant  for Measures of Human Receptor and post Receptor Activity