1. Articles in category: Ophthalmology

    1-24 of 5894 1 2 3 4 ... 244 245 246 »
    1. Influence of a New Software Version of the RTVue-100 Optical Coherence Tomograph on Ganglion Cell Complex Segmentation in Various Forms of Age-related Macular Degeneration

      Influence of a New Software Version of the RTVue-100 Optical Coherence Tomograph on Ganglion Cell Complex Segmentation in Various Forms of Age-related Macular Degeneration

      Purpose: Previously, we have shown that age-related macular degeneration (AMD) influences glaucoma classification with the ganglion cell complex (GCC) parameters of the RTVue-100 optical coherence tomograph (RTVue-OCT) in nonglaucomatous eyes. Now, we reevaluated the influence of AMD on GCC image segmentation and classification for glaucoma on the same eyes, using a new version of the software. Methods: GCC images of nonglaucomatous eyes [30 healthy, 19 with early/intermediate AMD, 16 with subfoveal choroidal neovascularization (CNV), and 19 after intravitreal antiangiogenic treatment of CNV, CNV-anti-VEGF] were reanalyzed with software versions 6.3 (the currently available version) and 6.12 (a version ...

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    2. Automatic tracking of pupillary dynamics from in vivo functional optical coherence tomography images

      Automatic tracking of pupillary dynamics from in vivo functional optical coherence tomography images

      A major challenge currently faced in measuring visually evoked optical changes in different retinal layers using in vivo and non-invasive functional optical coherence tomography (fOCT) is the need for pupillary dilation drugs to enable reliable measurement of the retinal functional responses. However, there are situations where the use of pupillary dilation drugs is not suitable in both clinical and animal ophthalmic research situations. To overcome this challenge, we propose a new approach to tracking visually evoked pupillary dynamics, based on the use of a fast scanning fOCT system and a novel computerised framework, which can then be used to isolate ...

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    3. Choroidal vessel characterization using en-face optical coherence tomography measurement

      Choroidal vessel characterization using en-face optical coherence tomography measurement

      The choroid plays an important role in the pathogenesis of many diseases of the back section of the eye. A comprehensive visualization and knowledge of the choroid is still lacking despite advances in imaging technologies. En-face Optical Coherence Tomography (OCT) provides detailed images useful to understand choroidal vasculature. In the paper, in order to get essential information about circulation-related ocular diseases, an image processing and measurement procedure is presented, capable of providing an efficient choroidal vessel segmentation and caliber estimation starting from en-face OCT images.

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    4. Retinal Pathology detected by optical coherence tomography in an animal model of Parkinson's disease - Schneider - 2014 - Movement Disorders - Wiley Online Library

      Retinal Pathology detected by optical coherence tomography in an animal model of Parkinson's disease - Schneider - 2014 - Movement Disorders - Wiley Online Library

      Background Optical coherence tomography (OCT) is a noninvasive procedure for analysis of retinal morphology. Significant changes in the thickness of the peripapillary retinal nerve fiber layer (RNFL) in Parkinson's disease (PD) have been reported, and the current study was performed to examine whether such changes can also be detected in an animal model of PD. Methods Optical coherence tomography measurements of peripapillary RNFL thickness, macula volume, and foveal thickness were obtained from 10 normal and five 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-treated cynomolgus monkeys with stable Parkinsonian signs. Results Average RNFL thickness was significantly decreased in Parkinsonian monkeys compared ...

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    5. Evaluation of Pachymetric Measurements with Scheimpflug Photography-Based System and Optical Coherence Tomography Pachymetry at Different Stages of Keratoconus

      Evaluation of Pachymetric Measurements with Scheimpflug Photography-Based System and Optical Coherence Tomography Pachymetry at Different Stages of Keratoconus

      The aim of this study was to compare the central and peripheral pachymetric measurements determined with Sirius system and Visante OCT and evaluate the agreement between them at different stages of keratoconus. Measurements were not significantly different in all patients and subgroups and showed high correlation for the corneal thicknesses of the entire cornea in different stages of keratoconus.

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    6. Anterior Segment Optical Coherence Tomography Imaging of Conjunctival Filtering Blebs after Glaucoma Surgery

      Anterior Segment Optical Coherence Tomography Imaging of Conjunctival Filtering Blebs after Glaucoma Surgery

      Time domain (TD) and spectral domain (SD) optical coherence tomography (OCT) are cross-sectional, noncontact, highresolution diagnostic modalities for posterior and anterior segment (AS) imaging.The AS-OCT provides tomographic imaging of the cornea, iris, lens, and anterior chamber (AC) angle in several ophthalmic diseases. In glaucoma, AS-OCT is utilized to evaluate the morphology of AS structures involved in the pathogenesis of the disease, to obtain morphometric measures of the AC, to evaluate the suitability for laser or surgical approaches, and to assess modifications after treatment. In patients undergoing surgery, AS-OCT is crucial in the evaluation of the filtering bleb functionality, permitting ...

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    7. OPTICAL COHERENCE TOMOGRAPHY DIFFERENCE MAPS AND AVERAGE MACULAR VOLUME FOR GEOGRAPHIC ATROPHY

      OPTICAL COHERENCE TOMOGRAPHY DIFFERENCE MAPS AND AVERAGE MACULAR VOLUME FOR GEOGRAPHIC ATROPHY

      Purpose: To demonstrate the ability to monitor geographic atrophy (GA) volumetrically through all retinal layers with high-resolution optical coherence tomography difference maps and average macular volume. Methods: Observational case report. Results: Two patients diagnosed with GA were followed up for multiple years with consecutive high-resolution optical coherence tomography studies along with fundus photography and fluorescein angiography or fundus autofluorescence. Difference maps visually reflect macular thinning associated with expansion of GA witnessed on alternative studies. In addition, these maps show progressive macular thinning within previously delineated areas of GA. Average macular volume quantitatively demonstrates the decreasing volume associated with the expanding ...

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    8. Reproducibility of Spectral-Domain Optical Coherence Tomography Retinal Thickness Measurements and Conversion to Equivalent Time-Domain Metrics in Diabetic Macular Edema

      Reproducibility of Spectral-Domain Optical Coherence Tomography Retinal Thickness Measurements and Conversion to Equivalent Time-Domain Metrics in Diabetic Macular Edema

      Importance Understanding measurement variability and relationships between measurements obtained on different optical coherence tomography (OCT) machines is critical for clinical trials and clinical settings. Objective To evaluate the reproducibility of retinal thickness measurements from OCT images obtained by time-domain (TD) (Stratus; Carl Zeiss Meditec) and spectral-domain (SD) (Cirrus; Carl Zeiss Meditec, and Spectralis; Heidelberg Engineering) instruments and formulate equations to convert retinal thickness measurements from SD-OCT to equivalent values on TD-OCT. Design, Setting, and Participants A cross-sectional observational study was conducted in private and institutional practices. Persons with diabetes mellitus who had at least 1 eye with central-involved diabetic macular ...

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    9. A FALSE COLOR FUSION STRATEGY FOR DRUSEN AND GEOGRAPHIC ATROPHY VISUALIZATION IN OPTICAL COHERENCE TOMOGRAPHY IMAGES

      A FALSE COLOR FUSION STRATEGY FOR DRUSEN AND GEOGRAPHIC ATROPHY VISUALIZATION IN OPTICAL COHERENCE TOMOGRAPHY IMAGES

      Purpose: To display drusen and geographic atrophy (GA) in a single projection image from three-dimensional spectral domain optical coherence tomography images based on a novel false color fusion strategy. Methods: We present a false color fusion strategy to combine drusen and GA projection images. The drusen projection image is generated with a restricted summed-voxel projection (axial sum of the reflectivity values in a spectral domain optical coherence tomography cube, limited to the region where drusen is present). The GA projection image is generated by incorporating two GA characteristics: bright choroid and thin retina pigment epithelium. The false color fusion method ...

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    10. DISTRIBUTION OF INTRARETINAL EXUDATES IN DIABETIC MACULAR EDEMA DURING ANTI-VASCULAR ENDOTHELIAL GROWTH FACTOR THERAPY OBSERVED BY SPECTRAL DOMAIN OPTICAL COHERENCE TOMOGRAPHY AND FUNDUS PHOTOGRAPHY

      DISTRIBUTION OF INTRARETINAL EXUDATES IN DIABETIC MACULAR EDEMA DURING ANTI-VASCULAR ENDOTHELIAL GROWTH FACTOR THERAPY OBSERVED BY SPECTRAL DOMAIN OPTICAL COHERENCE TOMOGRAPHY AND FUNDUS PHOTOGRAPHY

      Purpose: To evaluate changes in the distribution and morphology of intraretinal microexudates and hard exudates (HEs) during intravitreal anti-vascular endothelial growth factor therapy in patients with persistent diabetic macular edema. Methods: Twenty-four patients with persistent diabetic macular edema after photocoagulation were investigated in this prospective cohort study. Each eye was assigned to a loading dose of three anti-vascular endothelial growth factor treatments at monthly intervals. Additional single treatments were performed if diabetic macular edema persisted or recurred. Intraretinal exudates were analyzed over 6 months using spectral domain optical coherence tomography (SD-OCT) and fundus photography. Results: Before treatment, microexudates were detected ...

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    11. Astronaut Using Optical Coherence Tomography during an Ocular Health vision Test on the International Space Station

      Astronaut Using Optical Coherence Tomography during an Ocular Health vision Test on the International Space Station

      Flight Engineer Alexander Gerst uses the Optical Coherence Tomography camera during an Ocular Health vision test in the Harmony node of the International Space Station. Commander Steve Swanson (left) assists Gerst. Image credit: NASA. Larger image (1 MB): http://www.nasa.gov/sites/default/files/oh_vision_test.jpg

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    12. Simultaneous Investigation of Vascular and Retinal Pigment Epithelial Pathologies of Exudative Macular Diseases by Multi-Functional Optical Coherence Tomography

      Simultaneous Investigation of Vascular and Retinal Pigment Epithelial Pathologies of Exudative Macular Diseases by Multi-Functional Optical Coherence Tomography

      Purpose: To investigate exudative macular disease, multi-functional optical coherence tomography (MF-OCT) using a 1-μm probe band was developed. The clinical utility of MF-OCT was examined in a descriptive case series. Methods: Ten eyes of nine subjects with exudative macular disease, including one eye with age-related macular degeneration (AMD), one eye with idiopathic neovascular maculopathy, and eight eyes with polypoidal choroidal vasculopathy (PCV), were investigated. Areas of 6 × 6 mm 2 around the pathologic region were scanned with 512 × 1024 depth scans in 6.6 seconds. Structural OCT, Doppler optical coherence angiography (OCA) and cumulative phase retardation images were obtained ...

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    13. Measurement of Subfoveal Choroidal Thickness after Cataract Surgery in Enhanced Depth Imaging Optical Coherence Tomography

      Measurement of Subfoveal Choroidal Thickness after Cataract Surgery in Enhanced Depth Imaging Optical Coherence Tomography

      Purpose:To compare Subfoveal Choroidal Thickness (SFCT) before and after unenventful cataract surgery using Enhanced Depth Imaging Optical Coherence Tomography (EDI OCT). Methods:A prospective study was conducted on 115 eyes of 95 patients who had phacoemulsification. Measurements of SFCT were performed preoperatively and one day (D1), seven days (D7), one month (M1) and three months (M3) after surgery using the EDI OCT technique. Central Retinal Thickness (CRT) was measured before surgery and at M1 and M3. Results:The 95 patients had a mean age of 76±8.3 years. The mean SFCT at baseline was 224±75μm. It ...

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    14. Age-Related Changes in Human Corneal Epithelial Thickness Measured with Anterior Segment Optical Coherence Tomography

      Age-Related Changes in Human Corneal Epithelial Thickness Measured with Anterior Segment Optical Coherence Tomography

      Purpose: To measure corneal and limbal epithelial thickness (ET) in normal subjects and to evaluate its variation with age by using anterior segment optical coherence tomography (AS-OCT). Methods: 180 normal subjects (180 healthy eyes) were enrolled and divided into four groups according to age: A (0-20 years), B (21-40 years), C (41-60 years), D (>60 years). Cornea and limbus were imaged with OCT. Corneal ET (CET) was obtained automatically by the built-in analysis software of the OCT system. Limbal ET (LET) in four quadrants was manually measured from OCT images. Results: CET of central 2-mm diameter zone in groups A ...

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    15. Neural Network Analysis of Different Segmentation Strategies of Nerve Fiber Layer Assessment for Glaucoma Diagnosis

      Neural Network Analysis of Different Segmentation Strategies of Nerve Fiber Layer Assessment for Glaucoma Diagnosis

      Purpose: To compare the diagnostic performance of different segmentations of the nerve fiber layer (NFL) thickness measurements using an artificial neural network and to define the optimal number of sectors with best diagnostic ability for glaucoma diagnosis. Methods: A total of 117 glaucoma patients and 123 normal subjects were included in the study. NFL thickness measurements were performed using the Spectralis-OCT (Heidelberg Engineering) to obtain the NFL thickness average; measurements from 2 semicircles, 4 quadrants, and 6, 8, 12, 16, 24, 32, and 64 sectors; and 768 uniformly divided locations around the peripapillary NFL. An artificial neural network evaluation was ...

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    16. Association Between Transient Interface Fluid on Intraoperative OCT and Textural Interface Opacity After DSAEK Surgery in the PIONEER Study

      Association Between Transient Interface Fluid on Intraoperative OCT and Textural Interface Opacity After DSAEK Surgery in the PIONEER Study

      Purpose: The aim of this study was to examine the association between transient interface fluid (TIF) and textural interface opacity (TIO) after Descemet stripping automated endothelial keratoplasty (DSAEK) surgery using intraoperative optical coherence tomography (iOCT) in the PIONEER (Prospective Intraoperative and Perioperative Ophthalmic ImagiNg with Optical CoherEncE TomogRaphy) study. Methods: All consecutive eyes that underwent DSAEK between October 2011 and September 2013 from the PIONEER intraoperative and perioperative OCT study were included. iOCT images were captured after lenticule apposition with complete air fill and after air-fluid exchange. Postoperative day 1 OCT images were obtained. Outcome variables included the presence of ...

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    17. Misguided Progression Analysis by Optical Coherence Tomography: A Report of Two Cases

      Misguided Progression Analysis by Optical Coherence Tomography: A Report of Two Cases

      Spectral domain optical coherence tomography (SOCT) is an important tool for the diagnosis and management of glaucoma. In an effort to help automate the detection of progressive structural glaucomatous optic nerve damage, Carl Zeiss Meditec has developed Guided Progression Analysis (GPA) software in conjunction with the Cirrus SOCT (Carl Zeiss Meditec, Dublin, Calif., USA). Here, we report a case in which the GPA merged information from 2 different patients, and another case in which data from alternate eyes was compared, making the final analysis invalid.

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    18. Detection of Fovea-Threatening Diabetic Macular Edema by Optical Coherence Tomography to Maintain Good Vision by Prophylactic Treatment

      Detection of Fovea-Threatening Diabetic Macular Edema by Optical Coherence Tomography to Maintain Good Vision by Prophylactic Treatment

      Background/Aims: To establish a screening and treatment method for fovea-threatening diabetic macular edema (DME) using spectral-domain optical coherence tomography (SD-OCT). In order to maintain good visual acuity (VA), focal/grid laser treatment for screened fovea-threatening DME was evaluated based on macular thickness map images produced by SD-OCT. Methods: In 66 diabetic eyes with no visual deterioration, the sensitivity and the specificity of SD-OCT without the use of mydriatics for the detection of fovea-threatening DME were determined. A definite diagnosis of DME was made under mydriasis, using slitlamp biomicroscopy with a contact lens. Eyes with fovea-threatening DME then underwent prophylactic ...

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    19. Detection of Retinal Changes in Patients on Long Term Chloroquine/Hydroxy Chloroquine Therapy Using Optical Coherence Tomography

      Detection of Retinal Changes in Patients on Long Term Chloroquine/Hydroxy Chloroquine Therapy Using Optical Coherence Tomography

      Background: The best technique to diagnose chloroquine/ hydroxychloroquine-induced retinopathy changes at the earliest remains ambiguous at present. In this study, we evaluated the time-domain optical coherence tomography (OCT) to identify retinal changes associated with chloroquine and hydroxychloroquine. Methods: One hundred patients with immunological diseases were included in the study. Fifty of them had been on chloroquine and/or hydroxychloroquine therapy for at least five years and the other 50 patients as controls. Detailed ophthalmic examination including Amsler grid , colour vision , automated threshold white perimetry using 10-2 protocol on Humphrey field analyzer, fluorescein angiography when indicated and time domain Optical Coherence ...

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    20. The noninvasive predictive approach for choroidal vascular diffuse hyperpermeability in central serous chorioretinopathy: near-infrared reflectance and enhanced depth imaging

      The noninvasive predictive approach for choroidal vascular diffuse hyperpermeability in central serous chorioretinopathy: near-infrared reflectance and enhanced depth imaging

      Purpose To investigate near-infrared reflectance (NIR) findings in central serous chorioretinopathy (CSCR) and to predict the choroidal vascular diffuse hyperpermeability (CVDHP) by NIR and enhanced depth imaging spectral-domain optical coherence tomography (EDI SD-OCT) noninvasively. Methods Retrospective analysis of 52 eyes of 50 CSCR patients with serous macular detachment. All patients received NIR, indocyanine green angiography (ICGA), and EDI SD-OCT. NIR pattern (irregular, defected, masked and enhanced), double layer sign (DLS) in EDI SD-OCT and CVDHP in ICGA were evaluated. In addition, we measured the length of photoreceptor outer segment (LPOS), and subfoveal choroidal thickness (SFCT) by Heidelberg eye explorer software ...

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    21. RETINAL PIGMENT EPITHELIUM FINDINGS IN PATIENTS WITH ALBINISM USING WIDE-FIELD POLARIZATION-SENSITIVE OPTICAL COHERENCE TOMOGRAPHY

      RETINAL PIGMENT EPITHELIUM FINDINGS IN PATIENTS WITH ALBINISM USING WIDE-FIELD POLARIZATION-SENSITIVE OPTICAL COHERENCE TOMOGRAPHY

      Purpose: To investigate pigmentation characteristics of the retinal pigment epithelium (RPE) in patients with albinism using wide-field polarization-sensitive optical coherence tomography compared with intensity-based spectral domain optical coherence tomography and fundus autofluorescence imaging. Methods: Five patients (10 eyes) with previously genetically diagnosed albinism and 5 healthy control subjects (10 eyes) were imaged by a wide-field polarization-sensitive optical coherence tomography system (scan angle: 40 x 40[degrees] on the retina), sensitive to melanin contained in the RPE, based on the polarization state of backscattered light. Conventional intensity-based spectral domain optical coherence tomography and fundus autofluorescence examinations were performed. Retinal pigment epithelium-pigmentation ...

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    22. Automatic dynamic tear meniscus measurement in optical coherence tomography

      Automatic dynamic tear meniscus measurement in optical coherence tomography

      An image processing algorithm is developed for quantitative assessment of tear meniscus dynamics from continuous optical coherence tomography (OCT) measurements. Clinical utility of dynamic OCT tear meniscus measurement is assessed in studies of tear meniscus parameters. The results indicate that any apparent changes in the early post-blink phase meniscus parameters are essentially related to the longitudinal movements of the eye and not to the formation of tear meniscus corresponding to tear film build-up. Dynamic acquisition of tear film meniscus is essential for providing reliable estimates of its parameters such as height, depth, and area.

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    23. Image capture apparatus and method

      Image capture apparatus and method

      It has been very cumbersome to determine whether or not alignment is required before the fundus image is acquired after the tomographic image is acquired, causing the reduction in diagnostic efficiency. An ophthalmic apparatus is provided to solve this problem, which comprises an irradiation unit that irradiates an eye to be inspected with a first beam for acquiring a tomographic image of the eye and a second beam for acquiring a fundus image of the eye, the second beam having a beam diameter larger than the beam diameter of the first beam; and a determination unit that, based on information ...

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    24. Spectral optical coherence tomography

      Spectral optical coherence tomography

      The invention relates to an apparatus for generating a scannable optical delay for a beam of light and an apparatus for Fourier domain optical coherence tomography having said apparatus for generating a scannable optical delay in its reference arm (15). The light beam is directed to a pivotably driven mirror (10) from where it is reflected to a fixed mirror (12), and from there back retro reflected along the reference arm (5). Lens optics (9) are provided to ensure accurate optical alignment in several pivot positions of the pivotably driven mirror (10).

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