1. Articles from Anna C. S. Tan

    1-15 of 15
    1. The Application of Optical Coherence Tomography Angiography in Systemic Hypertension: A Meta-Analysis

      The Application of Optical Coherence Tomography Angiography in Systemic Hypertension: A Meta-Analysis

      Objective: Multiple studies have compared various optical coherence tomography angiography (OCTA) parameters in participants with systemic hypertension vs. controls and have presented discordant findings. We conducted a meta-analysis to pool together data from different studies to generate an overall effect size and find out whether OCTA parameter(s) significantly differed in participants with systemic hypertension as compared to controls. Methods: We conducted a literature search through a search of electronic databases to identify studies before 19 June 2021, which compared OCTA parameters in non-diabetic participants with systemic hypertension vs. controls. If the OCTA parameter had a minimum number of 3 ...

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    2. Developing a normative database for retinal perfusion using optical coherence tomography angiography

      Developing a normative database for retinal perfusion using optical coherence tomography angiography

      Visualizing and characterizing microvascular abnormalities with optical coherence tomography angiography (OCTA) has deepened our understanding of ocular diseases, such as glaucoma, diabetic retinopathy, and age-related macular degeneration. Two types of microvascular defects can be detected by OCTA: focal decrease because of localized absence and collapse of retinal capillaries, which is referred to as the non-perfusion area in OCTA, and diffuse perfusion decrease usually detected by comparing with healthy case-control groups. Wider OCTA allows for insights into peripheral retinal vascularity, but the heterogeneous perfusion distribution from the macula, parapapillary area to periphery hurdles the quantitative assessment. A normative database for OCTA ...

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    3. Anterior segment optical coherence tomography angiography for iris vasculature in pigmented eyes

      Anterior segment optical coherence tomography angiography for iris vasculature in pigmented eyes

      Purpose To compare anterior segment optical coherence tomography angiography (AS-OCTA) systems in delineating normal iris vessels and iris neovascularisation (NVI) in eyes with pigmented irides. Methods Prospective study from January 2019 to June 2019 of 10 consecutive patients with normal pigmented iris, had AS-OCTA scans with a described illumination technique, before using the same protocol in five eyes with NVI (clinical stages 1–3). All scans were sequentially performed using a spectral-domain OCTA (SD-OCTA), and a swept-source OCTA (SS-OCTA, Plex Elite 9000). Images were graded by two masked observers for visibility, artefacts and NVI characteristics. The main outcome measure was ...

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    4. Systemic hypertension associated retinal microvascular changes can be detected with optical coherence tomography angiography

      Systemic hypertension associated retinal microvascular changes can be detected with optical coherence tomography angiography

      A major complication of hypertension is microvascular damage and capillary rarefaction is a known complication of hypertensive end-organ damage which confers a higher risk of systemic disease such as stroke and cardiovascular events. Our aim was to study the effect of hypertension on the retinal microvasculature using non-invasive optical coherence tomography angiography (OCTA). We performed a case-control study of 94 eyes of 94 participants with systemic hypertension and 46 normal control eyes from the Singapore Chinese Eye Study using a standardized protocol to collect data on past medical history of hypertension, including the number and type of hypertensive medications and ...

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    5. Optical coherence tomography characteristics of taxane-induced macular edema and other multimodal imaging findings

      Optical coherence tomography characteristics of taxane-induced macular edema and other multimodal imaging findings

      Purpose To identify common optical coherence tomography (OCT) characteristics of taxane-related CME (T-CME) to differentiate it from CME associated with other causes (O-CME) and to present multimodal imaging findings of T-CME. Methods To differentiate T-CME from O-CME, pooled SD-OCT images from 14 previous publications and images obtained from our multicenter case series of 3 patients with multimodal imaging of T-CME were compared with 16 consecutive cases of O-CME. Images were graded by 2 masked retinal specialists based on the presence of pre-specified OCT characteristics such as CME centered around fovea, outer retinal cysts more prominent compared with inner retinal cysts ...

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    6. DIABETIC MACULAR ISCHEMIA Correlation of Retinal Vasculature Changes by Optical Coherence Tomography Angiography and Functional Deficit

      DIABETIC MACULAR ISCHEMIA Correlation of Retinal Vasculature Changes by Optical Coherence Tomography Angiography and Functional Deficit

      Purpose: To examine the relationship between macular microvasculature parameters and functional changes in persons with diabetic retinopathy (DR). Methods: Cross-sectional study of 76 eyes with varying levels of DR. Optical coherence tomography angiography (OCTA) quantified superficial and deep perifoveal vessel densities and foveal avascular zone areas. Retinal sensitivity was measured using microperimetry . Optical coherence tomography angiography parameters and retinal sensitivity were correlated. Results: Deep perifoveal vessel density decreased with increasing severity of DR (adjusted mean 51.93 vs. 49.89 vs. 47.96, P -trend = 0.005). Superficial and deep foveal avascular zone area increased with increasing DR severity (adjusted ...

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    7. Optical coherence tomography angiography in diabetic retinopathy: a review of current applications

      Optical coherence tomography angiography in diabetic retinopathy: a review of current applications

      Background Diabetic retinopathy (DR) is a leading cause of vision loss in adults. Currently, the standard imaging technique to monitor and prognosticate DR and diabetic maculopathy is dye-based angiography. With the introduction of optical coherence tomography angiography (OCTA), it may serve as a potential rapid, non-invasive imaging modality as an adjunct. Main text Recent studies on the role of OCTA in DR include the use of vascular parameters e.g., vessel density, intercapillary spacing, vessel diameter index, length of vessels based on skeletonised OCTA, the total length of vessels, vascular architecture and area of the foveal avascular zone. These quantitative ...

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    8. Future clinical applicability of optical coherence tomography angiography

      Future clinical applicability of optical coherence tomography angiography

      Optical coherence tomography angiography (OCT‐A) is an emerging technology that allows for the non‐invasive imaging of the ocular microvasculature. Despite the wealth of observations and numerous research studies illustrating the potential clinical uses of OCT‐A, this technique is currently rarely used in routine clinical settings. In this review, technical and clinical aspects of OCT‐A imaging are discussed, and the future clinical potential of OCT‐A is considered. An understanding of the basic principles and limitations of OCT‐A technology will better inform clinicians of its future potential in the diagnosis and management of ocular diseases.

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    9. Imaging Of Pigment Epithelial Detachments With Optical Coherence Tomography Angiography

      Imaging Of Pigment Epithelial Detachments With Optical Coherence Tomography Angiography

      Purpose: To investigate the utility of optical coherence tomography angiography (OCTA) for detecting pathologic vascularization within pigment epithelial detachments (PEDs). Methods: This was a retrospective, cross-sectional, consecutive case series. Multimodal imaging (structural OCT, fluorescein, and indocyanine green angiography) was used as the gold standard to classify PEDs as nonvascularized or vascularized. Optical coherence tomography angiography imaging of the PED was subsequently and independently evaluated to classify PEDs as vascularized or nonvascularized. Specifically, OCTA images were evaluated for the presence of abnormal flow on cross-sectional OCTA and the presence of a vascular complex on en face OCTA. Comparisons between OCTA and ...

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    10. Optical coherence tomography angiography: a review of current and future clinical applications

      Optical coherence tomography angiography: a review of current and future clinical applications

      Optical coherence tomography angiography is a non-invasive imaging technique that now allows for simultaneous in vivo imaging of the morphology as well as the vasculature in the eye. In this review, we provide an update on the existing clinical applications of optical coherence tomography angiography technology from the anterior to posterior segment of the eye. We also discuss the limitations of optical coherence tomography angiography technology, as well as the caveats to the interpretation of images. As current optical coherence tomography angiography systems are optimized for the retina, most studies have focused on interpreting images from conditions such as age ...

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    11. Identification of imaging features that determine quality and repeatability of retinal capillary plexus density measurements in OCT angiography

      Identification of imaging features that determine quality and repeatability of retinal capillary plexus density measurements in OCT angiography

      Purpose Optical coherence tomography angiography (OCT-A) potentially allows for rapid and non-invasive quantification of retinal capillary plexus density in various disease states. This study aims to identify the key features that influenced the repeatability of OCT-A measurements. Methods We obtained OCT-A images on two separate visits in 44 healthy eyes from 44 subjects, each imaged with using the Topcon DRI OCT Triton imaging system. The parafoveal vessel density within a 1.5 mm radius centred over the fovea was obtained with the built-in tool for the superficial and deep retinal plexuses. Repeatability of vessel density was determined by intraclass correlation ...

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    12. The Evolution of the Plateau, an Optical Coherence Tomography Signature Seen in Geographic Atrophy

      The Evolution of the Plateau, an Optical Coherence Tomography Signature Seen in Geographic Atrophy

      Purpose : Histologic details of progression routes to geographic atrophy (GA) in AMD are becoming available through optical coherence tomography (OCT). We studied the origins and evolution of an OCT signature called plateau in eyes with GA and suggested a histologic correlate. Methods : Serial eye-tracked OCT scans and multimodal imaging were acquired from eight eyes of seven patients with GA and plateau signatures over a mean follow-up of 7.7 years (range, 3.7–11.6). The histology of unrelated donor eyes with AMD was reviewed. Results : Drusenoid pigment epithelial detachment (PED) on OCT imaging progressed into wide-based mound-like signatures with ...

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    13. TYPE 3 NEOVASCULARIZATION IMAGED WITH CROSS-SECTIONAL AND EN FACE OPTICAL COHERENCE TOMOGRAPHY ANGIOGRAPHY

      TYPE 3 NEOVASCULARIZATION IMAGED WITH CROSS-SECTIONAL AND EN FACE OPTICAL COHERENCE TOMOGRAPHY ANGIOGRAPHY

      Purpose: To study the cross-sectional and en face optical coherence tomography angiography (OCTA) findings in Type 3 neovascularization (NV). Methods: Optical coherence tomography angiography imaging of 27 eyes of 23 patients with Type 3 NV was analyzed with 9 eyes having consecutive follow-up OCTA studies. Results: Type 3 NV appeared as a linear high-flow structure on cross-sectional OCTA corresponding to a high-flow tuft of vessels seen on en face OCTA. Cross-sectional OCTA seemed to enable the distinction between vascular and nonvascular intraretinal hyperreflective foci. Two patterns of flow were observed; Pattern 1 (11%): a flow signal confined to the neurosensory ...

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    14. Swept Source Optical Coherence Tomography Angiography for Contact Lens-Related Corneal Vascularization

      Swept Source Optical Coherence Tomography Angiography for Contact Lens-Related Corneal Vascularization

      Purpose . To describe a novel technique of adapting a swept-source optical coherence tomography angiography (OCTA) to image corneal vascularization. Methods . In this pilot cross-sectional study, we obtained 3 × 3 mm scans, where 100,000 A-scans are acquired per second with optical axial resolution of 8  μ m and lateral resolution of 20  μ m. This was performed with manual “XYZ” focus without the anterior segment lens, until the focus of the corneoscleral surface was clearly seen and the vessels of interest were in focus on the corresponding red-free image. En face scans were evaluated based on image quality score and repeatability. Results ...

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    15. Optical coherence tomography angiography of type 3 neovascularisation in age-related macular degeneration after antiangiogenic therapy

      Optical coherence tomography angiography of type 3 neovascularisation in age-related macular degeneration after antiangiogenic therapy

      Background/aims To assess the microvascular response of type 3 neovascularisation secondary to age-related macular degeneration (AMD) after antivascular endothelial growth factor (anti-VEGF) therapy using optical coherence tomography angiography (OCTA). Methods Consecutive patients diagnosed with AMD and type 3 neovascularisation based on clinical examination, structural optical coherence tomography and fluorescein angiography when available were retrospectively evaluated. En face OCTA imaging (3×3 mm scans) with quantitative microvascular analysis was performed at baseline and after a single anti-VEGF intravitreal injection. Results 17 eyes of 14 patients underwent OCTA before and after anti-VEGF treatment. OCTA demonstrated significant regression of small calibre type ...

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    1-15 of 15
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    Optical coherence tomography angiography of type 3 neovascularisation in age-related macular degeneration after antiangiogenic therapy Swept Source Optical Coherence Tomography Angiography for Contact Lens-Related Corneal Vascularization TYPE 3 NEOVASCULARIZATION IMAGED WITH CROSS-SECTIONAL AND EN FACE OPTICAL COHERENCE TOMOGRAPHY ANGIOGRAPHY The Evolution of the Plateau, an Optical Coherence Tomography Signature Seen in Geographic Atrophy Identification of imaging features that determine quality and repeatability of retinal capillary plexus density measurements in OCT angiography Optical coherence tomography angiography: a review of current and future clinical applications Imaging Of Pigment Epithelial Detachments With Optical Coherence Tomography Angiography Future clinical applicability of optical coherence tomography angiography Optical coherence tomography angiography in diabetic retinopathy: a review of current applications Anterior segment optical coherence tomography angiography for iris vasculature in pigmented eyes Optical coherence tomography findings in patients with transfusion-dependent β-thalassemia Higher-order regression three-dimensional motion-compensation method for real-time optical coherence tomography volumetric imaging of the cornea