1. Articles in category: Ophthalmology

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    1. Clinical and OCT Findings in a Case of a Presumed Perfluorooctane Retinal Acute Toxicity

      Clinical and OCT Findings in a Case of a Presumed Perfluorooctane Retinal Acute Toxicity

      Retinal acute toxicity may be produced by several etiologies. Iatrogenic toxicity is one of the most-feared complications related to vitreoretinal surgery. The authors report a case of retinal acute toxicity due to the use of perfluorooctane during an uneventful retinal detachment surgery done elsewhere. The aim of this report is to describe the clinical and optical coherence tomography features of this complication, which unfortunately occurred in more than 100 cases in Spain.

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    2. Semi-manual Vessel Density Analysis on Optical Coherence Tomography Angiography Images of Healthy Adults

      Semi-manual Vessel Density Analysis on Optical Coherence Tomography Angiography Images of Healthy Adults

      Optical coherence tomography angiography (OCTA) is a software upgrade on conventional spectral-domain or swept-source optical coherence tomography devices that enables non-invasive, dye-free, three dimensional analysis of the retinal vessels. Vessel density is a very important parameter almost in all retinal disorders. In the recent past, automated quantification software was built into some OCTA devices which can automatically calculate the retinal vessel density as well. In this study two semi-manual techniques are used in order to analyze the vessel density of healthy subjects' OCTA images. Vessel density is also measured with a new automated quantification program, and results of the three ...

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    3. Foveal avascular zone and vessel density in healthy subjects: An optical coherence tomography angiography study

      Foveal avascular zone and vessel density in healthy subjects: An optical coherence tomography angiography study

      Purpose: To report the normal characteristics and correlations of the foveal microvascular networks using optical coherence tomography angiography (OCTA) in a healthy Iranian population. Methods: Enface 3x3 OCTA images were obtained using the RTVue Avanti spectral-domain optical coherence tomography with AngioVue software (Optovue, Fremont, CA, USA). Foveal avascular zone (FAZ) area, central foveal point thickness and inner retinal thickness at the foveal center and the vascular density of the superficial retinal capillary plexus (SCP) and deep retinal capillary plexus (DCP) in the fovea were recorded. Results: Seventy normal eyes of 70 subjects (range, 9 to 71 years) were studied. Mean ...

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    4. Non-Invasive and Non-Destructive Determination of Corneal and Scleral Biomechanics Using Vibrational Optical Coherence Tomography: Preliminary Observations

      Non-Invasive and Non-Destructive Determination of Corneal and Scleral Biomechanics Using Vibrational Optical Coherence Tomography: Preliminary Observations

      Experimental measurements made in this study on human and porcine eyes suggest that the resonant frequency for both cornea and sclera varies from 130 to 150 Hz and increases slightly with increasing intraocular pressure. The values of the moduli calculated using the experimental values of the thickness are close to 2 MPa. Similar values of the modulus for cornea and sclera suggest that there is very little stress concentration at the cornea-scleral junction and that any stress concentration that occurs probably resides at the scleral attachment laterally and posteriorly. These moduli are close to those measured in vivo on human ...

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    5. Optical coherence tomography angiography in eyes with retinal vein occlusion

      Optical coherence tomography angiography in eyes with retinal vein occlusion

      Optical coherence angiography (OCTA) is a noninvasive technique that has been introduced in recent years to detect ophthalmological pathology. The growing usage of OCTA to detect retinal abnormalities can be attributed to its advantages over the reference-standard fluorescein angiography (FA), although both of these techniques can be used in association. OCTA's advantages include its dye independency, its ability to produce depth-resolved images of retinal and choroidal vessels that yield images of different vascular layers of the retina, and the better delineation of the foveal avascular zone. OCTA's disadvantages include the lack of normalized patient data, artefactual projection issues ...

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      Mentions: Cleveland Clinic
    6. Assessment of the effect of age on macular layer thickness in a healthy Chinese cohort using spectral-domain optical coherence tomography

      Assessment of the effect of age on macular layer thickness in a healthy Chinese cohort using spectral-domain optical coherence tomography

      Background To determine the effect of age on the thickness of individual retinal and choroidal vascular layers in the macula in an ophthalmologically healthy Chinese cohort by using spectral-domain optical coherence tomography (SD-OCT). Methods In all, 525 health eyes of 525 subjects were examined with SD-OCT. The instrument automatically obtained the regional retinal thickness of 8 layers. Subfoveal choroidal vascular layers’ thickness was measured using enhanced depth imaging mode. The correlation of age with layer thickness measurements was determined. Results No age-associated variation was found on retinal thickness (RT) in the fovea; however, the foveal thickness of outer nuclear layer ...

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    7. The Role of Optical Coherence Tomography in Differentiating Optic Disc Drusen from Optic Disc Edema

      The Role of Optical Coherence Tomography in Differentiating Optic Disc Drusen from Optic Disc Edema

      An elevated optic nerve head can be an ominous sign, sometimes signifying an underlying basis for raised intracranial pressure. Alternatively, patients may harbor a different mechanism for this optic nerve head appearance, including optic disc drusen (ODD), which does not confer any life-threatening implications. It is important to refine the approach to distinguishing ODD from papilledema because this is a relatively common, and important, conundrum encountered in clinical practice. Optical coherence tomography (OCT) is a noninvasive, readily accessible, and cost-effective ocular imaging technique that can improve the diagnostic accuracy for detecting ODD; or, instead, increase the index of suspicion for ...

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    8. Evaluation of peripapillary choroidal distribution in children by enhanced depth imaging optical coherence tomography

      Evaluation of peripapillary choroidal distribution in children by enhanced depth imaging optical coherence tomography

      Background To evaluate the peripapillary choroidal thickness (PPCT) in Chinese children aged 6 to 12 years old and to analyze correlative factors. Methods PPCT was measured with enhanced depth imaging optical coherence tomography (EDI-OCT) in 154 children (76 myopes and 78 emmetropia) aged 6 to 12 years, with spherical equivalent refractive errors between + 0.50 and − 5.50 diopters(D). Peripapillary choroidal imaging was performed using circular scans of a diameter of 3.4 mm around the optic disc. PPCT and the corresponding peripapillary retinal thickness (PPRT) were measured by EDI-OCT at nine positions: I, inferior; IN, inferonasal; IT, inferotemporal ...

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    9. Ganglion cell-inner plexiform layer thickness by swept-source optical coherence tomography in healthy Korean children: Normative data and biometric correlations

      Ganglion cell-inner plexiform layer thickness by swept-source optical coherence tomography in healthy Korean children: Normative data and biometric correlations

      The purpose of this study was to identify the normative values of ganglion cell-inner plexiform layer (GCIPL) thickness in healthy Korean children using swept-source optical coherence tomography (SS-OCT) and to investigate the correlations of age, refractive error, axial length (AL), retinal nerve fiber layer (RNFL) thickness and cup-to-disc (C/D) ratio with GCIPL thickness. Children aged between 3 and 17 who had visited our pediatric ophthalmology clinic were enrolled. Each subject underwent full ophthalmic examinations including RNFL thickness, C/D ratio and GCIPL thickness measurement by SS-OCT as well as AL measurement by partial-coherence interferometry. A total of 254 eyes ...

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    10. Comparison of cross sectional optical coherence tomography images of elevated optic nerve heads across acquisition devices and scan protocols

      Comparison of cross sectional optical coherence tomography images of elevated optic nerve heads across acquisition devices and scan protocols

      Background Optic nerve head measurements extracted from optical coherence tomography (OCT) show promise for monitoring clinical conditions with elevated optic nerve heads. The aim of this study is to compare reliability within and between raters and between image acquisition devices of optic nerve measurements derived from OCT scans in eyes with varying degrees of optic nerve elevation. Methods Wide angle line scans and narrow angle radial scans through optic nerve heads were obtained using three spectral domain(SD) OCT devices on 5 subjects (6 swollen optic nerves, 4 normal optic nerves). Three raters independently semi-manually segmented the internal limiting membrane ...

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    11. Retinal and optic nerve changes in microcephaly: An optical coherence tomography study

      Retinal and optic nerve changes in microcephaly:  An optical coherence tomography study

      Objective To investigate the morphology of the retina and optic nerve (ON) in microcephaly. Methods This was a prospective case-control study including 27 patients with microcephaly and 27 healthy controls. All participants underwent ophthalmologic examination and handheld optical coherence tomography (OCT) of the macula and ON head. The thickness of individual retinal layers was quantified at the foveal center and the parafovea (1,000 μm nasal and temporal to the fovea). For the ON head, disc diameter, cup diameter, cup-to-disc ratio, cup depth, horizontal rim diameter, rim area, peripapillary retinal thickness, and retinal nerve fiber layer thickness were measured. Results ...

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    12. Parafoveal Nonperfusion Analysis in Diabetic Retinopathy Using Optical Coherence Tomography Angiography

      Parafoveal Nonperfusion Analysis in Diabetic Retinopathy Using Optical Coherence Tomography Angiography

      Purpose : To describe a new technique for mapping parafoveal intercapillary areas (PICAs) using optical coherence tomography angiography (OCTA), and demonstrate its utility for quantifying parafoveal nonperfusion in diabetic retinopathy (DR). Methods : Nineteen controls, 15 diabetics with no retinopathy (noDR), 15 with nonproliferative diabetic retinopathy (NPDR), and 15 with proliferative diabetic retinopathy (PDR) were imaged with 10 macular OCTA scans. PICAs were automatically delineated on the averaged superficial OCTA images. Following creation of an eccentricity-specific reference database from the controls, all PICAs greater than 2 SD above the reference means for PICA area and minor axis length were identified as nonperfused ...

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    13. Optical coherence tomography angiography in intermediate uveitis

      Optical coherence tomography angiography in intermediate uveitis

      Purpose To investigate the involvement of the retinal and choriocapillaris microvasculature in intermediate uveitis on optical coherence tomography angiography (OCT-A) Design Case-control study Methods Patients and age-matched controls were imaged with swept-source OCT-A (PLEX Elite 9000, Zeiss). Using ImageJ superficial and deep retinal vasculature were semi-automatically analyzed for vessel (VD) and skeleton density (SD), vessel diameter index (VDI) and fractal dimension (FD). Choriocapillaris layer was automatically graded for mean signal intensity, signal intensity standard deviation, kurtosis of signal intensity distribution and flow-signal-voids. Results Twentynine intermediate uveitis eyes and 30 control eyes were included. Both superficial and deep retinal layers showed ...

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    14. Automated Layer Segmentation of Retinal Optical Coherence Tomography Images Using a Deep Feature Enhanced Structured Random Forests Classifier

      Automated Layer Segmentation of Retinal Optical Coherence Tomography Images Using a Deep Feature Enhanced Structured Random Forests Classifier

      Optical coherence tomography (OCT) is a high-resolution and non-invasive imaging modality that has become one of the most prevalent techniques for ophthalmic diagnosis. Retinal layer segmentation is very crucial for doctors to diagnose and study retinal diseases. However, manual segmentation is often a time-consuming and subjective process. In this work, we propose a new method for automatically segmenting retinal OCT images, which integrates deep features and hand-designed features to train a structured random forests classifier. The deep convolutional features are learned from deep residual network. With the trained classifier, we can get the contour probability graph of each layer, finally ...

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    15. Macular choroidal thickness in pregnant women with type 1, type 2 and gestational diabetes mellitus measured by spectral-domain optical coherence tomography

      Macular choroidal thickness in pregnant women with type 1, type 2 and gestational diabetes mellitus measured by spectral-domain optical coherence tomography

      Purpose: To analyze choroidal thickness (CT) of pregnant women with type 1 diabetes mellitus (DM), type 2 DM and gestational diabetes mellitus (GDM) using spectral-domain optical coherence tomography. Patients and methods: This cross-sectional study included 144 eyes of 72 pregnant women in the third trimester divided into four groups: 27 non-diabetic pregnant women; 15 pregnant women with GDM; 16 with type 2 DM and 14 with type 1 DM. CT was measured using optical coherence tomography at ten different locations. We also analyzed possible confounding factors, such as gestational age, glycosylated hemoglobin, time from DM diagnosis, hypertension and severity of ...

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    16. Ocular toxicity due to colours used during Holi celebration in India: Correlation of clinical findings with the anterior segment OCT

      Ocular toxicity due to colours used during Holi celebration in India: Correlation of clinical findings with the anterior segment OCT

      Purpose: To correlate the anatomical extent of ocular surface toxicity due to colours using anterior segment optical coherence tomography with the clinical findings. Methods: Patients presenting to our emergency department with ocular colour toxicity during the Holi festival celebrations from 2 nd March 2018 to 5 th March 2018 were assessed for any adnexal, conjunctival, corneal and anterior chamber findings, as well as findings on anterior segment optical coherence tomography (ASOCT). Results: A total of 21 patients were observed. The average age was 23 years with 16 patients being male (76.19%). Bilateral ocular involvement was more common (in 13 ...

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    17. Optic coherence tomography appearances of retinal astrocytic hamartoma and systemic features in tuberous sclerosis of Japanese patients

      Optic coherence tomography appearances of retinal astrocytic hamartoma and systemic features in tuberous sclerosis of Japanese patients

      Purpose: To describe the optical coherence tomography findings of retinal astrocytic hamartoma of tuberous sclerosis and to confirm the association between the type of retinal astrocytic hamartoma and systemic manifestations in Japanese patients. Study Design: A retrospective observational case series. Methods: The medical records of 35 patients with tuberous sclerosis who underwent ophthalmological examination were reviewed. The retinal astrocytic hamartomas were classified into four types based on the optical coherence tomography findings, and their association with systemic disease was evaluated. Results: A total of 40 retinal astrocytic hamartomas in 13 eyes of eight patients aged 4–28 years were identified ...

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    18. MACULAR GANGLION CELL LAYER THICKNESS MEASUREMENT BY SD-OCT IN NON GLAUCOMATOUS MYOPIC EYE AND ITS CORRELATION WITH SPHERICAL EQUIVALENT AND AXIAL LENGTH

      MACULAR GANGLION CELL LAYER THICKNESS MEASUREMENT BY SD-OCT IN NON GLAUCOMATOUS MYOPIC EYE AND ITS CORRELATION WITH SPHERICAL EQUIVALENT AND AXIAL LENGTH

      Purpose: To evaluate macular ganglion cell layer thickness in non glaucomatous myopic eye and its correlation with spherical equivalent and axial length. Material and methods : A Cross sectional observational study was carried out in 50 eyes who were reported myopes. A detailed ophthalmic examination was done and participants having raised IOP and field defects were excluded. The selected candidates were subjected to ganglion cell complex study by SD-OCT and their relationship against myopic refractive equivalents and axial length was evaluated. Result: Eligible subjects were in the age group of 18- 35 years. Out of the 50 eyes evaluated, 40% showed ...

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    19. Optical coherence tomography angiography in myopic choroidal neovascularization after intravitreal ranibizumab

      Optical coherence tomography angiography in myopic choroidal neovascularization after intravitreal ranibizumab

      Purpose: To describe the optical coherence tomography angiography characteristics of myopic patients with choroidal neovascularization secondary to pathologic myopia during ranibizumab therapy. Methods: Nineteen patients were enrolled in this prospective study (13 females, 6 males, mean age 55.25 ± 9.63 years) for a total of 20 eyes examined (14 right eyes, 6 left eyes). Images were analyzed independently by two examiners. Results: Mean follow-up was 5.75 ± 1.88 months, with a mean intravitreal injections of 1.90 ± 0.44. Mean best-corrected visual acuity at baseline was 0.39 ± 0.18 logMAR versus 0.26 ± 0.16 logMAR 6 ...

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    20. Visible-light optical coherence tomography oximetry based on circumpapillary scan and graph-search segmentation

      Visible-light optical coherence tomography oximetry based on circumpapillary scan and graph-search segmentation

      Visible-light optical coherence tomography (vis-OCT) enables retinal oximetry by measuring the oxygen saturation of hemoglobin (sO 2 ) from within individual retinal blood vessels. The sO 2 calculation requires reliable estimation of the true spectrum of backscattered light from the posterior vessel wall. Unfortunately, subject motion and image noise make averaging from multiple A-lines at the same depth position challenging, and lead to inaccurate sO 2 estimation. In this study, we developed an algorithm to reliably extract the backscattered light’s spectrum. We used circumpapillary scanning to sample the vessels repeatedly at the same location. A combination of cross-correlation and graph-search ...

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    21. Long scan depth optical coherence tomography on imaging accommodation: impact of enhanced axial resolution, signal-to-noise ratio and speed

      Long scan depth optical coherence tomography on imaging accommodation: impact of enhanced axial resolution, signal-to-noise ratio and speed

      Background Spectral domain optical coherence tomography (SD-OCT) was a useful tool to study accommodation in human eye, but the maximum image depth is limited due to the decreased signal-to-noise ratio (SNR). In this study, improving optical resolutions, speeds and the SNR were achieved by custom built SD-OCT, and the evaluation of the impact of the improvement during accommodation was investigated. Methods Three systems with different spectrometer designs, including two Charge Coupled Device (CCD) cameras and one Complementary Metal-Oxide-Semiconductor Transistor (CMOS) camera, were tested. We measured the point spread functions of a mirror at different positions to obtain the axial resolution ...

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    22. Optical Coherence Tomography of Small Retinoblastoma

      Optical Coherence Tomography of Small Retinoblastoma

      Purpose: To investigate hand-held optical coherence tomography (HHOCT) characteristics of small (<1 mm thickness) retinoblastoma. Design: Retrospective observational case series. Methods: Patient and tumor data were extracted from the medical record and analyzed along with HH-OCT scans. Determination of tumor layer of origin was performed using a layer-by-layer analysis of HH-OCT data and specific HH-OCT–related features were described. Results: There were 20 sub-millimeter retinoblastomas from 16 eyes of 15 patients. Mean largest tumor basal diameter by HH-OCT was 2.2 mm (median, 1.9; range, 0.7–4.1 mm), and mean tumor thickness was 468 µm (median, 441 ...

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    23. High-Resolution Anterior Segment Optical Coherence Tomography in Intraepithelial Versus Invasive Ocular Surface Squamous Neoplasia

      High-Resolution Anterior Segment Optical Coherence Tomography in Intraepithelial Versus Invasive Ocular Surface Squamous Neoplasia

      Purpose: To evaluate the imaging characteristics of intraepithelial and invasive ocular surface squamous neoplasia ( OSSN ) on high-resolution anterior segment optical coherence tomography (ASOCT). Methods: In this prospective cross-sectional study, 17 consecutive patients (10 intraepithelial and 7 invasive) with histopathologically proven OSSN were included. All patients underwent slit-lamp imaging and time-domain ASOCT at premarked sites. Management included standard complete surgical excision with margin clearance and cryotherapy for all cases. The correlation between imaging characteristics and histopathology sections at the premarked sites was analyzed to determine surrogate markers that may help differentiate intraepithelial from invasive OSSN . In addition, 3 patients with presumed ...

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    24. Influence of pterygium size on corneal higher-order aberration evaluated using anterior-segment optical coherence tomography

      Influence of pterygium size on corneal higher-order aberration evaluated using anterior-segment optical coherence tomography

      Background The prospective observation study aimed to evaluate changes in corneal higher-order aberrations induced by advancement of pterygium using an anterior-segment optical coherence tomography (AS-OCT) and Zernike aberration analysis. Methods The corneal topography of 284 eyes with primary pterygia originating from the nasal region was measured using an AS-OCT (SS-1000, Tomey). With anterior corneal elevation data, Zernike polynomial coefficients were calculated in diameters of 1.0, 3.0, and 5.0 mm, and the coma, spherical, coma-like, spherical-like, and total higher-order aberrations were obtained. Pterygium size was also measured as a ratio of positions of the pterygium end with respect ...

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