1. Articles in category: Ophthalmology

    1-24 of 9081 1 2 3 4 ... 377 378 379 »
    1. The Evolution of the Plateau, an Optical Coherence Tomography Signature Seen in Geographic Atrophy

      The Evolution of the Plateau, an Optical Coherence Tomography Signature Seen in Geographic Atrophy

      Purpose : Histologic details of progression routes to geographic atrophy (GA) in AMD are becoming available through optical coherence tomography (OCT). We studied the origins and evolution of an OCT signature called plateau in eyes with GA and suggested a histologic correlate. Methods : Serial eye-tracked OCT scans and multimodal imaging were acquired from eight eyes of seven patients with GA and plateau signatures over a mean follow-up of 7.7 years (range, 3.7–11.6). The histology of unrelated donor eyes with AMD was reviewed. Results : Drusenoid pigment epithelial detachment (PED) on OCT imaging progressed into wide-based mound-like signatures with ...

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    2. Imaging collector channel entrance with a new intraocular micro-probe swept-source optical coherence tomography

      Imaging collector channel entrance with a new intraocular micro-probe swept-source optical coherence tomography

      Purpose To describe the use of a newly developed side-viewing catheter probe to provide the cross-sectional images of collector channel entrance (CCE), achieved by swept-source optical coherence tomography (SS-OCT). Methods A side-viewing SS-OCT catheter probe was developed that has a core probe diameter of 0.15 mm and an outer diameter of 0.25 mm, for the purpose of imaging CCEs within eye globe. Cadaver eyes harvested from swine and human were used to demonstrate its feasibility. For porcine eyes, the probe imaged the CCE by accessing the region of the aqueous plexus (AP) as well as along the inner ...

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    3. System for eye examination by means of stress-dependent parameters

      System for eye examination by means of stress-dependent parameters

      The present disclosure relates to a system for examining an eye. The system comprises a microscopy system for generating an image plane image of an object region. An OCT system of the system is configured to acquire OCT data from the object region which reproduce the object region in different stress states. A data processing unit of the system is configured to determine at least one value of a stress-dependent parameter, depending on the OCT data. The system generates an output image that is dependent on the image plane image and is furthermore dependent on the stress-dependent parameter.

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    4. Quantitative microvascular analysis of retinal venous occlusions by spectral domain optical coherence tomography angiography

      Quantitative microvascular analysis of retinal venous occlusions by spectral domain optical coherence tomography angiography

      Purpose To quantitatively evaluate the retinal microvasculature in human subjects with retinal venous occlusions (RVO) using optical coherence tomography angiography (OCTA). Design Retrospective, cross-sectional, observational case series. Participants Sixty subjects (84 eyes) were included (20 BRVO, 14 CRVO, 24 unaffected fellow eyes, and 26 controls). Methods OCTA was performed on a prototype, spectral domain-OCTA system in the 3x3mm central macular region. Custom software was used to quantify morphology and density of retinal capillaries using four quantitative parameters. The vasculature of the segmented retinal layers and nonsegmented whole retina were analyzed. Main outcome measures Fractal dimension (FD), vessel density (VD), skeletal ...

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    5. Parapapillary Choroidal Microvasculature Dropout in Glaucoma A Comparison between Optical Coherence Tomography Angiography and Indocyanine Green Angiography

      Parapapillary Choroidal Microvasculature Dropout in Glaucoma  A Comparison between Optical Coherence Tomography Angiography and Indocyanine Green Angiography

      Purpose To investigate whether the parapapillary choroidal microvasculature dropout (MvD) determined by optical coherence tomography angiography (OCTA) in glaucomatous eyes indicates a true perfusion defect and whether the MvD accurately represents the area of nonperfusion. Design Observational case series. Participants Thirty primary open-angle glaucoma (POAG) patients with choroidal MvD as determined by OCTA and 13 POAG patients without this dropout. Methods Peripapillary circulation was evaluated using both OCTA and indocyanine green angiography (ICGA). For OCTA, the choroidal microvasculature was evaluated using 4.5×4.5-mm choroid–disc vessel density maps of OCTA images of the optic nerve head. An MvD ...

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    6. A 3.4-mm beam diameter system for retinal imaging with OCT and adaptive optics

      A 3.4-mm beam diameter system for retinal imaging with OCT and adaptive optics

      We present an adaptive-optics optical coherence tomography (AO-OCT) system with 3.4-mm beam diameter. A deformable mirror is used for the correction of two radial Zernike orders (defocus, vertical and oblique astigmatism). The aberrations are corrected sequentially with a Shack-Hartmann wave-front sensor and the deformable mirror. This system fills a gap between a standard clinical 1.2-mm beam diameter OCT system and a 6-mm beam diameter AO-OCT system. We also present 8° by 8° en face OCT images from a patient with macular degeneration. This system has a 25 cm by 50 cm footprint, which makes it considerably smaller to ...

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      Mentions: Barry Cense
    7. Dual illumination for cornea and retina imaging using spectral domain optical coherence tomography

      Dual illumination for cornea and retina imaging using spectral domain optical coherence tomography

      A dual illumination system is proposed for cornea and retina imaging using spectral domain optical coherence tomography (SD-OCT). The system is designed to acquire cornea and retina imaging with dual illumination with limited optics and using a single spectrometer. The beam propagation for cornea and retina imaging in dual illumination enables to acquire the images of different segments. This approach will reduce the imaging time for separate corneal and retinal imaging. The in vivo imaging of both the cornea and retina of a health volunteer shows the feasibility of the system for clinical applications.

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    8. Optical Coherence Tomography Angiography to Estimate Retinal Blood Flow in Eyes with Retinitis Pigmentosa

      Optical Coherence Tomography Angiography to Estimate Retinal Blood Flow in Eyes with Retinitis Pigmentosa

      Ophthalmologists sometimes face difficulties in identifying the origin of visual acuity (VA) loss in a retinitis pigmentosa (RP) patient, particularly before cataract surgery: cataract or the retinal disease state. Therefore, it is important to identify the significant factors correlating with VA. Nowadays, retinal blood flow in superficial and deep layers can be estimated non-invasively using optical coherence tomography angiography (OCTA). We estimated blood flow per retinal layer by using OCTA; investigated the correlation between VA and other parameters including blood flow and retinal thickness; and identified the most associated factor with VA in patients with RP. OCTA images in 68 ...

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    9. Speckle Noise Reduction in Optical Coherence Tomography Using 2D Curvelet Based Dictionary Learning

      Speckle Noise Reduction in Optical Coherence Tomography Using 2D Curvelet Based Dictionary Learning

      The process of interpretation of high-speed optical coherence tomography (OCT) images is restricted due to the large speckle noise. To address this problem, this paper proposes a new method using two-dimensional (2D) curvelet-based K-SVD algorithm for speckle noise reduction and contrast enhancement of intra-retinal layers of 2D spectral-domain OCT images. For this purpose, we take curvelet transform of the noisy image. Then, noisy sub-bands of different scales and rotations are separately thresholded with an adaptive data-driven thresholding method, then, each thresholded sub-band is denoised based on K-SVD dictionary learning with a variable size initial dictionary to be dependent on the ...

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    10. Ultra-high resolution polarization-sensitive optical coherence tomography for imaging of the retinal nerve fiber layer

      Ultra-high resolution polarization-sensitive optical coherence tomography for imaging of the retinal nerve fiber layer

      A spectrometer design with a multiple line line-scan camera and beam displacer is presented for ultra-high resolution optical coherence tomography measurements of the human retina at 840 nm. The beam displacer offsets the two orthogonal polarization states on the same line-scan camera, which reduces k-space mapping complexity, as data in both polarization channels can be mapped with the same procedure. Its coherence length is 2.8 μm in tissue (n = 1.38). Birefringence values of 1°/μm and higher were found in a circle with a radius of 2.5° eccentricity centered on the fovea, and in the raphe, pointing ...

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      Mentions: Barry Cense
    11. INTRAPAPILLARY PROLIFERATION IN OPTIC DISK PITS: Clinical Findings and Time-Related Changes

      INTRAPAPILLARY PROLIFERATION IN OPTIC DISK PITS: Clinical Findings and Time-Related Changes

      Purpose: To investigate the structural changes of intrapapillary proliferations associated with optic disk pits (ODPs) and optic disk pit maculopathy (ODP-M) using enhanced depth-spectral domain-optical coherence tomography (SD-EDI-OCT) and megahertz optical coherence tomography (MHz-OCT). Methods: Sixteen eyes of patients with ODPs were studied. Papillary and peripapillary areas were repeatedly examined with SD-EDI-OCT over time. To evaluate swept-source OCT, some of the patients additionally received MHz-OCT-imaging. Results: MHz-OCT or SD-EDI images showed the entire form of the pits from opening to bottom in 13 of the 16 cases. The shape of ODPs varied considerably. In patients with unilateral ODP, deep intrapapillary ...

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    12. Exploring Photoreceptor Reflectivity Through Multimodal Imaging Of Outer Retinal Tubulation In Advanced AGE-RELATED Macular Degeneration

      Exploring Photoreceptor Reflectivity Through Multimodal Imaging Of Outer Retinal Tubulation In Advanced AGE-RELATED Macular Degeneration

      Purpose: To investigate the microscopic structure of outer retinal tubulation (ORT) and optical properties of cone photoreceptors in vivo, we studied ORT appearance by multimodal imaging, including spectral domain optical coherence tomography (SD-OCT) and adaptive optics scanning laser ophthalmoscopy. Methods: Four eyes of four subjects with advanced age-related macular degeneration underwent color fundus photography, infrared reflectance imaging, SD-OCT, and adaptive optics scanning laser ophthalmoscopy with a high-resolution research instrument. Outer retinal tubulation was identified in closely spaced (11 μ m) SD-OCT volume scans. Results: Outer retinal tubulation in cross-sectional and en face SD-OCT was a hyporeflective area representing a lumen surrounded ...

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    13. DIRECTIONAL CHANGES IN TISSUE REFLECTIVITY MAY INFLUENCE FLOW DETECTION ON OPTICAL COHERENCE TOMOGRAPHY ANGIOGRAPHY

      DIRECTIONAL CHANGES IN TISSUE REFLECTIVITY MAY INFLUENCE FLOW DETECTION ON OPTICAL COHERENCE TOMOGRAPHY ANGIOGRAPHY

      Purpose: To determine if directional or anatomical changes in tissue reflectivity of Henle fiber layer (HFL) may influence flow detection on optical coherence tomography angiography (OCT-A). Methods: Cross-sectional analysis of consecutive cases undergoing OCT-A. Directional changes in visualization of HFL were either produced manually by moving the beam entrance within the pupil or observed occurring naturally because of tilting of the OCT line-scan within a myopic staphyloma. Areas of enhanced HFL visualization were identified on cross-sectional and en face structural OCT scans. Visualization of OCT-A flow within the superficial and the deep capillary plexuses were compared in areas with and ...

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      Mentions: K. Bailey Freund
    14. Fully Automated Robust System to Detect Retinal Edema, Central Serous Chorioretinopathy, and Age Related Macular Degeneration from Optical Coherence Tomography Images

      Fully Automated Robust System to Detect Retinal Edema, Central Serous Chorioretinopathy, and Age Related Macular Degeneration from Optical Coherence Tomography Images

      Maculopathy is the excessive damage to macula that leads to blindness. It mostly occurs due to retinal edema (RE), central serous chorioretinopathy (CSCR), or age related macular degeneration (ARMD). Optical coherence tomography (OCT) imaging is the latest eye testing technique that can detect these syndromes in early stages. Many researchers have used OCT images to detect retinal abnormalities. However, to the best of our knowledge, no research that presents a fully automated system to detect all of these macular syndromes is reported. This paper presents the world’s first ever decision support system to automatically detect RE, CSCR, and ARMD ...

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    15. Intravitreal cysticercosis with full thickness macular hole: management outcome and intraoperative optical coherence tomography features

      Intravitreal cysticercosis with full thickness macular hole: management outcome and intraoperative optical coherence tomography features

      Ocular cysticercosis is a serious condition with a potential for complete vision loss if left untreated. Intravitreal cysticercosis is the most common ocular form of cysticercosis and is associated with retinal detachment, retinal traction, subretinal scarring and vitritis. To the best of our knowledge, there is no report of the occurrence of a live intravitreal cysticercosis with a full thickness macular hole (FTMH) in the literature. We here report a case of live intravitreal cysticercosis with a FTMH along with its management and intraoperative optical coherence tomography features of the live cysticercus.

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    16. Second-Generation OCT Module Goes the Extra Mile

      Second-Generation OCT Module Goes the Extra Mile

      Device features increased speed and higher image contrast. D avid M. Brown, MD, a retinal physician with Retina Consultants of Houston, in Texas, was prompted to upgrade to Heidelberg Engineering’s OCT2 module for the Spectralis diagnostic imaging platform because of its increased scanning speed and throughput. “I increasingly found that the process of obtaining optical coherence tomography (OCT) caused patient flow to bottleneck at my practice,” he says. “The OCT2 module helps to mitigate that issue. I can obtain a complete volume scan within 12 to 15 seconds for each eye that is precisely image tracked to the last ...

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    17. Optical Coherence Tomography in Neuroretinitis: Epipapillary Infiltrates and Retinal Folds

      Optical Coherence Tomography in Neuroretinitis: Epipapillary Infiltrates and Retinal Folds

      Neuroretinitis is a form of papillitis associated with the delayed onset of an exudative macular star among other inflammatory ocular findings. We describe 4 patients with neuroretinitis who displayed several distinctive and novel findings on spectral-domain optical coherence tomography (OCT) that include "epipapillary infiltrates" and an atypical pattern of inner retinal folds. The recognition of these findings on OCT may help in the early diagnosis of neuroretinitis.

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    18. Role of Disorganization of Retinal Inner Layers as an Optical Coherence Tomography Biomarker in Diabetic and Uveitic Macular Edema

      Role of Disorganization of Retinal Inner Layers as an Optical Coherence Tomography Biomarker in Diabetic and Uveitic Macular Edema

      The role of optical coherence tomography (OCT) in characterizing normal and pathologic retinal architecture is still evolving. Numerous groups have tried to use OCT findings of retinal features as a surrogate for visual acuity in macular edema, but no traditional measure consistently accounts for visual outcomes. Retina specialists are still trying to process the data in the literature regarding this topic, as no good review currently exists. Dilraj S. Grewal, MD, and Glenn J. Jaffe, MD, provide us with an overview of the literature and focus on the role of disorganization of the retinal inner layers (DRIL) as an OCT ...

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      Mentions: Duke University
    19. Optical Coherence Tomography Angiography Features in Melanocytoma of the Optic Nerve

      Optical Coherence Tomography Angiography Features in Melanocytoma of the Optic Nerve

      Optic disc melanocytoma (ODM) is a pigmented tumor with malignant potential characterized clinically as a dark brown to black lesion with feathery margins. The authors report a case of ODM and describe the utility of optical coherence tomography angiography (OCTA) in detecting superficial tumor vascularization. This case report demonstrated the ability of OCTA to reveal the fine abnormal retinal vasculature on the surface of the lesion, a characteristic of ODM, which has been previously correlated with tumor growth.

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    20. Choriocapillaris Changes Imaged by OCT Angiography After Half-Dose Photodynamic Therapy for Chronic Central Serous Chorioretinopathy

      Choriocapillaris Changes Imaged by OCT Angiography After Half-Dose Photodynamic Therapy for Chronic Central Serous Chorioretinopathy

      BACKGROUND AND OBJECTIVE: To evaluate the choriocapillaris using optical coherence tomographic angiography (OCTA) after half-dose verteporfin photodynamic therapy (hd-PDT) for chronic central serous chorioretinopathy (CSC). PATIENTS AND METHODS: We studied six eyes (six patients) with chronic CSC treated by hd-PDT. OCTA was performed before, 1 week after, and 1 month after hd-PDT. The area of flow abnormality at the choriocapillaris level within the PDT spot after hd-PDT was compared with that before hd-PDT. RESULTS: Serous retinal detachment was diminished in all eyes, with three achieving complete resolution at 1 month. On OCTA, all eyes showed irregular choriocapillaris flow before hd-PDT ...

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    21. Measurements of the parapapillary atrophy zones in en face optical coherence tomography images

      Measurements of the parapapillary atrophy zones in en face optical coherence tomography images

      Objective To measure the parapapillary atrophy (PPA) area in en face images obtained with swept-source optical coherence tomography (SS-OCT), and to evaluate its relationship to glaucoma, myopia, and age in non-highly myopic subjects. Design Retrospective, cross-sectional study. Participants Fifty eyes of 30 subjects with open-angle glaucoma (G group) and forty-three eyes of 26 healthy control subjects (C group). Eyes with high myopia (spherical equivalent refractive error ≤ -8 diopters or axial length ≥ 26.5 mm) were excluded. Methods Mean age ± standard deviation was 59.9 ± 12.4 years. The beta zone and the gamma zone PPA areas were measured in en ...

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    22. Swept-source Optical Coherence Tomography Angiography Imaging in a Case of Uveal Melanoma

      Swept-source Optical Coherence Tomography Angiography Imaging in a Case of Uveal Melanoma

      A 52-year-old man was referred to our ocular oncology department for evaluating a uveal mass in his right eye. Fundus examination revealed an amelanotic, mushroom-shaped choroidal melanoma in the nasal periphery (Fig 1 A ) measuring 8 mm in diameter and 5.9 mm in thickness at B-scan ultrasonography (Fig 1B). Swept-source optical coherence tomography angiography (Fig 1 C ) (Zeiss PLEX Elite 9000) allowed a comprehensive study of the mass despite its unfavorable position and thickness with excellent visualization of its intrinsic vasculature and details comparable to indocyanine green angiography (Fig 1 D ). Seven months after stereotactic radiosurgery the patient is ...

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