1. Articles in category: Ophthalmology

    25-48 of 12918 « 1 2 3 4 5 ... 537 538 539 »
    1. Automated Quantification of Photoreceptor alteration in macular disease using Optical Coherence Tomography and Deep Learning

      Automated Quantification of Photoreceptor alteration in macular disease using Optical Coherence Tomography and Deep Learning

      Diabetic macular edema (DME) and retina vein occlusion (RVO) are macular diseases in which central photoreceptors are affected due to pathological accumulation of fluid. Optical coherence tomography allows to visually assess and evaluate photoreceptor integrity, whose alteration has been observed as an important biomarker of both diseases. However, the manual quantification of this layered structure is challenging, tedious and time-consuming. In this paper we introduce a deep learning approach for automatically segmenting and characterising photoreceptor alteration. The photoreceptor layer is segmented using an ensemble of four different convolutional neural networks. En-face representations of the layer thickness are produced to characterize ...

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    2. The effect of contact lens wear on retinal spectral domain optical coherence tomography

      The effect of contact lens wear on retinal spectral domain optical coherence tomography

      Background This study assessed the impact of contact lens wear on retinal spectral domain optical coherence tomography (SD‐OCT) image quality and macular thickness measurements, among subjects with myopia. Methods This was a prospective study including 34 subjects (26.59 ± 3.19 years) with myopia or myopic astigmatism. Twelve were imaged wearing spherical soft contact lenses, eight non‐contact lens wearers were imaged with a plano soft contact lens, and 14 with significant astigmatism were fitted with a rigid gas permeable (RGP) contact lens. For each group of contact lens types, the average image quality index (Q‐index), and the ...

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    3. Changes in the Retinal Microvasculature Measured Using Optical Coherence Tomography Angiography According to Age

      Changes in the Retinal Microvasculature Measured Using Optical Coherence Tomography Angiography According to Age

      In this cross-sectional study, we examined age-related changes in the retinal vessels of 100 healthy participants, aged from 5 to 80 years, and divided into four groups (G1, under 20 years of age; G2, from 20 to 39 years of age; G3, from 40 to 59 years of age; G4, age 60 years or older). All subjects underwent swept-source optical coherence tomography (SS-OCT) and OCT angiography (OCTA). The vascular density (VD) of the superficial (SCP) and deep capillary plexus (DCP), and choriocapillaris (CCP) were measured using OCTA. The vascular density of each capillary layer, foveal avascular zone (FAZ) area, ganglion ...

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    4. Optical coherence tomography angiography as a novel approach to contactless evaluation of sublingual microcirculation: A proof of principle study

      Optical coherence tomography angiography as a novel approach to contactless evaluation of sublingual microcirculation: A proof of principle study

      Microcirculatory disorders are crucial in pathophysiology of organ dysfunction in critical illness. Evaluation of sublingual microcirculation is not routinely conducted in daily practice due to time-consuming analysis and susceptibility to artifacts. We investigated the suitability of optical coherence tomography angiography (OCTA) for contactless evaluation of sublingual microcirculation. Sublingual microcirculation was imaged in 10 healthy volunteers, using an OCTA device and an incident dark field (IDF) illumination microscopy (current gold standard). OCTA images were analyzed with regard to flow density and perfused vessel density (PVD byOCTA ). IDF videos were analyzed following current recommendations. Flow density was automatically extracted from OCTA images ...

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    5. Retinal neurodegeneration in patients with end-stage renal disease assessed by spectral-domain optical coherence tomography

      Retinal neurodegeneration in patients with end-stage renal disease assessed by spectral-domain optical coherence tomography

      Spectral-domain optical coherence tomography (SD-OCT) represents a reliable tool for retinal layer volume and thickness measurement. The aim of this study was to evaluate retinal changes indicating neurodegenerative processes in patients with end-stage renal disease (ESRD) compared to healthy controls. This was a cross-sectional, single-center study comprising 32 ESRD patients and 38 controls. Sectoral retinal nerve fiber layer (RNFL) thickness and retinal layer volumes were obtained by SD-OCT. Age- and gender-adjusted retinal layer volumes such as total retinal volume (p = 0.037), ganglion cell layer volume (GCL, p = 0.003), ganglion cell layer – inner plexiform layer volume (GCL-IPL, p = 0 ...

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    6. HYPERREFLECTIVE FOVEAL SPOTS IN PATIENTS WITH VITREORETINAL ANOMALIES A Qualitative and Quantitative Analysis

      HYPERREFLECTIVE FOVEAL SPOTS IN PATIENTS WITH VITREORETINAL ANOMALIES A Qualitative and Quantitative Analysis

      Purpose: To describe structural optical coherence tomography (OCT) and OCT angiography features in patients who have developed hyperreflective foveal spots with or without vitreomacular interface abnormalities or with vitreous adhesion alone. Methods: The study design was observational and cross sectional. The presence of defined epiretinal membrane was considered an exclusion criterion. All patients underwent complete ophthalmologic examination, with structural OCT and OCT angiography acquisitions. Both qualitative and quantitative analyses of OCT angiography reconstructions were performed for superficial capillary plexus, deep capillary plexus, and choriocapillaris. Results: Thirty patients (20 men; mean age, 55.2 years) showing hyperreflective foveal spots on structural ...

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    7. Spectral Domain Optical Coherence Tomography Features

      Spectral Domain Optical Coherence Tomography Features

      Purpose: To investigate the long-term incidence and risk factors of macular hole (MH) development in the fellow eyes of patients with unilateral idiopathic MH. Methods: The retrospective case–control study involved the fellow eyes of 215 consecutive patients with idiopathic MH. The patients were classified into two groups according to the presence or development of MH in the fellow eye. The spectral domain optical coherence tomography features and clinical characteristics of each group were compared. Results: Twelve (5.6%) patients presented with bilateral MH at the initial visit, whereas 20 (9.3%) initially unilateral patients developed MH in the fellow ...

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    8. OCULAR MANIFESTATIONS OF PORETTI-BOLTSHAUSER SYNDROME: FINDINGS FROM MULTIMODAL IMAGING AND ELECTROPHYSIOLOG

      OCULAR MANIFESTATIONS OF PORETTI-BOLTSHAUSER SYNDROME: FINDINGS FROM MULTIMODAL IMAGING AND ELECTROPHYSIOLOG

      Background/Purpose: Poretti-Boltshauser syndrome is a rare, nonprogressive neurologic syndrome with characteristic cerebellar cysts on neuroimaging due to mutations in LAMA1 . The ophthalmic findings in Poretti-Boltshauser syndrome are not well described. Here, we report the ophthalmic findings from multimodal imaging and electrophysiology of a patient with genetically confirmed Poretti-Boltshauser syndrome . Methods: A 3-year-old boy with confirmed mutations in LAMA1 underwent examination under anesthesia with electroretinography and multimodal imaging including fundus photography, fluorescein angiography , optical coherence tomography , and optical coherence tomography angiography . Results: Dilated fundus examination was notable for retinal vascular anomalies, including a large area of nonperfusion in the temporal ...

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    9. QUANTITATIVE ASSESSMENT OF THE FOVEAL AVASCULAR ZONE USING OPTICAL COHERENCE TOMOGRAPHY ANGIOGRAPHY BEFORE AND AFTER SURGERY FOR IDIOPATHIC EPIRETINAL MEMBRANE

      QUANTITATIVE ASSESSMENT OF THE FOVEAL AVASCULAR ZONE USING OPTICAL COHERENCE TOMOGRAPHY ANGIOGRAPHY BEFORE AND AFTER SURGERY FOR IDIOPATHIC EPIRETINAL MEMBRANE

      Purpose: To investigate, using optical coherence tomography angiography , the foveal avascular zone (FAZar), the FAZ perimeter (FAZp), the acircularity index of the FAZ (FAZai), and the density of vessels surrounding the FAZ (FAZvd) before and after idiopathic epiretinal membrane surgery, and associations of these parameters with postoperative best-corrected visual acuity, letter score gain, and central foveal thickness. Methods: We retrospectively reviewed preoperative and postoperative (sixth month) medical records of 28 eyes of 28 patients who undergone epiretinal membrane surgery and had an intact ellipsoid zone. Results: There were significant increases in best-corrected visual acuity, FAZar, and FAZp and decreases in ...

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    10. Myopia and anterior segment optical coherence tomography findings in laser-treated retinopathy of prematurity eyes

      Myopia and anterior segment optical coherence tomography findings in laser-treated retinopathy of prematurity eyes

      Purpose To evaluate structural features and visual outcomes in eyes with a prior history of laser treatment for retinopathy of prematurity (ROP). Methods Laser-treated eyes for type 1 ROP, preterm monitored eyes, and full-term control eyes were included. LogMAR conversion of Snellen best-corrected visual acuity and spherical equivalent based on cycloplegic refraction were measured in children 5-15 years of age. Anterior segment optical coherence tomography (OCT) was used to study structural features, including anterior chamber angle (ACA) in a subset of eyes. Results A total of 50 eyes of 50 patients were included (19 full-term eyes, 19 laser-treated type 1 ...

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    11. Gradient Bosting Classifiers Combining Vessel Density and Tissue Thickness Measurements for Classifying Early to Moderate Glaucoma

      Gradient Bosting Classifiers Combining Vessel Density and Tissue Thickness Measurements for Classifying Early to Moderate Glaucoma

      Purpose To compare gradient boosting classifier (GBC) analysis of optical coherence tomography angiography (OCTA)-measured vessel density (VD) and OCT-measured tissue thickness to standard OCTA VD and OCT thickness parameters for classifying healthy eyes and eyes with early to moderate glaucoma. Design Comparison of diagnostic tools. Methods One-hundred-eight healthy eyes and 193 glaucomatous eyes with OCTA and OCT imaging of the macula and optic nerve head (ONH) were studied. Four GBCs were evaluated that combined 1) all macula VD and thickness measurements (Macula GBC), 2) all ONH VD and thickness measurements (ONH GBC), 3) all VD measurements from the macula ...

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    12. OCT Guided Punctal Stenosis Management

      OCT Guided Punctal Stenosis Management

      The study was conducted on 40 eyes of 24 patients have acquired inflammatory punctal stenosis and 20 eyes of 10 patients of normal asymptomatic subjects as control group. We studied the external punctal diameter, visibility of the internal punctum and punctal depth before treatment using AS-OCT, and then patients were re-evaluated after one month of treatment with preservative free methylprednisolone 5% eye drops.

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    13. Features of cotton wool spots in diabetic retinopathy: a spectral-domain optical coherence tomography angiography study

      Features of cotton wool spots in diabetic retinopathy: a spectral-domain optical coherence tomography angiography study

      Purpose To describe the features of cotton wool spots (CWSs) in diabetic retinopathy (DR) by using spectral-domain optical coherence tomography (SD-OCT) and optical coherence tomography angiography (OCT angiography). Methods We retrospectively studied patients with DR who presented CWSs and had been imaged by SD-OCT angiography. The retinal layer localisation and dimensions of the CWSs were assessed on SD-OCT, while the decorrelation signal generated by the CWSs and the vascular density (VD) of the superficial capillary plexus (SCP) and deep capillary plexus around the CWSs and in the macula were assessed on OCT angiography. Results A total of 87 eyes of ...

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    14. Normative database of peripapillary vessel density measured by optical coherence tomography angiography and correlation study

      Normative database of peripapillary vessel density measured by optical coherence tomography angiography and correlation study

      Purpose: To provide a normative data set of swept-source optical coherence tomography angiography (SS-OCTA) peripapillary vessel density (VD) measurements and assess correlations with age, gender, disc area and axial length (AL). Material and Methods: This was an observational cross-sectional study conducted on 346 right eyes of healthy subjects. Peripapillary SS-OCTA VD measurements were obtained in the retinal superficial capillary plexus (SCP), deep capillary plexus (DCP), and choriocapillaris (CC) in all four quadrants using the Triton device (Topcon, Nagoya, Japan). AL measurements were made by optical biometry. Results: Mean participant age was 37.7 ±19.8 years (range 5 – 83), AL ...

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    15. Classification of optical coherence tomography images using a capsule network

      Classification of optical coherence tomography images using a capsule network

      Background Classification of optical coherence tomography (OCT) images can be achieved with high accuracy using classical convolution neural networks (CNN), a commonly used deep learning network for computer-aided diagnosis. Classical CNN has often been criticized for suppressing positional relations in a pooling layer. Therefore, because capsule networks can learn positional information from images, we attempted application of a capsule network to OCT images to overcome that shortcoming. This study is our attempt to improve classification accuracy by replacing CNN with a capsule network. Methods From an OCT dataset, we produced a training dataset of 83,484 images and a test ...

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    16. Topographic analysis of macular choriocapillaris flow deficits in diabetic retinopathy using swept–source optical coherence tomography angiography

      Topographic analysis of macular choriocapillaris flow deficits in diabetic retinopathy using swept–source optical coherence tomography angiography

      Background The purpose of this study was to investigate the association between diabetic retinopathy (DR) severity and macular choriocapillaris (CC) flow deficit percentage (FD %) in different macular regions using swept-source optical coherence tomography angiography (SS-OCTA). Methods Diabetic patients with SS-OCTA images were graded by severity and retrospectively assessed. CC FD % was calculated in four different regions of the OCTA image: inner, middle, outer, and full-field region. The generalized estimating equations (GEE) approach for clustered eye data was used to determine effect size and significance of age and disease severity on FD % for each region. Results 160 eyes from 90 total ...

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    17. Three-dimensional visualization of opacifications in the murine crystalline lens by in vivo optical coherence tomography

      Three-dimensional visualization of opacifications in the murine crystalline lens by in vivo optical coherence tomography

      Diagnostic classification techniques used to diagnose cataracts, the world’s leading cause of blindness, are currently based on subjective methods. Here, we present optical coherence tomography as a noninvasive tool for volumetric visualization of lesions formed in the crystalline lens. A custom-made swept-source optical coherence tomography (SS-OCT) system was utilized to investigate the murine crystalline lens. In addition to imaging cataractous lesions in aged wildtype mice, we studied the structure and shape of cataracts in a mouse model of Alzheimer’s disease. Hyperscattering opacifications in the crystalline lens were observed in both groups. Post mortem histological analysis were performed to ...

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    18. Widefield optical coherence tomography angiography for early detection and objective evaluation of proliferative diabetic retinopathy

      Widefield optical coherence tomography angiography for early detection and objective evaluation of proliferative diabetic retinopathy

      Purpose To evaluate the utility of widefield optical coherence tomography angiography (WF-OCTA) compared with clinical examination in grading diabetic retinopathy in patients diagnosed clinically with proliferative diabetic retinopathy (PDR) or severe non-proliferative diabetic retinopathy (NPDR). Design This retrospective observational case series included patients diagnosed clinically with PDR or severe NPDR. Patients underwent standard clinical examination and WF-OCTA imaging (PLEX Elite 9000, Carl Zeiss Meditec AG) using 12×12 montage scans between August 2018 and January 2019. Two trained graders identified neovascularisation at the disc (NVD) and neovascularisation elsewhere (NVE) on WF-OCTA which were compared with the clinical examination, and to ...

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    19. Children's Hospital of Philadelphia Receives NIH Grant for Biomarkers of Vision Loss in Children with Optic Pathway Gliomas

      Children's Hospital of Philadelphia Receives NIH Grant for Biomarkers of Vision Loss in Children with Optic Pathway Gliomas

      Children's Hospital of Philadelphia Receives a 2020 NIH Grant for $611,652 for Biomarkers of Vision Loss in Children with Optic Pathway Gliomas. The principal investigator is Rogbert Avery. Below is a summary of the proposed work. Low-grade gliomas are the most common brain tumor in children and frequently involve the optic nerve, chiasm, and tract—so they are referred to as optic pathway gliomas (OPGs). OPGs cause vision loss, typically between 1 and 8 years of age, resulting in lifelong disability as well as reduced academic and vocational achievement. The long term goal of this research proposal is ...

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    20. Automatic optical path adjustment in home OCT

      Automatic optical path adjustment in home OCT

      Retinal imaging systems and related methods employ a user specific approach for controlling the reference arm length in an optical coherence tomography (OCT) imaging device. A method includes restraining a user's head relative to an OCT imaging device. A reference arm length adjustment module is controlled to vary a reference arm length to search a user specific range of reference arm lengths to identify a reference arm length for which the OCT image detector produces an OCT signal corresponding to the retina of the user. The user specific range of reference arm lengths covers a smaller range of reference ...

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      Mentions: Notal Vision
    21. Surgical apparatus for lamellar keratoplasty comprising an OCT detection unit

      Surgical apparatus for lamellar keratoplasty comprising an OCT detection unit

      The present invention relates to a surgical apparatus for dissecting a part of cornea during lamellar keratoplasty, which provides a surgical apparatus comprising: an injector unit including a hollow injection needle having a bevel structure at one end; a laser unit for emitting a laser for OCT imaging; an OCT detection unit for photographing a tomographic image of the cornea using the laser; a laser light sensor located on an inner surface of the bevel structure of the injection needle and connected to the laser unit and the OCT detection unit through an optical fiber; and a depth adjusting unit ...

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    22. Clinical characteristics and OCT analysis of a case series of posterior microphthalmos

      Clinical characteristics and OCT analysis of a case series of posterior microphthalmos

      Posterior microphthalmos is a rare condition that can be found in paediatric patients with increased farsightedness and reduced vision. A retrospective study is presented of 5 cases of posterior microphthalmia aged between 4 and 13 years. The following parameters were obtained: visual acuity, cycloplegic refractive error, optical biometry, slit lamp examination, intraocular pressure, and ocular ultrasound. The refraction, axial length and average visual acuity was + 15.35 Dp, 16.20 mm and 0.13, respectively. The fundus was examined, optical coherence tomography was performed, and also retinography and fluorescein angiography in one case. In all cases, the absence of foveal ...

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    23. Multimodal quantitative optical elastography of the crystalline lens with optical coherence elastography and Brillouin microscopy

      Multimodal quantitative optical elastography of the crystalline lens with optical coherence elastography and Brillouin microscopy

      Assessing the biomechanical properties of the crystalline lens can provide crucial information for diagnosing disease and guiding precision therapeutic interventions. Existing noninvasive methods have been limited to global measurements. Here, we demonstrate the quantitative assessment of the elasticity of crystalline lens with a multimodal optical elastography technique, which combines dynamic wave-based optical coherence elastography (OCE) and Brillouin microscopy to overcome the drawbacks of individual modalities. OCE can provide direct measurements of tissue elasticity rapidly and quantitatively, but it is a challenge to image transparent samples such as the lens because this technique relies on backscattered light. On the other hand ...

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    24. Microvascular changes in macula and optic nerve head after femtosecond laser-assisted LASIK: an optical coherence tomography angiography study

      Microvascular changes in macula and optic nerve head after femtosecond laser-assisted LASIK: an optical coherence tomography angiography study

      Background To measure the microcirculation change of macula and optic nerve head before and after femtosecond laser assisted laser in situ keratomileusis. Methods In total 45 eyes from 45 subjects, who underwent FS-LASIK during June 2017 to December 2017 in Guangdong Provincial People’s Hospital, were recruited in this study. Vessel density in macula and optic nerve head were measured by optical coherence tomography angiography before and after transient elevation in intraocular pressure caused by application of suction ring during surgery. Results Vessel density (VD) at superficial (SCP) plexus of macular region did not differ after surgery (F(3,132 ...

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