1. Articles in category: Ophthalmology

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    1. Statistical Models of Signal and Noise and Fundamental Limits of Segmentation Accuracy in Retinal Optical Coherence Tomography

      Statistical Models of Signal and Noise and Fundamental Limits of Segmentation Accuracy in Retinal Optical Coherence Tomography

      Optical coherence tomography (OCT) has revolutionized diagnosis and prognosis of ophthalmic diseases by visualization and measurement of retinal layers. To speed up quantitative analysis of disease biomarkers, an increasing number of automatic segmentation algorithms have been proposed to estimate the boundary locations of retinal layers. While the performance of these algorithms has significantly improved in recent years, a critical question to ask is how far we are from a theoretical limit to OCT segmentation performance. In this paper, we present the Cramèr-Rao lower bounds (CRLBs) for the problem of OCT layer segmentation. In deriving the CRLBs, we address the ...

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    2. Parafoveolar retinoblastoma regression with foveal preservation following intra-arterial chemotherapy documented on hand-held optical coherence tomography in a newborn

      Parafoveolar retinoblastoma regression with foveal preservation following intra-arterial chemotherapy documented on hand-held optical coherence tomography in a newborn

      Background Optical coherence tomography (OCT) has become an invaluable tool in retinoblastoma management, providing submillimeter visualization of tumor control following treatment. Herein, we document OCT-detection of a subtle tumor recurrence, allowing early intervention and achieving foveal microanatomy preservation. Case presentation A 3-week-old girl was diagnosed with bilateral familial retinoblastoma, classified as group D in the right eye (OD) and group B in the left eye (OS), and treated with intravenous chemoreduction. At 6-months follow-up, the right eye was under control, but the left eye revealed a subtle juxtafoveal tumor recurrence, documented on handheld OCT (HH-OCT) and measuring 2750 µm in ...

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    3. Deformation velocity imaging using optical coherence tomography and its applications to the cornea

      Deformation velocity imaging using optical coherence tomography and its applications to the cornea

      Optical coherence tomography (OCT) can monitor human donor corneas non-invasively during the de-swelling process following storage for corneal transplantation, but currently only resultant thickness as a function of time is extracted. To visualize and quantify the mechanism of de-swelling, we present a method exploiting the nanometer sensitivity of the Fourier phase in OCT data to image deformation velocities. The technique was demonstrated by non-invasively showing during de-swelling that osmotic flow through an intact epithelium is negligible and removing the endothelium approximately doubled the initial flow at that interface. The increased functional data further enabled the validation of a mathematical model ...

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      Mentions: Yalin Zheng
    4. Detecting Structural Progression in Glaucoma with Optical Coherence Tomography

      Detecting Structural Progression in Glaucoma with Optical Coherence Tomography

      Optical coherence tomography (OCT) is increasingly used to obtain objective measurements of the retinal nerve fiber layer (RNFL), optic nerve head, and macula for assessing glaucoma progression. Although OCT has been adopted widely in clinical practice, uncertainty remains concerning its optimal role. Questions include: What is the best structure to measure? What quantity of change is significant? Are structural changes relevant to the patient? How are longitudinal measurements affected by aging? How can changes resulting from aging be differentiated from true progression? How best should OCT be used alongside visual fields, and how often should OCT be performed? Recent studies ...

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    5. Identifying characteristic features of the retinal and choroidal vasculature in choroideremia using optical coherence tomography angiography

      Identifying characteristic features of the retinal and choroidal vasculature in choroideremia using optical coherence tomography angiography

      Clinical Study Identifying characteristic features of the retinal and choroidal vasculature in choroideremia using optical coherence tomography angiography A Abbouda , A M Dubis , A R Webster & M Moosajee Abstract Purpose Using optical coherence tomography angiography (OCTA) to investigate the area with flow in the superficial retinal vessel network (SVRN) and choriocapillaris (CC) layer among male subjects with choroideremia (CHM), female carriers, and normal controls to identify vascular changes. Patients and methods Images of SRVN and CC layer were acquired in 9 affected males, 5 female carriers, and 14 age- and gender-matched controls using the Angiovue software of the RTVue XR ...

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    6. Managing glaucoma with OCTA

      Managing glaucoma with OCTA

      Optical coherence tomography angiography (OCTA) is a new imaging technique that has the potential to move rapidly into routine clinical practice. OCTA comprises different OCT-based technologies, which enable the non-invasive assessment of retinal perfusion, based on red blood cell movement in the optic nerve head, the peripapillary and the macular retina. In addition to the benefits offered by the non-invasive nature of OCTA over invasive fluorescein angiography in macular diseases, including age-related macular degeneration and diabetic macula oedema, OCTA has been increasingly investigated for use in the detection of glaucoma and understanding the role of vascular alterations in the development ...

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    7. Quantitative Analysis of Three Distinct Retinal Capillary Plexuses in Healthy Eyes Using Optical Coherence Tomography Angiography

      Quantitative Analysis of Three Distinct Retinal Capillary Plexuses in Healthy Eyes Using Optical Coherence Tomography Angiography

      Purpose : To identify and quantify the three distinct retinal capillary plexuses and the foveal avascular zone (FAZ) in healthy subjects according to age using optical coherence tomography angiography (OCTA) with novel projection artifact removal (PAR) software and improved segmentation. Methods : All eyes in this cross-sectional study underwent OCTA imaging using RTVue XR Avanti with novel PAR AngioVue software. OCTA scans were analyzed and the three main parafoveal retinal capillary plexuses were segmented and vessel density and FAZ area were calculated. Results : A total of 152 normal eyes from 95 subjects (39 males, 56 females, mean age 42 ± 25 years) were ...

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    8. Pathophysiological correlations between fundus fluorescein angiography and optical coherence tomography results in patients with idiopathic epiretinal membranes

      Pathophysiological correlations between fundus fluorescein angiography and optical coherence tomography results in patients with idiopathic epiretinal membranes

      The aim of the current study was to determine the association between fundus fluorescein angiography (FFA) image results, optical coherence tomography (OCT) imaging results and visual functions in patients with idiopathic epiretinal membranes (ERMs). A total of 80 eyes from 40 patients diagnosed with ERM were analyzed. Best‑corrected visual acuity (BCVA) and metamorphopsia were measured using the Early Treatment Diabetic Retinopathy Study eye chart and M‑charts, respectively. Macular thickness and volume were determined using OCT. Macular vascular leakage and distortion, and foveal avascular zone (FAZ) diameters were assessed using FFA. BCVA and M‑chart results confirmed macular degeneration ...

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    9. Precision of a new ocular biometer in eyes with cataract using swept source optical coherence tomography combined with Placido-disk corneal topography

      Precision of a new ocular biometer in eyes with cataract using swept source optical coherence tomography combined with Placido-disk corneal topography

      The present study was to assess the precision (repeatability and reproducibility) of a new optical biometer (OA-2000, Tomey, Japan) based on swept-source optical coherence tomography (SS-OCT) and Placido disk topography in eyes with cataracts. Seventy-eight eyes from seventy-eight patients with cataracts were evaluated. Axial length (AL), anterior chamber depth (ACD), keratometry (K) over a 2.5 mm and 3.0 mm diameter, lens thickness (LT), central corneal thickness (CCT) and white-to-white (WTW) distance were measured by 2 skilled operators. OA-2000 measurements were highly repeatable and reproducible for all parameters (intraclass correlation, 0.925 to 1.000). OA-2000 derived K-values with ...

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    10. OPTICAL COHERENCE TOMOGRAPHY ANGIOGRAPHY IN PATIENTS WITH RETINITIS PIGMENTOSA

      OPTICAL COHERENCE TOMOGRAPHY ANGIOGRAPHY IN PATIENTS WITH RETINITIS PIGMENTOSA

      Purpose: To evaluate the correlation between the flow density measured by optical coherence tomography angiography and functional parameters in patients with retinitis pigmentosa. Methods: Twenty eyes of 20 patients with retinitis pigmentosa and 21 eyes of 21 healthy subjects were prospectively included in this study. Optical coherence tomography angiography was performed using RTVue XR Avanti with AngioVue (Optovue Inc). The macula was imaged with a 6 × 6-mm2 scan, whereas for the optic nerve head a 4.5 × 4.5-mm2 scan was taken. Visual acuity, visual field parameters (mean deviation and visual field index), full-field electroretinography, and multifocal electroretinography were tested ...

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    11. Optical coherence tomography and fundus autofluorescence findings in presumed congenital simple retinal pigment epithelium hamartoma

      Optical coherence tomography and fundus autofluorescence findings in presumed congenital simple retinal pigment epithelium hamartoma

      Aim: Presumed congenital simple retinal pigment epithelium hamartoma is a rare benign lesion of the macula that mimics congenital hypertrophy of the retinal pigment epithelium (RPE) and combined hamartoma of the retina and the RPE; newer imaging modalities can help in diagnosis. We report three patients with presumed congenital simple RPE hamartoma, and describe the enhanced-depth imaging optical coherence tomography (EDI-OCT) and fundus autofluorescence (FAF) findings. Methods: Two patients were asymptomatic; one had an intraocular foreign body in addition to the hamartoma. All had a similar jet black, elevated lesion in the macula, sparing the fovea. EDI-OCT showed a characteristic ...

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    12. OPTICAL COHERENCE TOMOGRAPHY ANGIOGRAPHY TO DETECT MACULAR CAPILLARY ISCHEMIA IN PATIENTS WITH INNER RETINAL CHANGES AFTER RESOLVED DIABETIC MACULAR EDEMA

      OPTICAL COHERENCE TOMOGRAPHY ANGIOGRAPHY TO DETECT MACULAR CAPILLARY ISCHEMIA IN PATIENTS WITH INNER RETINAL CHANGES AFTER RESOLVED DIABETIC MACULAR EDEMA

      To compare foveal vascular anatomy between patients with and without disorganization of retinal inner layers (DRILs) after resolved diabetic macular edema using optical coherence tomography angiography (OCTA). Methods: Twenty-four eyes of 21 age- and sex-matched patients with resolved diabetic macular edema were included in this retrospective, cross-sectional study. All eyes were imaged with enhanced high-definition line or cross-line structural B scans and 3 × 3-mm OCTA scans. Optical coherence tomography B scans were analyzed for the presence of DRIL, and based on this, eyes were classified as either DRIL present or DRIL absent. The foveal avascular zone area on OCTA was ...

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    13. Evaluation of retinal nerve fiber layer defect using wide-field en-face swept-source OCT images by applying the inner limiting membrane flattening

      Evaluation of retinal nerve fiber layer defect using wide-field en-face swept-source OCT images by applying the inner limiting membrane flattening

      Purpose The assessment of retinal nerve fiber layer defects (RNFLDs) is a useful part of glaucoma care. Here, we obtained en-face images of retinal layers below the inner limiting membrane (ILM) with swept source-optical coherence tomography (SS-OCT), and measured RNFLD angle with new software. Methods This study included 105 eyes of 105 normal tension glaucoma (NTG) patients (age, 59.8 ± 13.2). Exclusion criteria were best-corrected visual acuity < 0.5, axial length > 28 mm, nonglaucoma ocular disease, and systemic disease affecting the visual field. We obtained 12 x 9 mm 3D volume scans centered on the macula with SS-OCT (DRI ...

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    14. Detection of Ganglion Cell Loss in Preperimetric Glaucoma by Fourier-Domain Optical Coherence Tomography

      Detection of Ganglion Cell Loss in Preperimetric Glaucoma by Fourier-Domain Optical Coherence Tomography

      Background: Glaucoma is a multi-factorial optic neuropathy characterized by a loss of retinal ganglion cells with subsequent loss of the retinal nerve fi bers ultimately resulting in visual impairment. The macula region has a high density of retinal ganglion cells thereby being a likely region to detect early cell loss .Since glaucoma affects mainly the inner layers of the retina, Ganglion Cell Complex (GCC) mapping can help to detect glaucomatous damage early as compared to the total retinal thickness. Purpose: To map GCC thickness and average Macular Retinal (MR) thickness with high-speed FourierDomain Optical Coherence Tomography (FD-OCT) and correlate it ...

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    15. Macular capillary plexuses after epiretinal membrane surgery: an optical coherence tomography angiography study

      Macular capillary plexuses after epiretinal membrane surgery: an optical coherence tomography angiography study

      Aims To investigate macular vascular integrity using optical coherence tomography angiography (OCTA) in patients undergoing vitrectomy for idiopathic epiretinal membrane (ERM) removal and to determine its association with structural and visual outcomes. Methods Forty-three patients with unilateral ERM who were followed for ≥6 months after surgery were included. Ophthalmological evaluations included best-corrected visual acuity (BCVA) and spectral-domain OCT (SD-OCT) before surgery and 6 months after surgery. We obtained en face OCTA images of the superficial capillary plexus (SCP) and deep capillary plexus (DCP) for both eyes 6 months after ERM removal. We compared eyes with ERM to unaffected fellow eyes ...

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    16. Changes in Ocular Subfoveal Choroidal Thickness After Carotid Endarterectomy Using Enhanced Depth Imaging Optical Coherence Tomography: A Pilot Study

      Changes in Ocular Subfoveal Choroidal Thickness After Carotid Endarterectomy Using Enhanced Depth Imaging Optical Coherence Tomography: A Pilot Study

      The influence of both severe chronic carotid stenosis and carotid endarterectomy (CEA) on ocular tissue has been poorly evaluated. The goal of this study was to measure subfoveal choroidal thickness (SFCT), before and after CEA, in patients with severe carotid stenosis. Consecutive patients (n = 36) with severe carotid stenosis were prospectively included. Patients (n = 19) were followed up at 1 and 3 months after CEA. The SFCT was measured bilaterally using enhanced depth imaging optical coherence tomography (EDI-OCT). Preoperatively, the median SFCT of the ipsilateral eye did not differ significantly from the contralateral eye (223 vs 236 µm; P = .75 ...

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    17. The Optic Disc Drusen Studies Consortium Recommendations for Diagnosis of Optic Disc Drusen Using Optical Coherence Tomography

      The Optic Disc Drusen Studies Consortium Recommendations for Diagnosis of Optic Disc Drusen Using Optical Coherence Tomography

      Background: Making an accurate diagnosis of optic disc drusen (ODD) is important as part of the work-up for possible life-threatening optic disc edema. It also is important to follow the slowly progressive visual field defects many patients with ODD experience. The introduction of enhanced depth imaging optical coherence tomography (EDI-OCT) has improved the visualization of more deeply buried ODD. There is, however, no consensus regarding the diagnosis of ODD using OCT. The purpose of this study was to develop a consensus recommendation for diagnosing ODD using OCT. Methods: The members of the Optic Disc Drusen Studies (ODDS) Consortium are either ...

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    18. Challenges and advantages in wide-field optical coherence tomography angiography imaging of the human retinal and choroidal vasculature at 1.7-MHz A-scan rate

      Challenges and advantages in wide-field optical coherence tomography angiography imaging of the human retinal and choroidal vasculature at 1.7-MHz A-scan rate

      We present noninvasive, three-dimensional, depth-resolved imaging of human retinal and choroidal blood circulation with a swept-source optical coherence tomography (OCT) system at 1065-nm center wavelength. Motion contrast OCT imaging was performed with the phase-variance OCT angiography method. A Fourier-domain mode-locked light source was used to enable an imaging rate of 1.7 MHz. We experimentally demonstrate the challenges and advantages of wide-field OCT angiography (OCTA). In the discussion, we consider acquisition time, scanning area, scanning density, and their influence on visualization of selected features of the retinal and choroidal vascular networks. The OCTA imaging was performed with a field of ...

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    19. MINIMAL OPTICAL COHERENCE TOMOGRAPHY B-SCAN DENSITY FOR RELIABLE DETECTION OF INTRARETINAL AND SUBRETINAL FLUID IN MACULAR DISEASES

      MINIMAL OPTICAL COHERENCE TOMOGRAPHY B-SCAN DENSITY FOR RELIABLE DETECTION OF INTRARETINAL AND SUBRETINAL FLUID IN MACULAR DISEASES

      Purpose: To determine the minimal optical coherence tomography B-scan density for reliable detection of intraretinal and subretinal fluid. Methods: Spectral domain optical coherence tomography raster scanning (Spectralis; Heidelberg Engineering, Heidelberg, Germany) using a scan field of 20° × 20° of 97 B-scans with an interscan distance (ISD) of 60 μm was performed in 150 eyes of 150 consecutive patients at monitoring visits for intravitreal anti–vascular endothelial growth factor therapy. Using custom software, every other B-scan was repeatedly deleted to generate additional data sets with an ISD of 120 μm (49 B-scans), 240 μm (25 B-scans), and 480 μm (13 B-scans ...

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    20. Unilateral Choroidal Osteoma with Evidence of Choroidal Neovascularization Based on Ocular Coherence Tomography Angiography

      Unilateral Choroidal Osteoma with Evidence of Choroidal Neovascularization Based on Ocular Coherence Tomography Angiography

      Purpose: Choroidal osteoma is a rare tumor which features intraocular bone formation. This tumor can be complicated by choroidal neovascularization which is a cause of impaired vision in this condition. We present a case of choroidal osteoma with choroidal neovascularization as a complication. Methods: Case report with clinical and angiographic correlation. Results: A 16 year old female presented with a choroidal osteoma in the left eye complicated by choroidal neovascularization. The patient was treated with Bevacizumab; an intravitreal anti-Vascular Endothelial Growth Factor (Anti-VEGF). Following treatment there was improvement in vision as well as resolution of the choroidal neovascular membrane. Conclusion ...

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    21. Polypoidal Choroidal Vasculopathy on Swept-Source Optical Coherence Tomography Angiography with Variable Interscan Time Analysis

      Polypoidal Choroidal Vasculopathy on Swept-Source Optical Coherence Tomography Angiography with Variable Interscan Time Analysis

      Purpose : To use a novel optical coherence tomography angiography (OCTA) algorithm termed variable interscan time analysis (VISTA) to evaluate relative blood flow speeds in polypoidal choroidal vasculopathy (PCV). Methods : Prospective cross-sectional study enrolling patients with confirmed diagnosis of PCV. OCTA of the retina and choroid was obtained with a prototype swept-source OCT system. The acquired OCT volumes were centered on the branching vascular network (BVN) and polyps as determined by indocyanine-green angiography (ICGA). The relative blood flow speeds were characterized on VISTA-OCTA. Results : Seven eyes from seven patients were evaluated. Swept-source OCTA enabled detailed enface visualization of the BVN and ...

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    22. Retinal Nerve Fiber Layer Thickness Measurement Using Swept Source Optical Coherence Tomography in Healthy Korean

      Retinal Nerve Fiber Layer Thickness Measurement Using Swept Source Optical Coherence Tomography in Healthy Korean

      Purpose To investigate retinal nerve fiber layer (RNFL) thickness using swept source (SS)-optical coherence tomography (OCT) in healthy Koreans and to evaluate the effects of age on the distributional variability of thickness. Methods We performed a retrospective review of 309 normal eyes presenting for examination of peripapillary nerve fiber layer thickness measured by SS-OCT (DRI OCT-1, Atlantis SS-OCT, Topcon, Tokyo, Japan) from July 2014 to February 2016. The patients were between the ages of 20 and 79 without systemic or ocular disease. The patients were divided into 3 age groups of 20 to 39 years (85 eyes), 40 to ...

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    23. Optical Coherence Tomography Angiography of Punctate Inner Choroidopathy

      Optical Coherence Tomography Angiography of Punctate Inner Choroidopathy

      Purpose . To report a case of bilateral choroidal neovascularization (CNV) in punctate inner choroidopathy (PIC) visualized utilizing optical coherence tomography angiography (OCT-A). Methods . Case report. Results . A 29-year-old woman presented with new visual symptoms in both eyes. Fundoscopic exam revealed bilateral multifocal, small, well-defined lesions consistent with PIC. Optical coherence tomography demonstrated subretinal fluid and retinal pigment epithelium detachments (RPEDs) in both eyes. OCT-A revealed bilateral abnormal increased flow within the RPEDs consistent with CNV. Fluorescein angiography confirmed the presence of bilateral CNV. Conclusion . CNV secondary to PIC may be identified using noninvasive optical coherence tomography angiography.

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    24. Optical Coherence Tomography Angiography Macular and Peripapillary Vessel Perfusion Density in Healthy Subjects, Glaucoma Suspects, and Glaucoma Patients

      Optical Coherence Tomography Angiography Macular and Peripapillary Vessel Perfusion Density in Healthy Subjects, Glaucoma Suspects, and Glaucoma Patients

      Purpose : To evaluate macular and peripapillary vessel perfusion density (VD) in glaucoma suspects (GS) and glaucoma patients; to correlate ganglion cell–inner plexiform layer (GCIPL) and retinal nerve fiber layer (RNFL) thicknesses with macular and peripapillary VD; and to evaluate the diagnostic accuracy of the structural and vascular parameters. Methods : A consecutive series of GS, glaucoma patients, and healthy subjects was prospectively recruited from July 1, 2016, to January 31, 2017. All subjects underwent standard automated perimetry, spectral-domain optical coherence tomography (OCT), and 6 × 6-mm optical coherence tomography angiography (OCT-A) centered on the fovea and optic nerve. Results : Forty controls ...

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