The blood vessels which supply and drain the RETINA.
Central retinal vein and its tributaries. It runs a short course within the optic nerve and then leaves and empties into the superior ophthalmic vein or cavernous sinus.
Central retinal artery and its branches. It arises from the ophthalmic artery, pierces the optic nerve and runs through its center, enters the eye through the porus opticus and branches to supply the retina.
The minute vessels that collect blood from the capillary plexuses and join together to form veins.
Method of making images on a sensitized surface by exposure to light or other radiant energy.
Formation of new blood vessels originating from the retinal veins and extending along the inner (vitreal) surface of the retina.
Visualization of a vascular system after intravenous injection of a fluorescein solution. The images may be photographed or televised. It is used especially in studying the retinal and uveal vasculature.
The smallest divisions of the arteries located between the muscular arteries and the capillaries.
Any of the tubular vessels conveying the blood (arteries, arterioles, capillaries, venules, and veins).
A bilateral retinopathy occurring in premature infants treated with excessively high concentrations of oxygen, characterized by vascular dilatation, proliferation, and tortuosity, edema, and retinal detachment, with ultimate conversion of the retina into a fibrous mass that can be seen as a dense retrolental membrane. Usually growth of the eye is arrested and may result in microophthalmia, and blindness may occur. (Dorland, 27th ed)
The concave interior of the eye, consisting of the retina, the choroid, the sclera, the optic disk, and blood vessels, seen by means of the ophthalmoscope. (Cline et al., Dictionary of Visual Science, 4th ed)
The ten-layered nervous tissue membrane of the eye. It is continuous with the OPTIC NERVE and receives images of external objects and transmits visual impulses to the brain. Its outer surface is in contact with the CHOROID and the inner surface with the VITREOUS BODY. The outer-most layer is pigmented, whereas the inner nine layers are transparent.
Disease of the RETINA as a complication of DIABETES MELLITUS. It is characterized by the progressive microvascular complications, such as ANEURYSM, interretinal EDEMA, and intraocular PATHOLOGIC NEOVASCULARIZATION.
The portion of the optic nerve seen in the fundus with the ophthalmoscope. It is formed by the meeting of all the retinal ganglion cell axons as they enter the optic nerve.
Sudden ISCHEMIA in the RETINA due to blocked blood flow through the CENTRAL RETINAL ARTERY or its branches leading to sudden complete or partial loss of vision, respectively, in the eye.
A specialized transport barrier, in the EYE, formed by the retinal pigment EPITHELIUM, and the ENDOTHELIUM of the BLOOD VESSELS of the RETINA. TIGHT JUNCTIONS joining adjacent cells keep the barrier between cells continuous.
The thin, highly vascular membrane covering most of the posterior of the eye between the RETINA and SCLERA.
Blockage of the RETINAL VEIN. Those at high risk for this condition include patients with HYPERTENSION; DIABETES MELLITUS; ATHEROSCLEROSIS; and other CARDIOVASCULAR DISEASES.
A method of non-invasive, continuous measurement of MICROCIRCULATION. The technique is based on the values of the DOPPLER EFFECT of low-power laser light scattered randomly by static structures and moving tissue particulates.
Abnormal intravascular leukocyte aggregation and clumping often seen in leukemia patients. The brain and lungs are the two most commonly affected organs. This acute syndrome requires aggressive cytoreductive modalities including chemotherapy and/or leukophoresis. It is differentiated from LEUKEMIC INFILTRATION which is a neoplastic process where leukemic cells invade organs.
Methods and procedures for the diagnosis of diseases of the eye or of vision disorders.
Tubular vessels that are involved in the transport of LYMPH and LYMPHOCYTES.
The flow of BLOOD through or around an organ or region of the body.
Measurement of the blood pressure of the retinal vessels. It is used also for the determination of the near point of convergence (CONVERGENCE, OCULAR). (From Cline, et al., Dictionary of Visual Science, 4th ed)
The pressure of the fluids in the eye.
Examination of the interior of the eye with an ophthalmoscope.
A technique of inputting two-dimensional images into a computer and then enhancing or analyzing the imagery into a form that is more useful to the human observer.
The minute vessels that connect the arterioles and venules.
An objective determination of the refractive state of the eye (NEARSIGHTEDNESS; FARSIGHTEDNESS; ASTIGMATISM). By using a RETINOSCOPE, the amount of correction and the power of lens needed can be determined.
A value equal to the total volume flow divided by the cross-sectional area of the vascular bed.
Color of the iris.
A group of rare, idiopathic, congenital retinal vascular anomalies affecting the retinal capillaries. It is characterized by dilation and tortuosity of retinal vessels and formation of multiple aneurysms, with different degrees of leakage and exudates emanating from the blood vessels.
Devices for examining the interior of the eye, permitting the clear visualization of the structures of the eye at any depth. (UMDNS, 1999)
The distance between the anterior and posterior poles of the eye, measured either by ULTRASONOGRAPHY or by partial coherence interferometry.
The determination of oxygen-hemoglobin saturation of blood either by withdrawing a sample and passing it through a classical photoelectric oximeter or by electrodes attached to some translucent part of the body like finger, earlobe, or skin fold. It includes non-invasive oxygen monitoring by pulse oximetry.
An element with atomic symbol O, atomic number 8, and atomic weight [15.99903; 15.99977]. It is the most abundant element on earth and essential for respiration.
Atrophy of the optic disk which may be congenital or acquired. This condition indicates a deficiency in the number of nerve fibers which arise in the RETINA and converge to form the OPTIC DISK; OPTIC NERVE; OPTIC CHIASM; and optic tracts. GLAUCOMA; ISCHEMIA; inflammation, a chronic elevation of intracranial pressure, toxins, optic nerve compression, and inherited conditions (see OPTIC ATROPHIES, HEREDITARY) are relatively common causes of this condition.
An oval area in the retina, 3 to 5 mm in diameter, usually located temporal to the posterior pole of the eye and slightly below the level of the optic disk. It is characterized by the presence of a yellow pigment diffusely permeating the inner layers, contains the fovea centralis in its center, and provides the best phototropic visual acuity. It is devoid of retinal blood vessels, except in its periphery, and receives nourishment from the choriocapillaris of the choroid. (From Cline et al., Dictionary of Visual Science, 4th ed)
The veins and arteries of the HEART.
The property of blood capillary ENDOTHELIUM that allows for the selective exchange of substances between the blood and surrounding tissues and through membranous barriers such as the BLOOD-AIR BARRIER; BLOOD-AQUEOUS BARRIER; BLOOD-BRAIN BARRIER; BLOOD-NERVE BARRIER; BLOOD-RETINAL BARRIER; and BLOOD-TESTIS BARRIER. Small lipid-soluble molecules such as carbon dioxide and oxygen move freely by diffusion. Water and water-soluble molecules cannot pass through the endothelial walls and are dependent on microscopic pores. These pores show narrow areas (TIGHT JUNCTIONS) which may limit large molecule movement.
Inflammation of the retinal vasculature with various causes including infectious disease; LUPUS ERYTHEMATOSUS, SYSTEMIC; MULTIPLE SCLEROSIS; BEHCET SYNDROME; and CHORIORETINITIS.
The transparent, semigelatinous substance that fills the cavity behind the CRYSTALLINE LENS of the EYE and in front of the RETINA. It is contained in a thin hyaloid membrane and forms about four fifths of the optic globe.
A retrogressive pathological change in the retina, focal or generalized, caused by genetic defects, inflammation, trauma, vascular disease, or aging. Degeneration affecting predominantly the macula lutea of the retina is MACULAR DEGENERATION. (Newell, Ophthalmology: Principles and Concepts, 7th ed, p304)
The administration of substances into the eye with a hypodermic syringe.
PRESSURE of the BLOOD on the ARTERIES and other BLOOD VESSELS.
An abnormal increase in the amount of oxygen in the tissues and organs.
A phthalic indicator dye that appears yellow-green in normal tear film and bright green in a more alkaline medium such as the aqueous humor.
The circulation of the BLOOD through the MICROVASCULAR NETWORK.
Single pavement layer of cells which line the luminal surface of the entire vascular system and regulate the transport of macromolecules and blood components.
The physiological widening of BLOOD VESSELS by relaxing the underlying VASCULAR SMOOTH MUSCLE.
Recording of electric potentials in the retina after stimulation by light.
Patterns (real or mathematical) which look similar at different scales, for example the network of airways in the lung which shows similar branching patterns at progressively higher magnifications. Natural fractals are self-similar across a finite range of scales while mathematical fractals are the same across an infinite range. Many natural, including biological, structures are fractal (or fractal-like). Fractals are related to "chaos" (see NONLINEAR DYNAMICS) in that chaotic processes can produce fractal structures in nature, and appropriate representations of chaotic processes usually reveal self-similarity over time.
The administration of substances into the VITREOUS BODY of the eye with a hypodermic syringe.
Naturally occurring or experimentally induced animal diseases with pathological processes sufficiently similar to those of human diseases. They are used as study models for human diseases.
The original member of the family of endothelial cell growth factors referred to as VASCULAR ENDOTHELIAL GROWTH FACTORS. Vascular endothelial growth factor-A was originally isolated from tumor cells and referred to as "tumor angiogenesis factor" and "vascular permeability factor". Although expressed at high levels in certain tumor-derived cells it is produced by a wide variety of cell types. In addition to stimulating vascular growth and vascular permeability it may play a role in stimulating VASODILATION via NITRIC OXIDE-dependent pathways. Alternative splicing of the mRNA for vascular endothelial growth factor A results in several isoforms of the protein being produced.
Glaucoma in which the angle of the anterior chamber is open and the trabecular meshwork does not encroach on the base of the iris.
Unique slender cells with multiple processes extending along the capillary vessel axis and encircling the vascular wall, also called mural cells. Pericytes are imbedded in the BASEMENT MEMBRANE shared with the ENDOTHELIAL CELLS of the vessel. Pericytes are important in maintaining vessel integrity, angiogenesis, and vascular remodeling.
The physiological narrowing of BLOOD VESSELS by contraction of the VASCULAR SMOOTH MUSCLE.
An imaging method using LASERS that is used for mapping subsurface structure. When a reflective site in the sample is at the same optical path length (coherence) as the reference mirror, the detector observes interference fringes.
Bleeding from the vessels of the retina.
Diseases affecting the eye.
The use of green light-producing LASERS to stop bleeding. The green light is selectively absorbed by HEMOGLOBIN, thus triggering BLOOD COAGULATION.
An optical source that emits photons in a coherent beam. Light Amplification by Stimulated Emission of Radiation (LASER) is brought about using devices that transform light of varying frequencies into a single intense, nearly nondivergent beam of monochromatic radiation. Lasers operate in the infrared, visible, ultraviolet, or X-ray regions of the spectrum.
Separation of the inner layers of the retina (neural retina) from the pigment epithelium. Retinal detachment occurs more commonly in men than in women, in eyes with degenerative myopia, in aging and in aphakia. It may occur after an uncomplicated cataract extraction, but it is seen more often if vitreous humor has been lost during surgery. (Dorland, 27th ed; Newell, Ophthalmology: Principles and Concepts, 7th ed, p310-12).
A calcium-activated enzyme that catalyzes the hydrolysis of ATP to yield AMP and orthophosphate. It can also act on ADP and other nucleoside triphosphates and diphosphates. EC 3.6.1.5.
A form of fluorescent antibody technique commonly used to detect serum antibodies and immune complexes in tissues and microorganisms in specimens from patients with infectious diseases. The technique involves formation of an antigen-antibody complex which is labeled with fluorescein-conjugated anti-immunoglobulin antibody. (From Bennington, Saunders Dictionary & Encyclopedia of Laboratory Medicine and Technology, 1984)
Clarity or sharpness of OCULAR VISION or the ability of the eye to see fine details. Visual acuity depends on the functions of RETINA, neuronal transmission, and the interpretative ability of the brain. Normal visual acuity is expressed as 20/20 indicating that one can see at 20 feet what should normally be seen at that distance. Visual acuity can also be influenced by brightness, color, and contrast.
A family of spiro(isobenzofuran-1(3H),9'-(9H)xanthen)-3-one derivatives. These are used as dyes, as indicators for various metals, and as fluorescent labels in immunoassays.
A pathologic process consisting of the proliferation of blood vessels in abnormal tissues or in abnormal positions.
The movement of the BLOOD as it is pumped through the CARDIOVASCULAR SYSTEM.
Conditions which produce injury or dysfunction of the second cranial or optic nerve, which is generally considered a component of the central nervous system. Damage to optic nerve fibers may occur at or near their origin in the retina, at the optic disk, or in the nerve, optic chiasm, optic tract, or lateral geniculate nuclei. Clinical manifestations may include decreased visual acuity and contrast sensitivity, impaired color vision, and an afferent pupillary defect.
An ocular disease, occurring in many forms, having as its primary characteristics an unstable or a sustained increase in the intraocular pressure which the eye cannot withstand without damage to its structure or impairment of its function. The consequences of the increased pressure may be manifested in a variety of symptoms, depending upon type and severity, such as excavation of the optic disk, hardness of the eyeball, corneal anesthesia, reduced visual acuity, seeing of colored halos around lights, disturbed dark adaptation, visual field defects, and headaches. (Dictionary of Visual Science, 4th ed)
Refers to animals in the period of time just after birth.
Fluorescent probe capable of being conjugated to tissue and proteins. It is used as a label in fluorescent antibody staining procedures as well as protein- and amino acid-binding techniques.
A hypoperfusion of the BLOOD through an organ or tissue caused by a PATHOLOGIC CONSTRICTION or obstruction of its BLOOD VESSELS, or an absence of BLOOD CIRCULATION.
A membrane on the vitreal surface of the retina resulting from the proliferation of one or more of three retinal elements: (1) fibrous astrocytes; (2) fibrocytes; and (3) retinal pigment epithelial cells. Localized epiretinal membranes may occur at the posterior pole of the eye without clinical signs or may cause marked loss of vision as a result of covering, distorting, or detaching the fovea centralis. Epiretinal membranes may cause vascular leakage and secondary retinal edema. In younger individuals some membranes appear to be developmental in origin and occur in otherwise normal eyes. The majority occur in association with retinal holes, ocular concussions, retinal inflammation, or after ocular surgery. (Newell, Ophthalmology: Principles and Concepts, 7th ed, p291)
The finer blood vessels of the vasculature that are generally less than 100 microns in internal diameter.
The organ of sight constituting a pair of globular organs made up of a three-layered roughly spherical structure specialized for receiving and responding to light.
Fluid accumulation in the outer layer of the MACULA LUTEA that results from intraocular or systemic insults. It may develop in a diffuse pattern where the macula appears thickened or it may acquire the characteristic petaloid appearance referred to as cystoid macular edema. Although macular edema may be associated with various underlying conditions, it is most commonly seen following intraocular surgery, venous occlusive disease, DIABETIC RETINOPATHY, and posterior segment inflammatory disease. (From Survey of Ophthalmology 2004; 49(5) 470-90)
Highly specialized EPITHELIAL CELLS that line the HEART; BLOOD VESSELS; and lymph vessels, forming the ENDOTHELIUM. They are polygonal in shape and joined together by TIGHT JUNCTIONS. The tight junctions allow for variable permeability to specific macromolecules that are transported across the endothelial layer.
A ring of tissue extending from the scleral spur to the ora serrata of the RETINA. It consists of the uveal portion and the epithelial portion. The ciliary muscle is in the uveal portion and the ciliary processes are in the epithelial portion.
Neurons of the innermost layer of the retina, the internal plexiform layer. They are of variable sizes and shapes, and their axons project via the OPTIC NERVE to the brain. A small subset of these cells act as photoreceptors with projections to the SUPRACHIASMATIC NUCLEUS, the center for regulating CIRCADIAN RHYTHM.
White blood cells. These include granular leukocytes (BASOPHILS; EOSINOPHILS; and NEUTROPHILS) as well as non-granular leukocytes (LYMPHOCYTES and MONOCYTES).
A tricarbocyanine dye that is used diagnostically in liver function tests and to determine blood volume and cardiac output.
That portion of the electromagnetic spectrum in the visible, ultraviolet, and infrared range.
The statistical reproducibility of measurements (often in a clinical context), including the testing of instrumentation or techniques to obtain reproducible results. The concept includes reproducibility of physiological measurements, which may be used to develop rules to assess probability or prognosis, or response to a stimulus; reproducibility of occurrence of a condition; and reproducibility of experimental results.
Inflammation of part or all of the uvea, the middle (vascular) tunic of the eye, and commonly involving the other tunics (sclera and cornea, and the retina). (Dorland, 27th ed)
The layer of pigment-containing epithelial cells in the RETINA; the CILIARY BODY; and the IRIS in the eye.
Agents and endogenous substances that antagonize or inhibit the development of new blood vessels.
A subtype of DIABETES MELLITUS that is characterized by INSULIN deficiency. It is manifested by the sudden onset of severe HYPERGLYCEMIA, rapid progression to DIABETIC KETOACIDOSIS, and DEATH unless treated with insulin. The disease may occur at any age, but is most common in childhood or adolescence.
An infant during the first month after birth.
The 2nd cranial nerve which conveys visual information from the RETINA to the brain. The nerve carries the axons of the RETINAL GANGLION CELLS which sort at the OPTIC CHIASM and continue via the OPTIC TRACTS to the brain. The largest projection is to the lateral geniculate nuclei; other targets include the SUPERIOR COLLICULI and the SUPRACHIASMATIC NUCLEI. Though known as the second cranial nerve, it is considered part of the CENTRAL NERVOUS SYSTEM.
Histochemical localization of immunoreactive substances using labeled antibodies as reagents.
A light microscopic technique in which only a small spot is illuminated and observed at a time. An image is constructed through point-by-point scanning of the field in this manner. Light sources may be conventional or laser, and fluorescence or transmitted observations are possible.
Specialized PHOTOTRANSDUCTION neurons in the vertebrates, such as the RETINAL ROD CELLS and the RETINAL CONE CELLS. Non-visual photoreceptor neurons have been reported in the deep brain, the PINEAL GLAND and organs of the circadian system.
Investigative technique commonly used during ELECTROENCEPHALOGRAPHY in which a series of bright light flashes or visual patterns are used to elicit brain activity.

Expression of thrombospondin-1 in ischemia-induced retinal neovascularization. (1/2152)

Thrombospondin-1 is an extracellular matrix protein that inhibits endothelial cell proliferation, migration, and angiogenesis. This study was performed to investigate the role of thrombospondin-1 in ischemic retinal neovascularization. In a murine model of retinal neovascularization, thrombospondin-1 mRNA was increased from postnatal day 13 (P13), with a threefold peak response observed on P15, corresponding to the time of development of retinal neovascularization. Prominent expression of thrombospondin-1 was observed in neovascular cells, specifically, cells adjacent to the area of nonperfusion. It has been suggested that vascular endothelial growth factor (VEGF) plays a major role in ischemia-induced retinal neovascularization of this model, so we studied the effects of VEGF on thrombospondin-1 expression. In bovine retinal microcapillary endothelial cells, VEGF induced a biphasic response of thrombospondin-1 expression; VEGF decreased thrombospondin-1 mRNA 0.41-fold after 4 hours, whereas it increased, with a threefold peak response, after 24 hours. VEGF-induced endothelial cell proliferation was completely inhibited by exogenous thrombospondin-1 and increased by 37.5% with anti-thrombospondin-1 antibody. The present findings suggest that, in the ischemic retina, retinal neovascular cells increase thrombospondin-1 expression, and VEGF may stimulate endogenous thrombospondin-1 induction, which inhibits endothelial cell growth. VEGF-mediated thrombospondin-1 induction in ischemia-induced angiogenesis may be a negative feedback mechanism.  (+info)

Polyol formation and NADPH-dependent reductases in dog retinal capillary pericytes and endothelial cells. (2/2152)

PURPOSE: Dogs fed a diet containing 30% galactose experience retinal vascular changes similar to those in human diabetic retinopathy, with selective pericyte loss as an initial lesion. In the present study the relationship among reduced nicotinamide adenine dinucleotide phosphate (NADPH)-dependent reductases, polyol formation, and flux through the polyol pathway in cultured dog retinal capillary cells were investigated. METHODS: Pericytes and endothelial cells were cultured from retina of beagle dogs. NADPH-dependent reductases were characterized by chromatofocusing after gel filtration. Sugars in cultured cells were analyzed by gas chromatography, and flux through the polyol pathway was investigated by 19F nuclear magnetic resonance (NMR) with 3-fluoro-3-deoxy-D-glucose (3FG) as a substrate. The presence of aldose reductase and sorbitol dehydrogenase in these cells was examined by northern blot analysis. RESULTS: Two distinct peaks corresponding to aldose reductase and aldehyde reductase, the latter being dominant, were observed in pericytes by chromatofocusing. Culture in medium containing either 10 mM D-galactose or 30 mM D-glucose resulted in the accumulation of sugar alcohol in pericytes that was markedly reduced by aldose reductase inhibitors. 19F NMR spectra obtained from pericytes cultured for 5 days in medium containing 2 mM 3FG displayed the marked accumulation of 3-fluoro-deoxysorbitol but not 3-fluoro-deoxyfructose. No 3FG metabolism was observed in similarly cultured endothelial cells. With northern blot analysis, aldose reductase was detected in pericytes but not in endothelial cells. Sorbitol dehydrogenase was below the detectable limit in pericytes and endothelial cells. CONCLUSIONS: Aldose, aldehyde, and glyceraldehyde reductases are present in dog retinal capillary pericytes, with aldehyde reductase being the major reductase present. Polyol accumulation easily occurs in pericytes but not in endothelial cells.  (+info)

Necrosis and apoptosis after retinal ischemia: involvement of NMDA-mediated excitotoxicity and p53. (3/2152)

PURPOSE: Accumulated evidence has shown that apoptosis and necrosis contribute to neuronal death after ischemia. The present study was performed to study the temporal and spatial patterns of neuronal necrosis and apoptosis after ischemia in retina and to outline mechanisms underlying necrosis and apoptosis. METHODS: Retinal ischemia was induced by increasing intraocular pressure to a range of 160 mm Hg to 180 mm Hg for 90 minutes in adult rats. The patterns of neuronal cell death were determined using light and electron microscopy and were visualized by TdT-dUTP nick-end labeling (TUNEL). The mRNA expression profile of p53 was examined using reverse transcription-polymerase chain reaction (RT-PCR) and in situ hybridization histochemistry. Immunohistochemistry was performed using anti-p53, anti-microtubule associated protein-2, and anti-glial fibrillary acidic protein antibodies. RESULTS: Within 4 hours after ischemia, neurons in the inner nuclear cell layer (INL) and ganglion cell layer (GCL) underwent marked necrosis, made apparent by swelling of the cell body and mitochondria, early fenestration of the plasma membrane, and irregularly scattered condensation of nuclear chromatin. After 3 days, the INL and GCL neurons showed further degeneration through apoptosis marked by cell body shrinkage, aggregation, and condensation of nuclear chromatin. Apoptotic neurons were also observed sparsely in the outer nuclear cell layer. Intravitreal injections of MK-801 prevented early neuronal degeneration after ischemia. Of note, mRNA and protein levels of p53, the tumor suppressor gene known to induce apoptosis, were increased in the retinal areas undergoing apoptosis 1 to 3 days after ischemic injury. CONCLUSIONS: Ischemia produces the N-methyl-D-aspartate-mediated necrosis and slowly evolving apoptosis of neurons in the retina. The latter may depend on the expression of the p53 proapoptosis gene.  (+info)

Angiotensin II-induced constrictions are masked by bovine retinal vessels. (4/2152)

PURPOSE: To unmask the vasoconstricting effect of angiotensin II (Ang II) on retinal smooth muscle by studying its interaction with endothelium-derived paracrine substances. This study focused specifically on determining the changes in vascular diameter and the release of endothelial-derived vasodilators, nitric oxide (NO) and prostaglandin (PG) I2, from isolated retinal microvessels. METHODS: Bovine retinal central artery and vein were cannulated, and arterioles and venules were perfused with oxygenated/heparinized physiological salt solution at 37 degrees C. This ex vivo perfused retinal microcirculation model was used to observe the contractile effects of Ang II on arterioles and venules of different diameters. The NO and PGI2 synthase inhibitors, 1-NOARG and flurbiprofen, respectively, were used to unmask Ang II vasoconstriction; the changes in vascular diameters were then measured. Enzyme immunoassays were used to measure the release of cGMP (an index of NO release) and 6-keto-PG-F1alpha (a stable metabolite of PGI2) from isolated bovine retinal vessels. RESULTS: Topically applied Ang II (10(-10) M to 10(-4) M) caused significant (P < 0.05) arteriolar and venular constrictions in a dose-dependent manner, with the smallest retinal arterioles (7+/-0.2 microm luminal diameter) and venules (12+/-2 microm luminal diameter) significantly more sensitive than larger vessels. After the inhibition of endogenous NO and PGI2 synthesis by 1-NOARG and flurbiprofen, respectively, the vasoconstriction effects of Ang II became more pronounced. Again, the smallest vessels tested were significantly more sensitive, and synthesis of endothelial-derived relaxing factor (EDRF), therefore, may be most important in these vessels. Vasoactive doses of Ang II (10(-10) M to 10(-4) M) caused a dose-dependent increase in the release of NO and PGI2 from isolated bovine retinal vessels, indicating that the increase in EDRF may nullify direct Ang II-induced vasoconstriction. Interestingly, intraluminal administration of Ang II caused only vasodilation. CONCLUSIONS: This study demonstrates that the retinal vascular endothelium acts as a buffer against the vasoconstricting agent Ang II via release of vasodilators NO and PGI2, and the vasoconstriction effects due to Ang II are most prominent in the smallest diameter vessels.  (+info)

Riluzole improves functional recovery after ischemia in the rat retina. (5/2152)

PURPOSE: Retinal ischemia leads to neuronal death. The effects of riluzole, a drug that protects against the deleterious effect of cerebral ischemia by acting on several types of ion channels and blocking glutamatergic neurotransmission, were investigated in a rat model of retinal ischemic injury. METHODS: Retinal ischemia was induced by increasing intraocular pressure above systolic blood pressure for 30 minutes. Electroretinograms were recorded before ischemia and at different periods of reperfusion. Riluzole was injected or topically applied to the eye before or after ischemia and twice daily during the reperfusion period. Retinas were harvested for histopathology (toluidine blue and silver-impregnation stainings, Tdt-dUTP terminal nick-end labeling [TUNEL] method) and immunohistochemistry for cytoskeletal glial fibrillary acid protein and c-jun NH2-terminal kinase (p-JNK). RESULTS: Ischemia for 30 minutes caused a reduction of a- and b-waves of the electroretinogram. Systemic and topical treatments with riluzole significantly enhanced the recovery of the reduced a- and b-waves after defined reperfusion times. Riluzole also prevented or attenuated ischemia-induced retinal cell death (necrosis and apoptosis) and reduced the activation of p-JNK, c-jun phosphorylation, and the increase of cytoskeletal proteins induced by ischemic injury. CONCLUSIONS: Riluzole acted in vivo as a potent neuroprotective agent against pressure-induced ischemia. Therefore, riluzole may be a major drug for use in protection against retinal injury.  (+info)

Brightness alters Heidelberg retinal flowmeter measurements in an in vitro model. (6/2152)

PURPOSE: The Heidelberg Retinal Flowmeter (HRF), a laser Doppler flowmetry device, has captured interest as a research and clinical tool for measurement of ocular blood flow. Concerns remain about the range and accuracy of the values that it reports. METHODS: An in vitro blood-flow model was constructed to provide well-controlled laminar flow through a glass capillary for assessment by HRF. A change in material behind the glass capillary was used to simulate changing brightness conditions between eyes. RESULTS: Velocities reported by the HRF correlated linearly to true velocities below 8.8 mm/sec. Beyond 8.8 mm/sec, HRF readings fluctuated randomly. True velocity and HRF reported velocities were highly correlated, with r = 0.967 (P < 0.001) from 0.0 mm/sec to 2.7 mm/sec mean velocity using a light background, and r = 0.900 (P < 0.001) from 2.7 mm/sec to 8.8 mm/sec using a darker background. However, a large change in the y-intercept occurred in the calibration curve with the background change. CONCLUSIONS: The HRF may report velocities inaccurately because of varying brightness in the fundus. In the present experiment, a darker background produced an overreporting of velocities. An offset, possibly introduced by a noise correction routine, apparently contributed to the inaccuracies of the HRF measurements. Such offsets vary with local and global brightness. Therefore, HRF measurements may be error prone when comparing eyes. When used to track perfusion in a single eye over time, meaningful comparison may be possible if meticulous care is taken to align vessels and intensity controls to achieve a similar level of noise correction between measurements.  (+info)

Metabolic acidosis-induced retinopathy in the neonatal rat. (7/2152)

PURPOSE: Carbon dioxide (CO2)-induced retinopathy (CDIR) in the neonatal rat, analogous to human retinopathy of prematurity (ROP), was previously described by our group. In this model, it is possible that CO2-associated acidosis provides a biochemical mechanism for CDIR. Therefore, the effect of pure metabolic acidosis on the developing retinal vasculature of the neonatal rat was investigated. METHODS: A preliminary study of arterial blood pH was performed to confirm acidosis in our model. In neonatal rats with preplaced left carotid artery catheters, acute blood gas samples were taken 1 to 24 hours after gavage with either NH4Cl 1 millimole/100 g body weight or saline. In the subsequent formal retinopathy study, 150 newborn Sprague-Dawley rats were raised in litters of 25 and randomly assigned to be gavaged twice daily with either NH4Cl 1 millimole/100 g body weight (n = 75) or saline (n = 75) from day 2 to day 7. After 5 days of recovery, rats were killed, and retinal vasculature was assessed using fluorescein perfusion and ADPase staining techniques. RESULTS: In the preliminary pH study, the minimum pH after NH4Cl gavage was 7.10+/-0.10 at 3 hours (versus 7.37+/-0.03 in controls, mean +/- SD, P < 0.01). In the formal retinopathy study, preretinal neovascularization occurred in 36% of acidotic rats versus 5% of controls (P < 0.001). Acidotic rats showed growth retardation (final weight 16.5+/-3.0 g versus 20.2+/-2.6 g, P < 0.001). The ratio of vascularized to total retinal area was smaller in acidotic rats (94%+/-4% versus 96%+/-2%, P < 0.001). CONCLUSIONS: Metabolic acidosis alone induces neovascularization similar to ROP in the neonatal rat. This suggests a possible biochemical mechanism by which high levels of CO2 induce neovascularization and supports the suggestion that acidosis may be an independent risk factor for ROP.  (+info)

De novo lesions in presumed ocular histoplasmosis-like syndrome. (8/2152)

Two patients with multifocal choroiditis similar or identical to POHS are presented. Colour photographs and fluorescein angiography document the occurrence of de novo lesions in the originally involved eye. The cases also demonstrate the development of new choroidal lesions within the originally involved eye, the early evolution of the "basic choroidal lesion", and the need for fluorescein angiography for visualizing the underlying choroidal lesion.  (+info)

Purpose: To describe the prevalence of retinal microvascular characteristics and their associations with atherosclerosis in elderly, nondiabetic persons. Design and Participants: Population-based, cross-sectional study comprising 2050 men and women aged 69 to 97 years without diabetes, living in four communities. Methods: Participants underwent retinal photography and standardized grading of retinal microvascular characteristics, including retinopathy (e.g., microaneurysms, retinal hemorrhages), focal arteriolar narrowing, and arteriovenous nicking. In addition, calibers of retinal arterioles and venules were measured on digitized photographs to obtain an estimate of generalized arteriolar narrowing. Atherosclerosis and its risk factors were obtained from clinical examination and laboratory investigations. Main Outcome Measures: Prevalence of retinal microvascular abnormalities and their associations with measures of atherosclerosis. Results: The prevalence of retinal microvascular abnormalities ...
Retinal blood vessel segmentation has an important guiding significance for the analysis and diagnosis of cardiovascular diseases such as hypertension and diabetes. But the traditional manual method of retinal blood vessel segmentation is not only time-consuming and laborious but also cannot guarantee the accuracy and efficiency of diagnosis. Therefore, it is especially significant to create a computer-aided method of automatic and accurate retinal vessel segmentation. In order to extract the blood vessels contours of different diameters to realize fine segmentation of retinal vessels, we propose a Bidirectional Symmetric Cascade Network (BSCN) where each layer is supervised by vessel contour labels of specific diameter scale instead of using one general ground truth to train different network layers. In addition, to increase the multi-scale feature representation of retinal blood vessels, we propose the Dense Dilated Convolution Module (DDCM), which extracts retinal vessel features of different
TY - JOUR. T1 - Retinal pigment epithelial cells produce mitogenic factors for retinal microvascular cells in culture. T2 - A preliminary report. AU - Wong, H. C.. AU - Boulton, M. E.. AU - Clark, P.. AU - Bayly, M.. AU - Marshall, J.. PY - 1987/11. Y1 - 1987/11. N2 - Conditioned media from human retinal pigment epithelial cells have been shown to have mitogenic activity for retinal microvascular cells in vitro. The conditioned media stimulated the proliferation of both bovine retinal capillary endothelial cells and pericytes.. AB - Conditioned media from human retinal pigment epithelial cells have been shown to have mitogenic activity for retinal microvascular cells in vitro. The conditioned media stimulated the proliferation of both bovine retinal capillary endothelial cells and pericytes.. UR - http://www.scopus.com/inward/record.url?scp=0343457139&partnerID=8YFLogxK. UR - http://www.scopus.com/inward/citedby.url?scp=0343457139&partnerID=8YFLogxK. U2 - 10.1038/eye.1987.121. DO - ...
PURPOSE: To characterize the properties of the glucose transporters of bovine retinal capillary endothelial cells and pericytes and to determine the effects of increased glucose concentrations on glucose transport activity. METHODS: Primary cultures of bovine retinal capillary endothelial cells and pericytes were exposed to low and high glucose concentrations, and immunoblot analysis, 14C-3-O-methylglucose transport activity, and cytochalasin B binding assays were used to characterize the glucose transporters. RESULTS: GLUT1, but not GLUT3 or GLUT4 transporter isoforms, was present in plasma membranes isolated from each cell type. The EC50 for glucose transport was similar in endothelial cells and pericytes (3.94 to 0.48 mM versus 2.24 to 0.69 mM) and was consistent with the EC50 previously reported for GLUT1 transporters on other cells, as was the observation that insulin did not acutely stimulate glucose transport in either cell type. The Vmax for glucose transport was greater in pericytes ...
Automatic assessment of retinal vessels plays an important role in the diagnosis of various eye, as well as systemic diseases. A public screening is highly desirable for prompt and effective treatment, since such diseases need to be diagnosed at an early stage. Automated and accurate segmentation of the retinal blood vessel tree is one of the challenging tasks in the computer-aided analysis of fundus images today. We improve the concept of matched filtering, and propose a novel and accurate method for segmenting retinal vessels. Our goal is to be able to segment blood vessels with varying vessel diameters in high-resolution colour fundus images. All recent authors compare their vessel segmentation results to each other using only low-resolution retinal image databases. Consequently, we provide a new publicly available high-resolution fundus image database of healthy and pathological retinas. Our performance evaluation shows that the proposed blood vessel segmentation approach is at least comparable with
PURPOSE: Prior results have demonstrated a significant reduction in retinal blood flow in streptozotocin (STZ)-induced diabetic rats. These studies were extended to investigate whether retinal blood flow changes, in the diabetic rat model, could be prevented with strict glycemic control using insulin pumps. Retinal blood flow changes also were measured during hyperoxia and after intravitreal histamine infusion to validate the methodology. METHODS: Retinal blood flow changes were measured using video-based fluorescein angiography and computer-assisted image analysis. A total of 48 male Sprague-Dawley and 9 Brown Norway rats were used in these experiments. Retinal blood flow after primary insulin intervention was evaluated in diabetic rats implanted with mini-osmotic insulin pumps within 24 hours of STZ-induced diabetes. Diabetic rats, not treated with insulin, were used for comparison. RESULTS: Hyperoxia caused a significant (P = 0.001) reduction (54%) in retinal blood flow, whereas intravitreal ...
Rat Retinal Microvascular Endothelial Cells from Creative Bioarray are isolated from retinal tissue of 6-8 week old laboratory Sprague-Dawley rat. Rat Retinal Microvascular Endothelial Cells are grown in T75 tissue culture flasks pre-coated with gelatin-based coating solution for 2 min and incubated in Creative Bioarray Culture Complete Growth Medium generally for 3-7 days. Cultures are then expanded. Prior to shipping, cells at passage 3 are detached from flasks and immediately cryo-preserved in vials. Each vial contains at least 1x10^6 cells per ml and is delivered frozen. The method we use to isolate endothelial cells was developed based on a combination of established and our proprietary methods. These cells are pre-coated with PECAM-1 (CD31) antibody, following the application of magnetic beads pre-coated with secondary antibody ...
TY - JOUR. T1 - Retinal arteriolar narrowing and left ventricular hypertrophy in African Americans. The Atherosclerosis Risk in Communities (ARIC) study. AU - Tikellis, Gabriella. AU - Arnett, Donna K.. AU - Skelton, Thomas N.. AU - Taylor, Herman W.. AU - Klein, Ronald. AU - Couper, David J.. AU - Richey Sharrett, A.. AU - Yin Wong, Tien. PY - 2008/3/1. Y1 - 2008/3/1. N2 - Background: Whether microvascular disease contributes to the development of left ventricular hypertrophy (LVH) is unclear. We examined the relationship of retinal microvascular signs with LVH in an African-American population. Methods: A population-based, cross-sectional study of 1,439 middle-aged African-American participants in Jackson, Mississippi. A retinal photograph of one randomly selected eye was obtained and graded for presence of retinal microvascular signs (focal arteriolar narrowing, arterio-venous (AV) nicking, and retinopathy) according to standardized protocols. Retinal vessel diameter was measured from a ...
The issue where an embolism is formed deep in your veins is called deep capillary apoplexy. This embolism can obstruct blood that flows back to the heart. This problem generally occurs in the leg. When left without therapy, the embolisms can take a trip to the significant body organs like the lungs.. There differ means you could possibly adjust to lessen your threat for deep capillary apoplexy:. Given up cigarette smoking. Smoking cigarettes will certainly not just predispose you to numerous other professional issues, it might also boost your risk of developing deep capillary thrombosis. So stop smoking, stat!. Workout routinely. Regular workout will certainly not just help you manage your weight and make you really feel as well as appearance good, it could furthermore keep several scientific problems including deep capillary apoplexy at bay. Constantly make time for workout daily. Even a little operating or walking, done everyday could go a lengthy ways.. Talk to your medical ...
The problem where a blood clot is formed deep in your veins is called deep capillary apoplexy. This blood clot could block blood that recedes to the heart. This problem commonly takes place in the leg. When left without treatment, the blood clots might take a trip to the major body organs like the lungs.. There vary methods you could adjust to lessen your threat for deep capillary apoplexy:. Given up smoking. Smoking cigarettes will not only predispose you to different other clinical issues, it might also enhance your danger of setting up deep capillary apoplexy. So quit cigarette smoking, stat!. Exercise consistently. Routine workout will absolutely not just assist you manage your weight and make you truly feel along with look excellent, it can also maintain numerous scientific troubles including deep capillary apoplexy away. Always make time for exercise every day. Even a little running or strolling, done every day can go a long means.. Talk with your physician. If you are taking hormonal ...
The retina and brain share many neuronal and vasculature characteristics. We investigated the retinal microvasculature in Alzheimers disease (AD) and mild cognitive impairment (MCI) using optical coherence tomography angiography (OCTA). In this cross-sectional study, 24 AD participants, 37 MCI participants, and 29 controls were diagnosed according to internationally accepted criteria. OCTA images of the superficial and deep capillary plexus (SCP, DCP) of the retinal microvasculature were obtained using a commercial OCTA system (Zeiss Cirrus HD-5000 with AngioPlex, Carl Zeiss Meditec, Dublin, CA). The main outcome measures were vessel density (VD) and fractal dimension (FD) in the SCP and DCP within a 2.5-mm ring around the fovea which were compared between groups. Perfusion density of large vessels and foveal avascular zone (FAZ) area were additional outcome parameters. Age, gender, and race did not differ among groups. However, there was a significant difference in diabetes status (P = 0.039) and
Objective: To estimate the effects of maternal body mass index (BMI) and pregnancy weight gain on the retinal microvasculature among pregnant women. Methods: We studied 814 pregnant women aged 18-46 years who were recruited as part of the Growing Up in Singapore Toward Health Outcomes study, an ongoing birth cohort study from two government hospitals in Singapore since 2009. Recalled prepregnancy weight was recorded, and maternal anthropometric measurements of weight and height were performed at 26 weeks of gestation together with retinal photography. Results: In multiple linear regression models, each standard deviation increase of 26-week pregnancy BMI (4.57) was associated with narrower retinal arteriolar caliber (by 1.58 micrometers, P,.001), wider venular caliber (by 1.28 micrometers, P=.02), and increased retinal venular tortuosity (P=.01). Compared with mothers with normal weight, obese mothers (prepregnancy BMI greater than 30.0) had narrower retinal arteriolar caliber (118.81 compared ...
With improvements in fundus imaging technology and the increasing use of digital images in screening and diagnosis, the issue of automated analysis of retinal images is gaining more serious attention. We consider the problem of retinal vessel segmentation, a key issue in automated analysis of digital fundus images. We propose a texture-based vessel segmentation algorithm based on the notion of textons. Using a weak statistical learning approach, we construct textons for retinal vasculature by designing filters that are specifically tuned to the structural and photometric properties of retinal vessels. We evaluate the performance of the proposed approach using a standard database of retinal images. On the DRIVE data set, the proposed method produced an average performance of 0.9568 specificity at 0.7346 sensitivity. This compares well with the best-published results on the data set 0.9773 specificity at 0.7194 sensitivity [Proc. SPIE 5370, 648 (2004) ].. © 2007 Optical Society of America. Full ...
We present a novel application of optical microangiography (OMAG) imaging technique for visualization of depth-resolved vascular network within retina and choroid as well as measurement of total retinal blood flow in mice. A fast speed spectral domain OCT imaging system at 820nm with a line scan rate of 140 kHz was developed to image the posterior segment of eyes in mice. By applying an OMAG algorithm to extract the moving blood flow signals out of the background tissue, we are able to provide true capillary level imaging of the retinal and choroidal vasculature. The microvascular patterns within different retinal layers are presented. An en face Doppler OCT approach [Srinivasan et al., Opt Express 18, 2477 (2010)] was adopted for retinal blood flow measurement. The flow is calculated by integrating the axial blood flow velocity over the vessel area measured in an en face plane without knowing the blood vessel angle. Total retinal blood flow can be measured from both retinal arteries and veins. ...
From the Department of Neurology (S.R.L.), University of Maryland, Baltimore; Department of Medicine (T.H.M.), University of Mississippi Medical Center, Jackson; Centre for Eye Research Australia (T.Y.W.), University of Melbourne, Australia; Department of Epidemiology (M.S., J.C., A.R.S.), Johns Hopkins Bloomberg School of Public Health, Baltimore; Division of Behavioral Neurology (D.K.), Mayo Clinic College of Medicine, Rochester, MN; Departments of Biostatistics (D.J.C.) and Epidemiology (S.R.C.), University of North Carolina, Chapel Hill; Department of Ophthalmology and Visual Sciences (R.K.), University of Wisconsin School of Medicine and Public Health, Madison; and Department of Public Health Sciences (L.H.C.), Wake Forest University School of Medicine, Winston-Salem, NC ...
Quantitative retinal signs were mainly analyzed as continuous variables and qualitative retinal signs were analyzed as binary variables. The association between retinal signs and vascular risk factors was assessed using linear and logistic regression to adjust for age, gender, and race.. In the main analysis, we used linear regression to model each of the DSST score, gait speed, and square root of CES-D score as a function of a retinal sign and covariates, and we used logistic regression to model the probability of depressive mood. Standardized coefficients were computed to compare the strength of associations between retinal signs and each outcome. Depressive symptoms were analyzed in 2 different ways: (1) square root of CES-D score among participants not using antidepressant medications, because CES-D score may not accurately represent the burden of depressive symptoms in these participants; and (2) the presence of depressive mood, as defined, in all participants. Of those with data on all 5 ...
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Objective Currently, there are no published data on retinal microvasculature size in human infants born at term. The purpose of this study was to determine the normal retinal microvasculature measurements in human infants born at term with normal birth weight and to compare these results with measurements in children and adults. Methods Retinal arteriole and venule measurements were obtained in a cohort of 20 full-term infants. Digital retinal images were obtained from both eyes after pupillary dilation using a digital retinal camera. Measurements of vessel diameter were then obtained using semi-automated software. Results Twenty infants (9 female infants and 11 male infants) were analyzed. The retinal arteriole diameter was 66.8-123.0 μm (mean, 85.5 (14.3) μm), and the venule diameter was 102.0-167.8 μm (mean, 130.0 (16.0) μm). There were no differences in the arterial or venule diameters between the male and female infants (83.2 (12.2) vs. 88.3 (16.9); P = 0.4372; 124.3 (16.0) vs. 137.0 (18.0); P
TY - JOUR. T1 - BIGH3 protein and macrophages in retinal endothelial cell apoptosis. AU - Mondragon, Albert A.. AU - Betts-Obregon, Brandi S.. AU - Moritz, Robert J.. AU - Parvathaneni, Kalpana. AU - Navarro, Mary M.. AU - Kim, Hong Seok. AU - Lee, Chi Fung. AU - Lebaron, Richard G.. AU - Asmis, Reto. AU - Tsin, Andrew T.. PY - 2015/1. Y1 - 2015/1. N2 - Diabetes is a pandemic disease with a higher occurrence in minority populations. The molecular mechanism to initiate diabetes-associated retinal angiogenesis remains largely unknown. We propose an inflammatory pathway of diabetic retinopathy in which macrophages in the diabetic eye provide TGFβ to retinal endothelial cells (REC) in the retinal microvasculature. In response to TGFβ, REC synthesize and secrete a pro-apoptotic BIGH3 (TGFβ-Induced Gene Human Clone 3) protein, which acts in an autocrine loop to induce REC apoptosis. Rhesus monkey retinal endothelial cells (RhREC) were treated with dMCM (cell media of macrophages treated with high ...
The retina is a highly metabolically active tissue with large demands on the supply of nutrients. Disorders affecting the retina often include some vasculopathy with an impact on retinal circulation. Studies of retinal haemodynamics could thus help to detect, differentiate and diagnose diseases, to monitor changes in disease as well as progression and efficiency of the therapy.. The present studies were an attempt to validate and determine the clinical usefulness of a newly developed technique for studying the retinal circulation in human eyes.. We used different techniques to evaluate different parameters of retinal circulation. We examined how leukocyte velocity determined with Blue Field Simulation and transit times, mean transite time (MTT) and arterio-venous passage (AVP), and vessel diameter, determined from fluorescein angiograms, together reflects the retinal circulation. MTT was determined with a method based on an Impulse-Response technique, MTTIR.. In a study on monkeys we compared ...
A retinal vessel occlusion is a blockage in the blood vessel of your eye that can result in sight loss. There are two types of retinal blood vessels, arteries and veins. Either of these can become blocked and each of them can affect the eye in different ways. The visual loss caused by retinal vein and artery occlusions is painless. It is usual for only one eye to be involved at a time, but occasionally both eyes may be affected at the same time.
Cellular metabolic memory occurs in diabetic microvascular and macrovascular complications, but the underlying mechanisms remain unclear. Here, we investigate the role of sirtuin 1 (SIRT1) and metformin in this phenomenon. In bovine retinal capillary endothelial cells (BRECs) and retinas of diabetic rats, the inflammatory gene, nuclear factor-κB (NF-kB), and the proapoptotic gene, Bax, induced by hyperglycemia, remained elevated after returning to normoglycemia. BRECs with small interfering RNA-mediated SIRT1 knockdown had increased sensitivity to hyperglycemia stress, whereas SIRT1 overexpression or activation by metformin inhibited the increase of mitochondrial reactive oxygen species-mediated glyceraldehyde-3-phosphate dehydrogenase by poly (ADP-ribose) polymerase (PARP) activity through the upregulation of liver kinase B1/AMP-activated protein kinase (LKB1/AMPK), ultimately suppressing NF-κB and Bax expression. Furthermore, we showed that hyperglycemia led to PARP activation, which in turn ...
Diabetic neuropathy, nephropathy and retinopathy cause significant morbidity in patients with type 1 diabetes, even though improvements in treatment modalities delay the appearance and reduce the severity of these complications. To prevent or further delay the onset, it is necessary to better understand common underlying pathogenesis and to discover pre-clinical biomarkers of these complications.. Retinal vessel calibers have been associated with the presence of microvascular complications but their long-term predictive value has only been sparsely investigated.. We examined retinal vessel calibers as 16-year predictors of diabetic nephropathy, neuropathy and proliferative retinopathy in a young population-based Danish cohort with type 1 diabetes. We used semi-automated computer software to analyze vessel diameters on baseline retinal photos. Calibers of all vessels coursing through a zone 0.5-1 disc diameter from the disc margin were measured and summarized as the central artery and vein ...
Using various techniques to study retinal blood flow in patients with diabetes, researchers have drawn different conclusions regarding whether blood flow is increased or decreased (2-10,19,20). The present study indicates that retinal blood flow in diabetic patients with no or mild retinopathy is slightly elevated before the patients take their insulin but is reduced toward normal when blood glucose levels are normalized.. Compared with previous studies addressing the question of retinal blood flow in diabetes, the present approach offers several methodological advantages. Most importantly only a few studies have measured total retinal blood flow (3,4). The technique applied in this study, combining velocity data with diameter data is currently the only approach to study this in humans. As such, our data are in good agreement with a previous study indicating increased retinal blood flow in diabetes before the onset of diabetic retinopathy (4). Compared with this previous study, though, the ...
TY - JOUR. T1 - Characteristics of the retinal microvasculature in association with cardiovascular risk markers in children with overweight, obesity and morbid obesity. AU - Berendschot, Tos T..J.M.. AU - Rijks, Jesse. AU - Vreugdenhil, Anita. AU - Dorenbos, Elke. AU - Karnebeek, Kylie. AU - Joris, Peter. AU - Mensink, Ronald. AU - Plat, Jogchum. PY - 2019. Y1 - 2019. U2 - 10.1159/000499516. DO - 10.1159/000499516. M3 - Meeting Abstract. VL - 56. SP - 13. EP - 13. JO - Journal of Vascular Research. JF - Journal of Vascular Research. SN - 1018-1172. IS - S1. ER - ...
Edema & Retinal Vessels Attenuated & Retinopathy Symptom Checker: Possible causes include Hypertension. Check the full list of possible causes and conditions now! Talk to our Chatbot to narrow down your search.
Oxidative Medicine and Cellular Longevity is a unique peer-reviewed, Open Access journal that publishes original research and review articles dealing with the cellular and molecular mechanisms of oxidative stress in the nervous system and related organ systems in relation to aging, immune function, vascular biology, metabolism, cellular survival and cellular longevity. Oxidative stress impacts almost all acute and chronic progressive disorders and on a cellular basis is intimately linked to aging, cardiovascular disease, cancer, immune function, metabolism and neurodegeneration. The journal fills a significant void in todays scientific literature and serves as an international forum for the scientific community worldwide to translate pioneering
Retinal Scar & Retinal Vessels Attenuated & Subacute Clinical Course Symptom Checker: Possible causes include Retinopathy of Prematurity. Check the full list of possible causes and conditions now! Talk to our Chatbot to narrow down your search.
Systemic VEGF blockade does not alter retinal vessels ultrastructure or choriocapillaris fenestration.(A) TEM of a microvessel located in the GCL of sFlt1 expre
Abnormalities in the vascular pattern of the retina are associated with retinal diseases and are also risk factors for systemic diseases, especially cardiovascular diseases. The three-dimensional retinal vascular pattern is mostly formed congenitally, but is then modified over life, in response to aging, vessel wall dystrophies and long term changes in blood flow and pressure. A characteristic of the vascular pattern that is appreciated by clinicians is vascular tortuosity, i.e. how curved or kinked a blood vessel, either vein or artery, appears along its course. We developed a new quantitative metric for vascular tortuosity, based on the vessels angle of curvature, length of the curved vessel over its chord length (arc to chord ratio), number of curvature sign changes, and combined these into a unidimensional metric, Tortuosity Index (TI). In comparison to other published methods this method can estimate appropriate TI for vessels with constant curvature sign and vessels with equal arc to ...
Harvard Medical School researchers have identified a method to control a hormone that may be responsible for the most common cause of blindness. This discovery could lead to new ways of preventing and treating certain eye diseases - including diabetic retinopathy, retinopathy of prematurity, and prehaps age-related macular degeneration. The findings are reported in the June 13 Science.
There is growing evidence supporting the notion that endothelial dysfunction and inflammation are common events driving the development of various retinal microvascular changes in patients with hypertension, diabetes, and other metabolic disorders [30,31]. However, the synergistic impact of these commonly coexisting conditions on the development of retinopathy has not been fully elucidated. Our current study aimed to model the early and established detrimental effects of combining hypertension with diabetes on the development of retinopathy and retinal microvascular degeneration using diabetic spontaneously hypertensive rats, an established model for studying hypertension. Clinical evidence highlights the role of oxidative stress and endothelial dysfunction as previously indicated by increased levels of lipid peroxidation and platelet activation in patients with hypertension-related microvascular changes when compared with patients with or without early signs of retinopathy [3,30]. Our results ...
Trypsin digest is one of the most commonly used methods to analyze retinal vasculature. This manuscript describes the method in detail, ...
Figure 4. Protective effect of catalase on HREC outgrowths. Protective effect of catalase on H2O2 induced cytotoxicity in 6 days HREC outgrowths. A: HREC aggregate grown in basal tissue culture medium shows normal sprouting after 6 days. B: HREC aggregate in medium supplemented with 1 mM H2O2, demonstrating that oxidative stress blocks sprouting. C: HREC aggregate grown in medium + 1 mM H2O2 in presence of catalase administered through an AnoporeTM filter (starting concentration in the upper compartment: 400 U/ml). The sprouts develop normally, showing that filter administered catalase can exert a protective effect on endothelial cells against oxidative stress induced injury. Phase contrast micrographs. Original magnifications: x80. D: SigmaScan Pro quantification of the outgrowth pattern illustrated in A.. ...
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Retinal, Association, Blood, Blood Vessels, Human, Hyperoxia, Light, Microvasculature, Retinal Blood Vessels, Vasoconstriction, Vasodilation
The arteriovenous ratio is an objective way to assess the arteriolar narrowing related to several diseases such as hypertension. It is computed as the ratio between the artery and vein mean widths. However, its calculus is not straightforward since the experts do not use all the retinal vessels. This paper presents an automatic, precise and reproducible methodology for the AVR computation. We analyze the way the experts select the vessels in order to build a system which emulates them. The system was evaluated by two ophthalmologists in a data set of 86 images. The correlation results among the system and the experts are an indication of the reproducibility of the results.
Primary Human Retinal Microvascular Endothelial Cells or HRMECs (ACBRI 181) are initiated by elutriation of dispase dissociated normal human retina tissue.
Title:Mimicking Microvascular Alterations of Human Diabetic Retinopathy: A Challenge for the Mouse Models. VOLUME: 20 ISSUE: 26. Author(s):D. Ramos, A. Carretero, M. Navarro, L. Mendes-Jorge, V. Nacher, A. Rodriguez-Baeza and J. Ruberte. Affiliation:Center for Animal Biotechnology and Gene Therapy (CBATEG), Universitat Autonoma de Barcelona, E-08193-Bellaterra, Spain.. Keywords:Diabetes, retinopathy, microvascular complication, mouse model.. Abstract:Although it has become acceptable that neuroretinal cells are also affected in diabetes, vascular lesions continue to be considered as the hallmarks of diabetic retinopathy. Animal models are essential for the understanding and treatment of human diabetic retinopathy, and the mouse is intensively used as a model because of its similarity to human and the possibility to be genetically modified. However, until today not all retinal vascular lesions developed in diabetic patients have been reproduced in diabetic mice, and the reasons for this are not ...
Automated image processing has the potential to assist in the early detection of diabetes, by detecting changes in blood vessel diameter and patterns in the retina. This paper describes the development of segmentation methodology in the processing of retinal blood vessel images obtained using non-mydriatic colour photography. The methods used include wavelet analysis, supervised classifier probabilities and adaptive threshold procedures, as well as morphology-based techniques. We show highly accurate identification of blood vessels for the purpose of studying changes in the vessel network that can be utilized for detecting blood vessel diameter changes associated with the pathophysiology of diabetes. In conjunction with suitable feature extraction and automated classification methods, our segmentation method could form the basis of a quick and accurate test for diabetic retinopathy, which would have huge benefits in terms of improved access to screening people for risk or presence of diabetes ...
Although it has become acceptable that neuroretinal cells are also affected in diabetes, vascular lesions continue to be considered as the hallmarks of diabetic retinopathy. Animal models are essential for the understanding and treatment of human diabetic retinopathy, and the mouse is intensively used as a model because of its similarity to human and the possibility to be genetically modified. However, until today not all retinal vascular lesions developed in diabetic patients have been reproduced in diabetic mice, and the reasons for this are not completely understood. In this review, we will summarize retinal vascular lesions found in diabetic and diabetic-like mouse models and its comparison to human lesions. The goal is to provide insights to better understand human and mice differences and thus, to facilitate the development of new mouse models that mimic better human diabetic retinopathy ...
The broad functions of Tissue Culture Module are 1) isolation of primary cells from ocular tissue; 2) maintenance and passage of established cell lines, including storage; 3) large scale amplification of cell lines; 4) transient transfection of cells; 4) generation of stably transfected cell lines; 5) training in growth and maintenance of cells; 6) strategic advice in planning experiments and determining their feasibility; and 7) mycoplasma testing. Specialized cell types currently stored include human and bovine retinal capillary endothelial cells, human and bovine retinal capillary pericytes, a rat retinal Muller cell line, a human retinal pigmented epithelial cell line, human corneal epithelial cells, a rat retinal ganglion cell line, human umbilical vein and aortic endothelial cells, mouse and human lens epithelial cells and cell lines, and mouse photoreceptor cell line. Equipment used in the Tissue Culture Module includes: 6 single chamber water jacket CO2 incubators, Nikon TS 100 with ...
S. Roth, A. P. Crittenden; A345 EFFECTS OF ENFLURANE ON RETINAL BLOOD FLOW IN CATS. Anesthesiology 1990; 73:NA doi: https://doi.org/10.1097/00000542-199009001-00341. Download citation file:. ...
The expression profiles of normal human brain and retinal pericytes are shared with respect to several cytoskeletal, cellular adhesion and proinflammatory biomarkers. This suggests that pericytes from different vascular beds within the CNS are similar and that their physiology may be governed by their respective microenvironments. We found that brain and retinal pericytes were equally permissive for HCMV lytic replication by both laboratory adapted and clinical strains of virus. In IBRB, retinal pericytes were most permissive for HCMV infection when compared to retinal microvascular endothelial cells and Müller cells. HCMV infection elicited an angiogenic and proinflammatory cytokine response in pericytes after infection. From these studies we proposed a disease model (Figure 11) for HCMV dissemination across the IBRB into the retina that is similar to the model we proposed for HCMV dissemination across the BBB into the brain [20]. Our working model is that as HCMV traffics the IBRB initially, ...
en] PURPOSE. To examine the ability and mechanism of the 16 kDa N-terminal fragment of human prolactin (16K hPRL) in the inhibition of abnormal retinal neovascularization. METHODS. The 16K hPRL-encoding sequence was inserted into an adenoviral vector (16K-Ad). Western blot analysis verified the expression of 16K hPRL and inhibition of proliferation, confirming functional activity of the 16K hPRL in virus-infected adult bovine aortic endothelial (ABAE) cells. 16K hPRL inhibited retinal neovascularization in a mouse model of oxygen-induced retinopathy. The ability of recombinant 16K hPRL expressed in E. coli (r16K hPRL) was compared to that of endostatin in inducing apoptosis of cultured human retinal endothelial cells (HREC). RESULTS. 16K was expressed in virus-infected ABAE cells and resulted in a dose-dependent inhibition of cell proliferation. Eyes injected with 16K-Ad showed a reduction in preretinal neovascularization of 82.3 +/- 9.3% (P , 0.00001) when compared to uninjected controls. r16K ...
Blood Vessel Segmentation in Complex-Valued Magnetic Resonance Images with Snake Active Contour Model: 10.4018/jehmc.2010010104: Accurate blood vessel segmentation plays a crucial role in non-invasive blood flow velocity measurement based on complex-valued magnetic resonance images. We
Introduction: Oxygen delivery, or utilization, is a function of retinal blood flow and blood oxygen saturation. The retinal pigment epithelium (RPE), in particular, has been shown to have the highest levels of metabolic activity within the human body. Oxygen delivery is therefore of extreme importance to the maintenance of the health and integrity of the retina. Animal models presuppose that the oxygen tension in the retina is highest in the innermost layers at the level of the choriocapillaris, less in the photoreceptors and further decreases throughout the outer retinal structures. The choroid provides by far the largest component of the oxygen for consumption by the photoreceptors. A lack of oxygen stores in the inner retina therefore makes a constant supply crucial for its normal functioning. Blood flow dysfunction and subsequent hypoxia are both a feature in the pathogenesis of several major ocular diseases such as retinopathy of prematurity (ROP), age-related macular degeneration (ARMD), ...
This book provides comprehensive and up-to-date information on diagnosis, medical and surgical treatments for pediatric retinal vascular conditions, which are leading causes of childhood blindness throughout the world. Experienced ophthalmologists in the field discuss basic knowledge about these diseases and practical aspects of management such as exam under anesthesia, diagnostic approaches including spectral-domain hand-held optical coherence tomography (OCT) and OCT angiography. The reader will learn about the recent advances in medical and surgical treatments for pediatric retinal vascular diseases. The surgical treatments, anti-VEGF injections, laser photocoagulation and lens sparing vitrectomy are explained step-by-step and can be observed in several videos.. Both the general ophthalmologist who cares for children with retinal diseases and the specialist (pediatric ophthalmologists and vitreoretinal surgeon) will find this book to be an informative resource in providing best care for ...
TY - JOUR. T1 - Gremlin gene expression in bovine retinal pericytes exposed to elevated glucose.. AU - Kane, R.. AU - Stevenson, L.. AU - Godson, C.. AU - Stitt, Alan. AU - OBrien, C.. PY - 2005/12. Y1 - 2005/12. UR - http://www.scopus.com/inward/record.url?scp=28444435554&partnerID=8YFLogxK. U2 - 10.1136/bjo.2005.069591. DO - 10.1136/bjo.2005.069591. M3 - Article. C2 - 16299147. VL - 89(12). SP - 1638. EP - 1642. JO - British Journal of Ophthalmology. JF - British Journal of Ophthalmology. SN - 0007-1161. IS - 12. ER - ...
Recognised as the most common diabetic eye disease, diabetic retinopathy occurs due to changes in the blood vessels of the retina. A serious sight-threatening complication of diabetes, diabetic retinopathy occurs when blood vessels in the retina change. With this condition, retinal blood vessels may swell and leak fluid, or close off completely. In other circumstances, the surface of the retina may develop abnormal growth of new blood vessels. Two classifications for diabetic retinopathy describe its progression. In infancy, it is referred to as Non-Proliferative Diabetic Retinopathy (NPDR). ). In its more advanced form, Proliferative Diabetic Retinopathy (PDR) is the term applied to this condition.. There is a trusted eye doctor local to Wallaceburg who is able to provide diabetic retinopathy testing. Dr. David Oliphant is ready to help you establish effective management of your diabetic retinopathy symptoms before they can deteriorate.. ...
Etiology, Pathogenesis, ClassificationTop. Diabetic retinopathy is present in most patients with diabetes mellitus (DM) (after 20 years from diagnosis in almost all patients with type 1 DM and in more than half of patients with type 2 DM). It is the most frequent cause of new cases of blindness and visual impairment among adults aged 20 to 74 years in developed countries and is a frequent cause of glaucoma, cataracts, and other disorders in the eye at early ages. The key factors in the pathogenesis and progression of diabetic retinopathy are DM duration, baseline retinopathy at the diagnosis of DM, chronic hyperglycemia, nephropathy, dyslipidemia, and hypertension.. Retinopathy usually progresses from mild nonproliferative abnormalities (microaneurysm formation and intraretinal hemorrhages) to retinal capillary nonperfusion, cotton wool spots, increased numbers of hemorrhages, venous abnormalities, and intraretinal microvascular abnormalities. Eventually this leads to increased vascular ...
PURPOSE: Advanced glycation endproduct (AGE) formation on the basement membrane of retinal capillaries has been previously described but the impact of these adducts on capillary endothelial cell function vascular repair remains uncertain. This invest
Diabetic retinopathy is one of the leading causes of vision loss in industrialized countries. Despite recent advances, the biochemical basis for the development of this diabetic complication is uncertain. Although retinal circulation is unique in that it is readily observable noninvasively, retinal tissue is extremely difficult to study in humans because of the problems inherent in obtaining fresh, appropriate biopsy material. Moreover, because of the difficulties in working with animal models of diabetic retinopathy, such as the dog, many investigators have turned to cell-culture models, especially those using primary cultures of retinal capillary endothelial cells and pericytes. Diabetic retinopathy involves both morphological and functional changes in the retinal capillaries. Morphological changes include basement membrane thickening and pericyte disappearance; functional changes include one important early change-increased permeability-which may be attributable to endothelial cell changes ...
diabetes, it wont normally show any diabetic retinopathy symptoms.. Types of Diabetic Retinopathy. The two types include Background diabetic retinopathy (BDR) and Proliferative diabetic retinopathy (PDR).. Background Diabetic Retinopathy. BDR is characterized as initial stage of the disease and results in hemorrhages, lipoid exudates and microaneurysms. This causes leakage of blood vessels just under macula.. Proliferative Diabetic Retinopathy. It results in neovascularization, which is growth of blood vessels inside retina of human eye. This growth is dangerous as it shoots off blood vessels over retina. Sometimes, this growth moves into iris and may possibly rupture retina resulting in hemorrhages. It is also observed that blood vessels can separate retina and result in retinal detachment for the eye.. Also Read about Diabetic Neuropathy and its Symptoms. How to Diagnose Retina Problems?. The method of diagnosis is not sophisticated and rather easy. When diagnosing the issue, majority of ...
The blood vessels in the retina of the eye are abnormal in individuals with schizophrenia, according to the study Microvascular Abnormality in Schizophrenia as Shown by Retinal Imaging in the American Journal of Psychiatry. The senior researcher was Richie Poulton, Ph.D., codirector of the National Centre for Lifecourse Research at the University of Otago in Dunedin, New Zealand. The cohort included more than 1,000 individuals who were followed from birth to adulthood. At age 38, the subjects underwent retinal imaging. The researchers compared the retinal imaging results of 27 individuals who had developed schizophrenia with those of individuals who had not and found that the former had microvascular abnormalities reflective of insufficient brain oxygen supply. ...
My research focuses on assessing oxygen tension in retinal blood vessels from phosphorescence lifetime imaging data. To acquire phosphorescence lifetime images, a diode laser at a wavelength of 532 nm is expanded to a line with a cylindrical lens and focused at an oblique angle on the retina following intravenous injection of an oxygen-sensitive molecular probe. The level of retinal oxygenation is thought to play a significant role in retinal diseases, such as diabetic retinopathy and vascular occlusions. Imaging oxygen tension in the retinal vasculatures will provide information on fundamental mechanisms that implicate hypoxia in the development of retinal pathologies. The long-term goal of this project is to broaden knowledge of disease patho-physiology, and thereby advance diagnostic and therapeutic procedures ...
Having high levels of uncontrolled sugar in your blood can/will cause a blockage of the tiny blood vessels that bring oxygen to the retina. When the retina does not receive enough oxygen, the body will try to remedy this issue by producing new blood vessels which do not develop properly and may leak. People with untreated diabetes have a 25 per cent higher risk for blindness.. There are four types/progressive levels of diabetic retinopathy:. Early/mild diabetic retinopathy (nonproliferative diabetic retinopathy (NPDR). Nonproliferative means that new blood vessels are not growing or proliferating. This type of retinopathy is the most common form with the walls of the blood vessels in the retina becoming weak. There may be microaneurysms (tiny bulges in the walls of the blood vessels) which will leak blood and fluid into the retina. While this is occurring, the larger blood vessels may begin to dilate. As more blood vessels are involved and become blocked, NPDR progresses from mild to severe. In ...
Diabetic retinopathy (DR), one of the most common vascular complication of diabetes, is the leading cause of visual deficits and blindness around the world. The development of DR is divided into two stages: in the early stages, also called as nonproliferative stage, it is asymptomatic because the signs are not visible to the eye. however, some defects including microaneurysms, intraretinal hemorrhaging, narrowing or blocked retinal blood vessels can be seen by detection; in the second stage, known as proliferative diabetic retinopathy, where neovascularization appears at the back of the eye and extend into the vitreous of the eye, and these new blood vessels are fragile. If they leak blood, the bleeding causes shrinkage of the retina, leading to retinal detachment, and ultimately to blindness. It has been reported that vascular endothelial growth factor A, angiotensin-converting enzyme, paraoxonase, erythropoietin are associated with DR development and progression ...
Title: Retinal Blood Vessel Segmentation Using Extreme Learning Machine | Keywords: retinal image, vessel segmentation, Extreme Learning Machine (ELM), Gabor filter, Hessian matrix, bottom-hat transformation | Author: Fan Guo, Da Xiang, Beiji Zou, Chengzhang Zhu, and Shengnan Wang
Researchers used optical coherence tomography angiography to measure retinal microvascular blood flow in patients with systemic sclerosis with no clinical signs of retinal involvement.
Ocular diseases characterized by retinal neovascularization are among the principal causes of visual loss worldwide. In an effort to understand the components of the retinal angiogenesis and its regulation by various molecules, I developed a procedure to isolate retinal microvascular endothelial cells (EC) and pericytes from ...
Diabetic retinopathy is the leading cause of blindness in working-age adults. It is caused by oxygen starvation in the retina inducing aberrant formation of blood vessels that destroy retinal architecture. In humans, vitreal stromal cell-derived factor-1 (SDF-1) concentration increases as proliferative diabetic retinopathy progresses. Treatment of patients with triamcinolone decreases SDF-1 levels in the vitreous, with marked disease improvement. SDF-1 induces human retinal endothelial cells to increase expression of VCAM-1, a receptor for very late antigen-4 found on many hematopoietic progenitors, and reduce tight cellular junctions by reducing occludin expression. Both changes would serve to recruit hematopoietic and endothelial progenitor cells along an SDF-1 gradient. We have shown, using a murine model of proliferative adult retinopathy, that the majority of new vessels formed in response to oxygen starvation originate from hematopoietic stem cell-derived endothelial progenitor cells. We ...
Potential Imaging Biomarkers in the Development and Progression of Diabetic Retinopathy. By Julia Hafner, Sonja Karst and Ursula Schmidt-Erfurth. Diabetic retinopathy (DR) is the most prevalent microvascular complication of diabetes and a leading cause of preventable blindness in the working-age population. However, due to a lack of suitable biomarkers, its prediction in asymptomatic patients is insufficient. Currently, DR is diagnosed at a stage when typical morphologic lesions become fundoscopically visible. Yet, chronically elevated blood glucose levels lead to characteristic alterations in retinal vessel caliber, blood flow, oxygen saturation, and the capillary network, which precede DR lesions. Furthermore, emerging evidence suggests that retinal neurodegenerative changes occur early in diabetes, initiating a disintegration of the retinal neurovascular unit prior to the appearance of microvasculopathy in DR. This chapter will discuss recent research achievements toward understanding the ...
Our lead candidate, AXT107, is a synthetic 20-mer peptide, derived from non-collagenous sequences of the collagen IV protein. As described in our seminal publications in Science Translational Medicine and JCI Insight, AXT107 inhibits pro-angiogenic vascular endothelial growth factor receptor 2 (VEGFR2) and activates the vessel stabilizing receptor tyrosine kinase (Tie2), the two validated pathways for the treatment of retinal vascular diseases. Both mechanisms of actions are mediated by AXT107s interaction with and disruption of the VEGF co-receptors, integrin αvβ3 and integrin α5β1. AXT107 self-assembles into a gel-like depot residing below the visual axis after intravitreal injection and releasing the active drug gradually over months. This allows for AXT107 to potentially be dosed only once per year or even less frequently, rather than every 1 to 3 months as is required for currently approved therapies and those in clinical development for the treatment of retinal vascular diseases ...
Angiogenesis is essential for normal retinal development, however pathological retinal angiogenesis can lead to blindness. This occurs in conditions such as ret...
The accurate and timely monitoring of hypertension-related diseases is important for a population screening and follow up, to prevent the onset and to assure proper treatment. The evaluation of morphological characteristics of small resistance arteries in human beings in not easy. The gold standard is generally considered the evaluation of the media to lumen ratio of subcutaneous small vessels obtained by local biopsies and measured by wire or pressure micromyography. However, non-invasive techniques for evaluation of retinal arterioles were proposed, in particular two approaches seem to provide interesting information: scanning laser Doppler flowmetry and adaptive optics; both of them provide an estimation of the wall to lumen ratio (WLR) of retinal arterioles.. The Laboratory is involved in the assessment of the efficiency and efficacy of a recently developed non invasive diagnostic instrument, able to provide high-quality images of the retina, by means of adaptive optics. In collaboration ...
A congenital vascular abnormality that affects the great vessels and/or aortic arch. Representative examples include double aortic arch, aortic coarctation, and absence of a pulmonary artery.
Diabetic retinopathy is a leading cause of blindness in American adults. Its caused by changes in the blood vessels of the retina, the light sensitive layer of tissue at the back of the inner eye. In some people, retinal blood vessels may swell and leak fluid. In others, abnormal new blood vessels grow on the surface of the retina. These changes may result in vision loss or blindness.
Diabetic retinopathy is a leading cause of blindness in American adults. Its caused by changes in the blood vessels of the retina, the light sensitive layer of tissue at the back of the inner eye. In some people, retinal blood vessels may swell and leak fluid. In others, abnormal new blood vessels grow on the surface of the retina. These changes may result in vision loss or blindness.
Diabetic retinopathy is a leading cause of blindness in American adults. Its caused by changes in the blood vessels of the retina, the light sensitive layer of tissue at the back of the inner eye. In some people, retinal blood vessels may swell and leak fluid. In others, abnormal new blood vessels grow on the surface of the retina. These changes may result in vision loss or blindness.
Diabetic retinopathy is a leading cause of blindness in American adults. Its caused by changes in the blood vessels of the retina, the light sensitive layer of tissue at the back of the inner eye. In some people, retinal blood vessels may swell and leak fluid. In others, abnormal new blood vessels grow on the surface of the retina. These changes may result in vision loss or blindness.
Diabetic retinopathy is a leading cause of blindness in American adults. Its caused by changes in the blood vessels of the retina, the light sensitive layer of tissue at the back of the inner eye. In some people, retinal blood vessels may swell and leak fluid. In others, abnormal new blood vessels grow on the surface of the retina. These changes may result in vision loss or blindness.
Diabetic retinopathy is a leading cause of blindness in American adults. Its caused by changes in the blood vessels of the retina, the light sensitive layer of tissue at the back of the inner eye. In some people, retinal blood vessels may swell and leak fluid. In others, abnormal new blood vessels grow on the surface of the retina. These changes may result in vision loss or blindness.
Diabetic retinopathy is a leading cause of blindness in American adults. Its caused by changes in the blood vessels of the retina, the light sensitive layer of tissue at the back of the inner eye. In some people, retinal blood vessels may swell and leak fluid. In others, abnormal new blood vessels grow on the surface of the retina. These changes may result in vision loss or blindness.
This paper presents an efficient method for automatic segmentation of blood vessels in retinal images. A set of directional basis filters based on dyadic w
Chiquet, C., Gavard, O., MacGillivray, T. J., Bron, A. M., Semecas, R., Arnould, L., Trucco, M. & Aptel, F., 29 Jul 2019, In : Acta Ophthalmologica. 6 p.. Research output: Contribution to journal › Article. ...
Retinal vessels lack a functional sympathetic innervation. Further local responses to stretch, carbon dioxide, pH, and oxygen ... An arteriole is a small-diameter blood vessel in the microcirculation that extends and branches out from an artery and leads to ... Louwies, T; Int Panis, L; Kicinski, M; De Boever, P; Nawrot, Tim S (2013). "Retinal Microvascular Responses to Short-Term ... ISBN 0-13-981176-1. Riva, CE; Grunwald, JE; Petrig, BL (1986). "Autoregulation of human retinal blood flow. An investigation ...
A case with peculiar changes of the central retinal vessels. Acta Societatis ophthalmologicae Japonicae, Tokyo 1908, 12: 554. ... It mainly affects the aorta (the main blood vessel leaving the heart) and its branches, as well as the pulmonary arteries. ... It is now known that the blood vessel malformations that occur in the retina are an angiogenic response to the arterial ... The neurological symptoms of the disease vary depending on the degree; the nature of the blood vessel obstruction; and can ...
A case with peculiar changes of the central retinal vessels. Acta Societatis ophthalmologicae Japonicae, Tokyo 1908, 12: 554. ... Takayasu described a peculiar "wreathlike" appearance of the blood vessels in the back of the eye (retina). Two Japanese ...
Central retinal vein and/or central retinal arterial thrombosis. Small vessel thrombosis affecting one or more organs, systems ...
The transportation of all-trans-retinal back to RPE cells is not 100% efficient, and a small amount of all-trans-retinal can ... One of the consequences of diabetes is damage to blood vessels; damaged vessels are less able to carry oxygen, thus inhibiting ... In the Visual Cycle, exposure to light causes 11-cis-retinal to isomerize to all-trans-retinal (as part of the rhodopsin ... Without 11-cis-retinal, the rod photoreceptor cells no longer produce all-trans-retinol and production of A2E is halted. The ...
Characteristically, the abnormal vessels are localized and the retinal blood vessels peripheral to the abnormal ones seemingly ... In some eyes, retinal vessels form small nodules on the surface of the retina, known as angiomas. These can bleed and be ... If not treated, the retinal detachment can lead to ischemia and growth of new blood vessels over the iris and anterior chamber ... Laser coagulation or cryoablation (freezing) of the retina can be used to destroy the abnormal blood vessels. Retinal ...
There may be a few vessels (retinal or choroidal) at the edges. The surface may have irregular depression. Colobomas of the ... retinal dysplasia or retinal detachment, sensory nystagmus, cortical visual loss, and optic nerve hypoplasia. Treacher Collins ...
2013). "Regional variation in human retinal vessel oxygen saturation". Elsevier - Experimental Eye Research. 113: 143-147. doi: ...
2013). "Regional variation in human retinal vessel oxygen saturation". Exp Eye Res. 113: 143-7. doi:10.1016/j.exer.2013.06.001 ... Tunable Lasers For Retinal Imaging. Metabolic Hyperspectral Retinal Camera. F. P. Schäfer (ed.), Dye Lasers (Springer, 1990) F ... Tunable sources were recently used for the development of hyperspectral imaging for early detection of retinal diseases where a ...
ocular group: central retinal *ciliary (short posterior, long posterior, anterior). *Circulus arteriosus major ... Vessel length is the total length of the vessel measured as the distance away from the heart. As the total length of the vessel ... Vessel radius also affects the total resistance as a result of contact with the vessel wall. As the radius of the wall gets ... "Blood Vessels - Heart and Blood Vessel Disorders - Merck Manuals Consumer Version". Merck Manuals Consumer Version. Retrieved ...
The Purkinje tree is an image of the retinal blood vessels in one's own eye, first described by Purkyně in 1823.[10] It can be ... Normally the image of the retinal blood vessels is invisible because of adaptation. Unless the light moves, the image ... Another way in which the shadows of blood vessels may be seen is by holding a bright light against the eyelid at the corner of ... Light from this spot then casts shadows of the blood vessels (which lie on top of the retina) onto unadapted portions of the ...
and reduced ability of those cells to form blood vessels. Formation of additional capillaries and larger blood vessels ( ... Disorders of retinal capillaries contribute to the pathogenesis of age-related macular degeneration. Reduced capillary density ... They are short vessels that directly connect the arterioles and venules at opposite ends of the beds. Metarterioles are found ... Sinusoid blood vessels are primarily located in the bone marrow, lymph nodes,[citation needed] and adrenal glands. Some ...
... of blood vessels (for example, retinal and cerebral blood vessels) is known to be used as a medical sign. In ... A novel method for automatic evaluation of retinal vessel tortuosity. Proceedings of the 25th Annual International Conference ... Automated measurement of retinal vascular tortuosity. International Journal of Medical Informatics, Vol. 53, No. 2-3, p. 239- ... Evaluation of tortuosity of eye blood vessels using the integral of square of derivative of curvature // EMBEC'05: proceedings ...
Among all these syndromes, there exists some retinal vessel inflammation. The differences in the dots are usually in the size, ... The white dots are small and located in the posterior pole at the level of the retinal pigment epithelium (RPE). The white dots ... Ophthalmology Retina Retinal pigment epithelium [1], Tewari A, Elliot D. White Dot Syndromes. 2007. Emedicine from WebMD. ... AZOOR occurs in young to middle age adults and may eventually progress to retinal cell death. Symptoms include acute visual ...
When this occurs, blood from the retinal blood vessels can bleed into the vitreous. Retinal tear accounts for 11.4-44% of ... Abnormal blood vessels can form in the back of the eye of a person with diabetes. These new blood vessels are weaker and prone ... Some injuries can cause blood vessels in the back of the eye to bleed. Trauma is the leading cause of vitreous hemorrhage in ... Retinal tears are closed by Laser treatment or cryotherapy, and detached retinas are reattached surgically. Even after ...
CHV also causes a necrotizing vasculitis that results in hemorrhage around the blood vessels. Bruising of the belly may occur. ... Eye lesions include keratitis, uveitis, optic neuritis, retinitis, and retinal dysplasia. There is a high mortality rate, ...
It works by slowing the growth of new blood vessels. Bevacizumab was approved for medical use in the United States in 2004. It ... When used for eye disease side effects can include vision loss and retinal detachment. Bevacizumab is in the angiogenesis ...
... direct retinal damage, or occlusion of the blood vessels. The first mechanism is indirect damage by altering the blood vessels ... This can be caused by either physically blocking the vessels of the retinal artery branches or causing the arteries to narrow. ... The retina is supplied by small vessel branches from the central retinal artery. Proliferative retinopathy refers to damaged ... These pathologically overgrown blood vessels are often fragile, weak, and ineffective at perfusing the retinal tissues. These ...
In some rare cases (1%) the leukocoria is caused by Coats' disease (leaking retinal vessels). On photographs taken using a ...
... decreased foveal and retinal thickness; attenuation of retinal lamination; hyperreflectivity in the choroids (due to RPE and ... Other symptoms affecting vision may include night vision difficulties; optic disc pallor; narrow vessels; macular atrophy with ... pigment mottling; peripheral deep white dot deposits or retinal pigment epithelium (RPE) alterations in the inferonasal retina ...
External signs include dilated episcleral blood vessels (sentinel vessels). Extraocular erosion may produce a dark mass beneath ... Retinal detachment can be rarely caused by posterior extension of the tumor. Anterior uveitis is an uncommon presentation and ...
Niemeijer, M; Staal, J; Van Ginneken, B; Loog, M; Abràmoff, Michael D (2004). "Comparative study of retinal vessel segmentation ... Staal, J; Abramoff, Michael D; Niemeijer, M; Viergever, MA; van Ginneken, B (2004). "Ridge-based vessel segmentation in color ... He is inventor on 15 US and international patents and patent applications primarily related to retinal imaging. Abramoff ... Abramoff, Michael D; Garvin, Mona K; Sonka, Milan (2010). "Retinal Imaging and Image Analysis". IEEE Reviews in Biomedical ...
Glaucoma - loss of retinal ganglion cells which causes some loss of vision to blindness. Diabetic retinopathy - poor blood ... Adequate stimulus can be used to classify sensory receptors: Baroreceptors respond to pressure in blood vessels Chemoreceptors ... The first action potential occurs in the retinal ganglion cell. This pathway is the most direct way for transmitting visual ... Retinal ganglion cells are involved in the sympathetic response. Of the ~1.3 million ganglion cells present in the retina, 1-2 ...
However, the retinal pigment epithelium (RPE) rapidly becomes involved, leading to a retinal dystrophy primarily involving the ... Rarely, atrophy of the choriocapillaris and larger choroidal vessels is seen in patients at an early stage. The inclusion of ... In addition to the retinal findings, temporal pallor of the optic disc is commonly observed. As expected, visual field testing ...
These blood vessels sometimes leak, and these retinal hemorrhages may lead to the loss of central vision. Vision loss is a ... The most common problems arise in the skin and eyes, and later in blood vessels in the form of premature atherosclerosis. PXE ... It is unclear in what way this would lead to abnormalities in skin, eyes and blood vessels. It is thought that particular ... These cracks may allow small blood vessels that were originally held back by Bruch's membrane to penetrate the retina. ...
Within the fovea is a region devoid of retinal vessels known as the foveal avascular zone (FAZ). The geometric centre of the ...
Retinal vessels may tear in association with a retinal tear, or occasionally without the retina being torn. The risk of retinal ... Similarly, in some people with retinal lesions such as lattice retinal degeneration or chorio-retinal scars, the vitreous ... The risk of retinal tears and detachment associated with vitreous detachment is higher in patients with myopic retinal ... If a retinal vessel is torn, the leakage of blood into the vitreous cavity is often perceived as a "shower" of floaters. ...
During development it is through the choroidal fissure that the retinal vessels enter and leave the eye. While optic neural ... components (e.g. axons arising from retinal ganglion cells in the sensory retina) do not lie in the groove that is the choroid ...
April 2009). "Retinal vessels in patients with multiple sclerosis: baseline diameter and response to flicker light stimulation ... April 2009). "Rigidity of retinal vessels in patients with multiple sclerosis". Klin Monatsbl Augenheilkd. 226 (4): 276-9. doi: ... There is also loss of myelin-associated glycoprotein (MAG). The scars do not surround the blood vessels, and in fact, a rim of ... Pueyo V, Martin J, Fernandez J, Almarcegui C, Ara J, Egea C, Pablo L, Honrubia F (2008). "Axonal loss in the retinal nerve ...
Microscopically, the wall of retinal vessels may be thickened in some cases, while in other cases the wall may be thinned with ... In moderate to severe Coats' disease, massive retinal detachment and hemorrhage from the abnormal vessels may be seen. Imaging ... On funduscopic eye examination, the retinal vessels in early Coats' disease appear tortuous and dilated, mainly confined to the ... Just as the red-eye effect is caused by a reflection off blood vessels in the back of a normal eye, an eye affected by Coats' ...
... fasting glucose or HbA1c and complications such as retinal problems.[10] A fasting or random blood sugar is preferred over the ...
The blood vessels consist of arteries, capillaries and veins and are lined with a cellular endothelium which is quite unlike ... The lens is suspended behind the pupil and photoreceptive retinal cells cover the back of the eye. The pupil can be adjusted in ... Octopuses have a closed circulatory system, where the blood remains inside blood vessels. Octopuses have three hearts; a ... size and a retinal pigment screens incident light in bright conditions.[22] ...
Bio Diesel Powered Fast Attack Craft Of Indian Navy patrolling during IFR 2016.The green bands on the vessels are indicative of ...
Severe headaches develop and sufferers lose the ability to sit up.[4] Retinal venous dilation occurs in 59% of people with HACE ... This demonstrated that the blood-brain barrier was broken by cerebral blood vessels, thus interfering with white matter ... 5] Rarer symptoms include brisk deep tendon reflexes, retinal hemorrhages, blurred vision, extension plantar reflexes, and ...
TIA is now defined as a transient episode of neurologic dysfunction caused by focal brain, spinal cord, or retinal ischemia, ... or an occlusion occurring in the affected blood vessels due to a thrombus (thrombotic stroke) or embolus (embolic stroke).[20] ...
An angiogram will show whether the blood vessel is blocked by a clot, the blood vessel is narrowed, or if there is an ... or cardiac arrhythmias Nuchal rigidity Subhyaloid retinal hemorrhages Altered level of consciousness Anisocoria, Nystagmus ... of the blood vessels inside of your brain. It can also be used to see if you have emboli (blood clots) in your blood vessels. ... A craniotomy is sometimes done to remove blood, abnormal blood vessels, or a tumor. Medications may be used to reduce swelling ...
... retinal detachment - retinitis - retrovirus - REV - reverse transcriptase - ribonucleic acid (RNA) - ribosome - RNA - route of ... lymphatic vessels - lymphocyte - lymphoid interstitial pneumonitis (LIP) - lymphoid organs - lymphoid tissue - lymphokine- ...
In another variation the anterior communicating artery is a large vessel, such that a single internal carotid supplies both ... ocular group: central retinal *ciliary (short posterior, long posterior, anterior). *Circulus arteriosus major ... blood flow from the other blood vessels can often preserve the cerebral perfusion well enough to avoid the symptoms of ischemia ... which is also the same blood vessel that eventually feeds the circle of Willis via the vertebral artery. ...
... is a circular lymphatic-like vessel in the eye that collects aqueous humor from the anterior chamber and ... Retinal pigment epithelium. Cells. *Photoreceptor cells (Cone cell, Rod cell) → (Horizontal cell) → Bipolar cell → (Amacrine ... The canal is essentially an endothelium-lined tube, resembling that of a lymphatic vessel. On the inside of the canal, nearest ... Conventionally, the canal has been considered a blood vessel, but recent studies have revealed that the molecular identity of ...
... the formation of new blood vessels) and increased permeability (leakage from blood vessels), two of the primary pathological ... Retinal damage (extremely adverse). *Endophthalmitis (an infection inside the eye). *Vitreous haemorrhage (bleeding inside of ... This then reduces the growth of the blood vessels located within the eye and works to control the leakage and swelling.[2] ...
... is an ocular disease characterized by inflammation and possible blockage of retinal blood vessels, abnormal growth of new blood ... vessels (neovascularization), and recurrent retinal and vitreal hemorrhages. Eales' disease with a characteristic clinical ... Patients are often asymptomatic in the initial stages of retinal perivasculitis. Some patients may develop symptoms such as ... 3. Vitreoretinal surgery is required for nonresolving vitreous haemorrhage and tractional retinal detachment. •If active TB ...
retinal dehydrogenase activity. • allyl-alcohol dehydrogenase activity. • NADP-retinol dehydrogenase activity. Cellular ... blood vessels, lung, and liver.[8] It is a reduced nicotinamide-adenine dinucleotide phosphate (NADPH)-dependent enzyme ... It has been reported that he action of AR contributes to the activation of retinal microglia, suggesting that inhibition of AR ... Sato S, Lin LR, Reddy VN, Kador PF (August 1993). "Aldose reductase in human retinal pigment epithelial cells". Experimental ...
... while observing the retinal vessels through an ophthalmoscope. The pressure is gradually increased until the central retinal ... The approach worked on measuring ICP non-invasively by assessing changes in the retinal blood flow. However this is dependent ... The TCD measures the velocity of blood flow through the major intracranial vessels by emitting a high frequency (,2MHz) wave ... 2. Ophthalmodynamometry or the measurement of the retinal venous outflow pressure (VOP)[edit]. is performed by applying ...
... mainly due to vasodilation of the peripheral small blood vessels), swelling of the conjunctiva, itching, and increased ... Ocular ischemic syndrome / Central retinal vein occlusion. *Central retinal artery occlusion. *Branch retinal artery occlusion ...
The skin there is well supplied with blood vessels and helps the bird in incubation.[109] ... "The molecular basis for UV vision in birds: spectral characteristics, cDNA sequence and retinal localization of the UV- ...
Collin, S. P. (2010). "Evolution and Ecology of Retinal Photoreception in Early Vertebrates". Brain, Behavior and Evolution. 75 ... of cynodonts as channels that supplied blood vessels and nerves to vibrissae (whiskers) and suggested that this was evidence of ...
... retinal pigment epithelium, hepatocytes, mesangial cells in the kidney, endometrial cells, cervical cells and vaginal ... especially the delicate blood filtering vessels of the kidneys, causing kidney damage. Iron is removed from heme and salvaged ... degraded hemoglobin protein or hemoglobin that has been released from the blood cells too rapidly can clog small blood vessels ...
... the middle cervical ganglion resting upon the vessel. ... ocular group: central retinal *ciliary (short posterior, long ...
"DRIVE: Digital Retinal Images for Vessel Extraction". Image Sciences Institute, Utrecht University. Retrieved 20 April 2018.. ... Retinal diseases in dogs include retinal dysplasia, progressive retinal atrophy, and sudden acquired retinal degeneration. ... When light strikes 11-cis-retinal (in the disks in the rods and cones), 11-cis-retinal changes to all-trans-retinal which then ... Retinal vessel analysis is a non-invasive method to examine the small arteries and veins in the retina which allows to draw ...
The left image (right eye) shows lighter areas close to larger vessels, which has been regarded as a normal finding in younger ... are important to screen for diabetic retinopathy as visual loss due to diabetes can be prevented by retinal laser treatment if ... is done as part of a routine physical or complete eye examination.It is used to detect and evaluate symptoms of various retinal ...
Thus, carbon monoxide may have a physiological role in the body, such as a neurotransmitter or a blood vessel relaxant.[35] ... Some descriptions of carbon monoxide poisoning include retinal hemorrhages, and an abnormal cherry-red blood hue.[32] In most ...
... toads in an untextured surrounding cannot distinguish between the retinal image of a small moving object and the retinal image ... He then rotated a small stripe (bar) of contrasting cardboard (acting as a visual 'dummy') around the vessel to mimic either ... Their response characteristic results from integration in a neuronal network involving retinal gangion cells R2, R3, R4, ... In a textured surrounding, however, the induced moving retinal image is ignored. ...
Lee, K. E.; Klein, B. E. K.; Klein, R.; Meuer, S. M. (2007). "Association of Retinal Vessel Caliber to Optic Disc and Cup ... The central retinal artery (retinal artery) branches off the ophthalmic artery, running inferior to the optic nerve within its ... The central retinal artery is formed from the proximal part of the hyaloid artery after atrophy of its distal part has formed ... The central retinal artery supplies all the nerve fibers that form the optic nerve, which carries the visual information to the ...
ocular group: central retinal *ciliary (short posterior, long posterior, anterior). *Circulus arteriosus major ... vessels to semilunar ganglion. *superficial petrosal branch. *superior tympanic artery. *Orbital branches ...
Medium vessel vasculitis[edit]. These conditions are sometimes considered together with the small vessel vasculitides.[11] ... Retinal hemorrhages. *Neurological abnormalitis. *Treatment: steroids. Giant cell (temporal) arteritis. Chronic vasculitis of ... Small vessel vasculitis[edit]. There are several vasculitides that affect small vessels.[12] ... Seo P, Stone JH (December 2007). "Small-vessel and medium-vessel vasculitis". Arthritis Rheum. 57 (8): 1552-9. doi:10.1002/art. ...
... these vessels are placed one on either side of the frenulum linguæ. ... ocular group: central retinal *ciliary (short posterior, long posterior, anterior). *Circulus arteriosus major ... anastomosing with the vessels of the opposite side. ...
"Melanopsin-Expressing Retinal Ganglion-Cell Photoreceptors: Cellular Diversity and Role in Pattern Vision". Neuron. 67 (1): 49 ...
... and surgery to repair retinal detachment). Other biomedical companies also produce brands of hyaluronan for ophthalmic surgery. ... saw evidence that the host and engineered vessels joined within 2 weeks of implantation, indicating viability and functionality ...
"Sheets of retinal cells used by the team are harvested from aborted fetuses, which some people find objectionable." When these ... It will fuse with the jawbone and release chemicals that encourage nerves and blood vessels to connect with it. The process is ... Stem cells were also able to restore sight in one eye of a horse with retinal detachment, allowing the horse to return to daily ...
There are two types of retinal blood vessels, arteries and veins. Either of these can become blocked and each of them can ... The visual loss caused by retinal vein and artery occlusions is painless. It is usual for only one eye to be involved at a time ... A retinal vessel occlusion is a blockage in the blood vessel of your eye that can result in sight loss. ... Retinal vessel occlusion A retinal vessel occlusion is a blockage in the blood vessel of your eye that can result in sight loss ...
Retinal neovascularization occurs when the retina is deprived of oxygen. New blood vessels grow into the retina to increase the ... Research Provides Insight On A Leading Cause Of Blindness-Blocking Hormone Reduces Formation Of New Retinal Blood Vessels, May ... Research Provides Insight On A Leading Cause Of Blindness-Blocking Hormone Reduces Formation Of New Retinal Blood Vessels, May ... caused retinal neovascularization, an abnormal growth of new blood vessels that can destroy sight. Furthermore, they found that ...
Automated measurement of retinal blood vessel tortuosity Author(s): Vinayak Joshi; Joseph M. Reinhardt; Michael D. Abramoff ... The three-dimensional retinal vascular pattern is mostly formed congenitally, but is then modified over life, in response to ... We developed a new quantitative metric for vascular tortuosity, based on the vessels angle of curvature, length of the curved ... Abnormalities in the vascular pattern of the retina are associated with retinal diseases and are also risk factors for systemic ...
... the issue of automated analysis of retinal images is gaining more serious attention. We consider the problem of retinal vessel ... Automated segmentation of retinal blood vessels in spectral domain optical coherence tomography scans Matthäus Pilch, Yaroslava ... Automated segmentation of retinal blood vessels and identification of proliferative diabetic retinopathy Herbert F. Jelinek, ... Donald A. Adjeroh, Umasankar Kandaswamy, and J. Vernon Odom, "Texton-based segmentation of retinal vessels," J. Opt. Soc. Am. A ...
We used semi-automated computer software to analyze vessel diameters on baseline retinal photos. Calibers of all vessels ... Retinal vessel calibers have been associated with the presence of microvascular complications but their long-term predictive ... Retinal Vessel Calibers Predict Long-term Microvascular Complications in Type 1 Diabetes Mellitus: The Danish Cohort of ... We examined retinal vessel calibers as 16-year predictors of diabetic nephropathy, neuropathy and proliferative retinopathy in ...
Systemic VEGF blockade does not alter retinal vessels ultrastructure or choriocapillaris fenestration.(A) TEM of a microvessel ... pone-0003554-g003: Systemic VEGF blockade does not alter retinal vessels ultrastructure or choriocapillaris fenestration.(A) ... pone-0003554-g003: Systemic VEGF blockade does not alter retinal vessels ultrastructure or choriocapillaris fenestration.(A) ... Carried out the analysis of retinal function via electroretinograms (Figure 5): ES. Participated in immunohistochemistry, ...
... and propose a novel and accurate method for segmenting retinal vessels. Our goal is to be able to segment blood vessels with ... Automated and accurate segmentation of the retinal blood vessel tree is one of the challenging tasks in the computer-aided ... All recent authors compare their vessel segmentation results to each other using only low-resolution retinal image databases. ... Our performance evaluation shows that the proposed blood vessel segmentation approach is at least comparable with recent state- ...
Retinal Vessels Attenuated & Retinopathy Symptom Checker: Possible causes include Hypertension. Check the full list of possible ... adhesions Retinal arteries attenuated Retinal collateral vessels Retinal depigmentation Retinal deposits Retinal fold Retinal ... ischemia from attenuation of the retinal vessels or exudation from incompetent retinal vessels. [retinatoday.com] ... pigmentary retinal degeneration attenuation of retinal blood vessels retinal atrophy night [malacards.org] ...
In order to extract the blood vessels contours of different diameters to realize fine segmentation of retinal vessels, we ... But the traditional manual method of retinal blood vessel segmentation is not only time-consuming and laborious but also cannot ... In addition, to increase the multi-scale feature representation of retinal blood vessels, we propose the Dense Dilated ... Therefore, it is especially significant to create a computer-aided method of automatic and accurate retinal vessel segmentation ...
The retinal blood vessel segmentation for small and low contrast vessels is still a challenging problem. To solve this problem ... Segmentation of Retinal Blood Vessels Based on Cake Filter. Xi-Rong Bao, Xin Ge, Li-Huang She, and Shi Zhang ... Segmentation of retinal blood vessels is significant to diagnosis and evaluation of ocular diseases like glaucoma and systemic ... Then the real component fusion is used to separate the blood vessel from the background. Finally, the blood vessel network is ...
retinal vessel diameter [ Time Frame: 5 minutes ]. Secondary Outcome Measures : *retinal vessel reflectivity [ Time Frame: 5 ... Retinal blood flow measurement is of scientific and clinical value. For this purpose retinal vessel morphology (such as ... Multimodal Imaging of Retinal Vessels (MIR). The safety and scientific validity of this study is the responsibility of the ... Retinal Blood Vessels Age-Related Macular Degeneration Device: Optical coherence tomography Device: Fluorescein angiography ...
Prospective cohort study of retinal vessel diameters and risk of hypertension BMJ 2004; 329 :79 ... LDH designed the method of measuring retinal vessel diameters and critically reviewed the paper. TYW is guarantor. ... Prospective cohort study of retinal vessel diameters and risk of hypertension - August 12, 2004 ... Prospective cohort study of retinal vessel diameters and risk of hypertension. BMJ 2004; 329 doi: https://doi.org/10.1136/bmj. ...
In RP patients, the severity of visual field loss is correlated with retinal vessel attenuation. Quantitative retinal vessel ... Retinal vessel calibers were measured using a computer-based program as the central retinal artery and vein equivalent (CRAE ... Quantitative analysis of retinal vessel attenuation in eyes with retinitis pigmentosa.. Ma Y1, Kawasaki R, Dobson LP, Ruddle JB ... Retinal vessel attenuation is a key finding in the diagnosis of retinitis pigmentosa (RP), but there have been no studies to ...
Prospective cohort study of retinal vessel diameters and risk of hypertension BMJ 2004; 329 :79 ... Prospective cohort study of retinal vessel diameters and risk of hypertension. BMJ 2004; 329 doi: https://doi.org/10.1136/bmj. ...
Macular Retinal Vessel Oxygen Saturation Elevation in Chinese Central Serous Chorioretinopathy. Cheng Li,1 Xiaoxiao Feng,1 Xin ... To evaluate the retinal vessel oxygen saturation in central serous chorioretinopathy (CSC) cases among the Chinese. Methods. ... Relative oxygen saturation of retinal blood vessels was measured in 33 Chinese patients with single-eye CSC using the Oxymap T1 ... The mean saturation of the retinal arteriole (AS) and venule (VS), arteriovenous difference (AVS), and arteriole and venule ...
Higher blood pressure is connected to narrowing of retinal arterioles in young children, according to a study published online ... Blood Pressure, Retinal Vessel Diameters Connected in Children. MONDAY, June 29, 2020 -- Higher blood pressure is connected to ... Standardized protocols were used to screen 391 children aged 6 to 8 years for BP and retinal vessel diameters in 2014. In 2018 ... "Assessment of retinal microvascular health along with BP monitoring can improve cardiovascular risk stratification in early ...
The extraction of retinal vessels in pediatric retinal images is... ... Purpose Automatic segmentation of the retinal vasculature is a first step in computer-assisted diagnosis and treatment planning ... The extraction of retinal vessels in pediatric retinal images is challenging because of comparatively wide arterioles with a ... A method of vessel tracking for vessel diameter measurement on retinal images. In: Image processing, 2001. Proceedings. 2001 ...
Retinal vessel detection is an essential part of the computer-aided diagnosis of eye diseases. Due to non-perfect imaging ... Nonlinear retinal image enhancement for vessel detection Author(s): Xiaohong Wang; Xudong Jiang ... This work proposes a two-step nonlinear retinal image enhancement to compensate for those imperfections of retinal images. The ... Classification on the feature vector extracted from the enhanced retinal images is performed by using a linear SVM classifier. ...
Correctly identifying the retinal vessel map is a crucial step in disease identification, severity progression assessment, and ... The proposed method is observed to obtain a sensitivity of 0.8043, 0.8011, and 0.7974 for the Digital Retinal Images for Vessel ... This study proposes a directional multi-scale line detector technique for the segmentation of retinal vessels with the prime ... Techniques based on unsupervised learning methods utilize vessel morphology to classify vessel pixels. ...
Detection of Retinal Blood Vessel using Kirsch algorithm Nithin N, Anupkumar M Bongale and Jayakrishna R Abstract-This paper ... Fig 5 Retinal Blood Vessel Segmentation results of glaucomatous patients. © 2013 Journal of Computing Press, NY, USA, ISSN 2151 ... where all vessel pixels are set to one and all non-vessel pixels are assigned to zero. The standard classifications of a vessel ... Since the retinal blood vessels can be considered as required foreground information from fundus images, Kirsch algorithm can ...
Blood vessels usually have poor local contrast, and the application of existing edge detection algorithms yield results which ...
PubMed journal article Retinal vessel diameter and open-angle glaucoma: the Blue Mountains Eye Stud were found in PRIME PubMed ... Retinal vessel diameter and open-angle glaucoma: the Blue Mountains Eye Study.. Ophthalmology 2005; 112(2):245-50O ... "Retinal Vessel Diameter and Open-angle Glaucoma: the Blue Mountains Eye Study." Ophthalmology, vol. 112, no. 2, 2005, pp. 245- ... Retinal Vessel Diameter and Open-angle Glaucoma: the Blue Mountains Eye Study. Ophthalmology. 2005;112(2):245-50. PubMed PMID: ...
Location of Central Retinal Vessel Trunk Exit and Parapapillary Atrophy Jonas, JB (Dept. Ophthalmology, Friedrich-Alexander ... We determined the position of the central retinal vessel trunk exit on the lamina cribrosa surface and measured the area of ... The longer is the distance to the central retinal vessel trunk exit, the more enlarged is parapapillary atrophy and the smaller ... To evaluate whether the position of the central retinal vessel trunk exit on the lamina cribrosa spatially correlates with the ...
The fluorescence of FITC-dextran in small retinal vessels was too weak at 1 s and 2 s, but the retinal vessels were fully ... A: The retinal flatmount of a P17 oxygen-induced retinopathy mouse shows the fluorescence of small retinal vessels, avascular ... The total retinal vessels in P17 OIR mice could be fully observed under a fluorescence microscope 3 s after RO injection of FITC ... Retro-orbital injection of FITC-dextran is an effective and economical method for observing mouse retinal vessels.. Li S1, Li T ...
Retinal vessel segmentation is a critical procedure towards the accurate visualization, diagnosis, early treatment and surgery ... The Relationship Between Retinal Vessel Oxygenation and Spatial Distribution of Retinal Nonperfusion in Retinal Vascular ... Summary of "A Global and Local Enhanced Residual U-Net for Accurate Retinal Vessel Segmentation.". Retinal vessel segmentation ... Multimodal Imaging of Retinal Vessels. Retinal blood flow measurement is of scientific and clinical value. For this purpose ...
The automatic segmentation of blood vessels in retinal images is the crucial stage in any retina diagnosis systems. This ... A New Heuristic Function of Ant Colony System for Retinal Vessel Segmentation: 10.4018/978-1-5225-0571-6.ch083: ... "A New Heuristic Function of Ant Colony System for Retinal Vessel Segmentation." Medical Imaging: Concepts, Methodologies, Tools ... "A New Heuristic Function of Ant Colony System for Retinal Vessel Segmentation." In Medical Imaging: Concepts, Methodologies, ...
Using the computer-based Interactive Vessel Analysis program, central retinal artery equivalent (CRAE) and central retinal vein ... Keywords: retinitis pigmentosa, retinal vascular caliber, central retinal artery equivalent, central retinal vein equivalent ... Retinal vessel caliber is associated with some visual functions in patients with RP. ... To investigate the association between visual changes and retinal vessel attenuation in patients with retinitis pigmentosa (RP ...
Automated segmentation of retinal blood vessels in spectral domain optical coherence tomography scans Matthäus Pilch, Yaroslava ... We present a 3D reconstruction of retinal blood vessel trees using two views of fundus images. The problem is addressed by ... M. E. Martinez-Perez and A. Espinosa-Romero, "3D Reconstruction of Retinal Blood Vessels From Two Views," in Proceedings of the ... M. E. Martinez-Perez and A. Espinosa-Romero, "3D Reconstruction of Retinal Blood Vessels From Two Views," in Proceedings of the ...
ICD-10-PCS code 08UH0JZ for Supplement Left Retinal Vessel with Synthetic Substitute, Open Approach is a medical classification ...
Retinal vessel calibre measurements by optical coherence tomography angiography. British Journal of Ophthalmology 2017;101:989- ...
ICD-10-PCS code 08UH37Z for Supplement Left Retinal Vessel with Autologous Tissue Substitute, Percutaneous Approach is a ...
A blood vessel spur pruning method has been developed for removing the blood vessel spurs both on vessel medial lines and ... Improvement of retinal blood vessel detection by spur removal and Gaussian matched filtering compensation Author(s): Di Xiao; ... In this paper, we proposed approaches for improving the quality of blood vessel detection based on our initial blood vessel ... Retinal photography is a non-invasive and well-accepted clinical diagnosis of ocular diseases. Qualitative and quantitative ...
... but whether retinal vessels are altered is unknown. The aim of this study was to evaluate retinal vessel morphology in patients ... Increased number of retinal vessels in acromegaly. Publication. Publication. European Journal of Endocrinology , Volume 182 - ... Methods: Retinal vessel morphology of 26 patients with acromegaly was examined at diagnosis and 1 year after treatment and ... Increased number of retinal vessels in acromegaly. European Journal of Endocrinology, 182(3), 293-302. doi:10.1530/EJE-19-0778 ...
What is retinal blood vessels? Meaning of retinal blood vessels medical term. What does retinal blood vessels mean? ... Looking for online definition of retinal blood vessels in the Medical Dictionary? retinal blood vessels explanation free. ... of the tortuosity of retinal blood vessels, decreased mobility of vitreous gel, retinal stiffness, and rolled edges of retinal ... retinal blood vessels. ret·i·nal blood ves·sels. [TA] the blood vasculature of the retina, including the branches and ...
The ability to cannulate a retinal blood vessel should be efficacious in the treatment of vein and artery occlusion, ocular ... The micropipette is connected to tubing such that a medication may be injected through the micropipette into the blood vessel ... tumors and other retinal, vascular and optic nerve disorders that would benefit from diagnosis and/or treatment. ... or conversely, a small quantity of material may be removed from a blood vessel. Alternatively, a catheter, wire or stent may be ...
  • Retinal neovascularization occurs when the retina is deprived of oxygen. (eurekalert.org)
  • New blood vessels grow into the retina to increase the amount of oxygen. (eurekalert.org)
  • These blood vessels can cause scarring and bleeding, leading to a detached retina and blindness. (eurekalert.org)
  • After 14 days of VEGF neutralization, there was no effect on the inner and outer retina vasculature, but a significant increase in apoptosis of cells in the inner and outer nuclear layers.By four weeks, the increase in neural cell death was associated with reduced thickness of the inner and outer nuclear layers and a decline in retinal function as measured by electroretinograms. (nih.gov)
  • In order to extract the blood vessels' contours of different diameters to realize fine segmentation of retinal vessels, we propose a Bidirectional Symmetric Cascade Network (BSCN) where each layer is supervised by vessel contour labels of specific diameter scale instead of using one general ground truth to train different network layers. (biomedcentral.com)
  • In addition, to increase the multi-scale feature representation of retinal blood vessels, we propose the Dense Dilated Convolution Module (DDCM), which extracts retinal vessel features of different diameters by adjusting the dilation rate in the dilated convolution branches and generates two blood vessel contour prediction results by two directions respectively. (biomedcentral.com)
  • Using a weak statistical learning approach, we construct textons for retinal vasculature by designing filters that are specifically tuned to the structural and photometric properties of retinal vessels. (osapublishing.org)
  • Led by Lois E.H. Smith, of Children's Hospital in Boston and Harvard Medical School, the scientists demonstrated that a well-known hormone, called growth hormone (GH), caused retinal neovascularization, an abnormal growth of new blood vessels that can destroy sight. (eurekalert.org)
  • Retinal neovascularization afflicts people of all ages. (eurekalert.org)
  • We investigated the retinal microvasculature in Alzheimer's disease (AD) and mild cognitive impairment (MCI) using optical coherence tomography angiography (OCTA). (biomedcentral.com)
  • OCTA images of the superficial and deep capillary plexus (SCP, DCP) of the retinal microvasculature were obtained using a commercial OCTA system (Zeiss Cirrus HD-5000 with AngioPlex, Carl Zeiss Meditec, Dublin, CA). The main outcome measures were vessel density (VD) and fractal dimension (FD) in the SCP and DCP within a 2.5-mm ring around the fovea which were compared between groups. (biomedcentral.com)
  • Changes in the retinal microvasculature and capillary network may offer a valuable insight on the brain in AD. (biomedcentral.com)
  • Retinal blood vessel segmentation has an important guiding significance for the analysis and diagnosis of cardiovascular diseases such as hypertension and diabetes. (biomedcentral.com)
  • Current medical research shows that the abnormality of retinal vascular is not only manifested in ophthalmic diseases such as glaucoma and cataract but also directly related to the severity of cardiovascular diseases such as hypertension, coronary heart disease, diabetes, atherosclerosis [ 2 ]. (biomedcentral.com)
  • The experimental results show that compared with the state-of-art methods, the proposed method has strong robustness, it not only avoids the adverse interference of the lesion background but also detects the tiny blood vessels at the intersection accurately. (biomedcentral.com)
  • Aiming at the above problems, many researchers proposed to adopt deep learning methods for retinal blood vessel segmentation. (biomedcentral.com)
  • However, due to the difference in morphological scale in diameter, tortuosity, branching pattern or angles of the blood vessels, most methods can segment the thick and obvious blood vessels, but cannot segment the tiny blood vessels accurately. (biomedcentral.com)
  • It is important to highlight that these retinal changes in AD will require confirmation in studies with comparable methods in patient selection, scanning protocols, and analyses. (biomedcentral.com)
  • Conclusions: Middle-aged African Americans with generalized and focal retinal arteriolar narrowing were more likely to have LVH. (monash.edu)
  • Systemic VEGF blockade does not alter retinal vessels ultrastructure or choriocapillaris fenestration. (nih.gov)
  • We consider the problem of retinal vessel segmentation, a key issue in automated analysis of digital fundus images. (osapublishing.org)
  • We propose a texture-based vessel segmentation algorithm based on the notion of textons. (osapublishing.org)
  • But the traditional manual method of retinal blood vessel segmentation is not only time-consuming and laborious but also cannot guarantee the accuracy and efficiency of diagnosis. (biomedcentral.com)
  • Therefore, it is especially significant to create a computer-aided method of automatic and accurate retinal vessel segmentation. (biomedcentral.com)
  • All dense dilated convolution module outputs are fused to obtain the final vessel segmentation results. (biomedcentral.com)
  • Therefore, the research of retinal vessel segmentation technology is helpful to automatically and quickly obtain the morphological structure of blood vessels in retinal images and has extremely crucial clinical significance and practical value for assistant diagnosis and treatment of various related diseases [ 4 ]. (biomedcentral.com)
  • As shown in Fig. 1 , the manual segmentation results of the same retinal image by the two experts are not the same. (biomedcentral.com)
  • Generally speaking, the traditional manual method of retinal blood vessel segmentation is not only time-consuming and laborious but also cannot guarantee the accuracy and efficiency of diagnosis [ 6 ]. (biomedcentral.com)
  • Comparison of two manual segmentation results of the retinal. (biomedcentral.com)
  • Perfusion density of large vessels and foveal avascular zone (FAZ) area were additional outcome parameters. (biomedcentral.com)
  • By four weeks, the increase in neural cell death was associated with reduced thickness of the inner and outer nuclear layers and a decline in retinal function as measured by electroretinograms. (nih.gov)
  • In fact, Retinal vessel disease in the fundus is one of the vital causes of blindness and many can be prevented in advance by fundus retinal examination among a large number of irreversible blinding diseases. (biomedcentral.com)
  • The assessment of transformations in the retinal vascular structure has a strong potential in indicating a wide range of underlying ocular pathologies. (mdpi.com)
  • These population-based data suggest that generalized retinal arteriolar narrowing, an indicator of localized vascular change, is significantly associated with optic nerve damage caused by OAG. (unboundmedicine.com)
  • The Relationship Between Retinal Vessel Oxygenation and Spatial Distribution of Retinal Nonperfusion in Retinal Vascular Diseases. (bioportfolio.com)
  • We study the relationship between retinal vessel oxygenation and the spatial distribution of retinal nonperfusion using ultrawide field angiography in eyes with retinal vascular diseases. (bioportfolio.com)
  • Abnormalities in the vascular pattern of the retina are associated with retinal diseases and are also risk factors for systemic diseases, especially cardiovascular diseases. (spie.org)
  • The three-dimensional retinal vascular pattern is mostly formed congenitally, but is then modified over life, in response to aging, vessel wall dystrophies and long term changes in blood flow and pressure. (spie.org)
  • A characteristic of the vascular pattern that is appreciated by clinicians is vascular tortuosity, i.e. how curved or kinked a blood vessel, either vein or artery, appears along its course. (spie.org)
  • We developed a new quantitative metric for vascular tortuosity, based on the vessel's angle of curvature, length of the curved vessel over its chord length (arc to chord ratio), number of curvature sign changes, and combined these into a unidimensional metric, Tortuosity Index (TI). (spie.org)
  • Our results show that TI has potential to detect and evaluate abnormal retinal vascular structure in early diagnosis and prognosis of retinopathies. (spie.org)
  • Conclusions: Patients with acromegaly have an increased number of vascular branching points in the retina without an alteration of macroscopic vessel morphology. (eur.nl)
  • Retinal blood vessels typically appear tortuous, with most vascular occlusions associated with sickle retinopathy arising in the periphery of the retina where the vessels are narrowest. (thefreedictionary.com)
  • Retinal vascular calibres can be measured non-invasively using retinal photographs. (biomedcentral.com)
  • While the AVR is a poor marker of vascular changes at the retinal level [ 3 , 4 ], CRAE and CRVE have been shown more clinically useful. (biomedcentral.com)
  • CRAE and CRVE are more commonly used rather than using individual vessel calibres when examining their associations with vascular pathology. (biomedcentral.com)
  • The aim of this study was to assess the early pathological changes in retinal morphology and neuronal, inflammatory and vascular features consistent with diabetic retinopathy in the ob/ob mouse model of type 2 diabetes, to investigate whether features similar to those in human diabetic retinopathy were present. (springer.com)
  • The inflammation might damage retinal capillaries through the generation of reactive oxygen species, occlusion of vessels by leukostasis, promotion of retinal vascular leakage, and induction of endothelial cell death ( 1 , 14 - 16 ). (diabetesjournals.org)
  • From the presentations and discussions at the workshop emerged that, to date, changes in retinal vascular caliber appear to be among the earliest changes detected in the retina in diabetes. (diabetesjournals.org)
  • In this review we will focus on retinal vascular caliber as a potential biomarker for the three major microvascular complications of diabetes: retinopathy, nephropathy, and neuropathy. (diabetesjournals.org)
  • Zerumbone displayed similar characteristics to fenofibric acid in reducing retinal vascular permeability and leukostasis in diabetic rats. (mdpi.com)
  • The level of retinal oxygenation is thought to play a significant role in retinal diseases, such as diabetic retinopathy and vascular occlusions. (uic.edu)
  • Mice with Socs3 deficiency in neuronal and glial cells had substantially reduced vaso-obliterated retinal areas and increased pathological retinal neovascularization in response to oxygen-induced retinopathy, suggesting that loss of neuronal/glial SOCS3 increased both retinal vascular regrowth and pathological neovascularization. (sciencemag.org)
  • Furthermore, retinal expression of Vegfa (which encodes vascular endothelial growth factor A) was higher in these mice than in Socs3 flox/flox controls, indicating that neuronal and glial SOCS3 suppressed Vegfa expression during pathological conditions. (sciencemag.org)
  • At the end of the 24-week treatment, the retinas were isolated for histopathological examination under a light microscope, transmission electron microscopy, and determination of the retinal tumor necrosis factor-α (TNF-α), nuclear factor-kappa B (NF-κB), and vascular endothelial growth factor (VEGF) levels. (molvis.org)
  • Oral administration of the ginger extract resulted in significant reduction of hyperglycemia, the diameter of the retinal vessels, and vascular basement membrane thickness. (molvis.org)
  • Interestingly, retinal expression of APJ mRNA is observed during the formation of retinal vessels and traces the centrifugal extension of the superficial vasculature bed, whereas that of apelin mRNA is localized in "tip cells," an endothelial subpopulation that forms cell protrusions and directs the polarized extension of the vascular network. (ahajournals.org)
  • 13 Retinal astrocytes detect physiological levels of hypoxia and respond by secreting vascular endothelial growth factor (VEGF). (ahajournals.org)
  • VEGF induced by hypoxia inducible factor-1 (HIF-1) is a prerequisite for normal retinal vascular extension. (ahajournals.org)
  • 16,17 Knockout of insulin-like growth factor I (IGF-I) prevents normal retinal vascular growth even in the presence of VEGF, indicating that IGF-I (and perhaps other factors) is necessary for VEGF function. (ahajournals.org)
  • In their new paper, the researchers show that if they add key elements, including human endothelial cells, which line the inside of blood vessels, and human pericyte cells, which wrap around the endothelial cells, with animal collagen and other structural cells typically found in a skin graft, the cells start communicating and forming a biologically relevant vascular structure within the span of a few weeks. (genengnews.com)
  • 2005). Retinal vascular image analysis as a potential screening tool for cerebrovascular disease: a rationale based on homology between cerebral and retinal microvasculatures. (core.ac.uk)
  • Reflectance-compensated retinal vessel densities were calculated on projection-resolved superficial vascular complex (SVC), intermediate capillary plexus (ICP), and deep capillary plexus (DCP). (elsevier.com)
  • Using a multimodal imaging approach, the authors show retinal pigment epithelium restoration after a triple retinal pigment epithelium tear in an eye with neovascular age-related macular degeneration receiving continuous intravitreal anti-vascular endothelial growth factor therapy over an 8-year follow-up. (lww.com)
  • Filopodia extension in dll4 +/− retinal vessels required the vascular growth factor VEGF and was inhibited when VEGF signaling was blocked. (pnas.org)
  • Taken together, these data reveal Dll4 as a negative regulator of vascular sprouting and vessel branching that is required for normal vascular network formation during development. (pnas.org)
  • Retinal hypoxia poses a threat not only to the retinal tissue but can also act as stimulus initiating neovascularization in ocular pathologies, such as diabetic retinopathy (DR), age-related macular degeneration, and vascular occlusions. (arvojournals.org)
  • The aberrant vessels in the Vldlr −/− retinas, which invade normally avascular photoreceptors, are reminiscent of the vascular defects in retinal angiomatous proliferation, a subset of neovascular age-related macular degeneration (AMD) 7 , which is associated with high vitreous VEGFA levels in humans. (nature.com)
  • Figure 1: Retinal energy deficits are associated with vascular lesions in Vldlr −/− mice. (nature.com)
  • This study demonstrates an impairment in retinal vascular autoregulation in response to raised systemic blood pressure in diabetic subjects, more so at an elevated blood glucose level, thus providing a mechanism for the detrimental effect of hypertension on diabetic retinopathy. (nih.gov)
  • Current medical research shows that the abnormality of retinal vascular is not only manifested in ophthalmic diseases such as glaucoma and cataract but also directly related to the severity of cardiovascular diseases such as hypertension, coronary heart disease, diabetes, atherosclerosis [ 2 ]. (biomedcentral.com)
  • The morphometric characteristics of the retinal vascular network have been associated with risk markers of many systemic and vascular diseases. (qub.ac.uk)
  • A more precise assessment could be achieved by measurements of the vessels calibers directly and by characterization of this parameter in health status, and several vascular disorders. (umfcluj.ro)
  • Fundus photography appearance and formula calculation are described to systematize this novel approach of vascular risk factors based on retinal vessels caliber and branching pattern. (umfcluj.ro)
  • It appears that retinal blood vessels not only have sites to bind acetylcholine, perhaps to mediate physiologic responses, but might be capable of supplying acetylcholine for local vascular tone control. (elsevier.com)
  • Since astrocyte precursor cells did not populate the retina, retinal vascular progenitors could not form a network of vessels. (scilifelab.se)
  • Abstract-This paper presents a new method for detecting and extracting blood vessels in retinal fundus images using Kirsch edge detection algorithm. (scribd.com)
  • abstract = "Blood vessels from human, cat, pig and bovine retinas were analyzed for their contents of choline acetyltransferase (ChAT) and muscarinic binding sites. (elsevier.com)
  • Conclusions Narrowed retinal arterioles are associated with long term risk of hypertension, suggesting that structural alterations of the microvasculature may be linked to the development of hypertension. (bmj.com)
  • MONDAY, June 29, 2020 -- Higher blood pressure is connected to narrowing of retinal arterioles in young children, according to a study published online June 29 in Hypertension . (drugs.com)
  • The extraction of retinal vessels in pediatric retinal images is challenging because of comparatively wide arterioles with a light streak running longitudinally along the vessel's center, the central vessel reflex. (springer.com)
  • Oxygen saturation in retinal blood vessels is higher in dark than in 80 or 100 cd/m 2 light in human retinal arterioles and venules. (arvojournals.org)
  • Secondly, using the ODR with the lowest measurement variability, we sought to quantify retinal blood SO2 in arterioles and venules and investigate the relationship between retinal blood SO2 and total retinal blood flow (TRBF) in response to stepwise changes in PETO2 in healthy participants. (uwaterloo.ca)
  • The mean retinal blood SO2 value at baseline in arterioles for 4 participants was 95.19% ± 31.04% and venules was 53.89% ± 17.24% (p = 0.115). (uwaterloo.ca)
  • The retinal vasculature is comprised of arterioles and venules, appears to be piecewise line-shaped and its width is variable across the vessel length ( Abràmoff, Garvin & Sonka, 2010 ). (peerj.com)
  • The central vessel reflex appears as a strong reflection across the vessel centerline and is more evident in the arterioles of retinal images of children due to the difference in oximetry level than that of adults ( Fraz, Basit & Barman, 2013 ). (peerj.com)
  • The crossover of different arterioles and venules branches and its branch-points further complicates the vessel profile model. (peerj.com)
  • METHODS: We calculated the central retinal arterial equivalent (CRAE) and central retinal venular equivalent (CRVE) according to the formulas described by Parr-Hubbard and Knudtson including the six largest retinal arterioles and venules crossing through a concentric ring segment (measurement zone) around the optic nerve head. (aston.ac.uk)
  • CONCLUSIONS: Although the absolute value for CRAE and CRVE is changing significantly depending on the number of vessels included, AVR appears to be comparable as long as the same number of arterioles and venules is included. (aston.ac.uk)
  • No change, however, was observed for AVR calculated with six or five vessel pairs each.CONCLUSIONS: Although the absolute value for CRAE and CRVE is changing significantly depending on the number of vessels included, AVR appears to be comparable as long as the same number of arterioles and venules is included. (aston.ac.uk)
  • PURPOSE: The aim of this study was to analyze pulse wave propagation in the ocular circulation by assessing the phase delay between retinal arterioles and venules and calculating the pulse delay between the retinal and choroidal circulations in MS patients and in control subjects. (unibas.ch)
  • A modified Gaussian model that takes into account the central light reflection of arterioles is proposed to describe the vessel profile. (edu.au)
  • However, SDRA revealed that smokers' vessels showed both an increased level of arterial baseline diameter fluctuation before flicker stimulation (P 0.005) and an increased stiffness of retinal arterioles (P 0.035) compared with those in nonsmokers. (aston.ac.uk)
  • both of them provide an estimation of the wall to lumen ratio ( WLR ) of retinal arterioles. (unibs.it)
  • For this purpose retinal vessel morphology (such as diameter, vessel wall thickness, etc) determination is crucial. (clinicaltrials.gov)
  • To examine the relationship between open-angle glaucoma (OAG) and retinal vessel diameter among baseline participants in the Blue Mountains Eye Study. (unboundmedicine.com)
  • TY - JOUR T1 - Retinal vessel diameter and open-angle glaucoma: the Blue Mountains Eye Study. (unboundmedicine.com)
  • The overall objective is to investigate, whether retinal blood vessel diameter change during the energy consuming dark adaptation process and if responses vary between low and high blood g. (bioportfolio.com)
  • The aim of this paper was to investigate the correlation between the levels of CRP and chitinase 3 protein 1 (YKL-40) in blood samples with morphometric parameters of retinal blood vessels , number and diameter, on digital fundus photography, in patients with DMT2 and DR. (thefreedictionary.com)
  • We examined whether retinal vessel diameter in persons with type 1 diabetes mellitus is associated with changes in subclinical anatomical and functional indicators of diabetic nephropathy. (nih.gov)
  • Calibers of all vessels coursing through a zone 0.5-1 disc diameter from the disc margin were measured and summarized as the central artery and vein equivalents. (diabetesjournals.org)
  • The aim of this study was to examine the effect of an NO donor and COX inhibition on the diameter regulation of retinal vessels during hypoxia in healthy subjects. (arvojournals.org)
  • Diameter regulation of retinal vessels during hypoxia in healthy persons are affected by the inhibition of COX products, but not by increasing the NO concentration. (arvojournals.org)
  • Two independent graders measured the vessel calibre of the widest vein and artery in each peripapillary quadrant on a 3.4 mm diameter circle centred on the optic disc in the same location on both images. (uzh.ch)
  • The following parameters were measured (in pixels): 1) vertical diameter of the ONH (DD), 2) distance from the ONH edge to the first bifurcation point of the superior branch of the central retinal vein (UV), 3) distance from the ONH edge to the first bifurcation point of the inferior branch of the central retinal vein (LV), 4) ONH area, and 5) surface area of the cup of the ONH. (ovid.com)
  • One measure to quantify the severity of retinal arteriolar narrowing is the arteriolar-to-venular diameter ratio (AVR). (edu.au)
  • Continuous retinal vessel diameter m easurements: the future in retinal vessel assessment? (aston.ac.uk)
  • To establish an alternative method, sequential and diameter response analysis (SDRA), to determine dynamic retinal vessel responses and their time course in serial stimulation compared with the established method of averaged diameter responses and standard static assessment. (aston.ac.uk)
  • SDRA focuses on individual time and diameter responses, taking into account the fluctuation in baseline diameter, providing improved insight into reaction patterns when compared with established methods as delivered by retinal vessel analyzer (RVA) software. (aston.ac.uk)
  • As a validation of that finding, SDRA showed a strong relation between baseline retinal vessel diameter and subsequent dilatory response in both healthy subjects and smokers (P 0.001). (aston.ac.uk)
  • Fingerprint Dive into the research topics of 'Continuous retinal vessel diameter m easurements: the future in retinal vessel assessment? (aston.ac.uk)
  • Retinal artery diameter decreased with increasing age and increasing arterial blood pressure. (sparrho.com)
  • Validity and reproducibility of retinal arteriole and venule diameter measurements: ELSA-Brasil study. (sparrho.com)
  • 8 More recently, Kidoya et al showed that the apelin/APJ system is involved in the regulation of blood vessel diameter during angiogenesis. (ahajournals.org)
  • Retinal volume flow was determined from red cell velocity using laser Doppler velocimetry and from retinal vessel diameter measurements using digital image analysis of fundus photographs. (nih.gov)
  • However, due to the difference in morphological scale in diameter, tortuosity, branching pattern or angles of the blood vessels, most methods can segment the thick and obvious blood vessels, but cannot segment the tiny blood vessels accurately. (biomedcentral.com)
  • Static vessel analysis was performed to obtain central retinal arteriolar (CRAE) and venular (CRVE) diameter equivalents and the arterio-venous diameter ratio (AVR). (dshs-koeln.de)
  • The exercise-induced effects on retinal vessel diameter changes were relatively small and the clinical relevance remains to be investigated in larger and longer-term exercise trials. (dshs-koeln.de)
  • We show highly accurate identification of blood vessels for the purpose of studying changes in the vessel network that can be utilized for detecting blood vessel diameter changes associated with the pathophysiology of diabetes. (waikato.ac.nz)
  • Objective: To examine the relationship of blood pressure (BP) and use of angiotensin-receptor blocker or angiotensin-converting enzyme inhibitor to retinal vessel diameter in normotensive, normoalbuminuric persons with type 1 diabetes mellitus. (elsevier.com)
  • Individual arteriole and venule measurements were combined into summary indexes that reflect the average retinal arteriole (central retinal arteriole equivalent [CRAE]) and venule (central retinal venule equivalent [CRVE]) diameter of an eye, respectively. (elsevier.com)
  • Conclusion: Angiotensin-converting enzyme inhibitor or angiotensin-receptor blocker therapy does not affect retinal arteriole or venule diameter in normotensive persons with type 1 diabetes mellitus. (elsevier.com)
  • The lowest quintile of the arteriolar equivalent or arteriole-to-venule ratio was used to define generalized retinal arteriolar narrowing. (unboundmedicine.com)
  • It is not clear whether such a retinal arteriolar change reflects an ischemic process leading to optic nerve damage or results from loss of retinal neurons secondary to glaucoma. (unboundmedicine.com)
  • Mutations in the same gene have also been found in a simpler autosomal dominant disease known as Retinal Arteriolar Tortuosity ( 180000 ). (arizona.edu)
  • Plaisier E, Alamowitch S, Gribouval O, Mougenot B, Gaudric A, Antignac C, Roullet E, Ronco P. Autosomal-dominant familial hematuria with retinal arteriolar tortuosity and contractures: a novel syndrome . (arizona.edu)
  • Central retinal arteriolar and central retinal venular equivalents (CRAE and CRVE, respectively) were measured using semi-automated software from two monochromatic images: one taken with a red-free filter and one extracted from the green channel of a dual wavelength oximetry image. (biomedcentral.com)
  • Thereby the summarised arteriolar and venular calibres are referred to as central retinal arteriolar equivalent (CRAE) and central retinal venular equivalent (CRVE) from which the arterio-venous ratio (AVR) can be calculated. (biomedcentral.com)
  • The authors report the clinical features of a 61-year-old patient with a branch retinal vein occlusion caused by a retinal arteriolar macroaneurysm. (lww.com)
  • M. Elena Martinez-Perez and Arturo Espinosa-Romero, "Three-dimensional reconstruction of blood vessels extracted from retinal fundus images," Opt. (osapublishing.org)
  • We present a 3D reconstruction of retinal blood vessel trees using two views of fundus images. (osapublishing.org)
  • 2) The extraction of blood vessels and skeletons from two fundus images. (osapublishing.org)
  • We consider the problem of retinal vessel segmentation, a key issue in automated analysis of digital fundus images. (osapublishing.org)
  • Sebastian Gross, Monika Klein and Dorian Schneider, "Segmentation of Blood Vessel Structures in Retinal Fundus Images with Logarithmic Gabor Filters", Current Medical Imaging (2013) 9: 138. (eurekaselect.com)
  • Automated and accurate segmentation of the retinal blood vessel tree is one of the challenging tasks in the computer-aided analysis of fundus images today. (theiet.org)
  • But it is difficult to completely segment retinal blood vessels due to the intricate distribution of vessels [ 5 ], the low contrast between vessel and background, and lesion interference and uneven illumination in fundus images. (biomedcentral.com)
  • To investigate the association of vessel tortuosity with severity of diabetic retinopathy (DR) using optical coherence tomography angiography. (ovid.com)
  • The vessel tortuosity determined using optical coherence tomography angiography might be a useful parameter indicating the progression to PDR, circumventing the risk from invasive conventional angiography. (ovid.com)
  • PURPOSE To compare the vessel calibre measurements between optical coherence tomography angiography (OCTA) and colour fundus photography. (uzh.ch)
  • We examined the impact of axial length on superficial retinal vessel density (SRVD) and foveal avascular zone area (FAZA) measurement using optical coherence tomography angiography. (surrey.ac.uk)
  • Purpose: To compare retinal vessel density in eyes with geographic atrophy (GA) secondary to age-related macular degeneration (AMD) to age-matched healthy eyes by using projection-resolved optical coherence tomography angiography (PR-OCTA). (elsevier.com)
  • The segmented retinal images from the CHASE_DB1 database produced best case accuracy, sensitivity and specificity of 0.96, 0.74 and 0.98, respectively, and worst case measures of 0.94, 0.67 and 0.98, respectively. (springer.com)
  • If you are diabetic, then good diabetic control can help reduce the risk of blood vessel problems. (rnib.org.uk)
  • We have used the gold standard public database which contains retinal images of healthy patients, patients with diabetic retinopathy and glaucomatous patients. (scribd.com)
  • The aim of this study was to evaluate retinal vessel morphology in patients with acromegaly at diagnosis and after treatment and to describe the prevalence of diabetic retinopathy in patients with long-standing acromegaly and diabetes. (eur.nl)
  • We examined retinal vessel calibers as 16-year predictors of diabetic nephropathy, neuropathy and proliferative retinopathy in a young population-based Danish cohort with type 1 diabetes. (diabetesjournals.org)
  • The retinal vessels are early and prevalent targets of diabetic damage. (diabetesjournals.org)
  • Zerumbone ameliorates retinal damage by blocking advanced glycation end products and their receptor system in streptozotocin-diabetic rats. (mdpi.com)
  • In conclusion, treatment of diabetic rats with zerumbone attenuates the severity of retinal inflammation and angiogenesis, via inhibition of p38 MAPK and NF-κB signaling pathways. (mdpi.com)
  • [ncbi.nlm.nih.gov] Although bilateral acute retinal necrosis was suspected, azotemia resulting from diabetic nephropathy limited the use of acyclovir. (symptoma.com)
  • Herbert F. Jelinek, Michael J. Cree, Jorge J. G. Leandro, João V. B. Soares, Roberto M. Cesar, and A. Luckie, "Automated segmentation of retinal blood vessels and identification of proliferative diabetic retinopathy," J. Opt. (osa.org)
  • With a 40% increase in mean arterial blood pressure (MAP), there was a significant increase in retinal blood flow of 32.9 +/- 7.1% in non-diabetic controls. (nih.gov)
  • Retinal cameras are typically used to conduct diabetic retinal exams, but they can also reveal symptoms of other conditions such as hypertensive retinopathy, retinal tears, papilledema and more. (welchallyn.com)
  • Assessment of retinal microvascular health along with BP monitoring can improve cardiovascular risk stratification in early childhood. (drugs.com)
  • Retinal vessel calibers have been associated with the presence of microvascular complications but their long-term predictive value has only been sparsely investigated. (diabetesjournals.org)
  • Since Zingiber officinale (ginger) is known for its anti-inflammatory and antiangiogenic properties, we investigated the effects of its extract standardized to 5% 6-gingerol, the major active constituent of ginger, in attenuating retinal microvascular changes in rats with streptozotocin-induced diabetes. (molvis.org)
  • The current study showed that ginger extract containing 5% of 6-gingerol attenuates the retinal microvascular changes in rats with streptozotocin-induced diabetes through anti-inflammatory and antiangiogenic actions. (molvis.org)
  • As leading expert in retinal microcirculation, Imedos Systems GmbH develops and distributes innovative medical devices and systems for retinal vessel analysis to both protect and improve the microvascular health of patients worldwide. (mynewschannel.net)
  • 2009). Retinal microvascular abnormalities and cognitive decline: the ARIC 14-year follow-up study. (core.ac.uk)
  • 2001). Retinal microvascular abnormalities and incident stroke: the Atherosclerosis Risk in Communities Study. (core.ac.uk)
  • 2010). Retinal microvascular abnormalities and risk of lacunar stroke: Atherosclerosis Risk in Communities Study. (core.ac.uk)
  • The researchers compared the retinal imaging results of 27 individuals who had developed schizophrenia with those of individuals who had not and found that the former had microvascular abnormalities reflective of insufficient brain oxygen supply. (psychnews.org)
  • This precise measurement could contribute to the diagnosis and evolution characterization of microvascular disorders which affect the retinal vessels. (umfcluj.ro)
  • Retinal vessel calibers were measured using a computer-based program as the central retinal artery and vein equivalent (CRAE and CRVE). (nih.gov)
  • Central retinal arteriole equivalent (CRAE) and central retinal venule equivalent (CRVE) were computed. (nih.gov)
  • Here, we set out to explore two such markers - CRAE and CRVE - obtained with two different techniques: one using a red-free filter and the other one using a dual wavelength filter used for taking retinal oximetry images and extracting only the information from the green channel. (biomedcentral.com)
  • The observed accuracy, speed, robustness and simplicity suggest that the algorithm may be a suitable tool for automated retinal image analysis in large population-based studies. (springer.com)
  • QUARTZ (QUantitative Analysis of Retinal vessel Topology and siZe) is a fully automated retinal image analysis system that has been designed to process large numbers of retinal images and obtains quantitative measures of vessel morphology to be used in epidemiological studies. (qub.ac.uk)
  • The present study aims to reveal and quantify differences in vessel morphology between fundus photography, fundus angiography, and optical coherence tomography in health and disease. (clinicaltrials.gov)
  • In this article, we demonstrate characterization and oxygen saturation studies of human retinal blood vessels with Principal Component Analysis (PCA) based Spectroscopic Optical Coherence Tomography-based Angiography. (octnews.org)
  • Retinal angiography and colour Doppler of retrobulbar vessels in Takayasu arteritis. (docphin.com)
  • Matos KT, Arantes T, Souza AW, Ramos MH, Allemann N, Muccioli C. Retinal angiography and colour Doppler of retrobulbar vessels in Takayasu arteritis. (docphin.com)
  • The objective of this study was to evaluate and describe the ocular manifestations of TA, correlating the resistivity and pressure in retrobulbar vessels by colour Doppler and retinal angiography. (docphin.com)
  • Patients with TA received complete ophthalmologic examination, fluorescein and indocyanine green angiography, and colour Doppler ultrasound to evaluate blood flow in the retrobulbar vessels. (docphin.com)
  • A statistical correlation was found between peak systolic velocity (PSV) in the ophthalmic artery (OA) and Heidelberg retinal angiography (HRA) examination results (p = 0.006), and resistivity index (RI) in the OA was abnormal in patients with long (average, 14 years) versus short (average, 5.5 years) onset time of the disease (p = 0.035). (docphin.com)
  • Ophthalmology benefits from this fact given the significant number of existing retinal image modalities: color fundus retinography, fluorescein angiography, autofluorescence fundus retinography or red-free fundus retinography, among others. (groundai.com)
  • Chaudhuri S, Chatterjee S, Katz N, Nelson M, Goldbaum M (1989) Detection of blood vessels in retinal images using two-dimensional matched filters. (springer.com)
  • Xiaoyi J, Mojon D (2003) Adaptive local thresholding by verification-based multithreshold probing with application to vessel detection in retinal images. (springer.com)
  • Experimental results demonstrate that the proposed method of two-step nonlinear image enhancement visibly improves the vessel detection performance, achieving better accuracy than that without enhancement process on the both DRIVE and STARE databases. (spie.org)
  • An automated method of detection and extraction of blood vessels in retinal images composed of three steps matched filtering, fuzzy c-median (FCMED) clustering and label filtering is proposed [5,6]. (scribd.com)
  • Gabor filters are also used in detection of blood vessels [7]. (scribd.com)
  • in [11] have presented an algorithm for vessel detection in retinal color images which works based on local Radon transform and morphological reconstruction. (scribd.com)
  • in [12] have provided a feature-based method for early detection of exudates and proposed a method for extracting the blood vessel tree based on simple morphological operations. (scribd.com)
  • A preliminary result has demonstrated the robustness and good performance of the proposed approaches and their potential application for improving retinal blood vessel detection. (spie.org)
  • Vessel segmentation can assist in the detection of pathological changes which are possible indicators for arteriosclerosis, retinopathy, micro aneurysms and macular degeneration. (eurekaselect.com)
  • Loss is greatest within regions of GA. Vessel density may be more sensitive than retinal layer thickness measurement in the detection of inner retinal change in eyes with GA. (elsevier.com)
  • for the registration of retinal images, although their method, that also requires the detection of the optic disk, was not robust enough and failed in several images. (groundai.com)
  • Standardization of image capture protocols (same image size and undertaking a vessel averaging approach for oxygenation analysis) will enhance the detection of smaller physiological changes in eye disease. (arvojournals.org)
  • Quantitative analysis of retinal vessel attenuation in eyes with retinitis pigmentosa. (nih.gov)
  • With improvements in fundus imaging technology and the increasing use of digital images in screening and diagnosis, the issue of automated analysis of retinal images is gaining more serious attention. (osapublishing.org)
  • Automatic analysis of retinal blood images is of vital importance in diagnosis tasks of retinopathy. (groundai.com)
  • Fractal analysis of retinal digital images was performed by means of a computer-based program, and the data expressed as mean-D. Brain MRI lesion volume in FLAIR and T1-weighted images was assessed using MIPAV software. (core.ac.uk)
  • 2010). Fractal analysis of retinal vessels suggests that a distinct vasculopathy causes lacunar stroke. (core.ac.uk)
  • This is a cross-sectional study based on 74 patients (145 eyes) with RP who had visual field assessment with Goldmann permeter and good-quality retinal images for vessel size measurements identified by retrospective medial chart review (1973-2007) in the electrophysiology clinic of a tertiary eye hospital in Australia. (nih.gov)
  • CONCLUSIONS Vessel calibre measurements were significantly larger in OCTA images compared with colour fundus photographs, particularly for smaller vessels. (uzh.ch)
  • Summarised retinal vessel calibre measurements obtained from oximetry images are in good agreement to those obtained using red-free photographs. (biomedcentral.com)
  • Retinal oximetry measurements were acquired from 87 healthy volunteers using the IMEDOS Systems oxygen module. (arvojournals.org)
  • The least agreement was found for single vessel measurements and comparisons between different camera angles. (arvojournals.org)
  • The research pathway leading to noninvasive retinal oximetry measurements started in the mid-19th century with the discovery that hemoglobin exhibits a distinctly different absorption spectrum depending on the amount of oxygen bound. (arvojournals.org)
  • Retinal vessel oxygen saturation measurements using dual-wavelength retinal photography is a relatively new tool to assess the retinal metabolism in health and disease. (arvojournals.org)
  • Our results of DVA measurements after an IOP-lowering laser surgical intervention (CPC) reveal a significant recovery of the regulative capacity of retinal arteries in glaucoma patients that has up to now neither been properly documented nor appreciated. (openophthalmologyjournal.com)
  • We reported a clinical series of three patients affected by long-term JIA-uveitis with a follow-up of 16 years who developed unusual retinal vessel pattern modifications localized around the optic disc. (thefreelibrary.com)
  • At 25 years old, right fundus examination underlined a sheathing-like aspect of vessels at the emergence of the optic disc. (thefreelibrary.com)
  • When she was 21, fundus evaluation showed sheathed vessels emerging from the optic disc in both eyes (Figure 2). (thefreelibrary.com)
  • The effect on the reactive capacity of retinal vessels was assessed before and 6-8 weeks after CPC by means of the Dynamic Vessel Analyzer (DVA) using flicker light provocation. (openophthalmologyjournal.com)
  • Conclusions- Our results suggest that spatiotemporally regulated apelin/APJ signaling participates in retinal vascularization in a cooperative manner with VEGF or FGF2, and contributes to normal ocular development. (ahajournals.org)
  • Conclusions: Eyes with GA have reduced retinal vessel density in SVC, ICP, and DCP compared to those in controls. (elsevier.com)
  • CONCLUSIONS: The degree of early retinal vessel development is a significant predictor of outcome from retinopathy of prematurity. (duke.edu)
  • The interocular difference in retinal vessel rigidity was significantly correlated with the interocular difference in RNFL thickness in MS patients. (unibas.ch)
  • Compared with the RVA software method, SDRA demonstrated a marked difference in retinal vessel responses to flickering light (P 0.05). (aston.ac.uk)
  • The RVA software was unable to detect this difference or to find a difference in retinal vessel arteriovenous ratio between smokers and nonsmokers (P 0.243). (aston.ac.uk)
  • Alterations in blood glucose levels in diabetes cause changes in retinal blood vessels which swell, bleed or leak fluid into the back of the eye," said senior study author Ecosse Lamoureux of the Singapore Eye Research Institute and the Duke-NUS Medical School in Singapore. (thefreedictionary.com)
  • Central retinal vein not labeled, but region is visible - the vein is inside the optic nerve. (wikipedia.org)
  • The anatomy of the veins of the orbit of the eye varies between individuals, and in some the central retinal vein drains into the superior ophthalmic vein , and in some it drains directly into the cavernous sinus . (wikipedia.org)
  • 2003;44:988-995 MeSH entry for central retinal vein - National Library of Medicine - Medical Subject Headings - 2007 Interior of posterior half of bulb of left eye. (wikipedia.org)
  • A Global and Local Enhanced Residual U-Net for Accurate Retinal Vessel Segmentation. (bioportfolio.com)
  • However, they usually apply global image pre-processing and take the whole retinal images as input during network training, which have two drawbacks for accurate retinal vessel segmentation. (bioportfolio.com)
  • To address these drawbacks, this study proposes a Global and Local enhanced residual U-nEt (GLUE) for accurate retinal vessel segmentation, which benefits from both the globally and locally enhanced information inside the retinal region. (bioportfolio.com)
  • Therefore, it is especially significant to create a computer-aided method of automatic and accurate retinal vessel segmentation. (biomedcentral.com)
  • Platelet-derived growth factor over-expression in retinal progenitors results in abnormal retinal vessel formation. (scilifelab.se)
  • The total retinal vessels in P17 OIR mice could be fully observed under a fluorescence microscope 3 s after RO injection of FITC-dextran. (nih.gov)
  • Severity can range from mild vision loss to total retinal detachment and blindness. (encyclopedia.com)
  • In advanced cases, rubeosis iridis, subretinal fluid with xanthochromic particles, and total retinal detachment have been noted following argon laser photocoagulation. (aao.org)
  • Titled "Apl of My Eye", the project is a twoyear initiative from 2014 to 2016 "that addresses a critical medical concern in the Philippines" a pediatric eye ailment called retinopathy of prematurity, which according to medical journals, is the abnormal development of retinal blood vessels in the eyes of premature infants. (thefreedictionary.com)
  • Early retinal vessel development and iris vessel dilatation as factors in retinopathy of prematurity. (duke.edu)
  • OBJECTIVE: To determine whether the extent of retinal vessel development present on early screening examinations for retinopathy of prematurity has prognostic value? (duke.edu)
  • DESIGN: The prospectively collected data from the Multicenter Trial of Cryotherapy for Retinopathy of Prematurity were used to compare the development of acute retinopathy of prematurity and long-term structural and visual outcomes for eyes with differing extents of retinal vessel development. (duke.edu)
  • RESULTS: The chance of developing threshold retinopathy of prematurity was inversely related to the early degree of vessel development: 54% for zone I eyes, 25% for transitional eyes, and 8% for zone II eyes. (duke.edu)
  • Retinal blood flow measurement is of scientific and clinical value. (clinicaltrials.gov)
  • Retinal vessel attenuation is a key finding in the diagnosis of retinitis pigmentosa (RP), but there have been no studies to determine whether quantitative measurement of this retinal sign is useful. (nih.gov)
  • There was a high level of agreement between graders for measurement of vessel calibre in both colour fundus (intraclass correlation coefficient=0.93, coefficient of variation=0.07) and OCTA images (intraclass correlation coefficient=0.94, coefficient of variation=0.05). (uzh.ch)
  • Advancements in retinal imaging led to multiple custom built and commercially available devices, which allow indirect measurement of retinal vessel and tissue oxygen saturation parameters. (arvojournals.org)
  • A supervised method for retinal vessel segmentation in the images of multi-ethnic school children was developed based on ensemble classifier of bootstrapped decision trees. (springer.com)
  • The methodology is evaluated on CHASE_DB1, a relatively new public retinal image database of multi-ethnic school children, which is a subset of retinal images from the Child Heart and Health Study in England (CHASE) dataset. (springer.com)
  • Hoover AD, Kouznetsova V, Goldbaum M (2000) Locating blood vessels in retinal images by piecewise threshold probing of a matched filter response. (springer.com)
  • Due to non-perfect imaging environment, retinal images often appear with intensity variations and artificial noises. (spie.org)
  • This work proposes a two-step nonlinear retinal image enhancement to compensate for those imperfections of retinal images. (spie.org)
  • Classification on the feature vector extracted from the enhanced retinal images is performed by using a linear SVM classifier. (spie.org)
  • Siddalingaswamy and Prabhu in [9] have proposed a hybrid method for efficient segmentation of multiple oriented blood vessels in colour retinal images. (scribd.com)
  • To develop an automated vessel wall segmentation method using convolutional neural networks (CNN) to facilitate the quantification on magnetic resonance (MR) vessel wall images of patients with intrac. (bioportfolio.com)
  • Experimental results showed the improved approach gives better performance than baseline approach when it is tested on DRIVE database of retinal images. (igi-global.com)
  • We evaluate the performance of the proposed approach using a standard database of retinal images. (osapublishing.org)
  • Monochromatic images provide best contrast to measure vessel calibres. (biomedcentral.com)
  • This will reduce patient exposure to the camera flash and could provide sufficient quality images to reliably measure vessel calibres. (biomedcentral.com)
  • We obtained retinal images of one eye of 45 healthy participants. (biomedcentral.com)
  • The below images show (at left) normal formation of superficial (green) and deep (red) retinal vessels and (at right) excessive formation. (cincinnatichildrens.org)
  • Segmenting vessels accurately is a fundamental step in analysing retinal images. (groundai.com)
  • A fuzzy vessel tracking algorithm for retinal images based on fuzzy clustering. (ijcaonline.org)
  • Locating blood vessels in retinal images by piecewise threshold probing of a matched filter response. (ijcaonline.org)
  • The performance of active contour model is limited on retinal vessel segmentation as vessel images are usually corrupted with intensity inhomogeneity, low contrast, and weak boundary, which severely affect the segmentation results of retinal vessels. (edu.au)
  • Experiments on synthetic and real images and comparisons with other state‐of‐the‐art active contour models show that the proposed model can detect objects more accurate and robust, especially for vessels on retinal angiogram. (edu.au)
  • have been used in different proposals for retinal images. (groundai.com)
  • However, as the detected points are not necessarily representative characteristics of the retinal images contents, many of them may not be present across the different modalities. (groundai.com)
  • Specifically for retinal images, Legg et al. (groundai.com)
  • However, agreement between single vessels of consecutive images showed increased limits of agreement compared with saturation values calculated by averaging all or just the four major arcades of one image. (arvojournals.org)
  • The T1 oximeter obtains two separate retinal images at 570 nm and 600 nm 4 whereas the IMEDOS System uses a dual-wavelength filter to capture one single image. (arvojournals.org)
  • This work examines the blood vessel segmentation methodologies in two dimensional retinal images acquired from a fundus camera and a survey of techniques is presented. (kingston.ac.uk)
  • The performance of algorithms is compared and analyzed on two publicly available databases (DRIVE and STARE) of retinal images using a number of measures which include accuracy, true positive rate, false positive rate, sensitivity, specificity and area under receiver operating characteristic (ROC) curve. (kingston.ac.uk)
  • QUARTZ has been used to process retinal images from UK Biobank which is a large population-based cohort study. (qub.ac.uk)
  • In this paper, we address issues of robustness with respect to processing large datasets and validate QUARTZ using a subset of 4,692 UK Biobank retinal images. (qub.ac.uk)
  • Following validation, 135,867 retinal images (68,549 participants) from the UK Biobank study were processed by QUARTZ. (qub.ac.uk)
  • The present learning focus is developing the extraction of normal and isolated characteristics or marks in colour retinal images. (myprojectbazaar.com)
  • The adaptive filters are tuned to match the lump (part) of vessel to be extracted in green channel images. (myprojectbazaar.com)
  • This paper describes the development of segmentation methodology in the processing of retinal blood vessel images obtained using non-mydriatic colour photography. (waikato.ac.nz)
  • Excessive PDGF signaling is associated with proliferative retinal disorders. (scilifelab.se)
  • Muscarinic binding sites were less different (0.5 to 1.8 fmol/mg net weight) among the species studied, being the highest values in human retinal vessels. (elsevier.com)
  • Besides variation in contrast, uneven illumination during image capture, low quality of the captured retinal image and the presence of pathologies are the further added challenges for the development of robust automated retinal vessel segmentation methodologies ( Fraz & Barman, 2014 ). (peerj.com)
  • If someone has narrowing of their retinal arteries due to atherosclerosis, this can cause the hardened arteries to press onto the nearby veins. (rnib.org.uk)