1. Articles in category: Ophthalmology

    577-600 of 9362 « 1 2 ... 22 23 24 25 26 27 28 ... 388 389 390 »
    1. Two-dimensional fractal analysis of retinal tissue of healthy and diabetic eyes with optical coherence tomography

      Two-dimensional fractal analysis of retinal tissue of healthy and diabetic eyes with optical coherence tomography

      In the ophthalmic research, the measurement of the retinal thickness is usually employed for characterizing the structural changes of the retinal tissue. However, changes in the fractal dimension (FD) may provide additional information regarding the structure of the retinal layers and their early damage in ocular diseases. In the present paper, we investigated the possibility of detecting changes in the structure of the cellular layers of the retina by applying a two-dimensional fractal analysis to optical coherence tomography (OCT) images. OCT images were obtained from diabetic patients without retinopathy (DM, n = 38 eyes) and with mild diabetic retinopathy (MDR, n ...

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    2. THICKNESS OF THE MACULA, RETINAL NERVE FIBER LAYER, AND GANGLION CELL-INNER PLEXIFORM LAYER IN THE AGE-RELATED MACULAR DEGENERATION: The Repeatability Study of Spectral Domain Optical Coherence Tomography

      THICKNESS OF THE MACULA, RETINAL NERVE FIBER LAYER, AND GANGLION CELL-INNER PLEXIFORM LAYER IN THE AGE-RELATED MACULAR DEGENERATION: The Repeatability Study of Spectral Domain Optical Coherence Tomography

      Purpose: To determine the repeatability of measuring the thickness of the central macula, retinal nerve fiber layer, and ganglion cell-inner plexiform layer (GC-IPL) using spectral domain optical coherence tomography (Cirrus HD-OCT) in eyes with age-related macular degeneration. Methods: One hundred and thirty-four eyes were included. The measurement repeatability was assessed by an experienced examiner who performed two consecutive measurements using a 512 x 128 macular cube scan and a 200 x 200 optic disk cube scan. To assess changes in macular morphology in patients with age-related macular degeneration, the patients were divided into the following three groups according to the ...

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    3. Vascular flow density in pathological myopia: an optical coherence tomography angiography study

      Vascular flow density in pathological myopia: an optical coherence tomography angiography study

      Objectives To investigate vascular flow density in pathological myopia with optical coherence tomography (OCT) angiography. Design A prospective comparative study was conducted from December 2015 to March 2016. Setting Participants were recruited in Beijing Tongren Hospital. Participants A total of 131 eyes were enrolled, which were divided into three groups: 45 eyes with emmetropia (EM; mean spherical equivalent (MSE) 0.50D to −0.50D), 41 eyes with high myopia (HM; MSE ≤−6.00D, without pathological changes), and 45 eyes with pathological myopia (PM; MSE ≤−6.00D and axial length (AL) ≥26.5 mm, and with pathological changes). Main outcome measures ...

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    4. Advantages of Anterior Segment Optical Coherence Tomography Evaluation of the Kayser–Fleischer Ring in Wilson Disease

      Advantages of Anterior Segment Optical Coherence Tomography Evaluation of the Kayser–Fleischer Ring in Wilson Disease

      Abstract Purpose: To present anterior segment optical coherence tomography (AS-OCT) findings of the Kayser–Fleischer (KF) ring in Wilson disease (WD) and to discuss the potential advantages of evaluating the KF ring by AS-OCT. Methods: This is a retrospective case series of 7 patients with WD with KF rings seen in our institute during the study period (August 2015 to June 2016). All patients underwent slit-lamp examination of the cornea and AS-OCT (Optovue RTVue Premier). In 2 patients, the length of the KF ring was measured using the gray scale of AS-OCT. Results: The KF ring on the gray scale ...

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      Mentions: Optovue
    5. Smoothing Splines on Unit Ball Domains with Application to Corneal Topography

      Smoothing Splines on Unit Ball Domains with Application to Corneal Topography

      Abstract: Optical coherence tomography (OCT) is a non-invasive imaging technique used to study and understand internal structures of biological tissues such as the anterior chamber of the human eye. An interesting problem is the reconstruction of the shape of the biological tissue from OCT images, that is not only a good fit of the data but also respects the smoothness properties observed in the images. A similar problem arises in Magnetic Resonance Imaging (MRI). We cast the problem as a penalized weighted least squares regression with a penalty on the magnitude of the second derivative (Laplacian) of the surface. We ...

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    6. How OCT innovations changing glaucoma care

      How OCT innovations changing glaucoma care

      Optical coherence tomography (OCT) is swiftly improving the diagnosis of glaucoma, according to Joel S. Schuman, MD, who helped invent the technology. “It’s the most rapidly adopted ophthalmic technology in history,” said Dr. Schuman, professor and chairman, Department of Ophthalmology, NYU Langone Medical Center, NY. Related: Launch of Retina World Congress unites global thought-leaders Already, OCT studies have yielded key insights into the relationships of retinal nerve fiber layer thinning and vessel density to visual field loss, Dr. Schuman said. Delivering the Drs. Henry and Frederick Sutro Memorial Lecture at the 6th Annual Glaucoma 360 New Horizons Forum, Dr ...

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    7. Relationship between optical coherence tomography sector peripapillary angioflow-density and Octopus visual field cluster mean defect values

      Relationship between optical coherence tomography sector peripapillary angioflow-density and Octopus visual field cluster mean defect values

      Purpose To compare the relationship of Octopus perimeter cluster mean-defect (cluster MD) values with the spatially corresponding optical coherence tomography (OCT) sector peripapillary angioflow vessel-density (PAFD) and sector retinal nerve fiber layer thickness (RNFLT) values. Methods High quality PAFD and RNFLT images acquired on the same day with the Angiovue/RTVue-XR Avanti OCT (Optovue Inc., Fremont, USA) on 1 eye of 27 stable early-to-moderate glaucoma, 22 medically controlled ocular hypertensive and 13 healthy participants were analyzed. Octopus G2 normal visual field test was made within 3 months from the imaging. Results Total peripapillary PAFD and RNFLT showed similar strong positive ...

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    8. Retinal vessel density from optical coherence tomography angiography to differentiate early glaucoma, pre-perimetric glaucoma and normal eyes

      Retinal vessel density from optical coherence tomography angiography to differentiate early glaucoma, pre-perimetric glaucoma and normal eyes

      Purpose To evaluate optic nerve vascular density using swept source optical coherence tomography angiography (OCTA) in patients with early primary open angle glaucoma (POAG), pre-perimetric glaucoma and normal eyes. Methods This is a prospective, observational study including 56 eyes in total and divided into 3 groups; 20 eyes with mild POAG, 20 pre-perimetric glaucoma eyes, and 16 age-matched normal eyes as controls. The optic disc region was imaged by a 1050-nm-wavelength swept-source OCT system (DRI OCT Triton, TOPCON). Vessel density was assessed as the ratio of the area occupied by the vessels in 3 distinct regions: 1) within the optic ...

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    9. Optical Coherence Tomography Angiography Findings in Stargardt Disease

      Optical Coherence Tomography Angiography Findings in Stargardt Disease

      Background to assess vessel density of superficial capillary plexus (SCP), deep capillary plexus (DCP) and choriocapillaris (CC) in advanced Stargardt disease (STGD) using optical coherence tomography angiography (OCTA) and correlate these findings with macular function using pattern electroretinogram (PERG) and multifocal electroretinogram (mfERG). Methods Twelve patients (24 eyes) with advanced STGD underwent vessel densities and macular thickness measurements using OCTA. A control group of 24 healthy controls (24 eyes) was chosen for comparison. In the STGD group correlation between vessel density and macular thickness and between macular function and morphologic parameters were evaluated. Results Whole parafoveal vessel density (VD) of ...

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      Mentions: Optovue
    10. Prevalence of Different Optical Coherence Tomography Findings in a Spanish Cohort With High Myopia

      Prevalence of Different Optical Coherence Tomography Findings in a Spanish Cohort With High Myopia

      Purpose: To evaluate the prevalence of different optical coherence tomography (OCT) findings in European patients with high myopia. Methods: Cross-sectional study conducted in the Macula Unit of the University and Polytechnic Hospital La Fe (Valencia, Spain). A total of 134 myopic eyes of 69 patients (16 males and 53 females) were included. All patients underwent a spectral domain OCT examination at least once. The presence of tractional and atrophic myopic maculopathy and choroidal neovascularization (CNV) was evaluated through OCT scans. Results: The prevalence of tractional myopic maculopathy was found in 53.7% of the eyes. Within this group, 9.7 ...

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    11. Multimodal Assessment of Corneal Thinning Using Optical Coherence Tomography, Scheimpflug Imaging, Pachymetry, and Slit-Lamp Examination

      Multimodal Assessment of Corneal Thinning Using Optical Coherence Tomography, Scheimpflug Imaging, Pachymetry, and Slit-Lamp Examination

      Purpose: To assess the relationship between corneal thinning measured by clinician-graded slit-lamp examination compared with ultrasound pachymetry (USP), anterior segment optical coherence tomography (AS-OCT), and the Pentacam. Methods: Patients with corneal thinning underwent USP, AS-OCT, Pentacam measurements and standardized clinical grading by 2 cornea specialists estimating thinning on slit-lamp examination. Reproducibility of each testing modality was assessed using the intraclass correlation coefficient. Bland-Altman plots were used to determine precision and limits of agreement (LOA) between imaging modalities and clinical grading. Results: We included 22 patients with corneal thinning secondary to infectious or inflammatory keratitis. Mean percent stromal thinning estimated by ...

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    12. RELATION BETWEEN FLUORESCEIN ANGIOGRAPHIC AND SPECTRAL-DOMAIN OPTICAL COHERENCE TOMOGRAPHY FINDINGS OF BLOOD FLOW TURBULENCE AT ARTERIOVENOUS CROSSINGS IN THE RETINA

      RELATION BETWEEN FLUORESCEIN ANGIOGRAPHIC AND SPECTRAL-DOMAIN OPTICAL COHERENCE TOMOGRAPHY FINDINGS OF BLOOD FLOW TURBULENCE AT ARTERIOVENOUS CROSSINGS IN THE RETINA

      Purpose: To examine retinal blood flow at arteriovenous crossings using spectral-domain optical coherence tomography (SD-OCT). Methods: Retrospective observational case series of 11 arteriovenous crossings in 10 eyes examined by SD-OCT and fluorescein angiography on suspicion of manifest or imminent branch retinal vein occlusion. Results: Fluorescein angiographic evidence of turbulence was seen at 5 of 11 arteriovenous crossings, whereas laminar angiographic flow was intact at the crossing and downstream thereof at the remaining 6 crossings. On SD-OCT, chaotic reflectivity patterns were seen at the point of crossing and downstream thereof in all 5 cases with angiographic turbulence, whereas an intravascular trilayer ...

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    13. Efficient OCT volume reconstruction from slitlamp microscopes

      Efficient OCT volume reconstruction from slitlamp microscopes

      Since its introduction 25 years ago, Optical Coherence Tomography (OCT) has contributed tremendously to diagnostic and monitoring capabilities of pathologies in the field of ophthalmology. Despite rapid progress in hardware and software technology however, the price of OCT devices has remained high, limiting their use in private practice and in screening examinations. In this paper, we present a slitlamp-integrated OCT device, built with off-the-shelf components, which can generate high-quality volumetric images of the posterior eye segment. To do so, we present a novel strategy for 3D image reconstruction in this challenging domain that allows for state-ofthe- art OCT volumes to ...

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    14. QUANTITATIVE ANALYSIS OF OPTICAL COHERENCE TOMOGRAPHY ANGIOGRAPHY IN ADULT-ONSET FOVEOMACULAR VITELLIFORM DYSTROPHY

      QUANTITATIVE ANALYSIS OF OPTICAL COHERENCE TOMOGRAPHY ANGIOGRAPHY IN ADULT-ONSET FOVEOMACULAR VITELLIFORM DYSTROPHY

      Purpose: To quantify the foveal avascular zone area at superficial capillary plexus (SCP) and deep capillary plexus (DCP) and the global, parafoveal, and perifoveal vessel densities at SCP, DCP, and choriocapillaris using optical coherence tomography angiography in patients affected by adult-onset foveomacular vitelliform dystrophy (AOFVD). Methods: Twenty eyes of 20 consecutive patients (10 females, 50%) with AOFVD and 20 eyes of 20 healthy controls presenting at the Department of Ophthalmology of San Raffaele Hospital, Milan, Italy were enrolled. All patients underwent a complete ophthalmic examination, including 3-mm x 3-mm optical coherence tomography angiography centered on the macula. The vessel density ...

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    15. OPTICAL COHERENCE TOMOGRAPHY FINDINGS IN CYTOMEGALOVIRUS RETINITIS: A Longitudinal Study

      OPTICAL COHERENCE TOMOGRAPHY FINDINGS IN CYTOMEGALOVIRUS RETINITIS: A Longitudinal Study

      Purpose: To evaluate the vitreal, retinal, and choroidal features using spectral domain optical coherence tomography (SD-OCT) in eyes affected by cytomegalovirus (CMV) retinitis. Methods: Patients diagnosed with either active or inactive CMV retinitis were included in the study. Complete ophthalmic examination, serial color fundus photography, and SD-OCT (with and without enhanced depth imaging function) were performed for all the subjects at baseline and follow-up visits. The SD-OCT images were analyzed by two independent graders to evaluate the structural changes in areas of CMV retinitis. Prevalence data for vitreal, retinal, and choroidal SD-OCT features were collected. Results: Twelve eyes from 9 ...

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    16. Reproducibility and repeatability of optical coherence tomography imaging of the optic nerve head in normal beagle eyes

      Reproducibility and repeatability of optical coherence tomography imaging of the optic nerve head in normal beagle eyes

      Objective To assess the reproducibility and repeatability of an optical coherence tomography (OCT) device for imaging the optic nerve region of normal canines. Animals studied Twelve clinically healthy beagles. Procedures All animals were anesthetized, and an OCT device was used to image the optic disk region. Total disk area and retinal nerve fiber layer (NFL) thickness in eight segments were obtained from each image. Images were collected by two operators in succession and each operator took five scans, repositioning the device between measurements. B-scan segmentations and disk outlines were subsequently redrawn to obtain manual measurements, allowing for comparisons between automated ...

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    17. Accuracy of optical coherence tomography measurements of rectus muscle insertions in adult patients undergoing strabismus surgery

      Accuracy of optical coherence tomography measurements of rectus muscle insertions in adult patients undergoing strabismus surgery

      Purpose To assess the accuracy of anterior segment optical coherence tomography (AS-OCT) in measuring the distance of extraocular muscle (EOM) insertion to the limbus to improve preoperative assessment of adult patients undergoing strabismus surgery. Design Reliability analysis. Setting An institutional practice. Patient Population 74 adult patients scheduled for strabismus surgery on rectus muscles. Observation Procedure The distance between the EOM insertion and the limbus was measured preoperatively with AS-OCT. The value was compared to intraoperative measurement obtained with calipers. Additional measurements included the limbus-anterior chamber angle distance with AS-OCT and the axial length with IOLMaster. Main Outcome Measure Agreement between ...

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      Mentions: Craig A. McKeown
    18. Cystoid macular changes on optical coherence tomography in a patient with maternally inherited diabetes and deafness (MIDD)-associated macular dystrophy

      Cystoid macular changes on optical coherence tomography in a patient with maternally inherited diabetes and deafness (MIDD)-associated macular dystrophy

      The clinical presentation and optical coherence tomography findings in a patient with maternally inherited diabetes and deafness (MIDD) are presented to highlight the presence of macular cystoid spaces in some patients with this disease. Typically, patients with MIDD demonstrate progression of a pigmentary maculopathy into areas of geographic macular atrophy. At the time of initial visit, the 30-year-old patient had large macular cystoid changes in addition to retinal pigmentary changes in both eyes. The cystoid changes responded to treatment with systemic immunosuppression and a topical carbonic anhydrase inhibitor (CAI), recurred when treated with topical CAI monotherapy, and finally resolved after ...

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    19. Comparison of Anterior Chamber Parameters in Patients With Plateau Iris Configuration and Pupillary Block Using ASOCT

      Comparison of Anterior Chamber Parameters in Patients With Plateau Iris Configuration and Pupillary Block Using ASOCT

      Purpose: To quantitatively analyze the anterior chamber parameters in patients with pupillary block (PB) and plateau iris configuration (PIC) using anterior segment optical coherence tomography (ASOCT). Patients and Methods: In this cross-sectional study, nonglaucomatous subjects consecutively recruited and a total of 212 eyes divided into 3 groups of PIC (31 eyes), PB (60 eyes), and open angles (121 eyes) based on gonioscopic and ultrasound biomicroscopy findings. All patients underwent ASOCT imaging and A-scan biometry of both eyes. Anterior chamber depth (ACD), anterior chamber area (ACA), iris thickness (IT), iris curvature, lens vault (LV), anterior vault, and angle parameters including angle ...

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    20. Peripapillary perfused capillary density in primary open-angle glaucoma across disease stage: an optical coherence tomography angiography study

      Peripapillary perfused capillary density in primary open-angle glaucoma across disease stage: an optical coherence tomography angiography study

      Aims To assess peripapillary perfused capillary density (PCD) in primary open-angle glaucoma (POAG) across stage of disease. Methods In this observational, cross-sectional study, 60 eyes with varying stages of POAG and 24 control eyes were imaged on a spectral domain optical coherence tomography angiography system (AngioVue, Optovue, Fremont, California, USA) generating images centred on the optic nerve head. Major blood vessels were removed using custom automated software. PCD was calculated as a percentage as the ratio of pixels associated with perfused capillaries to the total number of pixels in the corresponding region-of-interest (ROI). Analysis of covariance was used to compare ...

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    21. Factors Associated with the Retinal Nerve Fiber Layer Loss after Acute Primary Angle Closure: A Prospective EDI-OCT Study

      Factors Associated with the Retinal Nerve Fiber Layer Loss after Acute Primary Angle Closure: A Prospective EDI-OCT Study

      Purpose To determine the factors associated with retinal nerve fiber layer (RNFL) loss in eyes with acute primary angle-closure (APAC), particularly focusing on the influence of the change in the anterior lamina cribrosa surface depth (LCD). Methods After the initial presentation, 30 eyes with unilateral APAC were followed up at the following specific time points over a 12-month period: 1 week, 1~2 months, 2~3 months, 5~6 months, and 11~12 months. These follow-ups involved intraocular pressure measurements, enhanced depth-imaging spectral-domain optical coherence tomography (SD-OCT) scanning of the optic disc, and measurements of the circumpapillary RNFL thickness. The ...

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    22. Peripapillary Vascular Changes in Nonarteritic Anterior Ischemic Optic Neuropathy by Optical Coherence Tomography Angiography: A Case Report | Open Access Journals

      Peripapillary Vascular Changes in Nonarteritic Anterior Ischemic Optic Neuropathy by Optical Coherence Tomography Angiography: A Case Report | Open Access Journals

      Background: To report the sequential peripapillary vascular changes in nonarteritic anterior ischemic optic neuropathy (NAION) with optical coherence tomography angiography (OCTA) Methods: A 60-year-old male presented with right eye painless vision loss leading to inferior field defects and right eye 0.5 vision. The sequential OCTA was performed at presentation and 5 months later to evaluate the peripapillary vascular changes. Results: At presentation, the OCTA revealed decreased peripapillary capillary perfusion in the area corresponding to the nerve fiber swelling, along with increased blood flow of the major retinal vessel. Five months later, the OCTA showed decreased blood flow in the ...

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