1. Articles in category: Ophthalmology

    1-24 of 6858 1 2 3 4 ... 284 285 286 »
    1. Computational high-resolution optical imaging of the living human retina

      Computational high-resolution optical imaging of the living human retina

      High-resolution in vivo imaging is of great importance for the fields of biology and medicine. The introduction of hardware-based adaptive optics (HAO) has pushed the limits of optical imaging, enabling high-resolution near diffraction-limited imaging of previously unresolvable structures 1 , 2 . In ophthalmology, when combined with optical coherence tomography, HAO has enabled a detailed three-dimensional visualization of photoreceptor distributions 3 , 4 and individual nerve fibre bundles 5 in the living human retina. However, the introduction of HAO hardware and supporting software adds considerable complexity and cost to an imaging system, limiting the number of researchers and medical professionals who could benefit ...

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    2. Relationship of ocular and systemic factors to the visibility of choroidal–scleral interface using spectral domain optical coherence tomography

      Relationship of ocular and systemic factors to the visibility of choroidal–scleral interface using spectral domain optical coherence tomography

      Purpose To assess the visibility of the choroidal–scleral interface (CSI) from spectral domain optical coherence tomography (SD-OCT) and evaluate the ocular and systemic factors influencing the visibility of CSI in healthy eyes from population-based Malay sample. Methods Participants were consecutively recruited from the population-based Singapore Malay Eye Study-2 (SiMES-2). SD-OCT images were obtained by Spectralis OCT with enhanced depth imaging (EDI) mode. Visibility of CSI was assessed by a grading system ranging from 0 to 2 scores. The reliability of choroidal thickness measurement in different grades of CSI visibility was assessed using intraclass correlation coefficient. Ordinal regression analyses were ...

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    3. Anterior Segment Optical Coherence Tomography-Guided Management Algorithm for Descemet Membrane Detachment After Intraocular Surgery

      Anterior Segment Optical Coherence Tomography-Guided Management Algorithm for Descemet Membrane Detachment After Intraocular Surgery

      Purpose: To evaluate the role of anterior segment optical coherence tomography (ASOCT) in the detection and management of Descemet membrane detachment (DMD) in cases of persistent corneal edema after intraocular surgery. An ASOCT-guided new algorithm for the management of such DMDs is described. Methods: Thirty-seven consecutive cases of persistent corneal edema of more than 2-week duration after intraocular surgery were included. All cases referred had no response to medical therapy. ASOCT was performed in all eyes. DMDs that were in the superior half of the cornea with a planar configuration alone were managed using intracameral air, and those with scrolled ...

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    4. Intraoperative Optical Coherence Tomography for Enhanced Depth Visualization in Deep Anterior Lamellar Keratoplasty From the PIONEER Study

      Intraoperative Optical Coherence Tomography for Enhanced Depth Visualization in Deep Anterior Lamellar Keratoplasty From the PIONEER Study

      Purpose: Deep anterior lamellar keratoplasty (DALK) is a challenging procedure that often results in conversion to penetrating keratoplasty. Preservation of Descemet membrane (DM) relies on indirect visualization of surgical planes. We describe a technique for enhanced visualization of key steps in DALK with intraoperative optical coherence tomography. Methods: Using a microscope-mounted spectral domain optical coherence tomography system, high-resolution images of various steps were obtained. Results: Specifically, images were obtained of the trephination depth and proximity of the cannula tract to DM. Other key steps such as air cannula placement, assessment of the DM position and integrity after attempted big-bubble delivery ...

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    5. Angiography Reveals Novel Features of the Retinal Vasculature in Healthy and Diabetic Mice

      Angiography Reveals Novel Features of the Retinal Vasculature in Healthy and Diabetic Mice

      The mouse retina is a commonly used animal model for the study of pathogenesis and treatment of blinding retinal vascular diseases such as diabetic retinopathy. In this study, we aimed to characterize normal and pathological variations in vascular anatomy in the mouse retina using fluorescein angiography visualized with scanning laser ophthalmoscopy and optical coherence tomography (SLO-OCT). We examined eyes from C57BL/6J wild type mice as well as the Ins2 Akita and Akimba mouse models of diabetic retinopathy using the Heidelberg Retinal Angiography (HRA) and OCT system. Angiography was performed on three focal planes to examine distinct vascular layers. For ...

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    6. Noninvasive Visualization and Analysis of the Human Parafoveal Capillary Network Using Swept Source OCT Optical Microangiography

      Noninvasive Visualization and Analysis of the Human Parafoveal Capillary Network Using Swept Source OCT Optical Microangiography

      Purpose. We characterized the foveal avascular zone (FAZ) and the parafoveal capillary network in healthy subjects using swept source OCT optical microangiography (OMAG). Methods. We acquired OMAG images of the macula of 19 eyes (13 healthy individuals) using a prototype swept source laser OCT. En face images of the retinal vasculature were generated for superficial and deep inner retinal layers (SRL/DRL) in regions of interest 250 (ROI-250) and 500 (ROI-500) μm from the FAZ border. Results. The mean area (mm 2 ) of the FAZ was 0.304 ± 0.132 for the SRL and 0.486 ± 0.162 for the ...

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    7. Effects of rigid contact lenses on optical coherence tomographic parameters in eyes with keratoconus

      Effects of rigid contact lenses on optical coherence tomographic parameters in eyes with keratoconus

      Background The aim was to evaluate the effect of irregular astigmatism on the retinal nerve fibre layer (RNFL), macular thickness and ganglion cell analysis obtained by spectral domain optical coherence tomography (OCT) in eyes with keratoconus. Methods Fifty-two eyes of 31 patients (20 females) with keratoconus that required correction of irregular astigmatism with rigid gas-permeable (RGP) contact lenses were included to this study. The average, superior, nasal, inferior, temporal and 12 clock hour sector's RNFL, ganglion cell and macular thickness analyses before and 30 minutes after RGP contact lens (Rose K2 -Menicon Z material, David Thomas Contact Lenses Ltd ...

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    8. Optical Coherence Tomography in an Infant with Walker-Warburg Syndrome

      Optical Coherence Tomography in an Infant with Walker-Warburg Syndrome

      Purpose: Walker-Warburg syndrome (WWS) is a type of congenital muscular dystrophy (CMD) characterised by severe brain malformation, lissencephaly, and congenital eye abnormalities. Despite the coexistence of various eye abnormalities, results from optical coherence tomography (OCT) in WWS have not previously been reported. We herein report specific OCT findings in an infant with WWS. Patients and Methods: The patient was a 14-day-old boy delivered by caesarean section at 38 weeks and 4 days of gestation and with a birth weight of 2,543 g. A cranial MRI showed lissencephaly, hydrocephalus, an encephalocele, and cerebellar hypoplasia, consistent with the diagnosis of WWS ...

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    9. Wide-field imaging of retinal vasculature using optical coherence tomography-based microangiography provided by motion tracking.

      Wide-field imaging of retinal vasculature using optical coherence tomography-based microangiography provided by motion tracking.

      Optical coherence tomography (OCT)-based optical microangiography (OMAG) is a high-resolution, noninvasive imaging technique capable of providing three-dimensional in vivo blood flow visualization within microcirculatory tissue beds in the eye. Although the technique has demonstrated early clinical utility by imaging diseased eyes, its limited field of view (FOV) and the sensitivity to eye motion remain the two biggest challenges for the widespread clinical use of the technology. Here, we report the results of retinal OMAG imaging obtained from a Zeiss Cirrus 5000 spectral domain OCT system with motion tracking capability achieved by a line scan ophthalmoscope (LSO). The tracking LSO ...

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    10. Classification Of Sclerochoroidal Calcification Based On Enhanced Depth Imaging Optical Coherence Tomography “MOUNTAIN-LIKE” Features

      Classification Of Sclerochoroidal Calcification Based On Enhanced Depth Imaging Optical Coherence Tomography “MOUNTAIN-LIKE” Features

      Purpose: To describe distinct enhanced depth optical coherence tomography patterns of sclerochoroidal calcification and their correlation to clinical features. Methods: Retrospective chart review of 67 eyes of 46 patients with spectral domain optical coherence tomography imaging. Results: The mean patient age at diagnosis was 68 years. There were 20 (43%) men and 26 (57%) women of white (n = 45, 98%) or Hispanic (n = 1, 2%) heritage. The most prominent sclerochoroidal calcification lesions were located in the superotemporal quadrant (n = 57, 85%) between the temporal arcades and the equator (n = 58, 87%). On enhanced depth optical coherence tomography, the sclerochoroidal calcification ...

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    11. Stereopsis And Optical Coherence Tomography Findings After Epiretinal Membrane Surgery

      Stereopsis And Optical Coherence Tomography Findings After Epiretinal Membrane Surgery

      Purpose: To evaluate stereopsis in patients undergoing vitrectomy for epiretinal membrane and to investigate the relationship between stereopsis and foveal microstructures. Methods: This study included 55 eyes of 55 patients who underwent vitrectomy for unilateral epiretinal membrane and 27 age-matched normal subjects. We examined stereopsis using the Titmus Stereo Test, TNO stereotest, and, optical coherence tomography before surgery and 6 months after surgery. Central foveal thickness, central retinal thickness at the parafovea (CRT-3 mm), macular volume, and retinal layer thickness were measured with the optical coherence tomography software and an image-processing program. Results: Epiretinal membrane surgery significantly improved stereopsis in ...

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    12. Optical Coherence Tomographic Findings Correspond to Histology

      Optical Coherence Tomographic Findings Correspond to Histology

      Purpose: To compare optical coherence tomography (OCT) and histology of outer retinal tubulation (ORT) secondary to advanced age-related macular degeneration in patients and in postmortem specimens, with particular attention to the basis of the hyperreflective border of ORT. Method: A private referral practice (imaging) and an academic research laboratory (histology) collaborated on two retrospective case series. High-resolution OCT raster scans of 43 eyes (34 patients) manifesting ORT secondary to advanced age-related macular degeneration were compared to high-resolution histologic sections through the fovea and superior perifovea of donor eyes (13 atrophic age-related macular degeneration and 40 neovascular age-related macular degeneration) preserved ...

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    13. Quantitative Comparison of Retinal Capillary Images Derived By Speckle Variance Optical Coherence Tomography With Histology

      Quantitative Comparison of Retinal Capillary Images Derived By Speckle Variance Optical Coherence Tomography With Histology

      Purpose. The purpose of this study was to correlate human retinal capillary network information derived from a prototype speckle variance optical coherence tomography (svOCT) device with histology to determine the utility of this instrument for quantitative angiography. Methods. A retina location 3 mm superior to the optic disk was imaged with svOCT in 14 healthy human eyes. Qualitative and quantitative features of capillary networks, including capillary diameter and density, were compared with perfusion-labeled histological specimens from the same eccentricity. Twelve human donor eyes with no history of eye disease were used for histological comparisons. Results. svOCT was able to clearly ...

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    14. New technology looks into the eye and brings cells into focus

      New technology looks into the eye and brings cells into focus

      Eye doctors soon could use computing power to help them see individual cells in the back of a patient’s eye, thanks to imaging technology developed by engineers at the University of Illinois. Such detailed pictures of the cells, blood vessels and nerves at the back of the eye could enable earlier diagnosis and better treatment for degenerative eye and neurological diseases. New technology uses computational techniques to more clearly see individual rods and cones, the cells that detect light in the back of the eye | Graphic by Alex Jerez Roman The technique applies adaptive optics – the method astronomers use ...

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    15. SPECTRAL DOMAIN OPTICAL COHERENCE TOMOGRAPHY EVIDENCE OF RETINAL NERVE FIBER LAYER AND GANGLION CELL LOSS IN ADULT PATIENTS WITH NEUROFIBROMATOSIS TYPE 1

      SPECTRAL DOMAIN OPTICAL COHERENCE TOMOGRAPHY EVIDENCE OF RETINAL NERVE FIBER LAYER AND GANGLION CELL LOSS IN ADULT PATIENTS WITH NEUROFIBROMATOSIS TYPE 1

      Purpose: To evaluate peripapillary retinal nerve fiber layer, macular retinal nerve fiber layer, and ganglion cell layer-inner plexiform layer thickness and analyze their correlations in adult patients with neurofibromatosis Type 1 (NF1) and disease-free controls. Methods: This cross-sectional study was performed at the Azienda Policlinico Umberto I, University of Rome "La Sapienza." All participants underwent complete ophthalmologic examination. Spectral domain optical coherence tomography was used to evaluate peripapillary retinal nerve fiber layer and obtain retinal segmentation measurements to assess macular retinal nerve fiber layer and ganglion cell layer-inner plexiform layer at 1,000 [mu]m nasal, temporal, superior, and inferior ...

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    16. CHOROIDAL THICKNESS IN RELATION TO ETHNICITY MEASURED USING ENHANCED DEPTH IMAGING OPTICAL COHERENCE TOMOGRAPHY

      CHOROIDAL THICKNESS IN RELATION TO ETHNICITY MEASURED USING ENHANCED DEPTH IMAGING OPTICAL COHERENCE TOMOGRAPHY

      Purpose: To investigate the posterior choroidal thickness in healthy subjects of three different ethnicities. Methods: In this prospective cross-sectional study, the choroidal thickness of 88 individuals (176 eyes) was measured using enhanced depth imaging-spectral domain optical coherence tomography. Subfoveal choroidal thickness was measured between the retinal pigment epithelium-Bruch membrane complex and chorioscleral interface. Nasal, temporal, superior, and inferior choroidal thicknesses at 0.5, 1.5, and 3.0 mm locations from the fovea were evaluated as well. Results: Males and females were perfectly matched by number in all groups. The mean age of the entire study population was 27.43 ...

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    17. A Simple Optical Coherence Tomography Quantification Method for Choroidal Neovascularization

      A Simple Optical Coherence Tomography Quantification Method for Choroidal Neovascularization

      Purpose: Therapeutic efficacy is routinely assessed by measurement of lesion size using flatmounted choroids and confocal microscopy in the laser-induced choroidal neovascularization (L-CNV) rodent model. We investigated whether optical coherence tomography (OCT) quantification, using an ellipsoid volume measurement, was comparable to standard ex vivo evaluation methods for this model and whether this approach could be used to monitor treatment-related lesion changes. Methods: Bruch's membrane was ruptured by argon laser in the dilated eyes of C57BL/6J mice, followed by intravitreal injections of anti-VEGF 164 or vehicle, or no injection. In vivo OCT images were acquired using Micron III or ...

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    18. Detection of retinal changes in idiopathic Parkinson's disease using high-resolution optical coherence tomography and heidelberg retina tomography

      Detection of retinal changes in idiopathic Parkinson's disease using high-resolution optical coherence tomography and heidelberg retina tomography

      Purpose The study was performed to analyse the retina of patients with Parkinson's disease (PD) for morphological changes compared to healthy controls (HC) using spectral-domain optical coherence tomography (SD-OCT) and confocal scanning laser ophthalmoscopy. Methods We enrolled 108 patients with idiopathic PD and 165 HC. All study participants underwent an ophthalmological examination to exclude ophthalmological disorder potentially interfering with the retinal analyses. Peripapillary retinal nerve fibre layer (RNFL) thickness and macular thickness and volume were measured by a SD-OCT device (Heidelberg Spectralis ® ). Stereometric parameters of the optic disc were acquired by Heidelberg Retina Tomograph (HRT III). Results The RNFL ...

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    19. Active eye-tracking for an adaptive optics scanning laser ophthalmoscope

      Active eye-tracking for an adaptive optics scanning laser ophthalmoscope

      We demonstrate a system that combines a tracking scanning laser ophthalmoscope (TSLO) and an adaptive optics scanning laser ophthalmoscope (AOSLO) system resulting in both optical (hardware) and digital (software) eye-tracking capabilities. The hybrid system employs the TSLO for active eye-tracking at a rate up to 960 Hz for real-time stabilization of the AOSLO system. AOSLO videos with active eye-tracking signals showed, at most, an amplitude of motion of 0.20 arcminutes for horizontal motion and 0.14 arcminutes for vertical motion. Subsequent real-time digital stabilization limited residual motion to an average of only 0.06 arcminutes (a 95% reduction). By ...

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    20. ROLE OF SD-OCT IN OCULAR HYPERTENSION

      ROLE OF SD-OCT IN OCULAR HYPERTENSION

      PURPOSE: To compare RNFL thickness in patients with ocular hypertension with that of controls. AIM: To study the role of SD-OCT in ocular hypertension. METHODS: 25 eyes of 15 patients with ocular hypertension and 25 eyes of 15 normal subjects seen in Regional Institute of Ophthalmology, Gandhi Medical College Bhopal were included in this prospective study conducted in the academic session of the year 2012 to 2013. Informed consent was obtained from all patients and controls. Ocular hypertensive eyes were defined as an IOP reading greater than 21 mmHg on at least two separate occasions, normal optic disc, visual fields ...

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    21. Image quality metrics for optical coherence angiography

      Image quality metrics for optical coherence angiography

      We characterized image quality in optical coherence angiography (OCA) en face planes of mouse cortical capillary network in terms of signal-to-noise ratio (SNR) and Weber contrast (Wc) through a novel mask-based segmentation method. The method was used to compare two adjacent B-scan processing algorithms, (1) average absolute difference (AAD) and (2) standard deviation (SD), while varying the number of lateral cross-sections acquired (also known as the gate length, N). AAD and SD are identical at N = 2 and exhibited similar image quality for N<10. However, AAD is relatively less susceptible to bulk tissue motion artifact than SD. SNR ...

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    22. Comparison of central corneal thickness: ultrasound pachymetry versus slit-lamp optical coherence tomography, specular microscopy, and Orbscan

      Comparison of central corneal thickness: ultrasound pachymetry versus slit-lamp optical coherence tomography, specular microscopy, and Orbscan

      Background: Central corneal thickness (CCT) can be measured by using contact and non-contact methods. Ultrasound pachymetry (US pachymetry) is a contact method for measuring CCT and is perhaps the most commonly used method. However, non-contact methods like scanning slit topography (Orbscan II), slit-lamp optical coherence tomography (SL-OCT), and specular microscopy are also used. Not many studies have correlated the measurement of CCT with all four modalities. The purpose of this study was to compare and correlate the CCT measurements obtained by US pachymetry with SL-OCT, specular microscopy, and Orbscan. Method: This is a prospective, comparative study done in an institutional ...

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    23. Assessment of hydroxychloroquine maculopathy after cessation of treatment: an optical coherence tomography and multifocal electroretinography study

      Assessment of hydroxychloroquine maculopathy after cessation of treatment: an optical coherence tomography and multifocal electroretinography study

      Objective: This study was conducted to evaluate the macular status of patients treated with hydroxychloroquine before and after cessation of treatment. Methods: Forty-two patients with systemic lupus erythematosus underwent ocular examination based on visual acuity evaluation, optical coherence tomography retinal thickness measurements, and multifocal electroretinography (mfERG) records at first visit. The tests were repeated 6 months after treatment withdrawal and compared to the findings at their first visit. Results: Mean visual acuity (measured in log minimum angle of resolution) of both eyes was statistically increased after hydroxychloroquine discontinuation (difference in means: 0.06 [ P <0.0001] and 0.01 [ P ...

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