1. Articles from Hao Zhou

    1-21 of 21
    1. Correlation Between Laser Speckle Flowgraphy and OCT-Derived Retinal and Choroidal Metrics in Healthy Human Eye

      Correlation Between Laser Speckle Flowgraphy and OCT-Derived Retinal and Choroidal Metrics in Healthy Human Eye

      Purpose: To investigate the correlation between laser speckle flowgraphy (LSFG) signals and the quantitative metrics derived from optical coherence tomography (OCT) in normal eyes. Methods: LSFG, OCT, and OCT angiography (OCTA) imaging were performed on normal participants using a custom-designed LSFG system and a commercial swept-source OCT system. Mean (PWM) and amplitude (PWA) of the LSFG pulse waveform were selected to quantify the LSFG signals. Retinal and choroidal maps were obtained using the standard 6 × 6 mm OCT and OCTA scans. Structural and vascular metrics maps, including thickness, vessel area density, vessel skeleton density, and vessel diameter index of the ...

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    2. Mitigating the effects of choroidal hyper- and hypo-transmission defects on choroidal vascularity index assessments using optical coherence tomography

      Mitigating the effects of choroidal hyper- and hypo-transmission defects on choroidal vascularity index assessments using optical coherence tomography

      Background: Changes in choroidal vascularity index (CVI) are associated with multiple choroid-related ocular diseases. CVI is calculated as the area/volume ratio of vessels in the choroid, which could be affected by alterations in regional signal intensities due to hypo-transmission defects (hypoTDs) caused by drusen and retinal pigment epithelium (RPE) detachments, and hyper-transmission defects (hyperTDs) caused by the absence of RPE. To develop a simulation model to verify the CVI assessments in eyes with hyper/hypoTDs and demonstrate that accurate CVIs can be achieved after attenuation correction on swept-source optical coherence tomography (SS-OCT). Methods: A simulation model was developed on ...

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    3. Swept-Source Optical Coherence Tomography Detection of Bruch’s Membrane and Choriocapillaris Abnormalities in Sorsby Macular Dystrophy

      Swept-Source Optical Coherence Tomography Detection of Bruch’s Membrane and Choriocapillaris Abnormalities in Sorsby Macular Dystrophy

      Purpose: Swept-source optical coherence tomography angiography (SS-OCTA) was used to analyze Bruch's membrane (BM) and choriocapillaris (CC) abnormalities in undiagnosed family members with Sorsby macular dystrophy (SMD). Methods: In a family with SMD (TIMP3 Tyr191Cys), SS-OCTA imaging was performed using the 6X6mm scan patter and previously validated algorithms to detect abnormalities in BM and the CC, as well as the presence of reticular pseudodrusen (RPD) and macular neovascularization (MNV). Genetic analyses were performed for TIMP3 mutations. Results: Of eight family members, two were previously diagnosed with SMD and six were asymptomatic. SS-OCTA imaging of the 33-year-old proband revealed type ...

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    4. Automatic geographic atrophy segmentation using optical attenuation in OCT scans with deep learning

      Automatic geographic atrophy segmentation using optical attenuation in OCT scans with deep learning

      A deep learning algorithm was developed to automatically identify, segment, and quantify geographic atrophy (GA) based on optical attenuation coefficients (OACs) calculated from optical coherence tomography (OCT) datasets. Normal eyes and eyes with GA secondary to age-related macular degeneration were imaged with swept-source OCT using 6 × 6 mm scanning patterns. OACs calculated from OCT scans were used to generate customized composite en face OAC images. GA lesions were identified and measured using customized en face sub-retinal pigment epithelium (subRPE) OCT images. Two deep learning models with the same U-Net architecture were trained using OAC images and subRPE OCT images. Model ...

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    5. Association between Different Grades of Myopic Tractional Maculopathy and OCT-Based Macular Scleral Deformation

      Association between Different Grades of Myopic Tractional Maculopathy and OCT-Based Macular Scleral Deformation

      Purpose: To investigate the characteristics of macular outward scleral height (MOSH) in different grades of myopic tractional maculopathy (MTM) and explore the risk factors for MTM. Methods: A total of 188 eyes (188 participants) with high myopia were divided into the no MTM (nMTM) group and the MTM group, which was further graded into foveoschisis, foveal detachment, full-thickness macular hole, and macular hole with retinal detachment. Swept-source optical coherence tomography was used to measure the MOSH. Results: No significant differences were found in axial length between the nMTM and MTM groups ( p = 0.295). The MOSH was significantly higher in ...

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    6. Interocular asymmetry of choroidal thickness and vascularity index measurements in normal eyes assessed by swept-source optical coherence tomography

      Interocular asymmetry of choroidal thickness and vascularity index measurements in normal eyes assessed by swept-source optical coherence tomography

      Background: To investigate the symmetry of interocular choroidal thickness and vascularity index measurements in normal eyes using swept-source optical coherence tomography (SS-OCT). Cross-sectional and observational study. This study included 244 eyes of 122 normal adults with ages uniformly distributed from 19 to 89 years. Methods: SS-OCT imaging was performed using a scanning pattern of 12×12 mm. Mean choroidal thickness (MCT) and choroidal vascularity index (CVI) measurements in the entire scanning region were obtained using a validated and published automatic method. The correlation and differences (including signed and absolute differences) between bilateral MCT and CVI measurements were analyzed at the ...

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    7. Choroidal Changes in Eyes With Polypoidal Choroidal Vasculopathy After Anti-VEGF Therapy Imaged With Swept-Source OCT Angiography

      Choroidal Changes in Eyes With Polypoidal Choroidal Vasculopathy After Anti-VEGF Therapy Imaged With Swept-Source OCT Angiography

      Purpose: Swept-source optical coherence tomography angiography was used to investigate choroidal changes and their association with pigment epithelial detachments (PEDs) in eyes with polypoidal choroidal vasculopathy (PCV) after treatment with vascular endothelial growth factor (VEGF) inhibitors. Methods: Patients with treatment-naïve PCV were included and underwent anti-VEGF therapy. Mean choroidal thickness (MCT), choroidal vascularity index (CVI), and PED volume measurements were obtained before and after treatment. Results: Thirty-four treatment-naïve PCV eyes from 33 patients were included. The PED volume decreased after treatment (P < 0.05). The MCT decreased from 223.0 ± 79.6 µm at baseline to 210.9 ...

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    8. Three-dimensional segmentation and depth-encoded visualization of choroidal vasculature using swept-source optical coherence tomography

      Three-dimensional segmentation and depth-encoded visualization of choroidal vasculature using swept-source optical coherence tomography

      The choroid provides nutritional support for the retinal pigment epithelium and photoreceptors. Choroidal dysfunction plays a major role in several of the most important causes of vision loss including age-related macular degeneration, myopic degeneration, and pachychoroid diseases such as central serous chorioretinopathy and polypoidal choroidal vasculopathy. We describe an imaging technique using depth-resolved swept-source optical coherence tomography (SS-OCT) that provides full-thickness three-dimensional (3D) visualization of choroidal anatomy including topographical features of individual vessels. Enrolled subjects with different clinical manifestations within the pachychoroid disease spectrum underwent 15 mm × 9 mm volume scans centered on the fovea. A fully automated method segmented ...

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    9. Swept-Source OCT Angiographic Characteristics of Treatment-Naïve Nonexudative Macular Neovascularization in AMD Prior to Exudation

      Swept-Source OCT Angiographic Characteristics of Treatment-Naïve Nonexudative Macular Neovascularization in AMD Prior to Exudation

      Purpose: To investigate the characteristics of treatment-naïve nonexudative macular neovascularization (MNV) in age-related macular degeneration before the onset of exudation using swept-source optical coherence tomography angiography. Methods: MNV area, choriocapillaris (CC) flow deficits (FDs), vessel area density (VAD), vessel skeleton density (VSD), retinal pigment epithelial detachment (PED) volume, mean choroidal thickness (MCT), and choroid vascularity index (CVI) measurements were assessed at two visits prior to exudation. We compared measurements made at the second visit and the rate of change between visits in eyes with and without exudation. The differences in these parameters between eyes with and without subsequent exudation ...

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    10. Choroidal Thickness by Handheld Swept-Source Optical Coherence Tomography in Term Newborns

      Choroidal Thickness by Handheld Swept-Source Optical Coherence Tomography in Term Newborns

      Purpose : To describe normative values for choroidal thickness in newborns and characterize their relationship to vitreoretinal features. Methods : Term newborns underwent awake, handheld swept-source optical coherence tomography (SS-OCT) in this prospective cohort study. An automated segmentation algorithm followed by manual adjustments measured choroidal thickness at the fovea and five perifoveal locations. Two masked, trained graders, with a third mediating disagreements, analyzed scans for vitreoretinal findings. OCT vitreoretinal findings, including dome-shaped macula, subretinal fluid, punctate hyperreflective vitreous opacities, persistent inner retinal layers, foveal ellipsoid zone, tractional and non-tractional vitreous bands, epiretinal membrane, cystoid macular edema, vessel elevation, scalloped retinal layers, hyporeflective ...

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    11. Morphologic Features of Myopic Choroidal Neovascularization in Pathologic Myopia on Swept-Source Optical Coherence Tomography

      Morphologic Features of Myopic Choroidal Neovascularization in Pathologic Myopia on Swept-Source Optical Coherence Tomography

      Purpose: To investigate the morphologic features and identify the risk factors of myopic choroidal neovascularization (CNV). Methods: Eighty-eight eyes of 69 consecutive patients with myopic CNV were included in this study. About 109 eyes of 78 pathologic myopia patients without myopic CNV were randomly selected as the control group. Morphologic features and parameters including scleral thickness (ST), choroidal thickness (CT), posterior staphyloma height and the presence of scleral perforating vessels were obtained and measured by swept-source optical coherence tomography (SS-OCT). Binary logistic regression analysis was performed to identify the risk factors for myopic CNV. Results: Patients with myopic CNV had ...

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    12. Correlations Between Choriocapillaris and Choroidal Measurements and the Growth of Geographic Atrophy using Swept Source OCT Imaging

      Correlations Between Choriocapillaris and Choroidal Measurements and the Growth of Geographic Atrophy using Swept Source OCT Imaging

      Purpose The correlations between enlargement rates (ERs) of geographic atrophy (GA) and choriocapillaris (CC) flow deficits (FDs), mean choroidal thickness (MCT), and choroidal vascularity index (CVI) were investigated using swept source optical coherence tomography (SS-OCT) in age-related macular degeneration (AMD). Design Retrospective review of prospective, observational case series. Methods Eyes with GA from AMD were imaged with SS-OCT (PLEX® Elite 9000; Carl Zeiss Meditec, Inc, Dublin, CA) using 6x6 mm scan pattern. GA lesions were identified and measured using custom en face structural images and annual square root ERs of GA were calculated. At baseline, CC FDs from different regions ...

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    13. Quantitative assessment of choriocapillaris flow deficits in diabetic retinopathy: A swept-source optical coherence tomography angiography study

      Quantitative assessment of choriocapillaris flow deficits in diabetic retinopathy: A swept-source optical coherence tomography angiography study

      Purpose To quantitatively assess choriocapillaris (CC) flow deficits in eyes with diabetic retinopathy (DR) using swept-source optical coherence tomography angiography (SS-OCTA). Methods Diabetic subjects with different stages of DR and age-matched healthy subjects were recruited and imaged with SS-OCTA. The en face CC blood flow images were generated using previously published and validated algorithms. The percentage of CC flow deficits (FD%) and the mean CC flow deficit size were calculated in a 5-mm-diameter circle centered on the fovea from the 6×6-mm scans. Results Forty-five diabetic subjects and 27 control subjects were included in the study. The CC FD% in ...

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    14. OCT Angiography to Predict Geographic Atrophy Progression using Choriocapillaris Flow Void as a Biomarker

      OCT Angiography to Predict Geographic Atrophy Progression using Choriocapillaris Flow Void as a Biomarker

      Purpose : To investigate the relationship between choriocapillaris (CC) flow void (FV) percentage and geographic atrophy (GA) growth rate, and study how variations in FV percentage surrounding GA predict regional GA growth. Methods : This prospective, longitudinal study enrolled subjects with GA secondary to nonexudative age-related macular degeneration. Optical coherence tomography angiography imaged the CC and FV percentage was evaluated using a validated algorithm. GA growth rate was measured as the difference in the square root of GA area divided by the months between baseline and follow-up imaging. Results : Twelve eyes from 7 subjects with a mean age of 80 ± 5 years ...

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    15. Impacts of Axial Length on Retinal and Choriocapillaris Blood Flow Quantification in Myopia with Swept-Source Optical Coherence Tomography Angiography

      Impacts of Axial Length on Retinal and Choriocapillaris Blood Flow Quantification in Myopia with Swept-Source Optical Coherence Tomography Angiography

      Purpose : To evaluate the impact of image magnification correction on retinal and choriocapillaris (CC) blood flow quantification using swept-source optical coherence tomography angiography (OCTA) in myopic eyes. Methods : Subjects with myopia were recruited for ocular biometry, refraction, and OCTA imaging with a 6 × 6-mm protocol. The retinal vascular area density (RVAD), retinal vascular skeleton density (RVSD), retinal flow impairment area (RFIA), percentage of CC flow deficits (FD%), and the mean size of CC flow deficits (FDs) were quantified within a 5-mm-diameter circle centered on the fovea before and after magnification correction using the Littman and the modified Bennett formulae. Results ...

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    16. Correlations between Different Choriocapillaris Flow Deficit Parameters in Normal Eyes using Swept Source OCT Angiography

      Correlations between Different Choriocapillaris Flow Deficit Parameters in Normal Eyes using Swept Source OCT Angiography

      Purpose Choriocapillaris (CC) imaging of normal eyes with swept-source optical coherence tomography SS-OCTA was performed, and the percentage of CC flow deficits (FD%) and the average area of CC flow deficits (FDa) were compared within given macular regions. Design A prospective, cross-sectional study. Methods Subjects with normal eyes ranging in age from their 20s through their 80s were imaged with SS-OCTA (PLEX Elite 9000, Carl Zeiss Meditec, Dublin, CA) using both 3x3 mm and 6x6 mm macular scan patterns. The CC images were generated using a previously published and validated algorithm. In both 3x3 mm and 6x6 mm scans, the ...

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    17. Quantifying choriocapillaris hypoperfusion in patients with choroidal neovascularization using swept-source OCT angiography

      Quantifying choriocapillaris hypoperfusion in patients with choroidal neovascularization using swept-source OCT angiography

      Purpose: To compare choriocapillaris flow voids (FV) in patients with neovascular age-related macular degeneration (AMD) with age-matched normal controls using swept-source optical coherence tomography angiography (SS-OCTA). Patients and methods: Eleven eyes of 11 subjects with neovascular AMD and 11 eyes of 11 age-similar normal subjects were imaged using SS-OCTA with a 6x6mm scanning pattern. Choriocapillaris FV, defined as a percentage of regions determined to have flow deficits divided by the total scanned region, was measured using a one standard deviation thresholding algorithm developed from a database of age-similar normal subjects. Results: Choriocapillaris FV was more extensive in patients with choroidal ...

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    18. Correlations Between Choriocapillaris Flow Deficits Around Geographic Atrophy and Enlargement Rates Based on Swept Source OCT Imaging

      Correlations Between Choriocapillaris Flow Deficits Around Geographic Atrophy and Enlargement Rates Based on Swept Source OCT Imaging

      Purpose To determine the possible correlation between the annual enlargement rates (ERs) of geographic atrophy (GA) with the percentage and size of the choriocapillaris (CC) flow deficits (FDs) surrounding GA, measured with swept source optical coherence tomography angiography (SS-OCTA) images. Design Prospective, observational case series. Participants Patients with GA secondary to non-exudative AMD. Methods Patients were imaged with a 100-kHz SS-OCTA instrument (PLEX Elite 9000, Carl Zeiss Meditec) using a 6x6 mm field of view scan pattern. GA area measurements were obtained from en face SS-OCT sub-RPE slab images. Visualization of the CC and quantification of FDs were performed using ...

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    19. Age-Dependent Changes in the Macular Choriocapillaris of Normal Eyes Imaged with Swept-Source OCT Angiography

      Age-Dependent Changes in the Macular Choriocapillaris of Normal Eyes Imaged with Swept-Source OCT Angiography

      Purpose Swept source optical coherence tomography angiography (SS-OCTA) was used to measure the age-dependent changes in macular choriocapillaris (CC) flow deficits (FDs) in normal eyes. Design A prospective, cross-sectional study. Methods Subjects with normal eyes ranging in age from their 20s to their 80s were imaged using a 100-kHz SS-OCTA instrument (PLEX ® Elite 9000, Carl Zeiss Meditec). Both 3x3 mm and 6x6 mm scans were used to image the macular CC. Visualization of the CC and quantification of FDs were performed using a previously validated algorithm. The percentage of FDs (FD%) in the central 1 mm circle (C 1 ), 1 ...

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    20. Attenuation correction assisted automatic segmentation for assessing choroidal thickness and vasculature with swept-source OCT

      Attenuation correction assisted automatic segmentation for assessing choroidal thickness and vasculature with swept-source OCT

      Swept source optical coherence tomography (SS-OCT) is being used more widely in clinical studies to investigate the choroid due to its deeper penetration under the retinal pigment epithelium and improved image quality compared with spectral domain OCT. However, automatic methods to reliably assess choroidal thickness and vasculature are still limited. This paper reports an approach that applies attenuation correction on SS-OCT structural scans to facilitate accurate automatic segmentation of the choroid and provides visualization of the choroidal vasculature without the necessity of OCT angiography. After attenuation correction, enhanced interlayer contrast at the choroidal-scleral interface was observed (from 0.13 ± 0 ...

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    21. A non‐invasive imaging and measurement using optical coherence tomography angiography for the assessment of gingiva: An in vivo study

      A non‐invasive imaging and measurement using optical coherence tomography angiography for the assessment of gingiva: An in vivo study

      Gingiva is the soft tissue that surrounds and protects the teeth. Healthy gingiva provides an effective barrier to periodontal insults to deeper tissue, thus is an important indicator to a patient’s periodontal health. Current methods in assessing gingival tissue health, including visual observation and physical examination with probing on the gingiva, are qualitative and subjective. They may become cumbersome when more complex cases are involved, such as variations in gingival biotypes where feature and thickness of the gingiva are considered. A non‐invasive imaging technique providing depth‐resolved structural and vascular information is necessary for an improved assessment of ...

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    A non‐invasive imaging and measurement using optical coherence tomography angiography for the assessment of gingiva: An in vivo study Attenuation correction assisted automatic segmentation for assessing choroidal thickness and vasculature with swept-source OCT Age-Dependent Changes in the Macular Choriocapillaris of Normal Eyes Imaged with Swept-Source OCT Angiography Correlations Between Choriocapillaris Flow Deficits Around Geographic Atrophy and Enlargement Rates Based on Swept Source OCT Imaging Quantifying choriocapillaris hypoperfusion in patients with choroidal neovascularization using swept-source OCT angiography Correlations between Different Choriocapillaris Flow Deficit Parameters in Normal Eyes using Swept Source OCT Angiography OCT Angiography to Predict Geographic Atrophy Progression using Choriocapillaris Flow Void as a Biomarker Quantitative assessment of choriocapillaris flow deficits in diabetic retinopathy: A swept-source optical coherence tomography angiography study Correlations Between Choriocapillaris and Choroidal Measurements and the Growth of Geographic Atrophy using Swept Source OCT Imaging Choroidal Thickness by Handheld Swept-Source Optical Coherence Tomography in Term Newborns The truth about invisible posterior vitreous structures Increased Macrophage-like Cell Density in Retinal Vein Occlusion as Characterized by en Face Optical Coherence Tomography