1. Articles in category: Ophthalmology

    577-600 of 6874 « 1 2 ... 22 23 24 25 26 27 28 ... 285 286 287 »
    1. Retinal Nerve Fiber Layer Defect Volume Deviation Analysis Using Spectral Domain Optical Coherence Tomography

      Retinal Nerve Fiber Layer Defect Volume Deviation Analysis Using Spectral Domain Optical Coherence Tomography

      Purpose: To report the retinal nerve fiber layer (RNFL) defect volume deviation according to structural RNFL loss in RNFL thickness maps Methods: RNFL defect is defined in RNFL thickness maps by the degree of RNFL loss. A 20% to 70% degree of RNFL loss was set with a 1% interval as the reference level for determining the boundary of RNFL defects. Each individual RNFL thickness map was compared to a normative database map and the region below the reference level was identified as an RNFL defect. The RNFL defect volume was calculated by summing the volumes of each pixel inside ...

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    2. Patient Characteristics Associated with Artifacts in Spectralis Optical Coherence Tomography Imaging of the Retinal Nerve Fiber Layer in Glaucoma

      Patient Characteristics Associated with Artifacts in Spectralis Optical Coherence Tomography Imaging of the Retinal Nerve Fiber Layer in Glaucoma

      Purpose To determine patient factors and eye conditions associated with artifacts in Spectralis optical coherence tomography (OCT) retinal nerve fiber layer (RNFL) scans. Design Retrospective cross-sectional study. Methods The prevalence of twelve artifact types were described in this review of 2313 eye scans from 1188 patients who underwent a complete eye exam with Spectralis OCT scanning during the period of September 2009 to July 2013. Generalized estimating equations model was utilized to analyze associations between increased artifact prevalence and 10 patient characteristics, which included age, sex, race, visual acuity, refractive error, astigmatism, cataract status, glaucoma staging, visual field reliability, and ...

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    3. Evaluation of filtering blebs exhibiting transconjunctival oozing using anterior segment optical coherence tomography

      Evaluation of filtering blebs exhibiting transconjunctival oozing using anterior segment optical coherence tomography

      Purpose To explore the features of filtering blebs exhibiting transconjunctival oozing via three-dimensional anterior segment optical coherence tomography (3D AS-OCT). Methods In this cross-sectional study, 131 eyes of 131 patients exhibiting filtering blebs were examined. Of those, 20 eyes were excluded as flat-shaped, non-functioning bleb. Transconjunctival oozing was defined as transconjunctival aqueous egress evident on the bleb surface, in the absence of any point leak observable using a slit-lamp, as confirmed by application of digital pressure. Total bleb height, the height of the fluid-filled cavity, and bleb wall thickness and density were measured using 3D AS-OCT. Patient age, the etiology ...

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    4. Automatic Vessel Shade-Robust Segmentation of Retinal Layers in OCT Images

      Automatic Vessel Shade-Robust Segmentation of Retinal Layers in OCT Images

      Optical Coherence Tomography (OCT) is a promising imaging technique used by ophthalmologists to diagnose diseases. Since retinal morphology can be identified on these images, several image processing-based methods are emerging with the purpose of extracting their information. The first step to tackle any automatic method to extract pathological features from these images is delimiting retinal layers automatically. This is the aim of this paper, which presents an active contour-based method to segment layer boundaries in the retina. Results obtained by this method present high accuracy and robustness, even when some of these layers are low defined or vessel shades are ...

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    5. University of Iowa Receives a NIH Grant for for Three-Dimensional Structure-Function Relationship in Glaucoma from SD-OCT

      University of Iowa Receives a  NIH Grant for for Three-Dimensional Structure-Function Relationship in Glaucoma from SD-OCT

      University of Iowa Receives a 2014 NIH Grant for $339,750 for Three-Dimensional Structure-Function Relationship in Glaucoma from SD-OCT. The principal investigator is Milan Sonka. The program began in 2--8 and ends in 2016. Below is a summary of the proposed work. This Phase-II proposal seeks to elucidate the structure-function relationships between visual field threshold sensitivity and the structural features of the retinal layers, the optic nerve head, and the connecting nerve fiber bundles in glaucoma. This proposal extends our successful Phase-I research that established structure- structure relationships among retinal quantitative indices. In this Phase II, further advancements of spectral ...

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    6. Duke University Receives NIH Grant for Whole Eye Optical Coherence Tomography to Improve Refractive Surgery and Eye Care.

      Duke University Receives NIH Grant for Whole Eye Optical Coherence Tomography to Improve Refractive Surgery and Eye Care.

      Duke University Receives a 2014 NIH Grant for $372,968 for Whole Eye Optical Coherence Tomography to Improve Refractive Surgery and Eye Care. The principal investigator is Anthony Kuo. The program began in 2014 and ends in 2019. Below is a summary of the proposed work. This research proposal from a multi-disciplinary team of ophthalmologists and biomedical engineers seeks to improve the accuracy of OCT representations of the eye and hence the clinical and research measurements made from OCT images. Hardware and algorithmic innovations will be made and then applied to two important clinical diagnostic measurements. In the anterior eye ...

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    7. Macular Findings Obtained by Spectral Domain Optical Coherence Tomography in Retinopathy of Prematurity

      Macular Findings Obtained by Spectral Domain Optical Coherence Tomography in Retinopathy of Prematurity

      Purpose. To examine the macular findings obtained with spectral domain optical coherence tomography (SD OCT) in infants with retinopathy of prematurity (ROP). Materials and Methods. The macular SD OCT images of 190 premature infants were analyzed. Data regarding central foveal thickness (CFT), cystoid macular edema (CME), and cyst grading were compared. The relationships of CFT with gestational age and birth weight were investigated. Results. The results were obtained from 358 eyes of 179 infants (81 females and 98 males) of a mean gestational age of weeks and a mean birth weight of  g. ROP was diagnosed in 126 eyes and ...

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      Mentions: Optovue iVue
    8. Histopathologic and Optical Coherence Tomography Observation After Descemet’s Stripping Endothelial Keratoplasty in Rabbits

      Histopathologic and Optical Coherence Tomography Observation After Descemet’s Stripping Endothelial Keratoplasty in Rabbits

      Objectives: To study the histopathologic and optical coherence tomography changes after Descemet’s Stripping Endothelial Keratoplasty in rabbits. Materials and Methods: Descemet’s Stripping Endothelial Keratoplasty was performed in 14 rabbit eyes and descemetorhexis was performed in 10 rabbits, as control. Histopathologic examination and anterior-segment optical coherence tomography were conducted in the Descemet’s Stripping Endothelial Keratoplasty group at 1, 2, 4, and 8 weeks. For the control group, histopathologic examination was performed before surgery and at 1, 2, 4, and 8 weeks after surgery. Results: In the Descemet’s Stripping Endothelial Keratoplasty group, corneas cleared completely within 2 weeks ...

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    9. Optical coherence tomography and electrophysiological findings in torpedo maculopathy

      Optical coherence tomography and electrophysiological findings in torpedo maculopathy

      Purpose To describe the morphofunctional findings in a 6-year-old child with a unilateral lesion of the temporal macula called “torpedo maculopathy” throughout a 1-year follow-up. Methods Evaluation of retinal morphology and function was assessed by means of spectral-domain OCT scans, best-corrected visual acuity, full-field flash electroretinogram (ERG), multifocal electroretinogram (mfERG) and pattern visual evoked potentials (VEP). Patient was examined every 4 months for a 1-year follow-up time. Results Torpedo maculopathy consisted in a sharply demarcated hypopigmented oval iuxta-macular lesion (1.5 DD wide × 0.7 DD high). The baseline visual acuity of the affected eye was 20/25. OCT showed ...

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    10. Detection of retinal nerve fibre layer degeneration in patients with Alzheimer's disease using optical coherence tomography: searching new biomarkers

      Detection of retinal nerve fibre layer degeneration in patients with Alzheimer's disease using optical coherence tomography: searching new biomarkers

      PURPOSE: To explore the features of filtering blebs exhibiting transconjunctival oozing via three-dimensional anterior segment optical coherence tomography (3D AS-OCT). METHODS: In this cross-sectional study, 131 eyes of 131 patients exhibiting filtering blebs were examined. Of those, 20 eyes were excluded as flat-shaped, non-functioning bleb. Transconjunctival oozing was defined as transconjunctival aqueous egress evident on the bleb surface, in the absence of any point leak observable using a slit-lamp, as confirmed by application of digital pressure. Total bleb height, the height of the fluid-filled cavity, and bleb wall thickness and density were measured using 3D AS-OCT. Patient age, the etiology ...

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    11. Optical density filters modeling media opacities cause decreased SD-OCT retinal layer thickness measurements with inter- and intra-individual variation

      Optical density filters modeling media opacities cause decreased SD-OCT retinal layer thickness measurements with inter- and intra-individual variation

      Purpose To assess the effect of media opacities on thickness measurements of the peripapillary retinal nerve fibre layer (pRNFL) and macular inner retinal layer (mIRL) performed with spectral-domain optical coherence tomography (SD-OCT) using a set of filters with known optical density. Methods Spectral-domain optical coherence tomography volume scans of the optic disc and the macular area were performed in 18 healthy volunteers, using Topcon-3DOCT-1000 Mark II. A set of five filters with optical density ranging from 0.04 to 0.69 was used. The correlation was calculated between the percentage change in thickness measurements (%ΔpRNFL and %ΔmIRL) and the change ...

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    12. Photoreceptor inner segment ellipsoid band integrity on spectral domain optical coherence tomography

      Photoreceptor inner segment ellipsoid band integrity on spectral domain optical coherence tomography

      Spectral domain optical coherence tomography cross-sectional imaging of the macula has conventionally been resolved into four bands. However, some doubts were raised regarding authentication of the existence of these bands. Recently, a number of studies have suggested that the second band appeared to originate from the inner segment ellipsoids of the foveal cone photoreceptors, and therefore the previously called inner segment-outer segment junction is now referred to as inner segment ellipsoidband. Photoreceptor dysfunction may be a significant predictor of visual acuity in a spectrum of surgical and medical retinal diseases. This review aims to provide an overview and summarizes the ...

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    13. Zeiss Meditec sales hit by currency fluctuations

      Zeiss Meditec sales hit by currency fluctuations

      Shares in Carl Zeiss Meditec , the clinical wing of the optics and microscopy giant, dropped in value by around 6 per cent on the Frankfurt stock exchange after the company just missed its annual sales target. For the year ending September 30, the Germany-headquartered firm delivered revenues of €909 million. That was up very slightly on the figure of €906 million for the previous year, but below the range of €910 million to €940 million estimated back in May – something blamed largely on currency effects. CEO Ludwin Monz said of the result: “In spite of adverse currency trends and to ...

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    14. Dual illumination OCT at 1050nm and 840nm for whole eye segment imaging

      Dual illumination OCT at 1050nm and 840nm for whole eye segment imaging

      We presented an improved dual channel dual focus spectral domain optical coherence tomography (SD-OCT) with two illuminations at 840 nm and 1050 nm for whole eye segment imaging and biometry in vivo. The two light beams were coupled and optically optimized to scan the anterior and posterior segment of the eye simultaneously. This configuration with dichroic mirrors integrated in the sample arm enables us to acquire images from the anterior segment and retina effectively with minimum loss of sample signal. In addition, the full resolved complex (FRC) method was applied to double the imaging depth for the whole anterior segment ...

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    15. Noninvasive Ocular Angiography by Optical Coherence Tomography (Book Chapter)

      Noninvasive Ocular Angiography by Optical Coherence Tomography (Book Chapter)

      Diabetic retinopathy, age-related macular degeneration, and glaucoma are all associated with impaired circulation. Noninvasive assessment of ocular circulation would be very powerful for understanding and diagnosing these eye diseases. Using high-speed optical coherence tomography (OCT), we developed a new OCT angiography algorithm called split-spectrum amplitude-decorrelation angiography (SSADA) for imaging ocular microcirculation. Here, the system and theory of this novel OCT angiography technique are reviewed; its capabilities for imaging retinal, choroidal, and optic nerve head blood flow are demonstrated; and its limitation is discussed.

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    16. Ultrahigh-Speed Swept-Source OCT Angiography in Exudative AMD

      Ultrahigh-Speed Swept-Source OCT Angiography in Exudative AMD

      BACKGROUND AND OBJECTIVE: To investigate the potential of ultrahigh-speed swept-source optical coherence tomography angiography (OCTA) to visualize retinal and choroidal vascular changes in patients with exudative age-related macular degeneration (AMD). PATIENTS AND METHODS: Observational, prospective cross-sectional study. An ultrahigh-speed swept-source prototype was used to perform OCTA of the retinal and choriocapillaris microvasculature in 63 eyes of 32 healthy controls and 19 eyes of 15 patients with exudative AMD. MAIN OUTCOME MEASURE: qualitative comparison of the retinal and choriocapillaris microvasculature in the two groups. RESULTS: Choroidal neovascularization (CNV) was clearly visualized in 16 of the 19 eyes with exudative AMD, located ...

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    17. OCT Angiography in Healthy Human Subjects

      OCT Angiography in Healthy Human Subjects

      BACKGROUND AND OBJECTIVE: To noninvasively evaluate the retinal microvasculature in healthy human subjects with optical coherence tomography angiography (OCTA). PATIENTS AND METHODS: Cross-sectional, observational study of five healthy subjects. OCTA was performed on 3 × 3 mm(2) sections centered on the fovea, nasal macula, and temporal macula. Retinal vasculature was assessed within three horizontal slabs consisting of the inner, middle, and outer retina. The vasculature within each retinal slab was reconstructed using phase-based and intensity contrast-based algorithms and visualized as separate en face images. RESULTS: OCTA in healthy subjects demonstrates capillary networks consistent with previous histological studies. No retinal vessels ...

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    18. High-Speed Ultrahigh-Resolution OCT of Bruch's Membrane in Membranoproliferative Glomerulonephritis Type 2

      High-Speed Ultrahigh-Resolution OCT of Bruch's Membrane in Membranoproliferative Glomerulonephritis Type 2

      Membranoproliferative glomerulonephritis (MPGN) type 2 is characterized by electron-dense deposits in the glomerular basement membrane and drusen-like deposits in Bruch's membrane. Over time, atrophic changes in the retina and retinal pigment epithelium occur, which can progress to choroidal neovascularization (CNV). This report describes a patient with MPGN type 2 who developed progressive loss of vision secondary to CNV. High-speed ultrahigh-resolution optical coherence tomography (UHR-OCT) showed an irregular Bruch's membrane that measured 10 μm beneath the foveal center. High-speed UHR-OCT can potentially be used to analyze Bruch's membrane in secondary ocular manifestations of diseases such as MPGN type ...

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    19. Fundus autofluorescence and optical coherence tomography findings in pigmented paravenous retinochoroidal atrophy

      Fundus autofluorescence and optical coherence tomography findings in pigmented paravenous retinochoroidal atrophy

      Pigmented paravenous retinochoroidal atrophy (PPRCA) is a rare ocular disease with unknown etiology characterized by bilateral retinal pigment epithelium (RPE) and choroidal atrophy along retinal veins usually found incidentally during an eye examination. 1 In the past, fluorescein angiography (FA), electrophysiologic tests, and visual field testing have helped in the diagnosis. 1–3 Noninvasive imaging techniques including fundus autofluorescence (FAF) and spectral-domain optical coherence tomography (SD-OCT) are now available to assist retina specialists in the diagnosis of retinal degenerations, dystrophies, 4,5 and also drug toxicity.

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    20. Optical coherence tomography for the diagnosis, monitoring and guiding of treatment for neovascular age-related macular degeneration: a systematic review and economic evaluation

      Optical coherence tomography for the diagnosis, monitoring and guiding of treatment for neovascular age-related macular degeneration: a systematic review and economic evaluation

      Background Age-related macular degeneration is the most common cause of sight impairment in the UK. In neovascular age-related macular degeneration (nAMD), vision worsens rapidly (over weeks) due to abnormal blood vessels developing that leak fluid and blood at the macula. Objectives To determine the optimal role of optical coherence tomography (OCT) in diagnosing people newly presenting with suspected nAMD and monitoring those previously diagnosed with the disease. Data sources Databases searched: MEDLINE (1946 to March 2013), MEDLINE In-Process & Other Non-Indexed Citations (March 2013), EMBASE (1988 to March 2013), Biosciences Information Service (1995 to March 2013), Science Citation Index (1995 to ...

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    21. Eye Shape Using Partial Coherence Interferometry, Autorefraction, and SD-OCT

      Eye Shape Using Partial Coherence Interferometry, Autorefraction, and SD-OCT

      Purpose: Peripheral refraction and retinal shape may influence refractive development. Peripheral refraction has been shown to have a high degree of variability and can take considerable time to perform. Spectral domain optical coherence tomography (SD-OCT) and peripheral axial length measures may be more reliable, assuming that the retinal position is more important than the peripheral optics of the lens/cornea. Methods: Seventy-nine subjects' right eyes were imaged for this study (age range, 22 to 34 years; refractive error, -10 to +5.00). Thirty-degree SD-OCT (Spectralis, Heidelberg Engineering, Heidelberg, Germany) images were collected in a radial pattern along with peripheral refraction ...

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    22. Diagnostic ability of retinal nerve fiber layer imaging by swept source optical coherence tomography in glaucoma

      Diagnostic ability of retinal nerve fiber layer imaging by swept source optical coherence tomography in glaucoma

      Purpose To evaluate the diagnostic accuracies of swept-source optical coherence tomography (OCT) wide-angle and peripapillary retinal nerve fiber layer (RNFL) thickness measurements for glaucoma detection. Design Cross-sectional case-control study. Methods In this study we enrolled 144 glaucomatous eyes of 106 subjects and 66 eyes of 42 healthy subjects from the Diagnostic Innovations in Glaucoma Study. Glaucoma was defined by the presence of repeatable abnormal standard automated perimetry results and/or progressive glaucomatous optic disc change on masked grading of stereophotographs. Wide-angle and peripapillary RNFL thicknesses were assessed using swept-source OCT. Peripapillary RNFL thickness was also evaluated using spectral-domain OCT. Areas ...

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    23. Advanced Imaging for Glaucoma Study: Design, Baseline Characteristics, and Inter-Site Comparison

      Advanced Imaging for Glaucoma Study: Design, Baseline Characteristics, and Inter-Site Comparison

      Purpose To report the baseline characteristics of the participants in the Advanced Imaging for Glaucoma Study. To compare the participating sites for variations among subjects and the performance of imaging instruments. Design Multi-center longitudinal observational cohort study Methods A total of 788 participants (1,329 eyes) were enrolled from three academic referral centers. There were 145 participants (289 eyes) in the normal group, 394 participants (663 eyes) in the glaucoma suspect/preperimetric glaucoma group, and 249 participants (377 eyes) in the perimetric glaucoma group. Participants underwent a full clinical exam, standard automated perimetry, and imaging with time-domain and Fourier-domain optical ...

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    24. Identification and biometry of horizontal extraocular muscle tendons using optical coherence tomography

      Identification and biometry of horizontal extraocular muscle tendons using optical coherence tomography

      Purpose To purpose if this study was to determine whether the horizontal rectus muscle tendons (HRMTs) can be observed using anterior segment optical coherence tomography (AS-OCT) and to determine the repeatability of its measurements. Also, this study aimed to observe and measure the different external ocular structures at the level of the horizontal rectus muscle (HRM) insertion. Methods This was a retrospective, observational, descriptive and comparative study. Images were obtained utilizing the RTVue 100 CAM system. Eyes were analyzed at the three and nine o’clock position. Scans were performed for three different locations: the limbus, the ciliary body and ...

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