1. Articles in category: Ophthalmology

    577-600 of 9077 « 1 2 ... 22 23 24 25 26 27 28 ... 377 378 379 »
    1. Agreement and clinical comparison between a new swept-source optical coherence tomography-based optical biometer and an optical low-coherence reflectometry biometer

      Agreement and clinical comparison between a new swept-source optical coherence tomography-based optical biometer and an optical low-coherence reflectometry biometer

      Purpose To compare measurements taken using a swept-source optical coherence tomography-based optical biometer (IOLmaster 700) and an optical low-coherence reflectometry biometer (Lenstar 900), and to determine the clinical impacts of differences in their measurements on intraocular lens (IOL) power predictions. Methods Eighty eyes of 80 patients scheduled to undergo cataract surgery were examined with both biometers. The measurements made using each device were axial length (AL), central corneal thickness (CCT), aqueous depth (AQD), lens thickness (LT), mean keratometry (MK), white-to-white distance (WTW), and pupil diameter (PD). Holladay 2 and SRK / T formulas were used to calculate IOL power. Differences in ...

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    2. Anterior segment optical coherence tomography in subtypes of angle closure glaucoma

      Anterior segment optical coherence tomography in subtypes of angle closure glaucoma

      Primary angle-closure glaucoma (ACG) is a serious ocular health care problem especially in Asia, increasing in prevalence as one moves towards the Eastern part of Asia. 1 The disease causes a significant burden of blindness and visual disability in regions where it is most prevalent. With the advent of SD-OCTs, anterior and posterior segment mechanisms of the disease have been better elucidated. However, like primary open-angle glaucoma, ACG likely represents different phenotypes yet to be identified through research on the genetics. In the meantime, significant amount of ongoing research is devoted to better understanding the contribution of various well-defined mechanisms ...

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    3. Novel Macular Findings on Optical Coherence Tomography in Incontinentia Pigmenti

      Novel Macular Findings on Optical Coherence Tomography in Incontinentia Pigmenti

      Incontinentia pigmenti (IP) is a rare, X-linked disease with ophthalmic findings in 35% to 77% of cases. 1 - 4 Classic retinal manifestations include peripheral retinal ischemia and subsequent sequelae, but phenotypic presentations are myriad. 1 - 4 Foveal hypoplasia is a known manifestation of IP, and foveal architectural abnormalities in older children have recently been described on optical coherence tomography (OCT). 1 , 5 In the present case, a 3-week-old girl with IP was referred after being noted to have a vitreous hemorrhage on ophthalmic screening examination. Clinical examination revealed bilateral peripheral retinal neovascularization and associated preretinal hemorrhage. Following examination and all ...

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    4. Relationship between macular thickness measurement and signal strength using Stratus optical coherence tomography

      Relationship between macular thickness measurement and signal strength using Stratus optical coherence tomography

      Purpose: To examine the relationship between signal strength and macular thickness as measured by Stratus optical coherence tomography (OCT)’s fast macular thickness protocol in healthy subjects. Methods: In this prospective cross-sectional study 79 eyes of 42 healthy subjects were enrolled. The age, gender, and eye (right vs left) of each subject were recorded. The Stratus OCT fast macular thickness scan protocol was used and the macular thickness was measured with retinal thickness map analysis. Each eye was imaged at least six times to acquire images with signal strengths of 4, 5, 6, 7, 8, and 9 out of 10 ...

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    5. Use of Retinal Optical Coherence Tomography to Detect Congenital Zika Syndrome

      Use of Retinal Optical Coherence Tomography to Detect Congenital Zika Syndrome

      First identified in rhesus monkeys in Uganda in 1947, the Zika virus (ZIKV), a flavirus spread most commonly by the Aedes aegypti and Aedes albopictus mosquitos, 1 was not implicated in human disease until 1953, when it was recognized in Nigeria to produce a mild, febrile illness. The virus, related to the pathogens that cause yellow fever, dengue, and the West Nile virus, 1 has emerged recently as a serious health care threat resulting in widespread panic across the globe, particularly in the Pacific and the Americas. The recent outbreak began in Brazil in 2015, with over 1 million people ...

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    6. Corneal Thickness Measurements Using 2 Kinds of Spectral Domain Optical Coherence Tomography, Pentacam, Ultrasound Pachymetry

      Corneal Thickness Measurements Using 2 Kinds of Spectral Domain Optical Coherence Tomography, Pentacam, Ultrasound Pachymetry

      Purpose To compare the measurements of central corneal thickness (CCT) obtained using two kinds of spectral domain optical coherence tomography (OCT), Pentacam®, and ultrasound pachymetry (USP). Methods CCT was measured by Cirrus OCT®, Spectralis OCT®, Pentacam®, and USP in 32 eyes from 32 subjects without ocular disease of the anterior segment. Results The average CCT measurements using Cirrus OCT®, Spectralis OCT®, Pentacam®, and USP were 549.2 ± 28.7 µm, 545.2 ± 25.4 µm, 554.0 ± 27.8 µm, and 548.4 ± 27.9 µm respectively. The measurements were significantly highly correlated with each other (Pearson's correlation coefficient ...

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    7. The Analysis of Retinal Nerve Fiber Layer in Amblyopia Using Spectral Domain Optical Coherence Tomography

      The Analysis of Retinal Nerve Fiber Layer in Amblyopia Using Spectral Domain Optical Coherence Tomography

      Purpose To determine whether retinal nerve fiber layer (RNFL) thickness and optic nerve head parameters differ in the amblyopic and normal fellow eyes of hyperopic anisometropic amblyopic patients using spectral domain optical coherence tomography (SD-OCT). Methods This study included 30 patients with hyperopic anisometropic amblyopia; patient eyes were divided into 30 anisometropic amblyopic eyes and 30 normal fellow eyes. RNFL thickness, disc area, rim area, average cup-to-disc ratio, and cup volume were obtained using SD-OCT. Axial length was obtained using the IOL Master®, and the interocular differences between group were analyzed. Results Nasal quadrant RNFL thickness of amblyopic eyes was ...

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    8. An anomaly detection approach for the identification of DME patients using spectral domain optical coherence tomography images

      An anomaly detection approach for the identification of DME patients using spectral domain optical coherence tomography images

      This paper proposes a method for automatic classification of spectral domain OCT data for the identification of patients with retinal diseases such as Diabetic Macular Edema (DME). We address this issue as an anomaly detection problem and propose a method that not only allows the classification of the OCT volume, but also allows the identification of the individual diseased B-scans inside the volume. Our approach is based on modeling the appearance of normal OCT images with a Gaussian Mixture Model (GMM) and detecting abnormal OCT images as outliers. The classification of an OCT volume is based on the number of ...

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    9. Utility of the Swept Source Optical Coherence Tomography for Measurements of Central Corneal Thickness

      Utility of the Swept Source Optical Coherence Tomography for Measurements of Central Corneal Thickness

      Purpose To evaluate the efficacy of swept source optical coherence tomography (SS-OCT) by comparing the measurement of central corneal thickness (CCT) to the measurement obtained using Orbscan II, anterior segment optical coherence tomography (AS-OCT) and ultrasound pachymetry. Methods One examiner measured the CCT in 65 eyes of 65 healthy subjects using Orbscan II, AS-OCT, SS-OCT and ultrasound pachymetry. The mean values and correlations were analyzed. Results The average CCT measurements obtained using Orbscan II, AS-OCT, SS-OCT and ultrasound pachymetry were 534.83 ± 38.46, 517.80 ± 32.48, 528.22 ± 33.71 and 528.02 ± 34.90 µm, respectively. A ...

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    10. Machine learning based detection of age-related macular degeneration (AMD) and diabetic macular edema (DME) from optical coherence tomography (OCT) images

      Machine learning based detection of age-related macular degeneration (AMD) and diabetic macular edema (DME) from optical coherence tomography (OCT) images

      Non-lethal macular diseases greatly impact patients’ life quality, and will cause vision loss at the late stages. Visual inspection of the optical coherence tomography (OCT) images by the experienced clinicians is the main diagnosis technique. We proposed a computer-aided diagnosis (CAD) model to discriminate age-related macular degeneration (AMD), diabetic macular edema (DME) and healthy macula. The linear configuration pattern (LCP) based features of the OCT images were screened by the Correlation-based Feature Subset (CFS) selection algorithm. And the best model based on the sequential minimal optimization (SMO) algorithm achieved 99.3% in the overall accuracy for the three classes of ...

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    11. Visualization of 3 Distinct Retinal Plexuses by Projection-Resolved Optical Coherence Tomography Angiography in Diabetic Retinopathy

      Visualization of 3 Distinct Retinal Plexuses by Projection-Resolved Optical Coherence Tomography Angiography in Diabetic Retinopathy

      Importance Projection artifacts in optical coherence tomography angiography (OCTA) blur the retinal vascular plexuses together and limit visualization of the individual plexuses. Objective To describe projection-resolved (PR) OCTA in eyes with diabetic retinopathy (DR) and healthy eyes. Design, Setting, and Participants In this case-control study, patients with DR and healthy controls were enrolled in this observational study from January 26, 2015, to December 4, 2015, at a tertiary academic center. Spectral-domain, 70-kHz OCT obtained 3 × 3-mm macular scans. The PR algorithm suppressed projection artifacts. A semiautomated segmentation algorithm divided PR-OCTA into superficial, intermediate, and deep retinal plexuses. Two masked graders ...

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    12. Projection Artifact Removal Improves Visualization and Quantitation of Macular Neovascularization Imaged by Optical Coherence Tomography Angiography

      Projection Artifact Removal Improves Visualization and Quantitation of Macular Neovascularization Imaged by Optical Coherence Tomography Angiography

      Purpose To visualize and quantify the size and vessel density of macular neovascularization (MNV) using optical coherence tomography angiography (OCTA) with a projection artifact removal algorithm. Design Multicenter, observational study. Participants Subjects with MNV in ≥1 eye. Methods Patients were imaged using either a swept-source OCTA prototype system or a spectral-domain OCTA prototype system. The optical microangiography (OMAG) algorithm was used to generate the OCTA images. Projection artifacts from the overlying retinal circulation were removed from the OMAG OCTA images using a novel algorithm. After removal of the projection artifacts from the OCTA images, we assessed the size and vascularity ...

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    13. Validating the usefulness of the 'Random Forests’ classifier to diagnose early glaucoma with optical coherence tomography

      Validating the usefulness of the 'Random Forests’ classifier to diagnose early glaucoma with optical coherence tomography

      Purpose To validate the usefulness of the 'Random Forests’ classifier to diagnose early glaucoma with spectral domain optical coherence tomography (SD-OCT). Method Design: Comparison of diagnostic algorithms Setting: multiple institutional practice Study participants Training dataset included 94 eyes of 94 open angle glaucoma (OAG) patients and 84 eyes of 84 normal subjects and testing dataset included 114 eyes of 114 OAG patients and 82 eyes of 82 normal subjects. In both groups, OAG eyes with mean deviation (MD) values better than -5.0 dB were included. Observation Procedure Using the training dataset, classifiers were built to discriminate between glaucoma and ...

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    14. Optical coherence tomography in an optic tract lesion, Retinal nerve fiber layer changes

      Optical coherence tomography in an optic tract lesion, Retinal nerve fiber layer changes

      A 49-year-old woman, status post temporal lobe resection, reported a hemianopia. Examination revealed a right afferent pupillary defect, horizontal bow-tie atrophy OD (temporal and nasal), and temporal atrophy OS. Optical coherence tomography showed a bow-tie pattern OD and predominant superior and inferior nerve fiber layer loss OS (figure 1; figure e-1 at Neurology.org ). The pattern OD is due to the combination of papillomacular bundle and nasal RNFL loss. The pattern OS is due to nerve fiber layer loss temporal to the fovea and, coupled with papillomacular bundle loss, produces temporal pallor. 1 MRI confirmed left optic tract atrophy (figure ...

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    15. 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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    16. Peripapillary choroidal thickness in Chinese children using enhanced depth imaging optical coherence tomography

      Peripapillary choroidal thickness in Chinese children using enhanced depth imaging optical coherence tomography

      AIM : To evaluate the peripapillary choroidal thickness (PPCT) in Chinese children, and to analyze the influencing factors. METHODS : PPCT was measured with enhanced depth imaging optical coherence tomography (EDI-OCT) in 70 children (53 myopes and 17 non-myopes) aged 7 to 18y, with spherical equivalent refractive errors between 0.50 and -5.87 diopters (D). Peripapillary choroidal imaging was performed using circular scans of a diameter of 3.4 mm around the optic disc. PPCT was measured by EDI-OCT in six sectors: nasal (N), superonasal (SN), superotemporal (ST), temporal (T), inferotemporal (IT) and inferonasal (IN), as well as global RNFL thickness ...

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    17. SD-OCT AND MICROPERIMSD-OCT AND MICROPERIMETRIC CORRELATED CHANGES IN PROGRESSIVE X-LINKED RETINOSCHISIS AFTER VITRECTOMY: A CASE REPORT

      SD-OCT AND MICROPERIMSD-OCT AND MICROPERIMETRIC CORRELATED CHANGES IN PROGRESSIVE X-LINKED RETINOSCHISIS AFTER VITRECTOMY: A CASE REPORT

      Purpose: To report optical coherence tomography and microperimetric correlated changes in a case of bilateral foveal schisis in progressive X-linked retinoschisis (XLRS) treated with vitrectomy, inner limiting membrane (ILM) peeling, and air tamponade. Methods: One case report. Results: An 18-year-old boy with bilateral foveal schisis in progressive XLRS underwent vitrectomy, ILM peeling and air tamponade in both eyes. At baseline and follow-up (1 month in right eye, 6 months in left eye), visual acuity test, optical coherence tomography, retinal sensitivity map, and fixation stability study were performed. At the end of follow-up, in both eyes, the largest foveal schisis cavities ...

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    18. Quantitative Evaluation of Phase Retardation in Filtering Blebs Using Polarization-Sensitive Optical Coherence Tomography

      Quantitative Evaluation of Phase Retardation in Filtering Blebs Using Polarization-Sensitive Optical Coherence Tomography

      Purpose : Polarization-sensitive optical coherence tomography (PS-OCT) can detect and evaluate scar fibrosis of the filtering blebs after glaucoma surgery. Although the change in phase retardation reportedly reflects bleb function, quantitative assessment of phase retardation in ocular tissues has not been conducted. We aimed to establish quantitative methods to investigate changes in phase retardation in the blebs after surgery using PS-OCT. Methods : Twenty-two blebs of 22 patients who had undergone glaucoma filtration surgery were consecutively examined for 4 months. Phase retardation was measured by PS-OCT and quantitatively analyzed to evaluate its relationship with bleb function based on intraocular pressure and medication ...

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    19. Long working distance OCT with a compact 2f retinal scanning configuration for pediatric imaging

      Long working distance OCT with a compact 2f retinal scanning configuration for pediatric imaging

      Young and/or autistic children cannot be imaged with tabletop or handheld optical coherence tomography (OCT) because of their lack of attention and fear of large objects close to their face. We demonstrate a prototype retinal swept-source OCT system with a long working distance (from the last optical element to the subject’s eye) to facilitate pediatric imaging. To reduce the number of optical elements and axial length compared to the traditional 4

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    20. Automated segmentation errors when using optical coherence tomography to measure retinal nerve fiber layer thickness in glaucoma

      Automated segmentation errors when using optical coherence tomography to measure retinal nerve fiber layer thickness in glaucoma

      Purpose To characterize the error of optical coherence tomography (OCT) measurements of retinal nerve fiber layer (RNFL) thickness when using automated retinal layer segmentation algorithms without manual refinement. Design: cross-sectional study Methods Setting: glaucoma clinical practice. Study Population: 3490 scans from 412 eyes of 213 individuals with a diagnosis of glaucoma or glaucoma suspect. Observational Procedures: We used spectral domain OCT (Spectralis, Heidelberg Engineering, Heidelberg, Germany) to measure RNFL thickness in a 6-degree peripapillary circle, and exported the native 'automated segmentation only' results. In addition, we exported the results after 'manual refinement' to correct errors in the automated segmentation of ...

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    21. Enhanced Depth Imaging Optical Coherence Tomography of Optic Nerve Head Drusen

      Enhanced Depth Imaging Optical Coherence Tomography of Optic Nerve Head Drusen

      Purpose Enhanced depth imaging (EDI) spectral-domain optical coherence tomography (SD OCT) has been recognized as the most sensitive tool to diagnose optic nerve head drusen (ONHD). The relationship between OCT characteristics and visual loss has not been well documented. This study compares EDI SD OCT–determined morphologic characteristics of drusen in eyes with or without visual field (VF) defects. Design Descriptive study of patients attending the neuro-ophthalmology service of Moorfields Eye Hospital between January 2013 and October 2014. Subjects Patients with diagnosed ONHD and EDI SD OCT imaging of the optic nerve head. Methods Eyes with and without VF defects ...

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    22. NASA Technical Reports Server (NTRS) - Exploratory Analysis of Carbon Dioxide Levels, Ultrasound and Optical Coherence Tomography Measures of the Eye During ISS Missions

      NASA Technical Reports Server (NTRS) - Exploratory Analysis of Carbon Dioxide Levels, Ultrasound and Optical Coherence Tomography Measures of the Eye During ISS Missions

      Enhanced screening for the Visual Impairment/Intracranial Pressure (VIIP) syndrome has been implemented to better characterize the ocular and vision changes observed in some long-duration crewmembers. This includes implementation of in-flight ultrasound in 2010 and optical coherence tomography (OCT) in 2013. Potential risk factors for VIIP include cardiovascular health, diet, anatomical and genetic factors, and environmental conditions. Carbon dioxide (CO2), a potent vasodilator, is chronically elevated on the International Space Station (ISS) relative to ambient levels on Earth, and is a plausible risk factor for VIIP. In an effort to understand the possible associations between CO2 and VIIP, this study ...

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    23. The Choroid and Optical Coherence Tomography

      The Choroid and Optical Coherence Tomography

      The choroid is the most vascular tissue in the eye and it plays an important role in the pathophysiology of various common chorioretinal diseases such as central serous retinopathy, age-related macular degeneration and degenerative myopia. Quantitative assessment of the choroid has been quite challenging with traditional imaging modalities such as indocyanine green angiography and ultrasonography due to limited resolution and repeatability. With the advent of optical coherence tomography (OCT) technology, detailed visualization of the choroid in vivo is now possible. Measurements of choroidal thickness have also enabled new directions in research to study normal and pathological processes within the choroid ...

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