1. Articles in category: Ophthalmology

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    1. Effect of Pterygium Removal Combined with Conjunctival Autograft on Corneal Parameters in Swept-Source Imaging

      Effect of Pterygium Removal Combined with Conjunctival Autograft on Corneal Parameters in Swept-Source Imaging

      Background: Both pterygium ingrowth and excision determine alterations in corneal topography. The aim of this study was to evaluate the influence of pterygium removal combined with conjunctival autografts in addition to the use of human fibrin tissue glue on changes in corneal parameters as measured by 3-D swept-source anterior segment optical coherence tomography (AS-OCT) imaging. Methods: Sixteen eyes (16 patients) with pterygium that qualified for surgical treatment were enrolled in this study. Eye examination, slit lamp, and 3-D AS-OCT (CASIA 2) assessment were performed before the surgery and 7 days, 1 month, and 6 months after pterygium excision. Topographic parameters ...

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    2. Interleaving Automatic Segmentation and Expert Opinion for Retinal Conditions

      Interleaving Automatic Segmentation and Expert Opinion for Retinal Conditions

      Optical coherence tomography (OCT) has become the leading diagnostic tool in modern ophthalmology. We are interested here in developing a support tool for the segmentation of retina layers. The proposed method relies on graph theory and geodesic distance. As each retina layer is characterised by different features, the proposed method interleaves various gradients during detection, such as horizontal and vertical gradients or open-closed gradients. The method was tested on a dataset of 750 OCT B-Scan Spectralis provided by the Ophthalmology Department of the County Emergency Hospital Cluj-Napoca. The method has smaller signed error on layers B1, B7 and B8, with ...

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    3. Noninvasive Estimation of Pulsatile and Static Intracranial Pressure by Optical Coherence Tomography

      Noninvasive Estimation of Pulsatile and Static Intracranial Pressure by Optical Coherence Tomography

      Purpose: To explore the ability of optical coherence tomography (OCT) to noninvasively estimate pulsatile and static intracranial pressure (ICP). Methods: An OCT examination was performed in patients who underwent continuous overnight monitoring of the pulsatile and static ICP for diagnostic purpose. We included two patient groups, patients with idiopathic intracranial hypertension (IIH; n = 20) and patients with no verified cerebrospinal fluid disturbances (reference; n = 12). Several OCT parameters were acquired using spectral-domain OCT (RS-3000 Advance; NIDEK, Singapore). The ICP measurements were obtained using a parenchymal sensor (Codman ICP MicroSensor; Johnson & Johnson, Raynham, MA, USA). The pulsatile ICP was determined as ...

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      Mentions: Nidek
    4. Choroidal Lymphoma: Diagnostic Value of Combined Indocyanine Green Angiography and Optical Coherence Tomography

      Choroidal Lymphoma: Diagnostic Value of Combined Indocyanine Green Angiography and Optical Coherence Tomography

      Objective: To compare multimodal imaging findings in patients with choroidal lymphoma (CL). Methods: Multicenter retrospective observational case series. Multimodal imaging features of patients with CL were reviewed with particular attention to the patterns of choroidal infiltration on indocyanine green angiography (ICGA) and optical coherence tomography (OCT). Results: Eighteen eyes of 15 patients were included in this study. Average tumor thickness on ultrasonography was 2.6 mm (range, 1.2-5.7 mm). Choroidal infiltration on ICGA was characterized by multifocal, round areas (300-500 microns diameter) of hypocyanescence in all cases, whereas OCT at the same region disclosed diffuse choroidal infiltration. By ...

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    5. High speed, long range, deep penetration swept source OCT for structural and angiographic imaging of the anterior eye

      High speed, long range, deep penetration swept source OCT for structural and angiographic imaging of the anterior eye

      This study reports the development of prototype swept-source optical coherence tomography (SS-OCT) technology for imaging the anterior eye. Advances in vertical-cavity surface-emitting laser (VCSEL) light sources, signal processing, optics and mechanical designs, enable a unique combination of high speed, long range, and deep penetration that addresses the challenges of anterior eye imaging. We demonstrate SS-OCT with a 325 kHz A-scan rate, 12.2 µm axial resolution (in air), and 15.5 mm depth range (in air) at 1310 nm wavelength. The ultrahigh 325 kHz A-scan rate not only facilitates biometry measurements by minimizing acquisition time and thus reducing motion, but ...

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    6. Lateral Resolution of a Commercial Optical Coherence Tomography Instrument

      Lateral Resolution of a Commercial Optical Coherence Tomography Instrument

      Purpose : The lateral resolution of an optical coherence tomography (OCT) instrument was considered to be equal to the illumination spot size on the retina. To evaluate the potential lateral resolution of the Spectralis OCT, an instrument calculated to have a 14 µm resolution. Methods : The lateral point spread function (PSF) was evaluated using diamond abrasive powder 0 to 1 µm in diameter in silicone elastomer and a validated target with 800 nm FeO particles in urethane. The amplitude transfer function was calculated from human OCT images. Finally, resolution was measured using the 1951 USAF target. Results : Measurement of the lateral ...

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    7. Automated foveal location detection on spectral-domain optical coherence tomography in geographic atrophy patients

      Automated foveal location detection on spectral-domain optical coherence tomography in geographic atrophy patients

      Purpose: To develop a fully automated algorithm for accurate detection of fovea location in atrophic age-related macular degeneration (AMD), based on spectral-domain optical coherence tomography (SD-OCT) scans. Methods: Image processing was conducted on a cohort of patients affected by geographic atrophy (GA). SD-OCT images (cube volume) from 55 eyes (51 patients) were extracted and processed with a layer segmentation algorithm to segment Ganglion Cell Layer (GCL) and Inner Plexiform Layer (IPL). Their en face thickness projection was convolved with a 2D Gaussian filter to find the global maximum, which corresponded to the detected fovea. The detection accuracy was evaluated by ...

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    8. Evaluation of the choriocapillaris after photodynamic therapy for chronic central serous chorioretinopathy. A review of optical coherence tomography angiography (OCT-A) studies

      Evaluation of the choriocapillaris after photodynamic therapy for chronic central serous chorioretinopathy. A review of optical coherence tomography angiography (OCT-A) studies

      Purpose: Emerging evidence suggests that choroidal microcirculation and microstructural changes after verteporfin photodynamic therapy (vPDT) for chronic central serous chorioretinopathy (CSC) can be shown in detail using OCT-Angiography (OCT-A). The use of OCT-A for the examination of choriocapillaris (CC) has attracted significant attention as the technique offers potential explanations for the effects of vPDT on choroidal tissue. Methods: A meticulous literature search was performed in the PubMed database without restriction on year of publication until June 2021. The reference list of all electronically retrieved articles was carefully reviewed for potentially relevant articles that had not been identified. Results: We identified ...

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    9. Detection of occludable angle with anterior segment optical coherence tomography and Pentacam as non-contact screening methods

      Detection of occludable angle with anterior segment optical coherence tomography and Pentacam as non-contact screening methods

      Purpose: To evaluate diagnostic capacity for occludable anterior chamber angle detection with anterior segment optical coherence tomography (AS-OCT) and Pentacam. Methods: Observational cross-sectional study with AS-OCT and Pentacam. AS-OCT measures: angle opening distance from Schwalbe line (SL) perpendicular (AOD-SL-Perp) and vertical to iris (AOD-SL-Vert), and iridotrabecular angle (ITA). Pentacam measures: anterior chamber depth (ACD), anterior chamber volume (ACV), and anterior chamber angle (ACA). We analysed Spearman's correlation with gonioscopic classification. Area under receiver operating characteristic curves (AUCs) for occludable angle detection were compared. Agreement between iridocorneal values of methods was evaluated. Results: Seventy-four left eyes of 74 patients. Correlation ...

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    10. Assessment of Artifacts in Swept-Source Optical Coherence Tomography Angiography for Glaucomatous and Normal Eyes

      Assessment of Artifacts in Swept-Source Optical Coherence Tomography Angiography for Glaucomatous and Normal Eyes

      urpose: To evaluate the frequency of and identify the factors that influence the artifacts of swept-source optical coherence tomography angiography (SS-OCTA) in glaucomatous and normal eyes. Methods: Artifacts of OCTA images of open-angle glaucoma (OAG) and normal subjects were analyzed using SS-OCTA. Univariate and multivariate logistic regression analyses were performed to evaluate the association of age, sex, best-corrected visual acuity, axial length (AL), intraocular pressure, presence and severity of OAG, and image quality score (IQS) with the presence of artifacts. Results: Images from 4426 subjects were included in the study. At least one type of artifact was present in 24 ...

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    11. Progression of cRORA (Complete RPE and Outer Retinal Atrophy) in Dry Age-Related Macular Degeneration Measured Using SD-OCT

      Progression of cRORA (Complete RPE and Outer Retinal Atrophy) in Dry Age-Related Macular Degeneration Measured Using SD-OCT

      Purpose: The purpose of this study was to evaluate the long-term rate of progression and baseline predictors of geographic atrophy (GA) using complete retinal pigment epithelium and outer retinal atrophy (cRORA) annotation criteria. Methods: This is a retrospective study. Columns of GA were manually annotated by two graders using a self-developed software on optical coherence tomography (OCT) B-scans and projected onto the infrared images. The primary outcomes were: (1) rate of area progression, (2) rate of square root area progression, and (3) rate of radial progression towards the fovea. The effects of 11 additional baseline predictors on the primary outcomes ...

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    12. Agreement of different OCT scan directions for individual retinal-layer thickness measurements in multiple sclerosis subjects with prior unilateral optic neuritis

      Agreement of different OCT scan directions for individual retinal-layer thickness measurements in multiple sclerosis subjects with prior unilateral optic neuritis

      The similarities between horizontal and vertical Optical Coherence Tomography (OCT) scans for the individual retinal layer thickness measurements in the macula was evaluated. Two volumetric scans (B-scans oriented horizontally and vertically) were performed in 64 multiple sclerosis subjects with history of unilateral optic neuritis and 64 healthy controls. The agreement between the thickness measurements with horizontal and vertical OCT scans was evaluated in 3 groups of eyes: healthy controls, eyes with history of optic neuritis and the fellow eyes. The mean difference in individual layer thickness between the scans was smaller than the instrument's axial resolution in all 3 ...

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    13. Volumetric directional optical coherence tomography

      Volumetric directional optical coherence tomography

      Photoreceptor loss and resultant thinning of the outer nuclear layer (ONL) is an important pathological feature of retinal degenerations and may serve as a useful imaging biomarker for age-related macular degeneration. However, the demarcation between the ONL and the adjacent Henle’s fiber layer (HFL) is difficult to visualize with standard optical coherence tomography (OCT). A dedicated OCT system that can precisely control and continuously and synchronously update the imaging beam entry points during scanning has not been realized yet. In this paper, we introduce a novel imaging technology, Volumetric Directional OCT (VD-OCT), which can dynamically adjust the incident beam ...

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    14. £10 test at Stratford Specsavers saved my life from brain tumour

      £10 test at Stratford Specsavers saved my life from brain tumour

      The 55-year-old from Stratford thanks his lucky stars every day now after a scan revealed he needed urgent medical attention and, after various tests, a nine-hour operation to remove a tumour. Matt admits he ignored the warning signs and put his dizzy spells and constant headache down to getting old when the reality was he had a tumour the size of a golf ball growing in his head. Even his seven-year-old Doberman, Zeb, had tried warning Matt about the cancerous growth by licking and sniffing his head when they were sat in the car after their daily walk. Matt did ...

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      Mentions: Specsavers
    15. Thickness of retinal pigment epithelium–Bruch’s membrane complex in adult Chinese using optical coherence tomography

      Thickness of retinal pigment epithelium–Bruch’s membrane complex in adult Chinese using optical coherence tomography

      Purpose To study thickness of RPE–BM complex in adult Chinese subjects and its correlation with systemic and ocular biometric parameters. Design Population-based longitudinal study. Cross-sectional study. Participants The population-based Beijing Eye Study 2011 included 3468 individuals with a mean age of 64.6 ± 9.8 years (range: 50–93 years). Methods A detailed ophthalmic examination was performed including spectral-domain optical coherence tomography (SD OCT) for measurement of the thickness of RPE–BM complex. Use Heidelberg software “Heidelberg Eye Explorer” for segmentation and measurements. Main outcome measure Thickness of RPE–BM complex. Results In total, 3276 people (6530 eyes) were ...

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    16. Interocular symmetry of optical coherence tomography parameters in healthy children and adolescents

      Interocular symmetry of optical coherence tomography parameters in healthy children and adolescents

      Evaluation of interocular asymmetry of optical coherence tomography (OCT) parameters is important for the glaucoma and optic neuropathies. This study was performed to evaluate the interocular asymmetry of OCT parameters in healthy children and adolescents. The circumpapillary retinal nerve fiber layer (RNFL) thickness, optic nerve head (ONH) parameters, and macular ganglion cell-inner plexiform layer (GCIPL) thickness were measured in 620 eyes of 310 healthy children and adolescents using Cirrus HD-OCT. The interocular asymmetry (right eye–left eye) in the OCT parameters was analyzed. The mean ± standard deviation age was 10.3 ± 3.7 years (range 5–17). The right eyes ...

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    17. Fluorescein Leakage and Optical Coherence Tomography Angiography Features of Microaneurysms in Diabetic Retinopathy

      Fluorescein Leakage and Optical Coherence Tomography Angiography Features of Microaneurysms in Diabetic Retinopathy

      Background and Objective. To correlate optical coherence tomography angiography (OCTA) characteristics of diabetic microaneurysms (MAs) with leakage status on fluorescein angiography (FA). Patients and Methods. 167 MAs from 39 diabetic eyes were analyzed using OCTA and FA simultaneously. The characteristics of MAs on OCTA en face, OCT en face, and OCT B-scan with flow overlay were evaluated and correlated with fluorescein leakage status. Results. Thirty-six, fifty-two, and seventy-nine MAs showed no, mild, and severe leakage on FA, respectively. Most MAs (61.7%) were centered in the inner nuclear layer. Cystoid spaces were observed adjacent to 60 (35.9%) MAs. MAs ...

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    18. Microperimetry, Humphrey field analyzer, and optical coherence tomography in detecting glaucoma: a comparative performance study

      Microperimetry, Humphrey field analyzer, and optical coherence tomography in detecting glaucoma: a comparative performance study

      Purpose To evaluate and compare the diagnostic performance of microperimetry (MP), visual field (VF) 10-2 and 24-2 tests, and spectral-domain optical coherence tomography (SD-OCT) in primary open-angle glaucoma (POAG). Methods The study consisted of 35 POAG and 42 control eyes were enrolled in this prospective study. Eligible participants were ≥ 50 years old. VF assessments were carried out using the Humphrey field analyzer (HFA) and Macular Integrity Assessment. Optic nerve head (ONH), retinal nerve fiber layer thickness (RNFLT), and ganglion cell inner-plexiform-layer thickness (GCIPLT) were measured by SD-OCT. Areas under the receiver operating characteristic curves (AUC) and sensitivities at 95% specificity ...

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    19. Optical Coherence Tomography Identifies Visual Pathway Involvement Earlier than Visual Function Tests in Children with MRI-Verified Optic Pathway Gliomas

      Optical Coherence Tomography Identifies Visual Pathway Involvement Earlier than Visual Function Tests in Children with MRI-Verified Optic Pathway Gliomas

      This study investigates whether optical coherence tomography (OCT) could add useful information in the examination of children with optic pathway glioma (OPG) at high risk of devel- oping vision loss. For this purpose, the relationship between ganglion cell-inner plexiform layer (GC-IPL) thickness and visual function, evaluated with tests of visual acuity (VA) and visual field (VF), as well as tumor site according to magnetic resonance imaging (MRI), were examined in a geographically defined group of children with OPG. Methods: Children aged <18 years with OPG underwent ophthalmic examination including VA, VF (Zeiss HFA perimetry) and OCT imaging (Zeiss Cirrus HD-OCT ...

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    20. Quantitative optical coherence tomography for longitudinal monitoring of postnatal retinal development

      Quantitative optical coherence tomography for longitudinal monitoring of postnatal retinal development

      A better study of the postnatal retinal development is not only essential for the in-depth understanding of the nature of the vision system but also may provide insights for treatment developments of eye conditions, such as retinopathy of premature (ROP). To date, quantitative analysis of postnatal retinal development is primarily limited to end- point histological examination. This study is to validate in vivo optical coherence tomog- raphy (OCT) for longitudinal monitoring of postnatal retinal development in developing mouse eyes. Three-dimensional (3D) frame registration and super averaging were adopted to investigate the fine structure of the retina. Interestingly, a hyporeflective layer ...

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    21. Elevated Intracranial Pressure in Patients with Craniosynostosis by Optical Coherence Tomography

      Elevated Intracranial Pressure in Patients with Craniosynostosis by Optical Coherence Tomography

      Background: Craniosynostosis may lead to elevated intracranial pressure, which may be implicated with impaired neurocognitive development. However, accurately measuring intracranial pressure is challenging, and patterns in craniosynostosis patients are poorly characterized. Spectral-domain optical coherence tomography may enable noninvasive assessment of intracranial pressure in pediatric patients with craniosynostosis. Methods: Pediatric patients with craniosynostosis undergoing surgical intervention between 2014 and 2019 prospectively underwent optical coherence tomographic evaluation. Intracranial pressure was directly measured intraoperatively in a subset of cases. Optical coherence tomographic parameters were compared to directly measured intracranial pressure and used for pattern assessment. Results: Optical coherence tomography was performed in 158 ...

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    22. Evaluation of Capillary and Other Vessel Contribution to Macular Perfusion Density Measured with Optical Coherence Tomography Angiography

      Evaluation of Capillary and Other Vessel Contribution to Macular Perfusion Density Measured with Optical Coherence Tomography Angiography

      Parafoveal circulation of the superficial retinal capillary plexus is usually measured with vessel density, which determines the length of capillaries with circulation, and perfusion density, which calculates the percentage of the evaluated area that has circulation. Perfusion density also considers the circulation of vessels larger than capillaries, although the contribution of these vessels to the first is not usually evaluated. As both measurements are automatically generated by optical coherence tomography angiography devices, this paper proposes a method for estimating the contribution of vessels larger than capillaries by using a coefficient of determination between vessel and perfusion densities. This method can ...

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    23. Correlation of retinal alterations with vascular structure of macular neovascularisation in swept-source optical coherence tomography angiography in age-related macular degeneration

      Correlation of retinal alterations with vascular structure of macular neovascularisation in swept-source optical coherence tomography angiography in age-related macular degeneration

      Purpose: The aim of this study was to find out whether the vascular architecture of untreated macular neovascularisations (MNV) in neovascular age-related macular degeneration (nAMD) as visualised with optic coherence tomography angiography (OCTA) is associated with functional and known morphological alterations of the retina in optic coherence tomography (SD-OCT). Methods: The study design was retrospective with consecutive patient inclusion. In 107 patients with newly diagnosed nAMD, MNV were detected by means of OCTA and automated quantitative vascular analysis was performed. The MNV characteristics measured were area, flow density, total vascular length (sumL), density of vascular nodes (numN), fractal dimension (FD ...

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    24. Optical coherence tomography angiography findings in pigmented paravenous chorioretinal atrophy

      Optical coherence tomography angiography findings in pigmented paravenous chorioretinal atrophy

      Purpose: To analyze the retino-choroidal vascular characteristics of patients affected by pigmented paravenous chorio-retinal atrophy (PPCRA) by means of optical coherence tomography angiography (OCTA). Methods: The study was designed as an observational, cross-sectional case series. Multimodal imaging included fundus autofluorescence (FAF), structural optical coherence tomography (OCT) and OCT angiography (OCTA). The quantitative OCTA analyses included the calculation of the vessel density (VD) and choriocapillaris porosity. Results: Overall, 12 patients (24 eyes) affected by PPCRA were recruited. Structural OCT of the areas involved by PPCRA as visualized on FAF showed a complete EZ and ELM absence, with thinning of ganglion cell ...

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