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)

Examples of retinal diseases include:

1. Age-related macular degeneration (AMD): a leading cause of vision loss in people over the age of 50, AMD affects the macula, the part of the retina responsible for central vision.
2. Diabetic retinopathy (DR): a complication of diabetes that damages blood vessels in the retina and can cause blindness.
3. Retinal detachment: a condition where the retina becomes separated from the underlying tissue, causing vision loss.
4. Macular edema: swelling of the macula that can cause vision loss.
5. Retinal vein occlusion (RVO): a blockage of the small veins in the retina that can cause vision loss.
6. Retinitis pigmentosa (RP): a group of inherited disorders that affect the retina and can cause progressive vision loss.
7. Leber congenital amaurosis (LCA): an inherited disorder that causes blindness or severe visual impairment at birth or in early childhood.
8. Stargardt disease: a rare inherited disorder that affects the retina and can cause progressive vision loss, usually starting in childhood.
9. Juvenile macular degeneration: a rare inherited disorder that causes vision loss in young adults.
10. Retinal dystrophy: a group of inherited disorders that affect the retina and can cause progressive vision loss.

Retinal diseases can be diagnosed with a comprehensive eye exam, which includes a visual acuity test, dilated eye exam, and imaging tests such as optical coherence tomography (OCT) or fluorescein angiography. Treatment options vary depending on the specific disease and can include medication, laser surgery, or vitrectomy.

It's important to note that many retinal diseases can be inherited, so if you have a family history of eye problems, it's important to discuss your risk factors with your eye doctor. Early detection and treatment can help preserve vision and improve quality of life for those affected by these diseases.

The growth of new blood vessels in the retina is a natural response to hypoxia (lack of oxygen) and inflammation caused by these diseases. However, these new blood vessels are fragile and can cause damage to the retina, leading to vision loss. In some cases, RNV can also lead to vitreous hemorrhage, retinal detachment, or glaucoma, which can further exacerbate vision loss.

The diagnosis of RNV is typically made through a comprehensive eye exam, including a visual acuity test, dilated eye exam, and imaging tests such as fluorescein angiography or optical coherence tomography (OCT). Treatment options for RNV depend on the underlying cause of the condition and may include medications, laser therapy, or vitrectomy.

In summary, retinal neovascularization is a common complication of various retinal diseases that can lead to vision loss if left untreated. Early detection and prompt treatment are essential to prevent further damage and preserve visual function.

The exact cause of ROP is not known, but it is thought to be related to the immaturity of the retina and the high levels of oxygen in incubators used to care for premature babies. The risk of developing ROP increases with the degree of prematurity, with infants born before 28 weeks gestation being at highest risk.

ROP typically develops in two stages:

1. Stage 1: Early ROP - This stage is characterized by the formation of small blood vessels and immature retinal tissue.
2. Stage 2: Advanced ROP - This stage is characterized by the proliferation of abnormal blood vessels, bleeding, and scarring in the retina.

There are several subtypes of ROP, including:

1. Type 1 ROP: Mildest form of the disease, with few or no complications.
2. Type 2 ROP: More severe form of the disease, with abnormal blood vessel growth and scarring in the retina.
3. Type 3 ROP: Most severe form of the disease, with widespread scarring and bleeding in the retina.

Treatment for ROP typically involves monitoring the infant's eye development closely and applying laser therapy to the affected areas if necessary. In severe cases, surgery may be required to remove abnormal blood vessels or scar tissue.

Prevention of ROP is primarily focused on reducing the risk factors, such as prematurity and oxygen exposure. This includes:

1. Proper management of gestational diabetes to prevent preterm birth.
2. Close monitoring of fetal development and early delivery if necessary.
3. Careful regulation of oxygen levels in incubators to avoid over-oxygenation.
4. Early detection and treatment of infections that can lead to preterm birth.
5. Avoiding excessive use of ophthalmic drugs that can be harmful to the developing retina.

Early detection and timely intervention are crucial for effective management and prevention of ROP. Regular eye exams and screening are necessary to identify the disease in its early stages, when treatment is most effective.

There are two main types of DR:

1. Non-proliferative diabetic retinopathy (NPDR): This is the early stage of DR, where the blood vessels in the retina become damaged and start to leak fluid or bleed. The symptoms can be mild or severe and may include blurred vision, floaters, and flashes of light.
2. Proliferative diabetic retinopathy (PDR): This is the advanced stage of DR, where new blood vessels start to grow in the retina. These vessels are weak and can cause severe bleeding, leading to vision loss.

DR is a common complication of diabetes, and it is estimated that up to 80% of people with diabetes will develop some form of DR over their lifetime. The risk of developing DR increases with the duration of diabetes and the level of blood sugar control.

Early detection and treatment of DR can help to prevent vision loss, so it is important for people with diabetes to have regular eye exams to monitor their retinal health. Treatment options for DR include laser surgery, injections of anti-vascular endothelial growth factor (VEGF) medications, and vitrectomy, a surgical procedure to remove the vitreous gel and blood from the eye.

Preventing Diabetic Retinopathy

While there is no surefire way to prevent diabetic retinopathy (DR), there are several steps that people with diabetes can take to reduce their risk of developing this complication:

1. Control blood sugar levels: Keeping blood sugar levels within a healthy range can help to slow the progression of DR. This can be achieved through a combination of diet, exercise, and medication.
2. Monitor blood pressure: High blood pressure can damage the blood vessels in the retina, so it is important to monitor and control blood pressure to reduce the risk of DR.
3. Maintain healthy blood lipids: Elevated levels of low-density lipoprotein (LDL) cholesterol and lower levels of high-density lipoprotein (HDL) cholesterol can increase the risk of DR.
4. Quit smoking: Smoking can damage the blood vessels in the retina and increase the risk of DR.
5. Maintain a healthy weight: Obesity is a risk factor for DR, so maintaining a healthy weight can help to reduce the risk of this complication.
6. Get regular eye exams: Regular eye exams can help to detect DR in its early stages, when it is easier to treat and prevent vision loss.

Preventing Diabetic Retinopathy

While there is no cure for diabetic retinopathy (DR), there are several treatment options available to help manage the condition and prevent vision loss. These include:

1. Laser surgery: This is a common treatment for early-stage DR, where a laser is used to shrink abnormal blood vessels in the retina and reduce the risk of further damage.
2. Injection therapy: Medications such as anti-vascular endothelial growth factor (VEGF) injections can be used to shrink abnormal blood vessels and reduce swelling in the retina.
3. Vitrectomy: In severe cases of DR, a vitrectomy may be performed to remove scar tissue and blood from the center of the eye.
4. Blood pressure control: Maintaining healthy blood pressure can help to slow the progression of DR.
5. Blood glucose control: Keeping blood sugar levels under control can also slow the progression of DR.
6. Follow-up care: Regular follow-up appointments with an eye doctor are important to monitor the progress of DR and adjust treatment as needed.

Early detection and treatment of diabetic retinopathy can help to prevent vision loss and improve outcomes for individuals with this complication of diabetes. By managing blood sugar levels, blood pressure, and cholesterol, and by getting regular eye exams, individuals with diabetes can reduce their risk of developing DR and other diabetic complications.

There are two main types of retinal artery occlusion: central retinal artery occlusion (CRAO) and branch retinal artery occlusion (BRAO). Central retinal artery occlusion occurs when the central retinal artery, which supplies blood to the macula, becomes blocked. This can cause sudden vision loss in one eye, often with a painless, blinding effect. Branch retinal artery occlusion, on the other hand, occurs when one of the smaller retinal arteries that branch off from the central retinal artery becomes blocked. This can cause vision loss in a specific part of the visual field, often with some preserved peripheral vision.

Retinal artery occlusion is often caused by a blood clot or other debris that blocks the flow of blood through the retinal arteries. It can also be caused by other conditions such as diabetes, high blood pressure, and atherosclerosis (the buildup of plaque in the arteries).

Retinal artery occlusion is a medical emergency that requires prompt treatment. Treatment options may include intravenous injection of medications to dissolve the clot or other debris, laser surgery to repair damaged retinal tissue, and/or vitrectomy (surgical removal of the vitreous gel) to remove any blood or debris that has accumulated in the eye.

In summary, retinal artery occlusion is a serious condition that can cause sudden vision loss and potentially lead to permanent blindness. It is important to seek medical attention immediately if you experience any symptoms of retinal artery occlusion, such as sudden vision loss or blurred vision in one eye, flashes of light, floaters, or pain in the eye.

The symptoms of RVO can vary depending on the severity of the blockage, but may include:

* Blurred vision
* Double vision
* Flashes of light
* Eye pain
* Reduced peripheral vision

RVO is typically diagnosed through a comprehensive eye exam, which may include imaging tests such as fluorescein angiography or optical coherence tomography (OCT).

Treatment for RVO depends on the severity of the condition and may include:

* Medications to reduce inflammation and improve blood flow
* Injections of medication into the eye
* Laser surgery to clear blockages or reduce inflammation
* Vitrectomy, a surgical procedure to remove the vitreous gel and blood from the eye

Early diagnosis and treatment of RVO can help prevent or reduce vision loss. However, in some cases, permanent vision loss may occur despite treatment.

Preventing RVO is not always possible, but controlling risk factors such as high blood pressure, diabetes, and hypertension can help reduce the likelihood of developing the condition. Maintaining a healthy lifestyle, including regular exercise, a balanced diet, and not smoking, can also help reduce the risk of RVO.

Leukostasis can cause a range of symptoms depending on the location of the affected tissue or organ, including fever, pain, swelling, and difficulty with breathing or blood flow. Treatment options for leukostasis depend on the underlying cause and may include antibiotics, anti-inflammatory medications, or surgery to remove the accumulated white blood cells.

Retinal telangiectasis is a relatively rare condition, but it can be associated with other health conditions such as high blood pressure, diabetes, and sickle cell disease. It can also be caused by certain medications or injuries to the eye.

Symptoms of retinal telangiectasis can include blurred vision, floaters, flashes of light, and distorted vision. In some cases, the condition can lead to retinal detachment, which is a more serious complication that can cause blindness if left untreated.

Diagnosis of retinal telangiectasis typically involves a comprehensive eye exam, including a visual acuity test, dilated eye exam, and imaging tests such as fluorescein angiography or optical coherence tomography (OCT).

Treatment for retinal telangiectasis depends on the severity of the condition and can include close monitoring, medications to control underlying conditions such as high blood pressure, and in some cases, laser surgery or vitrectomy to repair damaged blood vessels. Early detection and treatment can help to slow the progression of the condition and preserve vision.

Optic atrophy is a condition where there is a degeneration or loss of the optic nerve fibers, leading to vision loss. It can be caused by various factors such as trauma, inflammation, tumors, and certain medical conditions like multiple sclerosis.

The symptoms of optic atrophy may include:

1. Blind spots in the visual field
2. Difficulty perceiving colors
3. Difficulty adjusting to bright light
4. Double vision or other abnormalities in binocular vision
5. Eye pain or discomfort
6. Loss of peripheral vision
7. Nausea and vomiting
8. Sensitivity to light
9. Tunnel vision
10. Weakness or numbness in the face or extremities.

The diagnosis of optic atrophy is based on a comprehensive eye exam, which includes a visual acuity test, dilated eye exam, and other specialized tests such as an OCT (optical coherence tomography) scan.

Treatment for optic atrophy depends on the underlying cause and may include medications to manage inflammation or infection, surgery to remove a tumor or repair damaged tissue, or management of associated conditions such as diabetes or multiple sclerosis. In some cases, vision loss due to optic atrophy may be permanent and cannot be reversed, but there are strategies to help improve remaining vision and adapt to any visual impairment.

The exact cause of retinal vasculitis is not known, but it is believed to be an autoimmune disorder, meaning that the body's immune system mistakenly attacks its own tissues. It can occur at any age but is more common in adults between 30 and 60 years old.

Symptoms of retinal vasculitis include:

1. Blurred vision or blind spots
2. Floaters (specks or cobwebs in vision)
3. Flashes of light
4. Redness and pain in the eye
5. Sensitivity to light
6. Blindness in one or both eyes

Retinal vasculitis is diagnosed through a comprehensive eye exam, including a visual acuity test, dilated eye exam, and imaging tests such as fluorescein angiography and optical coherence tomography (OCT).

Treatment options for retinal vasculitis include:

1. Corticosteroids to reduce inflammation
2. Immunosuppressive drugs to suppress the immune system
3. Anti-vascular endothelial growth factor (VEGF) injections to prevent the growth of new blood vessels
4. Photodynamic therapy to damage and shrink the abnormal blood vessels
5. Vitrectomy, a surgical removal of the vitreous gel and any blood or scar tissue in the eye

The prognosis for retinal vasculitis varies depending on the severity and location of the disease, but it can lead to significant vision loss if left untreated. It is important to seek medical attention if symptoms persist or worsen over time.

There are many different types of retinal degeneration, each with its own set of symptoms and causes. Some common forms of retinal degeneration include:

1. Age-related macular degeneration (AMD): This is the most common form of retinal degeneration and affects the macula, the part of the retina responsible for central vision. AMD can cause blind spots or distorted vision.
2. Retinitis pigmentosa (RP): This is a group of inherited conditions that affect the retina and can lead to night blindness, loss of peripheral vision, and eventually complete vision loss.
3. Leber congenital amaurosis (LCA): This is a rare inherited condition that causes severe vision loss or blindness at birth or within the first few years of life.
4. Stargardt disease: This is a rare inherited condition that causes progressive vision loss and can lead to blindness.
5. Retinal detachment: This occurs when the retina becomes separated from the underlying tissue, causing vision loss.
6. Diabetic retinopathy (DR): This is a complication of diabetes that can cause damage to the blood vessels in the retina and lead to vision loss.
7. Retinal vein occlusion (RVO): This occurs when a blockage forms in the small veins that carry blood away from the retina, causing vision loss.

There are several risk factors for retinal degeneration, including:

1. Age: Many forms of retinal degeneration are age-related and become more common as people get older.
2. Family history: Inherited conditions such as RP and LCA can increase the risk of retinal degeneration.
3. Genetics: Some forms of retinal degeneration are caused by genetic mutations.
4. Diabetes: Diabetes is a major risk factor for diabetic retinopathy, which can cause vision loss.
5. Hypertension: High blood pressure can increase the risk of retinal vein occlusion and other forms of retinal degeneration.
6. Smoking: Smoking has been linked to an increased risk of several forms of retinal degeneration.
7. UV exposure: Prolonged exposure to UV radiation from sunlight can increase the risk of retinal degeneration.

There are several treatment options for retinal degeneration, including:

1. Vitamin and mineral supplements: Vitamins A, C, and E, as well as zinc and selenium, have been shown to slow the progression of certain forms of retinal degeneration.
2. Anti-vascular endothelial growth factor (VEGF) injections: These medications can help reduce swelling and slow the progression of diabetic retinopathy and other forms of retinal degeneration.
3. Photodynamic therapy: This involves the use of a light-sensitive medication and low-intensity laser light to damage and shrink abnormal blood vessels in the retina.
4. Retinal implants: These devices can be used to restore some vision in people with advanced forms of retinal degeneration.
5. Stem cell therapy: Research is ongoing into the use of stem cells to repair damaged retinal cells and restore vision.

It's important to note that early detection and treatment of retinal degeneration can help to slow or stop the progression of the disease, preserving vision for as long as possible. Regular eye exams are crucial for detecting retinal degeneration in its early stages, when treatment is most effective.

Hyperoxia can cause damage to the body's tissues and organs, particularly the lungs and brain. In severe cases, hyperoxia can lead to respiratory failure, seizures, and even death.

There are several ways to diagnose hyperoxia, including:

1. Blood tests: These can measure the levels of oxygen in the blood.
2. Arterial blood gas (ABG) analysis: This is a test that measures the amounts of oxygen and carbon dioxide in the blood.
3. Pulse oximetry: This is a non-invasive test that measures the amount of oxygen in the blood by shining a light through the skin.

Treatment for hyperoxia depends on the underlying cause, but may include:

1. Oxygen therapy: This involves administering oxygen to the patient through a mask or nasal tubes.
2. Medications: These may be used to treat any underlying conditions that are causing hyperoxia.
3. Mechanical ventilation: In severe cases, this may be necessary to support the patient's breathing.

In summary, hyperoxia is a condition where there is too much oxygen in the body, and it can cause damage to the body's tissues and organs. Diagnosis is typically made through blood tests or other tests, and treatment may involve oxygen therapy, medications, or mechanical ventilation.

1) They share similarities with humans: Many animal species share similar biological and physiological characteristics with humans, making them useful for studying human diseases. For example, mice and rats are often used to study diseases such as diabetes, heart disease, and cancer because they have similar metabolic and cardiovascular systems to humans.

2) They can be genetically manipulated: Animal disease models can be genetically engineered to develop specific diseases or to model human genetic disorders. This allows researchers to study the progression of the disease and test potential treatments in a controlled environment.

3) They can be used to test drugs and therapies: Before new drugs or therapies are tested in humans, they are often first tested in animal models of disease. This allows researchers to assess the safety and efficacy of the treatment before moving on to human clinical trials.

4) They can provide insights into disease mechanisms: Studying disease models in animals can provide valuable insights into the underlying mechanisms of a particular disease. This information can then be used to develop new treatments or improve existing ones.

5) Reduces the need for human testing: Using animal disease models reduces the need for human testing, which can be time-consuming, expensive, and ethically challenging. However, it is important to note that animal models are not perfect substitutes for human subjects, and results obtained from animal studies may not always translate to humans.

6) They can be used to study infectious diseases: Animal disease models can be used to study infectious diseases such as HIV, TB, and malaria. These models allow researchers to understand how the disease is transmitted, how it progresses, and how it responds to treatment.

7) They can be used to study complex diseases: Animal disease models can be used to study complex diseases such as cancer, diabetes, and heart disease. These models allow researchers to understand the underlying mechanisms of the disease and test potential treatments.

8) They are cost-effective: Animal disease models are often less expensive than human clinical trials, making them a cost-effective way to conduct research.

9) They can be used to study drug delivery: Animal disease models can be used to study drug delivery and pharmacokinetics, which is important for developing new drugs and drug delivery systems.

10) They can be used to study aging: Animal disease models can be used to study the aging process and age-related diseases such as Alzheimer's and Parkinson's. This allows researchers to understand how aging contributes to disease and develop potential treatments.

Open-angle glaucoma can lead to damage to the optic nerve, which can cause vision loss and even blindness if left untreated. It is important for individuals at risk for open-angle glaucoma to receive regular eye exams to monitor their eye pressure and prevent any potential vision loss.

Risk factors for developing open-angle glaucoma include:

* Increasing age
* Family history of glaucoma
* African or Hispanic ancestry
* Previous eye injuries or surgeries
* Long-term use of corticosteroid medications
* Diabetes or other health conditions that can damage blood vessels.

There are several treatment options available for open-angle glaucoma, including:

* Eye drops to reduce eye pressure
* Oral medications to reduce eye pressure
* Laser surgery to improve drainage of fluid from the eye
* Incisional surgery to improve drainage of fluid from the eye.

It is important for individuals with open-angle glaucoma to work closely with their eye care professional to determine the best course of treatment and monitor their condition regularly.

Retinal hemorrhage can cause vision loss or blindness if not treated promptly. The bleeding can lead to scarring, which can cause permanent damage to the retina and affect vision. In some cases, retinal hemorrhage can be a sign of a more serious underlying condition that requires immediate medical attention.

Retinal hemorrhage is diagnosed through a comprehensive eye exam, which includes a visual acuity test, dilated eye exam, and imaging tests such as fluorescein angiography or optical coherence tomography. Treatment options for retinal hemorrhage depend on the underlying cause and can include laser surgery, medication, or vitrectomy.

In summary, retinal hemorrhage is a serious condition that can cause vision loss or blindness if not treated promptly. It is essential to seek medical attention if symptoms such as blurred vision, flashes of light, or floaters are noticed. Early detection and treatment can help prevent or reduce vision loss in cases of retinal hemorrhage.

There are many different types of eye diseases, including:

1. Cataracts: A clouding of the lens in the eye that can cause blurry vision and blindness.
2. Glaucoma: A group of diseases that damage the optic nerve and can lead to vision loss and blindness.
3. Age-related macular degeneration (AMD): A condition that causes vision loss in older adults due to damage to the macula, the part of the retina responsible for central vision.
4. Diabetic retinopathy: A complication of diabetes that can cause damage to the blood vessels in the retina and lead to vision loss.
5. Detached retina: A condition where the retina becomes separated from the underlying tissue, leading to vision loss.
6. Macular hole: A small hole in the macula that can cause vision loss.
7. Amblyopia (lazy eye): A condition where one eye is weaker than the other and has reduced vision.
8. Strabismus (crossed eyes): A condition where the eyes are not aligned properly and point in different directions.
9. Conjunctivitis: An inflammation of the conjunctiva, the thin membrane that covers the white part of the eye and the inside of the eyelids.
10. Dry eye syndrome: A condition where the eyes do not produce enough tears, leading to dryness, itchiness, and irritation.

Eye diseases can be caused by a variety of factors, including genetics, age, environmental factors, and certain medical conditions. Some eye diseases are inherited, while others are acquired through lifestyle choices or medical conditions.

Symptoms of eye diseases can include blurry vision, double vision, eye pain, sensitivity to light, and redness or inflammation in the eye. Treatment options for eye diseases depend on the specific condition and can range from medication, surgery, or lifestyle changes.

Regular eye exams are important for detecting and managing eye diseases, as many conditions can be treated more effectively if caught early. If you experience any symptoms of eye disease or have concerns about your vision, it is important to see an eye doctor as soon as possible.

The retina is a layer of cells that lines the inside of the eye and senses light to send visual signals to the brain. When the retina becomes detached, it can no longer function properly, leading to vision loss or distortion.

Retinal detachment can be caused by a variety of factors, including:

1. Age-related changes: As we age, the vitreous gel that fills the eye can become more liquid and pull away from the retina, causing a retinal detachment.
2. Injury or trauma: A blow to the head or a penetrating injury can cause a retinal detachment.
3. Medical conditions: Certain conditions, such as diabetes, high blood pressure, and sickle cell disease, can increase the risk of developing a retinal detachment.
4. Genetic factors: Some people may be more prone to developing a retinal detachment due to inherited genetic factors.

Symptoms of retinal detachment may include:

1. Flashes of light: People may see flashes of light in the peripheral vision.
2. Floaters: Specks or cobwebs may appear in the vision, particularly in the periphery.
3. Blurred vision: Blurred vision or distorted vision may occur as the retina becomes detached.
4. Loss of vision: In severe cases, a retinal detachment can cause a complete loss of vision in one eye.

If you experience any of these symptoms, it is important to seek medical attention immediately. A comprehensive eye exam can diagnose a retinal detachment and determine the appropriate treatment.

Treatment for retinal detachment typically involves surgery to reattach the retina to the underlying tissue. In some cases, laser surgery may be used to seal off any tears or holes in the retina that caused the detachment. In more severe cases, a scleral buckle or other device may be implanted to support the retina and prevent further detachment.

In addition to surgical treatment, there are some lifestyle changes you can make to help reduce your risk of developing a retinal detachment:

1. Quit smoking: Smoking has been linked to an increased risk of retinal detachment. Quitting smoking can help reduce this risk.
2. Maintain a healthy blood pressure: High blood pressure can increase the risk of retinal detachment. Monitoring and controlling your blood pressure can help reduce this risk.
3. Wear protective eyewear: If you participate in activities that could potentially cause eye injury, such as sports or working with hazardous materials, wearing protective eyewear can help reduce the risk of retinal detachment.
4. Get regular eye exams: Regular comprehensive eye exams can help detect any potential issues with the retina before they become serious problems.

Overall, a retinal detachment is a serious condition that requires prompt medical attention to prevent long-term vision loss. By understanding the causes and symptoms of retinal detachment, as well as making lifestyle changes to reduce your risk, you can help protect your vision and maintain good eye health.

Pathologic neovascularization can be seen in a variety of conditions, including cancer, diabetic retinopathy, and age-related macular degeneration. In cancer, for example, the formation of new blood vessels can help the tumor grow and spread to other parts of the body. In diabetic retinopathy, the growth of new blood vessels in the retina can cause vision loss and other complications.

There are several different types of pathologic neovascularization, including:

* Angiosarcoma: a type of cancer that arises from the cells lining blood vessels
* Hemangiomas: benign tumors that are composed of blood vessels
* Cavernous malformations: abnormal collections of blood vessels in the brain or other parts of the body
* Pyogenic granulomas: inflammatory lesions that can form in response to trauma or infection.

The diagnosis of pathologic neovascularization is typically made through a combination of physical examination, imaging studies (such as ultrasound, CT scans, or MRI), and biopsy. Treatment options vary depending on the underlying cause of the condition, but may include medications, surgery, or radiation therapy.

In summary, pathologic neovascularization is a process that occurs in response to injury or disease, and it can lead to serious complications. It is important for healthcare professionals to be aware of this condition and its various forms in order to provide appropriate diagnosis and treatment.

There are several different types of glaucoma, including:

* Open-angle glaucoma: This is the most common form of glaucoma, and is caused by slowed drainage of fluid from the eye.
* Closed-angle glaucoma: This type of glaucoma is caused by a blockage in the drainage channels of the eye, leading to a sudden increase in pressure.
* Normal-tension glaucoma: This type of glaucoma is caused by damage to the optic nerve even though the pressure in the eye is within the normal range.
* Congenital glaucoma: This is a rare type of glaucoma that is present at birth, and is caused by a developmental defect in the eye's drainage system.

Symptoms of glaucoma can include:

* Blurred vision
* Loss of peripheral vision
* Eye pain or pressure
* Redness of the eye
* Seeing halos around lights

Glaucoma is typically diagnosed with a combination of visual acuity tests, dilated eye exams, and imaging tests such as ultrasound or MRI. Treatment for glaucoma usually involves medication to reduce pressure in the eye, but may also include surgery to improve drainage or laser therapy to prevent further damage to the optic nerve.

Early detection and treatment of glaucoma is important to prevent vision loss, so it is important to have regular eye exams, especially if you are at risk for the condition. Risk factors for glaucoma include:

* Age (over 60)
* Family history of glaucoma
* Diabetes
* High blood pressure
* African or Hispanic ancestry

Overall, glaucoma is a serious eye condition that can cause vision loss if left untreated. Early detection and treatment are key to preventing vision loss and maintaining good eye health.

There are several types of ischemia, including:

1. Myocardial ischemia: Reduced blood flow to the heart muscle, which can lead to chest pain or a heart attack.
2. Cerebral ischemia: Reduced blood flow to the brain, which can lead to stroke or cognitive impairment.
3. Peripheral arterial ischemia: Reduced blood flow to the legs and arms.
4. Renal ischemia: Reduced blood flow to the kidneys.
5. Hepatic ischemia: Reduced blood flow to the liver.

Ischemia can be diagnosed through a variety of tests, including electrocardiograms (ECGs), stress tests, and imaging studies such as CT or MRI scans. Treatment for ischemia depends on the underlying cause and may include medications, lifestyle changes, or surgical interventions.

Epiretinal Membrane Treatment:

Surgical removal of the membrane is the most common treatment for epiretinal membrane. The procedure, called vitrectomy, involves removing the vitreous gel and the membrane from the eye. Laser photocoagulation can also be used to shrink the membrane and relieve symptoms.

It's important to note that not all epiretinal membranes require treatment. Some people may experience no vision problems and may not need any treatment at all. In other cases, the condition may resolve on its own over time. Your eye doctor will be able to determine the best course of action for your specific case.

Epiretinal Membrane Causes:

The exact cause of epiretinal membranes is not fully understood, but they are thought to arise from scar tissue that forms on the retina in response to injury or inflammation. They can also be associated with other eye conditions such as age-related macular degeneration, diabetic retinopathy, and retinal detachment.

Epiretinal Membrane Symptoms:

Symptoms of epiretinal membrane may include:

* Blurred vision
* Distorted vision (e.g., wavy lines or shapes)
* Difficulty reading or performing other daily tasks
* Metamorphopsia (visual distortion)

Epiretinal Membrane Diagnosis:

Your eye doctor will perform a comprehensive eye exam to diagnose epiretinal membrane. This may include a visual acuity test, dilated eye exam, and imaging tests such as optical coherence tomography (OCT) or ultrasonography.

Epiretinal Membrane Prognosis:

In some cases, epiretinal membranes can resolve on their own over time without treatment. However, if the membrane is causing significant vision loss or distortion, your eye doctor may recommend surgical removal. The prognosis for surgical treatment of epiretinal membrane is generally good, with many patients experiencing improved vision following the procedure.

Epiretinal Membrane Treatment:

Treatment for epiretinal membrane depends on the severity of symptoms and may include:

* Watchful waiting: In some cases, your eye doctor may recommend monitoring the membrane over time to see if it resolves on its own.
* Vitrectomy: This is a surgical procedure in which the vitreous gel is removed from the eye and the epiretinal membrane is removed or peeled off the retina.
* Laser photocoagulation: This is a non-surgical procedure that uses lasers to create small burns around the edges of the membrane, causing it to shrink and pull away from the retina.

Epiretinal Membrane Prevention:

There is no known way to prevent epiretinal membranes from forming, but there are some risk factors that may increase your likelihood of developing one. These include:

* Age: Epiretinal membranes are more common in older adults.
* Family history: If you have a family history of epiretinal membranes, you may be at higher risk.
* Previous eye surgery or trauma: People who have had eye surgery or suffered an eye injury may be at higher risk for developing an epiretinal membrane.

Epiretinal Membrane Prognosis:

The prognosis for epiretinal membranes is generally good, especially if the membrane is removed surgically. In some cases, vision may improve spontaneously over time without treatment. However, if left untreated, an epiretinal membrane can cause permanent vision loss. It is important to follow your eye doctor's recommendations for monitoring and treatment to ensure the best possible outcome.

Epiretinal Membrane Complications:

Complications of epiretinal membranes are rare but can include:

* Retinal detachment: This is a serious complication that occurs when the retina pulls away from the underlying tissue.
* Glaucoma: This is a condition that can cause vision loss and is often associated with increased pressure in the eye.
* Macular hole: This is a small hole in the macula, the part of the retina responsible for central vision.

Epiretinal Membrane Surgery:

If an epiretinal membrane is causing vision problems or is not improving with monitoring alone, surgery may be recommended. The goal of surgery is to remove the membrane and prevent it from recurring. There are several types of surgery that can be used to treat epiretinal membranes, including:

* Scleral buckle surgery: This involves sewing a flexible band around the eye to push the retina back into place.
* Vitrectomy: This is a procedure that removes the vitreous gel and any blood or scar tissue that may be causing problems.
* Photocoagulation: This is a procedure that uses laser light to shrink the membrane and seal off any leaky blood vessels.

It's important to note that not all epiretinal membranes require surgery, and in some cases, monitoring alone may be sufficient. Your eye doctor will be able to recommend the best course of treatment based on your specific condition and symptoms.

Symptoms of macular edema may include blurred vision, distorted vision, blind spots, and sensitivity to light. Diagnosis is typically made through a comprehensive eye exam, including a visual acuity test and imaging tests such as optical coherence tomography (OCT).

Treatment for macular edema depends on the underlying cause of the condition. In some cases, medications such as anti-vascular endothelial growth factor (VEGF) injections or corticosteroids may be prescribed to reduce fluid buildup and swelling in the retina. In more severe cases, surgical intervention may be necessary, such as a vitrectomy to remove the vitreous gel and relieve pressure on the retina.

Prevention of macular edema includes managing underlying conditions such as diabetes and age-related macular degeneration, as well as maintaining regular eye exams to detect and treat any changes in the retina early on. Early detection and treatment can help prevent vision loss from macular edema.

There are several different types of uveitis, including:

1. Anterior uveitis: This type affects the front part of the eye and is the most common form of uveitis. It is often caused by an infection or injury.
2. Posterior uveitis: This type affects the back part of the eye and can be caused by a systemic disease such as sarcoidosis or juvenile idiopathic arthritis.
3. Intermediate uveitis: This type affects the middle layer of the eye and is often caused by an autoimmune disorder.
4. Panuveitis: This type affects the entire uvea and can be caused by a systemic disease such as vasculitis or Behçet's disease.

Symptoms of uveitis may include:

* Eye pain
* Redness and swelling in the eye
* Blurred vision
* Sensitivity to light
* Floaters (specks or cobwebs in your vision)
* Flashes of light

If you experience any of these symptoms, it is important to see an eye doctor as soon as possible. Uveitis can be diagnosed with a comprehensive eye exam, which may include imaging tests such as ultrasound or MRI. Treatment for uveitis depends on the cause and severity of the condition, but may include medication to reduce inflammation, antibiotics for infections, or surgery to remove any diseased tissue.

Early diagnosis and treatment are important to prevent complications such as cataracts, glaucoma, and blindness. If you have uveitis, it is important to follow your doctor's recommendations for treatment and monitoring to protect your vision.

Symptoms of type 1 diabetes can include increased thirst and urination, blurred vision, fatigue, weight loss, and skin infections. If left untreated, type 1 diabetes can lead to serious complications such as kidney damage, nerve damage, and blindness.

Type 1 diabetes is diagnosed through a combination of physical examination, medical history, and laboratory tests such as blood glucose measurements and autoantibody tests. Treatment typically involves insulin therapy, which can be administered via injections or an insulin pump, as well as regular monitoring of blood glucose levels and appropriate lifestyle modifications such as a healthy diet and regular exercise.

There are two variants of retinal vessel analysis which are based on a special fundus camera, the Retinal Vessel Analyzer which ... the examination is completely non-invasive and non-demanding for the person undergoing retinal vessel analysis. Retinal vessel ... In static retinal vessel analysis this is a snapshot, in dynamic vessel analysis (DVA) a 12.5 Hz optoelectric flickering light ... the smallest vessels in the human body). The value of the examination with the Retinal Vessel Analyzer has been documented in a ...
Eye vessels Lee, K. E.; Klein, B. E. K.; Klein, R.; Meuer, S. M. (2007). "Association of Retinal Vessel Caliber to Optic Disc ... The central retinal artery (retinal artery) branches off the ophthalmic artery, running inferior to the optic nerve within its ... The central retinal artery pierces the eyeball close to the optic nerve, sending branches over the internal surface of the ... The central retinal artery supplies blood to all the nerve fibers that form the optic nerve, which carries the visual ...
The central retinal vein is the venous equivalent of the central retinal artery. Like that blood vessel, it can suffer from ... The central retinal vein (retinal vein) is a short vein in the retina of the eye. It travels through the optic nerve to drain ... Eye vessels Hayreh, Sohan Singh (2017). "Central Retinal Vein Occlusion". Reference Module in Neuroscience and Biobehavioral ... The central retinal vein varies between individuals. in some the central retinal vein drains into the superior ophthalmic vein ...
Collateral vessels develop to help drain the affected area. branch retinal vein occlusion is four times more common than ... Central retinal vein occlusion Central retinal artery occlusion Branch retinal artery occlusion "Retina and vitreous". Basic ... Branch retinal vein occlusion is a common retinal vascular disease of the elderly. It is caused by the occlusion of one of the ... The eye examination findings of acute branch retinal vein occlusion include superficial hemorrhages, retinal edema, and often ...
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 ... Riva, CE; Grunwald, JE; Petrig, BL (1986). "Autoregulation of human retinal blood flow. An investigation with laser Doppler ...
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 ...
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. F. P. Schäfer (ed.), Dye Lasers (Springer, 1990) F. J. Duarte and L. W. Hillman (eds.), Dye ... Tunable sources were recently used for the development of hyperspectral imaging for early detection of retinal diseases where a ...
Patz, Arnall (December 1965). "The Effects of Oxgyen on Immature Retinal Vessels". Investigative Ophthalmology & Visual Science ... He also conducted pioneering research in the 1960s into the use of lasers in the treatment of retinal disorders. He received ... He was also a founder of the Johns Hopkins' Retinal Vascular Center. In the late 1960s, Patz also conducted pioneering research ... 2: Retinal Vascular Disorders. St. Louis: Mosby. ISBN 9780801637629. OCLC 954478221. Patz, Arnall; Fine, Stuart L. (1977). ...
2013). "Regional variation in human retinal vessel oxygen saturation". Experimental Eye Research. 113: 143-147. doi:10.1016/j. ... retinal vessel oxygen saturation ), in the biomedical field in addition to neurology and dermatology for the identification and ... retinal imaging). More recently, in June 2015, Photon etc. expanded its expertise in nanotechnology and launched a new division ...
2013). "Regional variation in human retinal vessel oxygen saturation". Experimental Eye Research. 113: 143-147. doi:10.1016/j. ...
Central retinal vein and/or central retinal arterial thrombosis. Small vessel thrombosis affecting one or more organs, systems ...
... 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. 53 (2-3): 239-252. doi: ... Evaluation of tortuosity of eye blood vessels using the integral of square of derivative of curvature // EMBEC'05: proceedings ...
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 ...
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 ...
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. ... The neurological symptoms of the disease vary depending on the degree; the nature of the blood vessel obstruction; and can ... In the Western world, atherosclerosis is a more frequent cause of obstruction of the aortic arch vessels than Takayasu's ...
Among all these syndromes, there exists some retinal vessel inflammation. The differences in the dots are usually in the size, ... The lesion may occur within the choroid, between Bruch's membrane and retinal pigment epithelium, or between the retinal ... The white dots are small and located in the posterior pole at the level of the retinal pigment epithelium. The white dots may ... There are yellow-white placoid lesions in the posterior pole at the level of the retinal pigment epithelium. Some suggest a ...
These are the cotton wool exudates and small haemorrhages along the retinal vessels and macula. Fulminant FES - This type of ... Retinal changes similar to Purtscher's retinopathy may also be present. Retinal changes happens in 50% of the patients with FES ...
Explanation of the sheathing of the retinal vessels in Tuberous Sclerosis. Description of MRI and other features of acute ... Pradhan, Sunil (1991). "Focal Sheathing of Retinal Arteries in Tuberous Sclerosis". Pediatric Neurosurgery. 17 (5): 279-280. ...
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, ...
Formed by endothelium of retinal vessels and epithelium of retinal pigment. Blood-air barrier - Membrane separating alveolar ... Blood-retinal barrier: non-fenestrated capillaries of the retinal circulation and tight-junctions between retinal epithelial ... ciliary epithelium and retinal pigment epithelium. It is a physical barrier between the local blood vessels and most parts of ... A physical barrier between the blood vessels and the seminiferous tubules of the animal testes Blood-thymus barrier - Barrier ...
... the retinal vascular endothelium and the retinal pigment epithelium. Retinal blood vessels that are similar to cerebral blood ... The retinal pigment epithelium maintains the outer blood-retinal barrier. Diabetic retinopathy, eye damage that frequently ... Blood-retinal barrier. Retrieved on July 19, 2007. Vinores, SA (1995). "Assessment of blood-retinal barrier integrity". ... It consists of non-fenestrated capillaries of the retinal circulation and tight-junctions between retinal epithelial cells ...
... the vessels can pull the retina away from the back wall of the eye causing a traction retinal detachment. Although retinal ... Retinal Detachment Resource Guide from the National Eye Institute (NEI) Overview of retinal detachment from eMedicine Retinal ... Rhegmatogenous retinal detachment - A rhegmatogenous retinal detachment occurs due to a hole or tear (both of which are ... Retinal detachment can occur more frequently after surgery for cataracts. The estimated of risk of retinal detachment after ...
"Genetic Programming with Alternative Search Drivers for Detection of Retinal Blood Vessels". {{cite journal}}: Cite journal ...
Digital Retinal Images for Vessel Extraction (DRIVE) STructured Analysis of the REtina (STARE) High-Resolution Fundus (HRF) ... Vessel tracking is the ability of the algorithm to detect "centerline" of vessels. These centerlines are maximal peak of vessel ... Imaging is used to recognize early signs of abnormal retinal blood vessels. Manual analysis of these images can be time- ... Biradar, S; Jadhav, AS (2015). "A survey on blood vessel segmentation and optic disc segmentation of retinal images" (PDF). ...
There may be a few vessels (retinal or choroidal) at the edges. The surface may have irregular depression. Coloboma of the iris ... retinal dysplasia or retinal detachment, sensory nystagmus, cortical visual loss, and optic nerve hypoplasia. Treacher Collins ...
2020). "A visual framework to create photorealistic retinal vessels for diagnosis purposes". Journal of Biomedical Informatics ...
A retinal scan is a biometric technique that uses unique patterns on a person's retina blood vessels. It is not to be confused ... Because retinal blood vessels absorb light more readily than the surrounding tissue, the amount of reflection varies during the ... The National Center for State Courts estimate that retinal scanning has an error rate of one in ten million. A retinal scan is ... Although retinal patterns may be altered in cases of diabetes, glaucoma or retinal degenerative disorders, the retina typically ...
"Comparative study of retinal vessel segmentation methods on a new publicly available database". Proc SPIE Med Imag. Medical ... "Retinal Physician - CONVERSATIONS IN RETINA: A Conversation With Michael Abràmoff, MD, PhD". Retinal Physician. Retrieved 2018- ... Abramoff, Michael D; Garvin, Mona K; Sonka, Milan (2010). "Retinal Imaging and Image Analysis". IEEE Reviews in Biomedical ... SPIETV (February 23, 2012), Automated detection of retinal disease: when Moore's law meets Baumol's cost disease, retrieved ...
... 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 damage ... These pathologically overgrown blood vessels are often fragile, weak, and ineffective at perfusing the retinal tissues. These ...
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 ... such as the retinal blood vessels (see Purkinje tree below). Some may be individual red blood cells swollen due to osmotic ... 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 ...
Peak serum concentration (Cmax) is achieved after 1 hour, but its effect on blood vessels is seen only after 3 hours. The half- ... Wiedemann, Meike; de Lima, Vera M. Fernandes; Hanke, Wolfgang (1996-04-01). "Effects of antimigraine drugs on retinal spreading ... This drug decreases the permeability and fragility of blood vessels, which reduces the number of migraine days and attenuates ...
... and less commonly there may be twisted retinal blood vessels or optic nerve hypoplasia. The eye anomalies can result in an ...
Though the exact pathogenesis of this disorder is unknown, the retinal and brain biopsy findings suggest a small vessel ... Both patients underwent fluorescein retinal angiography that demonstrated multifocal retinal artery occlusions without evidence ... Retinal Artery Wall Plaques in Susac Syndrome. American Journal of Ophthalmology 135: 483-6; 2003 Susac JO, Murtagh FR, Egan RA ... Partial vision loss is often present and caused by branch retinal artery occlusions. The presence of refractile or non- ...
Labauge P, Krivosic V, Denier C, Tournier-Lasserve E, Gaudric A (Jun 2006). "Frequency of retinal cavernomas in 60 patients ... are vascular malformations in the brain and spinal cord made of dilated capillary vessels. CCM3 encodes a protein called ...
Physical barrier between the local blood vessels and most parts of the eye itself Blood-retinal barrier - Part of the blood- ... A physical barrier between the blood vessels and the seminiferous tubules of the animal testes Blood-thymus barrier - Barrier ...
... is a form of retinopathy due to retinal bleeding secondary to rupture of retinal vessels caused by ... sub-hyaloid or sub-internal limiting membrane hemorrhage occur due to rupture of retinal vessels caused by a strenuous physical ... may cause sudden increase in intrathoracic or intra-abdominal pressure may lead to rupture of superficial retinal blood vessels ... Salmon JF (13 December 2019). "Retinal vascular disease". Kanski's clinical ophthalmology : a systematic approach (9th ed.). ...
Theories suggest that the dis edema is due to retinal vascular leakage into and surrounding the optic nerve and disruption of ... Fundus examination often reveals dilated telangiectatic vessels over the disc also. Diabetic papillopathy has many ...
Blood vessels enter the central nervous system through holes in the meningeal layers. The cells in the blood vessel walls are ... Wong, RO (1999). "Retinal waves and visual system development". Annual Review of Neuroscience. St. Louis, MO. 22: 29-47. doi: ... Several hypothalamic nuclei receive input from sensors located in the lining of blood vessels, conveying information about ... it to generate waves of activity that originate spontaneously at a random point and then propagate slowly across the retinal ...
... the retina separates into several layers and may detach A retinal vessel occlusion is a blockage in the blood vessel at the ... Retinal haemorrhage (H35.7) Separation of retinal layers Central serous retinopathy Retinal detachment: Detachment of retinal ... Peripheral retinal degeneration (H35.5) Hereditary retinal dystrophy (H35.5) Retinitis pigmentosa - genetic disorder; tunnel ... H35.0) Hypertensive retinopathy - burst blood vessels, due to long-term high blood pressure (H35.0/E10-E14) Diabetic ...
The normal blood vessel is open, allowing for adequate blood flow. When catecholamines activate the alpha receptor, the vessel ... Polycythemia Duodenal somatostatinoma Retinal and choroidal vascular changes Paraganglioma/Pheochromocytoma Pheochromocytoma ... Norepinephrine causes vessels to narrow, thereby limiting blood flow and inducing ischemia. Multiple organ dysfunction syndrome ... This complication is related to the impact that alpha and beta-adrenoceptor antagonists have on blood vessels combined with the ...
Puyo L, Paques M, Atlan M (2020). "Retinal blood flow reversal in out-of-plane vessels imaged with laser Doppler holography". ... The retinal nerve fiber layer can be assessed with imaging techniques such as optical coherence tomography, scanning laser ... In glaucoma visual field defects result from damage to the retinal nerve fiber layer. Field defects are seen mainly in primary ... These injectable medications can lead to a dramatic decrease in new vessel formation and, if injected early enough in the ...
There are also several neuroprosthetic devices that aim to restore vision, including retinal implants. The first ... possibly due to endothelial incorporation of the Stentrode into the vessel wall. First-in-human trials with the Stentrode are ... marking the first time a brain-computer interface was implanted via the patient's blood vessels, eliminating the need for open ...
Retinal venous dilation occurs in 59% of people with HACE. Rarer symptoms include brisk deep tendon reflexes, retinal ... This demonstrated that the blood-brain barrier was broken by cerebral blood vessels, thus interfering with white matter ...
A common sign of diabetes is the degradation of blood vessels in various tissues throughout the body. Retinopathy refers to ... LSD1 may play a major role in diabetic retinopathy through the downregulation of Sod2 in retinal vascular tissue, leading to ... It is believed that much of the retinal vascular degeneration characteristic of diabetic retinopathy is due to impaired ...
Upon photoisomerization by a photon the cis-retinal is converted to trans-retinal causing activation of rhodopsin which ... Specifically in blood vessels, the increase in Ca2+ concentration from IP3 releases nitric oxide, which then diffuses into the ... It binds rhodopsin, a well-characterized GPCR that binds all-cis retinal in its inactive state. ...
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 Cases & Brief Reports. 4 (2): 140-2. doi:10.1097/ICB.0b013e31819955bf. PMID 25390387. Forbes BA, Sahm DF, Weissfeld AS ... organisms carried by blood vessels to the eye from another site of infection). Other non-infectious causes include toxins, ...
April 2007). "Limited peripheral T cell anergy predisposes to retinal autoimmunity". Journal of Immunology. 178 (7): 4276-83. ... and ophthalmic examination may show dilated ciliary blood vessels and the presence of cells in the anterior chamber. Uveitis ... December 2003). "An immunologically privileged retinal antigen elicits tolerance: major role for central selection mechanisms ... Non-neoplastic: retinitis pigmentosa intraocular foreign body juvenile xanthogranuloma retinal detachment Neoplastic: ...
In the same years, Fyodorov converted a seagoing vessel, the Peter I, into an eye clinic, part of the institute, which sailed ... At present, the center treats cataract, refractive abnormalities, glaucoma, vitreal, retinal and optic nerve pathology, corneal ...
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 ...
Furthermore, pigs, along with bats and quails, are recognized as a mixing vessel of influenza viruses because they have both α- ... such as respiratory and retinal epithelial cells. AIVs prefer sialic acids with an α-2,3 linkage, which are most common in ... Pigs, bats, and quails have receptors for both mammalian and avian IAVs, so they are potential "mixing vessels" for ... raising concerns that horses may be mixing vessels for reassortment. In canines, the only IAVs in circulation are equine- ...
... 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 the ... This then reduces the growth of the blood vessels located within the eye and works to control the leakage and swelling. ...
In a study of patients with a disease similar to Conorenal (renal-retinal Senior-Loken) the authors state "We show that ... or clusters of blood vessels that act as filters in the kidney) were features of the syndrome. A recent article by Beals and ... The loss of cystoproteins may lead to dysregulated growth.[citation needed] The link to a ciliar dysfunction in the Retinal ... Our studies emphasize the central role of ciliary dysfunction in the pathogenesis of renal-retinal Senior Loken Syndrome." In ...
In the other 75% it is a complication of medical procedures involving the blood vessels, such as vascular surgery or ... retinal manifestations and the role of carotid endarterectomy". J Vasc Surg. 11 (5): 635-641. doi:10.1016/0741-5214(90)90208-R ... The main problem is the distinction between cholesterol embolism and vasculitis (inflammation of the small blood vessels), ... causing an obstruction in blood vessels further away. Most commonly this causes skin symptoms (usually livedo reticularis), ...
FFA is used to identify Retinal periphlebitis (inflammation of the peripheral blood vessels in the eye) or peripheral non- ... in 1880 and is a rare ocular disease characterized by inflammation and possible blockage of retinal blood vessels, abnormal ... There may also be other signs that are identified via eye examination that can show retinal tears and retinal detachment that ... Eye floaters may develop indicating the possibility of the progression of the disease to a point where retinal detachment is a ...
See also: retinal ganglion cell Oculomotor nerve (cranial nerve 3) Eye movement (except rotation), including constriction of ... Stimulation of stretch sensors that sense dilation of various blood vessels may result in pain, for example headache caused by ... Baroreceptors respond to pressure in blood vessels Chemoreceptors respond to chemical stimuli Hydroreceptors respond to changes ...
Zefram Cochrane and helps him successfully launch Earth's first warp-capable vessel and achieve first contact with the Vulcans ... Nirenberg, Sheila; Pandarinath, Chethan (August 13, 2012). "Retinal prosthetic strategy with the capacity to restore normal ...
Conversely, the blood vessels in the lower legs are under great pressure because of the weight of fluid pressing down on them. ... giraffe vision is more binocular and the eyes are larger with a greater retinal surface area. Giraffes may see in colour: 85 ... When it raises again, the blood vessels constrict and push blood into the brain so the animal does not faint. The jugular veins ... The skin under the blotches may regulate the animal's body temperature, being sites for complex blood vessel systems and large ...
Cardiac imaging techniques include coronary catheterization, echocardiogram, intravascular ultrasound, retinal vessel analysis ...
It has been reported that the action of AR contributes to the activation of retinal microglia, suggesting that inhibition of AR ... blood vessels, lung, and liver. It is a reduced nicotinamide-adenine dinucleotide phosphate (NADPH)-dependent enzyme catalyzing ... Sato S, Lin LR, Reddy VN, Kador PF (August 1993). "Aldose reductase in human retinal pigment epithelial cells". Experimental ... Akagi Y, Kador PF, Kuwabara T, Kinoshita JH (November 1983). "Aldose reductase localization in human retinal mural cells". ...
... central retinal artery, 9.5 +/- 3.1 cm/s; central retinal vein, 5.7 +/- 1.5 cm/s; and ophthalmic artery, 31.6 +/- 9.0 cm/s. ... pulsed Doppler ultrasonography of central retinal vessels and ophthalmic arteries of 72 normal subjects gave the following ... central retinal vein, 5.7 +/- 1.5 cm/s; and ophthalmic artery, 31.6 +/- 9.0 cm/s. Doppler shifts in the central retinal vessels ... Doppler ultrasonography of the ophthalmic and central retinal vessels Arch Ophthalmol. 1991 Apr;109(4):532-6. doi: 10.1001/ ...
The aim of this study was to quantitatively investigate the retinal vessels in these disorders, using dynamic vessel analyzer ( ... This study demonstrate that Alzheimers and MCI subjects are characterized by a significant impairment of the retinal ... Furthermore, a prospective longitudinal evaluation of retinal vessels in MCI subjects might clarify if retinal vascular ... Inter-method agreement in retinal blood vessels diameter analysis between Dynamic Vessel Analyzer and optical coherence ...
An automatic retinal vessel segmentation system can effectively facilitate clinical diagnosis and ophthalmological research. ... Experimentally, sufficient comparative experiments have been enforced on three retinal vessel segmentation datasets, DRIVE, ... Technically, this problem suffers from various degrees of vessel thickness, perception of details, and contextual feature ... Accurate retinal vessel segmentation is a challenging problem in color fundus image analysis. ...
Retinal vessel diameters and microvascular abnormalities in patients with carotid stenosis before and 6 months after carotid ... Retinal vessel diameters and microvascular abnormalities in patients with carotid stenosis before and 6 months after carotid ... title = "Retinal vessel diameters and microvascular abnormalities in patients with carotid stenosis before and 6 months after ... Retinal vessel diameters and microvascular abnormalities in patients with carotid stenosis before and 6 months after carotid ...
Ali, Aziah and Hussain, Aini and Wan Zaki, Wan Mimi Diyana (2018) Effects of Color Constancy Algorithm on Retinal Blood Vessel ... One of the important steps towards a fully automated retinal image diagnosis system is automatic segmentation of blood vessels ... Image Processing, Blood Vessel Segmentation, Color Constancy. Subjects:. T Technology , TA Engineering (General). Civil ... We compared two different algorithms for color constancy, namely Gray World and White Patch that are applied to retinal image ...
Detecting the optic cup excavation in retinal fundus images by automatic detection of vessel kinking. ICPR, 2012.. ICPR 2012. ... Detecting the optic cup excavation in retinal fundus images by automatic detection of vessel kinking}", year = 2012, }. ...
Tortuous retinal vessels with occasional arteriovenous communications. Ocular signs that may indicate the presence of infantile ... The leptomeningeal blood vessel circumference was decreased, while blood vessel density was increased in SWS. [30] ... These may be isolated to the skin, associated with lesions in the choroidal vessels of the eye or the leptomeningeal vessels of ... Malformed cortical vessels in SWS have been reported to be innervated only by noradrenergic sympathetic nerve fibers, [29] and ...
... new blood vessels form, but are weak and prone to leakage. Scar tissue forms which may lead to retinal detachment and blindness ... Mild NPDR refers to the early stages where blood vessels begin to swell and leak.(NEI, 2015) In moderate cases of NPDR, blood ... Diabetic retinopathy (DR) occurs when high blood sugar damages the blood vessels below the retina. There are two primary types ... NPDR is considered severe when the retina becomes oxygen deprived and signals growth factors to form new blood vessels.(NEI, ...
Proliferation of new vessels and fibrous tissues. * Contraction of fibrous tissue and hemorrhage and/or retinal detachment due ... Prolliferative Diabetic Retinopathy - New vessels on the disc (NVD). - New vessels elsewhere on the retina (NVE). - Preretinal ... Increased vascular permeability of retinal capillaries. * Closure of retinal capillaries and arterioles. * ... Focal neuropathy is an uncommon condition believed to occur after the acute occlusion of a blood vessel produces ischemia in a ...
Categories: Retinal Vessels Image Types: Photo, Illustrations, Video, Color, Black&White, PublicDomain, CopyrightRestricted 22 ...
The choroid is a collection of blood vessels supplying the retina. CEA can also cause retinal or scleral coloboma, coloboma of ... "Hereditary Retinal Diseases" (PDF). Proceedings of the 31st World Congress of the World Small Animal Veterinary Association ... the optic disc, retinal detachment, or intraocular hemorrhage. It can be diagnosed by fundoscopy by the age of six or seven ...
Juvenile retinoschisis: Tiny splits in the retinal layers and cavities filled with blood vessels and blisters. Over time, blood ... Fluorescein angiography: This test involves an injection of a dye into the vein in the arm to highlight blood vessels in the ... Stargardt disease: Yellowish-white flecks in or around the macula and atrophy of the retinal pigment epithelium, which is the ... Exudative macular degeneration is a progressive eye disease that causes leaky blood vessels and can lead to vision loss. Learn ...
Retinal vessels were of normal calibre but each macula exhibited fine stippling shown by fluorescein angiography (Horgan & ... In some cases the retinal vessels have appeared narrowed early. In another group of cases the retina has appeared oedematous ... Because the etiology was originally thought to be retinal ischaemia, multiple methods have been used to cause retinal ... Horgan SE & Williams RW (1995) Chronic retinal toxicity due to quinine in Indian Tonic water Eye 9: 637-638.. Jaeger A, Sauder ...
The orange arrows indicate RGC axon bundles, and the red arrows indicate blood vessels. B, The k values for mice before (black ... retinal pigment epithelium. The green arrows exemplify retinal thickness measurements, the blue arrows exemplify the GCIPL ... C, D, Distribution of retinal thickness measurements from the central (C) and the peripheral regions (D). E, F, GCIPL thickness ... BAX knock-out mice (BAX−/−) showed increased retinal and RGC axon bundle thickness. A, Example fibergrams (left panels) and ...
It can damage the small blood vessels in the retina, the back part of your eye. This condition is called diabetic retinopathy. ... Blood vessels that are blocked. *Small amounts of bleeding (retinal hemorrhages) and fluid leaking into the retina ... It is used to keep vessels from leaking, or to shrink abnormal vessels. ... Retinal detachment -- Scarring that may cause part of the retina to pull away from the back of your eyeball. ...
... including the growth of new blood vessels, are common in people with diabetes. PDR can lead to retinal tissue death, permanent ... abnormal blood vessels in the light-sensing retina. These blood vessels are prone to bleeding into the gel-like vitreous that ... These drug treatments decrease the growth of blood vessels in the eye and prevent rebleeds while the blood in the vitreous is ... Prior to the development of surgical and laser treatments to remove blood and regress abnormal blood vessel growth, PDR was a ...
Blood vessels that are blocked. *Small amounts of bleeding (retinal hemorrhages) and fluid leaking into the retina ... It is used to keep vessels from leaking, or to shrink abnormal vessels. ... Retinal detachment -- Scarring that may cause part of the retina to pull away from the back of your eyeball. ... If you already have damage to the blood vessels in your eye, some types of exercise can make the problem worse. Check with your ...
Title: A Retinal Image Enhancement Technique for Blood Vessel Segmentation Algorithm Authors: A. M. R. R. Bandara, P. W. G. R. ...
Biometrics-machine recognition of fingerprints, voice, retinal blood vessel patterns, etc. *Object-oriented, reusable software ... Augmented reality-visual overlay of context-relevant information presented by means of heads-up display (HUD), retinal laser " ...
Ophthalmoscopic examination reveals nothing unusual in the nerve head, vessels or retinal background. The vision for distance, ...
This blood vessel damage can cause fluid and blood to leak into the retina. The larger retinal vessels can start to dilate and ... abnormal blood vessels. The growth of the new blood vessels can cause bleeding inside the eye and stimulate scar tissue, which ... When the retinas blood supply is cut off, the eye attempts to grow new blood vessels. However, they dont grow properly and, ... The primary cause of diabetic retinopathy is too much sugar in the bloodstream leading to damage of the tiny blood vessels that ...
Estrogens can cause a blood clot in the retinal vessels of the eye. Seek emergency care right away if you experience vision ... or retinal vessels of the eye.. *Estrogens can increase the risk of endometrial cancer, breast cancer, and ovarian cancer. The ...
Retinal vessel multifractals predict pial collateral status in patients with acute ischemic stroke Year: 2022 ...
State-of-the-art retinal vessel segmentation with minimalistic models ». Scientific Reports. vol. 12 , nº 1. ... Automatic classification and triage of diabetic retinopathy from retinal images based on a convolutional neural networks (CNN) ... Non-uniform label smoothing for diabetic retinopathy grading from retinal fundus images with deep neural networks ». ...
... the vessels grow out from the optic disc and only reach the periphery of the eye 1 month after birth (Kanski, 2011) ROP was ... is a proliferative disorder of the immature retinal vasculature The retina has no blood vessels until around 16 weeks ... Left untreated, infants are at risk of developing strabismus, myopia, vitreous haemorrhage, vitreo-retinal fibrosis, retinal ... The retina has no blood vessels until around 16 weeks gestation; the vessels grow out from the optic disc and only reach the ...
High saturated-fat diets can cause plaque buildup along blood vessel walls, including the macular vessels, which impedes blood ... The bleeding causes scarring and retinal tissue death. About 80 to 85 percent of those with MD have the atrophic form; but most ... Smoking can decrease blood supply by causing a narrowing of the blood vessels and a thickening of the blood, much the same as ... There is a rich supply of blood vessels that carry oxygen and important nutrients to the retina that are required for healthy ...
  • Scar tissue forms which may lead to retinal detachment and blindness). (cdc.gov)
  • In 1968, a group of experts developed a grading system for DR called the Arlie House Classification of DR.(Wu L, 2013) The system grades stereo photographs and classifies DR in 13 levels: level 10 indicates no retinopathy and level 85 signifies retinal detachment or severe vitreous hemorrhage. (cdc.gov)
  • CEA can also cause retinal or scleral coloboma, coloboma of the optic disc, retinal detachment , or intraocular hemorrhage. (wikipedia.org)
  • Retinal detachment -- Scarring that may cause part of the retina to pull away from the back of your eyeball. (medlineplus.gov)
  • It may also be used to repair retinal detachment. (medlineplus.gov)
  • 4] New vessels develop on the posterior hyaloid face, the iris and in the angle causing vitreous haemorrhage, retinal detachment and neovascular glaucoma. (who.int)
  • This stage is characterized by all the above signs plus new because of haemorrhage, tractional retinal detachment or vessels growing at the disc or elsewhere (Figure 2a). (who.int)
  • Inflammatory swelling of the choroid may cause fluid to accumulate behind the retina, resulting in partial or total retinal detachment. (vin.com)
  • Ophthalmologic findings include macular edema and blot hemorrhages (10), cotton wool spots (1), retinal vasculitis (4), exudative retinal detachment (2), and anterior uveitis (1). (cdc.gov)
  • Diabetic retinopathy (DR) occurs when high blood sugar damages the blood vessels below the retina. (cdc.gov)
  • AOA, 2015) With NPDR, the blood vessels of the retina leak, causing the macula to swell. (cdc.gov)
  • NPDR is considered severe when the retina becomes oxygen deprived and signals growth factors to form new blood vessels. (cdc.gov)
  • The choroid is a collection of blood vessels supplying the retina. (wikipedia.org)
  • It can damage the small blood vessels in the retina, the back part of your eye. (medlineplus.gov)
  • Diabetic retinopathy is caused by damage from diabetes to blood vessels of the retina. (medlineplus.gov)
  • If your eye doctor notices new blood vessels growing in your retina (neovascularization) or you develop macular edema, treatment is usually needed. (medlineplus.gov)
  • Laser eye surgery creates small burns in the retina where there are abnormal blood vessels. (medlineplus.gov)
  • A consequence of diabetes, PDR involves the growth of new, abnormal blood vessels in the light-sensing retina. (nih.gov)
  • This latest DRCR Retina Network study lets us understand how outcomes in the modern era of retinal surgery compare to treatment with intraocular anti-VEGF injections for vitreous hemorrhage from PDR. (nih.gov)
  • There is a rich supply of blood vessels that carry oxygen and important nutrients to the retina that are required for healthy vision, and disruption of this vasculature can be a contributing factor in MD. The retina has no pain nerve fibers, therefore most diseases that affect the retina do not cause pain. (drweil.com)
  • The second, exudative or wet MD, is caused by leaks in the blood vessels of the retina. (drweil.com)
  • One of these is diabetic retinopathy, a complication that's caused by damage to the blood vessels in the light-sensitive tissue in the back of the eye called the retina. (kelsey-seybold.com)
  • This blood vessel damage can cause fluid and blood to leak into the retina. (kelsey-seybold.com)
  • Advanced diabetic retinopathy (proliferative diabetic retinopathy) is the more severe form of the condition, during which poor blood flow to the retina can lead to the growth of new, abnormal blood vessels. (kelsey-seybold.com)
  • The growth of the new blood vessels can cause bleeding inside the eye and stimulate scar tissue, which over time can cause the retina to detach from the back of the eye. (kelsey-seybold.com)
  • The primary cause of diabetic retinopathy is too much sugar in the bloodstream leading to damage of the tiny blood vessels that deliver nourishment to the retina. (kelsey-seybold.com)
  • If a branch of the retinal artery is blocked, part of the retina will not receive enough blood and oxygen. (stlukes-stl.com)
  • The blood vessels which supply and drain the RETINA. (bvsalud.org)
  • Infection of the retina by cytomegalovirus characterized by retinal necrosis, hemorrhage, vessel sheathing, and retinal edema. (bvsalud.org)
  • therefore, we investigated the prevalence among 33 patients with retinal vein and artery occlu- sions and 80 controls. (who.int)
  • The retinal artery occlusion may last for only a few seconds or minutes, or it may be permanent. (stlukes-stl.com)
  • The most likely diagnosis is a central retinal artery occlusion (CRAO) due to dermal fillers. (medscape.com)
  • Research demonstrates that delivery of larger amounts of filler material, rapid injections, infiltration of material with too much pressure, and placement into vessels that may lead to retrograde flow to the central retinal artery present the greatest risk for blindness. (medscape.com)
  • Retinal artery occlusion causes catastroph- embolysis, and there are only 2 reports on ic, sudden visual loss. (who.int)
  • More than 90% of eyes with successful use of Reynard and Hanscom's central retinal artery occlusion (CRAO) method [ 4 ], with some modifications, for have a sudden, painless decrease in visual the treatment of retinal artery occlusion. (who.int)
  • Doppler shifts in the central retinal vessels were absent at intraocular pressures above 80 mm Hg. (nih.gov)
  • Association between blood pressure and retinal vessel diameters among police officers in the US Northeast. (cdc.gov)
  • Complement factor h polymorphism, inflammatory mediators, and retinal vessel diameters: the rotterdam study. (cdc.gov)
  • These blood vessels are prone to bleeding into the gel-like vitreous that fills the eye, causing vision loss. (nih.gov)
  • These drug treatments decrease the growth of blood vessels in the eye and prevent rebleeds while the blood in the vitreous is being absorbed. (nih.gov)
  • Medicines that are injected into the eyeball may help prevent abnormal blood vessels from growing and improve macular edema. (medlineplus.gov)
  • 3] Intra-retinal fluid can accumulate in the macular and is known as macular oedema. (who.int)
  • High saturated-fat diets can cause plaque buildup along blood vessel walls, including the macular vessels, which impedes blood flow. (drweil.com)
  • The role of OCT in the assessment and management of retinal diseases has become significant in understanding the vitreoretinal relationships and the internal architecture of the retinal structure. (biomedcentral.com)
  • OCT has also improved diagnosis and management of retinal diseases by reducing reliance on insensitive tests such as perimetry and subjective disc grading. (biomedcentral.com)
  • Methods of Studying Retinal Vessels in Health and Diseases. (bvsalud.org)
  • Antinuclear antithrombin, protein C, protein S or pres- antibodies were investigated with standard- ence of antiphospholipid antibodies, are ized enzyme-linked immunosorbent assay common in patients with retinal vein occlu- sions and may contribute to the etiology of (ELISA). (who.int)
  • Ocular changes linked to FeLV are related to the ability of the virus to induce immunosuppression, hematologic changes and tumor formation, and include nodular uveal tumors, often with secondary uveitis, retinal dysplasia, retinal hemorrhages and pupillary changes. (vin.com)
  • Technically, this problem suffers from various degrees of vessel thickness, perception of details, and contextual feature fusion. (harvard.edu)
  • BAX knock-out mice (BAX −/− ) showed increased retinal and RGC axon bundle thickness. (jneurosci.org)
  • The green arrows exemplify retinal thickness measurements, the blue arrows exemplify the GCIPL measurements, and the orange arrows exemplify RGC axon bundle measurements. (jneurosci.org)
  • C , Distribution of retinal thickness measurements for CTRL (black) and BAX −/− (red) mice. (jneurosci.org)
  • At 12 d after ONC injury, mice exhibited reduced retinal and RGC axon bundle thickness. (jneurosci.org)
  • Though thickness differences may characterize regions with early pathological signs from normal regions, differences in optical properties and texture descriptors of normal and abnormal retinal tissue may also provide additional information of disease development in pathological eyes. (biomedcentral.com)
  • Accurate retinal vessel segmentation is a challenging problem in color fundus image analysis. (harvard.edu)
  • An automatic retinal vessel segmentation system can effectively facilitate clinical diagnosis and ophthalmological research. (harvard.edu)
  • One of the important steps towards a fully automated retinal image diagnosis system is automatic segmentation of blood vessels from the retinal image. (mmu.edu.my)
  • The complete vision loss, as opposed to focal paracentral scotoma that is characteristic of retinal ischemia secondary to antiphospholipid antibodies , essentially rules out this diagnosis. (medscape.com)
  • These small vessels are one of the key indicators for early detection of diabetic retinopathy. (mmu.edu.my)
  • Diabetic retinopathy is a microangiopathy affecting retinal capillaries and venules that occurs in a response to persistent hyperglycaemia. (who.int)
  • Early diabetic retinopathy (non-proliferative diabetic retinopathy - NPDR) is the more common form of the condition, which causes the walls of the retina's blood vessels to weaken. (kelsey-seybold.com)
  • The most important retinal pathology caused by diabetes is diabetic retinopathy (DR), which is characterized by blood vessels damage. (biomedcentral.com)
  • Retinal arteries may become blocked when a blood clot or fat deposits get stuck in the arteries. (stlukes-stl.com)
  • The aim of this study was to quantitatively investigate the retinal vessels in these disorders, using dynamic vessel analyzer (DVA) and optical coherence tomography angiography (OCTA) analysis. (nature.com)
  • The sensitivity of Optical Coherence Tomography (OCT) images to identify retinal tissue morphology characterized by early neural loss from normal healthy eyes is tested by calculating structural information and fractal dimension. (biomedcentral.com)
  • This causes retinal ischemia and results in release of vascular endothelial growth factors that stimulate growth of new vessels. (who.int)
  • [ 1 ] Its hallmark features include necrotizing granulomatous inflammation and pauci-immune vasculitis in small- and medium-sized blood vessels. (medscape.com)
  • CNS manifestations include vasculitis of small to medium-sized vessels of the brain or spinal cord and granulomatous masses that involve the orbit, optic nerve, meninges, or brain. (medscape.com)
  • It is used to keep vessels from leaking, or to shrink abnormal vessels. (medlineplus.gov)
  • Differences in optical properties and roughness measures of normal and abnormal retinal tissue may provide additional information of disease development in pathological eyes. (biomedcentral.com)
  • Ophthalmoscopic examination reveals nothing unusual in the nerve head, vessels or retinal background. (druglibrary.org)
  • Within the eye the damaged vessels may leak blood and fluid into the surrounding tissues and cause vision problems. (mountsinai.org)
  • Structural weakness of the wall of the capillaries results in development of aneurysms, exudation of plasma fluid and bleeding on the retinal surface. (who.int)
  • Temporal arteritisis inflammation and damage to the blood vessels that supply blood to the head, neck, upper body and arms. (stlukes-stl.com)
  • To prevent more blood vessels from forming, vitrectomy is usually paired with a laser treatment (laser photocoagulation). (nih.gov)
  • There have also been 2 postmarketing reports of electroretinogram changes, 1 case of lens subluxation after vitrectomy that took place 12 days after ocriplasmin injection, a 0.3% incidence of an impaired pupillary response, a 0.18% incidence of ellipsoid zone or inner/outer segment junction changes, and 2 cases of retinal vessel attenuation. (medscape.com)
  • tion and retinal flourescein angiography. (who.int)
  • Mild NPDR refers to the early stages where blood vessels begin to swell and leak. (cdc.gov)
  • In this paper, we investigate the effects of performing color constancy algorithm on retinal image prior to segmentation step. (mmu.edu.my)
  • We compared two different algorithms for color constancy, namely Gray World and White Patch that are applied to retinal image before it is used as an input to the segmentation algorithm. (mmu.edu.my)
  • As a result, tiny bulges or microaneurysms can develop and protrude from the smaller vessel walls. (kelsey-seybold.com)
  • In particular, retinal vascular occlusions says for anticardiolipin antibodies and lupus in patients with primary APS, i.e. with an- anticoagulant. (who.int)
  • Experimentally, sufficient comparative experiments have been enforced on three retinal vessel segmentation datasets, DRIVE, CHASEDB1, and the unhealthy dataset STARE. (harvard.edu)
  • It is characterized by endothelial dysfunction and vasospasm of vessels which can be observed by an ocular fundal examination. (bvsalud.org)
  • A lack of antioxidants , such as vitamin C, vitamin E and lutein may increase the ability of plaque to stick to the blood vessel walls and promote the damage of the tissue. (drweil.com)
  • While it can slow or stop the progression of the condition, future retinal damage and vision loss are still possible. (kelsey-seybold.com)
  • NEI, 2015) In PDR, new blood vessels form, but are weak and prone to leakage. (cdc.gov)
  • If you already have damage to the blood vessels in your eye, some types of exercise can make the problem worse. (medlineplus.gov)
  • So-called "retinal migraines" do occur, but they are associated with migraine headaches , which this patient does not report. (medscape.com)
  • Qualitatively, the outputs with color constancy applied have more small vessels, which were mostly left undetected in outputs with no color constancy. (mmu.edu.my)
  • It also affects the small vessels of the heart, kidney and brain as well as those supplying peripheral nerves. (who.int)
  • The gas used to pressurize the vessel is usually 100% oxygen. (medscape.com)
  • Smoking can decrease blood supply by causing a narrowing of the blood vessels and a thickening of the blood, much the same as in a heart attack or stroke. (drweil.com)
  • Especially in cats, neovascularisation on the iris surface rapidly develops, with visible blood vessels ("rubeosis iridis") and change in the iris color. (vin.com)
  • Duavee can increase the risk of serious cardiovascular problems, including stroke and blood clots in the legs, lungs, or retinal vessels of the eye. (canadapharmacy.com)