1. Articles from praveen j. patel

    1-24 of 29 1 2 »
    1. The Relationship Between Ambient Atmospheric Fine Particulate Matter (PM2.5) and Glaucoma in a Large Community Cohort

      The Relationship Between Ambient Atmospheric Fine Particulate Matter (PM2.5) and Glaucoma in a Large Community Cohort

      Purpose : Glaucoma is more common in urban populations than in others. Ninety percent of the world's population are exposed to air pollution above World Health Organization (WHO) recommended limits. Few studies have examined the association between air pollution and glaucoma. Methods : Questionnaire data, ophthalmic measures, and ambient residential area air quality data for 111,370 UK Biobank participants were analyzed. Particulate matter with an aerodynamic diameter < 2.5 μm (PM 2.5 ) was selected as the air quality exposure of interest. Eye measures included self-reported glaucoma, intraocular pressure (IOP), and average thickness of macular ganglion cell–inner plexiform layer ...

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    2. Objective evaluation of proliferative diabetic retinopathy using optical coherence tomography

      Objective evaluation of proliferative diabetic retinopathy using optical coherence tomography

      Purpose To present the routine use of optical coherence tomography (OCT) and OCT angiography (OCTA) for the objective diagnosis and monitoring of proliferative diabetic retinopathy (PDR). Design Retrospective observational case series. Subjects Patients with diabetic retinopathy imaged using a standardized PDR-protocol Methods Patients routinely imaged with a standardized PDR-protocol between March 2017 and January 2019 were included. This included a 12x9 mm structural OCT volume centered on the macula and a 6x6 mm OCTA scan centered on the optic nerve head obtained using a Topcon swept-source system (DRI OCT-1 Triton, Topcon, Tokyo, Japan). Ultra-widefield fluorescein angiography (FA) was also performed ...

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    3. Effect of total anti-VEGF treatment exposure on patterns of choroidal neovascularisation assessed by optical coherence tomography angiography in age-related macular degeneration: a retrospective case series

      Effect of total anti-VEGF treatment exposure on patterns of choroidal neovascularisation assessed by optical coherence tomography angiography in age-related macular degeneration: a retrospective case series

      Objective To compare clinical characteristics of patients suffering from neovascular age-related macular degeneration (nAMD) with mature and immature choroidal neovascularisation (CNV) as assessed by optical coherence tomography angiography (OCTA). To explore the effect of total anti-vascular endothelial growth factor exposure on the occurrence of mature CNV when correcting for potential confounders. Methods and analysis In this retrospective case series, we included 40 eyes of 36 patients with nAMD with CNV assessed by OCTA at the Manchester Eye Hospital between June 2016 and June 2017. A retinal specialist masked to patient information graded CNV depicted on OCTA scans. For statistical comparisons ...

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    4. Feature Of The Week 07/08/2018: Retinal Nerve Fibre Layer Thickness & Cognition - Results from UK Biobank

      Feature Of The Week 07/08/2018: Retinal Nerve Fibre Layer Thickness & Cognition - Results from UK Biobank

      Importance: Identifing potential screening tests for future cognitive decline is a priority for developing treatments for and the prevention of dementia. Objective: To examine the potential of retinal nerve fiber layer (RNFL) thickness measurement in identifying those at greater risk of cognitive decline in a large community cohort of healthy people. Design, Setting, and Participants: UK Biobank is a prospective, multicenter, community-based study of UK residents aged 40 to 69 years at enrollment who underwent baseline retinal optical coherence tomography imaging, a physical examination, and a questionnaire. The pilot study phase was conducted from March 2006 to June 2006, and ...

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    5. Association of Retinal Nerve Fiber Layer Thinning With Current and Future Cognitive Decline A Study Using Optical Coherence Tomography

      Association of Retinal Nerve Fiber Layer Thinning With Current and Future Cognitive Decline A Study Using Optical Coherence Tomography

      Importance Identifing potential screening tests for future cognitive decline is a priority for developing treatments for and the prevention of dementia. Objective To examine the potential of retinal nerve fiber layer (RNFL) thickness measurement in identifying those at greater risk of cognitive decline in a large community cohort of healthy people. Design, Setting, and Participants UK Biobank is a prospective, multicenter, community-based study of UK residents aged 40 to 69 years at enrollment who underwent baseline retinal optical coherence tomography imaging, a physical examination, and a questionnaire. The pilot study phase was conducted from March 2006 to June 2006, and ...

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    6. Characteristic optical coherence tomography findings in patients with primary vitreoretinal lymphoma: a novel aid to early diagnosis

      Characteristic optical coherence tomography findings in patients with primary vitreoretinal lymphoma: a novel aid to early diagnosis

      Background The diagnosis of primary vitreoretinal lymphoma (PVRL) poses significant difficulties; presenting features are non-specific and confirmation usually necessitates invasive vitreoretinal biopsy. Diagnosis is often delayed, resulting in increased morbidity and mortality. Non-invasive imaging modalities such as spectral domain optical coherence tomography (SD-OCT) offer simple and rapid aids to diagnosis. We present characteristic SD-OCT images of patients with biopsy-positive PVRL and propose a number of typical features, which we believe are useful in identifying these lesions at an early stage. Methods Medical records of all patients attending Moorfields Eye Hospital between April 2010 and April 2016 with biopsy-positive PVRL were ...

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    7. Agreement of swept-source and spectral-domain optical coherence-tomography retinal thickness measurements in neovascular age-related macular degeneration

      Agreement of swept-source and spectral-domain optical coherence-tomography retinal thickness measurements in neovascular age-related macular degeneration

      Changes in macular thickness measurements in neovascular age-related macular degeneration (nAMD) are thought to reflect disease activity, and can be used to guide treatment with antiangiogenic agents. 1 Both spectral-domain optical coherence tomography (SD-OCT) and the more recently introduced swept-source optical coherence tomography (SS-OCT) have onboard segmentation algorithms that deliver automated retinal thickness measurements. Agreement between OCT derived macular thickness measurements is critical for monitoring of patients if these modalities are to be used interchangeably. This prospective cross-sectional study sought to determine the limits of agreement between SD-OCT (Spectralis; Heidelberg Engineering) and SS-OCT (DRI OCT-1 Atlantis; Topcon Medical Systems) in ...

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    8. 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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    9. Optical Coherence Tomography in the UK Biobank Study – Rapid Automated Analysis of Retinal Thickness for Large Population-Based Studies

      Optical Coherence Tomography in the UK Biobank Study – Rapid Automated Analysis of Retinal Thickness for Large Population-Based Studies

      Purpose To describe an approach to the use of optical coherence tomography (OCT) imaging in large, population-based studies, including methods for OCT image acquisition, storage, and the remote, rapid, automated analysis of retinal thickness. Methods In UK Biobank, OCT images were acquired between 2009 and 2010 using a commercially available “spectral domain” OCT device (3D OCT-1000, Topcon). Images were obtained using a raster scan protocol, 6 mm x 6 mm in area, and consisting of 128 B-scans. OCT image sets were stored on UK Biobank servers in a central repository, adjacent to high performance computers. Rapid, automated analysis of retinal ...

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    10. Repeatability of swept-source optical coherence tomography retinal and choroidal thickness measurements in neovascular age-related macular degeneration

      Repeatability of swept-source optical coherence tomography retinal and choroidal thickness measurements in neovascular age-related macular degeneration

      Background The aim was to determine the intrasession repeatability of swept-source optical coherence tomography (SS-OCT)-derived retinal and choroidal thickness measurements in eyes with neovascular age-related macular degeneration (nAMD). Methods A prospective study consisting of patients with active nAMD enrolled in the Distance of Choroid Study at Moorfields Eye Hospital, London. Patients underwent three 12×9 mm macular raster scans using the deep range imaging (DRI) OCT-1 SS-OCT (Topcon) device in a single imaging session. Retinal and choroidal thicknesses were calculated for the ETDRS macular subfields. Repeatability was calculated according to methods described by Bland and Altman. Results 39 eyes ...

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    11. Spectral-domain optical coherence tomography retinal and choroidal thickness metric repeatability in age related macular degeneration - American Journal of Ophthalmology

      Spectral-domain optical coherence tomography retinal and choroidal thickness metric repeatability in age related macular degeneration - American Journal of Ophthalmology

      Purpose To determine the intrasession repeatability of spectral domain-OCT (SD-OCT)-derived macular retinal and choroidal metrics in patients with neovascular age-related macular degeneration (nAMD) in the Distance of Choroid Study (DOCS) Design Validity and reliability analysis Methods Enrolled patients underwent repeated SD-OCT imaging using the Spectralis OCT. A single technician certified for clinical trials took 3 macular volume scans. Retinal thicknesses were calculated for each of the nine Early Treatment Diabetic Retinopathy Study (ETDRS) macular subfields. Center-point thickness and total macular volume were also included in the analysis. Manual subfoveal choroidal thickness measurements were made by a masked observer. Results ...

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    12. Spectral-Domain Optical Coherence Tomography Imaging in 67,321 Adults

      Spectral-Domain Optical Coherence Tomography Imaging in 67,321 Adults

      Purpose To derive macular thickness measures and their associations by performing rapid, automated segmentation of spectral-domain optical coherence tomography (SD OCT) images collected and stored as part of the UK Biobank (UKBB) study. Design Large, multisite cohort study in the United Kingdom. Analysis of cross-sectional data. Participants Adults from the United Kingdom aged 40 to 69 years. Methods Participants had nonmydriatic SD OCT (Topcon 3D OCT-1000 Mark II; Topcon GB, Newberry, Berkshire, UK) performed as part of the ocular assessment module. Rapid, remote, automated segmentation of the images was performed using custom optical coherence tomography (OCT) image analysis software (Topcon ...

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    13. Interobserver agreement in detecting spectral-domain optical coherence tomography features of diabetic macular edema

      Interobserver agreement in detecting spectral-domain optical coherence tomography features of diabetic macular edema

      Purpose To evaluate interobserver agreement for the detection of spectral-domain optical coherence tomography (SDOCT) features of diabetic macular edema (DME). Method Cross-sectional study in which 2 retinal specialists evaluated SDOCT scans from eyes receiving treatment for DME. Scans from 50 eyes with DME of 39 patients were graded for features of DME including intra-retinal fluid (IRF), diffuse retinal oedema (DRE), hyper-reflective foci (HRF), subretinal fluid (SRF), macular fluid and vitreomacular traction (VMT). Features were graded as present or absent at zones involving the fovea, 1mm from the fovea and the whole scan of 49 line scans. Analysis was performed using ...

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    14. 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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    15. Ophthalmic imaging

      Ophthalmic imaging

      Introduction or background The last two decades have seen a revolution in ophthalmic imaging. In this review we present an overview of the breadth of ophthalmic imaging modalities in use today and describe how the role of ophthalmic imaging has changed from documenting abnormalities visible on clinical examination to the detection of clinically silent abnormalities which can lead to an earlier and more precise diagnosis. Sources of data This review is based on published literature in the fields of ophthalmic imaging and with focus on most commonly used imaging modalities. Areas of agreement New imaging techniques enable non-invasive evaluation of ...

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    16. Characterization of Punctate Inner Choroidopathy Using Enhanced Depth Imaging Optical Coherence Tomography

      Characterization of Punctate Inner Choroidopathy Using Enhanced Depth Imaging Optical Coherence Tomography

      Purpose To perform qualitative and quantitative analyses of retinal and choroidal morphology in patients with punctate inner choroidopathy (PIC) using enhanced depth imaging optical coherence tomography (EDI-OCT). Design Cross-sectional, consecutive series. Participants A total of 2242 patients attending 2 tertiary referral uveitis clinics at Moorfields Eye Hospital were screened; 46 patients with PIC diagnosis were identified, and 35 eyes (35 patients) had clinically inactive PIC had EDI-OCT images that met the inclusion criteria. Methods Punctate inner choroidopathy lesions were qualitatively assessed for retinal features, such as (1) focal elevation of the retinal pigment epithelium (RPE), (2) focal atrophy of the ...

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    17. Quantitative Analysis of Diabetic Macular Ischemia using Optical Coherence Tomography

      Quantitative Analysis of Diabetic Macular Ischemia using Optical Coherence Tomography

      Purpose: To describe the optical coherence tomography (OCT) features of diabetic macular ischemia (DMI), and correlate these findings with visual acuity (VA). Methods: Clinical and imaging data were collected from 100 patients with type 2 diabetes. Qualitative grading of DMI severity was determined according to criteria defined by the Early Treatment Diabetic Retinopathy Study. Quantitative analysis of foveal avascular zone (FAZ), and OCT images were performed using custom software. Results: In all eyes, the outer retina was thicker in eyes with DMI, (167.4 ± 18.5 µm) versus (150.4 ± 31.4 µm) (p=0.04). However, sub analysis of ...

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    18. Using Spectral-Domain Optical Coherence Tomography Imaging to Identify the Presence of Retinal Silicone Oil Emulsification After Silicone Oil Tamponade

      Using Spectral-Domain Optical Coherence Tomography Imaging to Identify the Presence of Retinal Silicone Oil Emulsification After Silicone Oil Tamponade

      Purpose: To describe small hyperreflective areas using spectral-domain optical coherence tomography (SD-OCT) imaging in eyes that have had silicone oil tamponade. Methods: Retrospective case series of 11 eyes of 11 patients. The authors retrospectively identified patients who underwent vitrectomy and silicone oil tamponade secondary to a rhegmatogenous retinal detachment (nine patients), panuveitis with retinal necrosis (one patient), or recurrent full-thickness macular hole surgery (one patient) who had manifestations of silicone oil emulsion on SD-OCT imaging. Patients were monitored during the postoperative period by clinical examination and using SD-OCT. A model eye in which emulsified silicone oil had been injected in ...

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    19. Choroidal assessment in idiopathic panuveitis using optical coherence tomography

      Choroidal assessment in idiopathic panuveitis using optical coherence tomography

      Background Idiopathic panuveitis is a diagnosis of exclusion that lacks distinguishing features on fluorescein and indocyanine green angiography. Choroidal hypoperfusion or ischaemia has been implicated in panuveitis of different aetiologies. In this study, we use enhanced depth imaging optical coherence tomography (OCT) to examine the choroid and its vasculature in patients with this disease. Methods In this retrospective, cross-sectional study, OCT-derived measurements of retinal and choroidal thickness were obtained after manual segmentation using custom software. Choroidal measurements were further subdivided into Haller’s large vessel layer (HLVL) and Sattler’s medium vessel layer (SMVL), and correlated with clinical parameters. Results ...

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    20. Repeatability and Reproducibility of Choroidal Vessel Layer Measurements in Diabetic Retinopathy using Enhanced Depth Optical Coherence Tomography

      Repeatability and Reproducibility of Choroidal Vessel Layer Measurements in Diabetic Retinopathy using Enhanced Depth Optical Coherence Tomography

      Purpose: To describe novel segmentation protocols for choroidal layers - Sattler's medium and Haller's large vessel layers, using enhanced depth imaging optical coherence tomography (EDI-OCT), and to examine the repeatability and reproducibility of these measurements in eyes with diabetic retinopathy. Methods: Fifty-one patients with Type 2 diabetes mellitus were imaged using custom EDI scanning protocols. Detailed segmentation was performed to quantify the retina, choroid, Haller's large, and Sattler's medium vessel layers in the total macular circle (TMC) and foveal central subfield (FCS). The coefficient of repeatability (CR) and intraclass correlation coefficient (ICC) were used as a measure ...

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    21. Repeatability of Spectralis OCT measurements of macular thickness and volume in diabetic macular edema

      Repeatability of Spectralis OCT measurements of macular thickness and volume in diabetic macular edema

      Purpose. We estimated coefficients of repeatability for Spectralis optical coherence tomography ( OCT )–derived automated retinal thickness and volume measurements in subjects with center- involving diabetic macular edema (DME). Methods. A total of 50 eyes of 50 consecutive patients with center-involving DME underwent four consecutive “fast” volume scans at a single session using one OCT device operated by one of two experienced operators. Bl and -Altman coefficients of repeatability (CR) were calculated for automated reinal thickness measurements in the nine Early Treatment of Diabetic Retinopathy Study (ETDRS) subfields, center point thickness , and total macular volume . Scans were evaluated for significant automated ...

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    22. Evaluation of Age-related Macular Degeneration With Optical Coherence Tomography

      Evaluation of Age-related Macular Degeneration With Optical Coherence Tomography

      Abstract: Age-related macular degeneration (AMD) is the leading cause of severe visual loss in people aged 50 years or older in the developed world. In recent years, major advances have been made in the treatment of AMD, with the introduction of anti-angiogenic agents, offering the first hope of significant visual recovery for patients with neovascular AMD. In line with these advances, a new imaging modality—optical coherence tomography (OCT)—has emerged as an essential adjunct for the diagnosis and monitoring of patients with AMD. The ability to accurately interpret OCT images is thus a prerequisite for both retina specialists and ...

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    23. Assessment of Differential Pharmacodynamic Effects using Optical Coherence Tomography in Neovascular Age-Related Macular Degeneration

      Assessment of Differential Pharmacodynamic Effects using Optical Coherence Tomography in Neovascular Age-Related Macular Degeneration

      Purpose: To assess the differential pharmacodynamic effects of bevacizumab (Avastin), pegaptanib (Macugen), and verteporfin photodynamic therapy (PDT), using novel OCT parameters, in a recently completed phase III/IV clinical trial. Methods: Data from 122 patients participating in the Avastin (Bevacizumab) for Choroidal neovascularization (ABC) trial, were evaluated. Stratus OCT images were analyzed using custom software - changes in volume of the neurosensory retina, subretinal fluid (SRF), pigment epithelium detachment (PED), and subretinal tissue, were calculated over the 54-week trial period. Results: Reductions in retinal oedema were more than twice as great from bevacizumab than pegaptanib (-0.82 mm3 versus -0.31 ...

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    24. 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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    1. (29 articles) Praveen J. Patel
    2. (18 articles) University College London
    3. (15 articles) Adnan Tufail
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    Topographic variation and interocular symmetry of macular choroidal thickness using enhanced depth imaging optical coherence tomography Assessment of Differential Pharmacodynamic Effects using Optical Coherence Tomography in Neovascular Age-Related Macular Degeneration Evaluation of Age-related Macular Degeneration With Optical Coherence Tomography Repeatability of Spectralis OCT measurements of macular thickness and volume in diabetic macular edema Association of Retinal Nerve Fiber Layer Thinning With Current and Future Cognitive Decline A Study Using Optical Coherence Tomography Special Section Guest Editorial: Advances in Retinal Imaging Optical coherence tomography angiography-derived flow density: a review of the influencing factors Changes in retinal and choriocapillaris density in diabetic patients receiving anti-vascular endothelial growth factor treatment using optical coherence tomography angiography Optical coherence tomography of patients with Parkinson’s disease and progressive supranuclear palsy Automatic quantification of superficial foveal avascular zone in optical coherence tomography angiography implemented with deep learning OCT-Based Periodontal Inspection Framework New World Resources and Perimeter Medical Imaging Provide Updates Regarding Their Amalgamation Transaction and Announce Amended and Restated Arrangement Agreement