Retinal blood vessel segmentation has an important guiding significance for the analysis and diagnosis of cardiovascular diseases such as hypertension and diabetes. But the traditional manual method of retinal blood vessel segmentation is not only time-consuming and laborious but also cannot guarantee the accuracy and efficiency of diagnosis. Therefore, it is especially significant to create a computer-aided method of automatic and accurate retinal vessel segmentation. In order to extract the blood vessels contours of different diameters to realize fine segmentation of retinal vessels, we propose a Bidirectional Symmetric Cascade Network (BSCN) where each layer is supervised by vessel contour labels of specific diameter scale instead of using one general ground truth to train different network layers. In addition, to increase the multi-scale feature representation of retinal blood vessels, we propose the Dense Dilated Convolution Module (DDCM), which extracts retinal vessel features of different
PURPOSE: To characterize the properties of the glucose transporters of bovine retinal capillary endothelial cells and pericytes and to determine the effects of increased glucose concentrations on glucose transport activity. METHODS: Primary cultures of bovine retinal capillary endothelial cells and pericytes were exposed to low and high glucose concentrations, and immunoblot analysis, 14C-3-O-methylglucose transport activity, and cytochalasin B binding assays were used to characterize the glucose transporters. RESULTS: GLUT1, but not GLUT3 or GLUT4 transporter isoforms, was present in plasma membranes isolated from each cell type. The EC50 for glucose transport was similar in endothelial cells and pericytes (3.94 to 0.48 mM versus 2.24 to 0.69 mM) and was consistent with the EC50 previously reported for GLUT1 transporters on other cells, as was the observation that insulin did not acutely stimulate glucose transport in either cell type. The Vmax for glucose transport was greater in pericytes ...
Automatic assessment of retinal vessels plays an important role in the diagnosis of various eye, as well as systemic diseases. A public screening is highly desirable for prompt and effective treatment, since such diseases need to be diagnosed at an early stage. Automated and accurate segmentation of the retinal blood vessel tree is one of the challenging tasks in the computer-aided analysis of fundus images today. We improve the concept of matched filtering, and propose a novel and accurate method for segmenting retinal vessels. Our goal is to be able to segment blood vessels with varying vessel diameters in high-resolution colour fundus images. All recent authors compare their vessel segmentation results to each other using only low-resolution retinal image databases. Consequently, we provide a new publicly available high-resolution fundus image database of healthy and pathological retinas. Our performance evaluation shows that the proposed blood vessel segmentation approach is at least comparable with
PURPOSE: Prior results have demonstrated a significant reduction in retinal blood flow in streptozotocin (STZ)-induced diabetic rats. These studies were extended to investigate whether retinal blood flow changes, in the diabetic rat model, could be prevented with strict glycemic control using insulin pumps. Retinal blood flow changes also were measured during hyperoxia and after intravitreal histamine infusion to validate the methodology. METHODS: Retinal blood flow changes were measured using video-based fluorescein angiography and computer-assisted image analysis. A total of 48 male Sprague-Dawley and 9 Brown Norway rats were used in these experiments. Retinal blood flow after primary insulin intervention was evaluated in diabetic rats implanted with mini-osmotic insulin pumps within 24 hours of STZ-induced diabetes. Diabetic rats, not treated with insulin, were used for comparison. RESULTS: Hyperoxia caused a significant (P = 0.001) reduction (54%) in retinal blood flow, whereas intravitreal ...
Rat Retinal Microvascular Endothelial Cells from Creative Bioarray are isolated from retinal tissue of 6-8 week old laboratory Sprague-Dawley rat. Rat Retinal Microvascular Endothelial Cells are grown in T75 tissue culture flasks pre-coated with gelatin-based coating solution for 2 min and incubated in Creative Bioarray Culture Complete Growth Medium generally for 3-7 days. Cultures are then expanded. Prior to shipping, cells at passage 3 are detached from flasks and immediately cryo-preserved in vials. Each vial contains at least 1x10^6 cells per ml and is delivered frozen. The method we use to isolate endothelial cells was developed based on a combination of established and our proprietary methods. These cells are pre-coated with PECAM-1 (CD31) antibody, following the application of magnetic beads pre-coated with secondary antibody ...
The issue where an embolism is formed deep in your veins is called deep capillary apoplexy. This embolism can obstruct blood that flows back to the heart. This problem generally occurs in the leg. When left without therapy, the embolisms can take a trip to the significant body organs like the lungs.. There differ means you could possibly adjust to lessen your threat for deep capillary apoplexy:. Given up cigarette smoking. Smoking cigarettes will certainly not just predispose you to numerous other professional issues, it might also boost your risk of developing deep capillary thrombosis. So stop smoking, stat!. Workout routinely. Regular workout will certainly not just help you manage your weight and make you really feel as well as appearance good, it could furthermore keep several scientific problems including deep capillary apoplexy at bay. Constantly make time for workout daily. Even a little operating or walking, done everyday could go a lengthy ways.. Talk to your medical ...
The problem where a blood clot is formed deep in your veins is called deep capillary apoplexy. This blood clot could block blood that recedes to the heart. This problem commonly takes place in the leg. When left without treatment, the blood clots might take a trip to the major body organs like the lungs.. There vary methods you could adjust to lessen your threat for deep capillary apoplexy:. Given up smoking. Smoking cigarettes will not only predispose you to different other clinical issues, it might also enhance your danger of setting up deep capillary apoplexy. So quit cigarette smoking, stat!. Exercise consistently. Routine workout will absolutely not just assist you manage your weight and make you truly feel along with look excellent, it can also maintain numerous scientific troubles including deep capillary apoplexy away. Always make time for exercise every day. Even a little running or strolling, done every day can go a long means.. Talk with your physician. If you are taking hormonal ...
Objective: To estimate the effects of maternal body mass index (BMI) and pregnancy weight gain on the retinal microvasculature among pregnant women. Methods: We studied 814 pregnant women aged 18-46 years who were recruited as part of the Growing Up in Singapore Toward Health Outcomes study, an ongoing birth cohort study from two government hospitals in Singapore since 2009. Recalled prepregnancy weight was recorded, and maternal anthropometric measurements of weight and height were performed at 26 weeks of gestation together with retinal photography. Results: In multiple linear regression models, each standard deviation increase of 26-week pregnancy BMI (4.57) was associated with narrower retinal arteriolar caliber (by 1.58 micrometers, P,.001), wider venular caliber (by 1.28 micrometers, P=.02), and increased retinal venular tortuosity (P=.01). Compared with mothers with normal weight, obese mothers (prepregnancy BMI greater than 30.0) had narrower retinal arteriolar caliber (118.81 compared ...
With improvements in fundus imaging technology and the increasing use of digital images in screening and diagnosis, the issue of automated analysis of retinal images is gaining more serious attention. We consider the problem of retinal vessel segmentation, a key issue in automated analysis of digital fundus images. We propose a texture-based vessel segmentation algorithm based on the notion of textons. Using a weak statistical learning approach, we construct textons for retinal vasculature by designing filters that are specifically tuned to the structural and photometric properties of retinal vessels. We evaluate the performance of the proposed approach using a standard database of retinal images. On the DRIVE data set, the proposed method produced an average performance of 0.9568 specificity at 0.7346 sensitivity. This compares well with the best-published results on the data set 0.9773 specificity at 0.7194 sensitivity [Proc. SPIE 5370, 648 (2004) ].. © 2007 Optical Society of America. Full ...
We present a novel application of optical microangiography (OMAG) imaging technique for visualization of depth-resolved vascular network within retina and choroid as well as measurement of total retinal blood flow in mice. A fast speed spectral domain OCT imaging system at 820nm with a line scan rate of 140 kHz was developed to image the posterior segment of eyes in mice. By applying an OMAG algorithm to extract the moving blood flow signals out of the background tissue, we are able to provide true capillary level imaging of the retinal and choroidal vasculature. The microvascular patterns within different retinal layers are presented. An en face Doppler OCT approach [Srinivasan et al., Opt Express 18, 2477 (2010)] was adopted for retinal blood flow measurement. The flow is calculated by integrating the axial blood flow velocity over the vessel area measured in an en face plane without knowing the blood vessel angle. Total retinal blood flow can be measured from both retinal arteries and veins. ...
From the Department of Neurology (S.R.L.), University of Maryland, Baltimore; Department of Medicine (T.H.M.), University of Mississippi Medical Center, Jackson; Centre for Eye Research Australia (T.Y.W.), University of Melbourne, Australia; Department of Epidemiology (M.S., J.C., A.R.S.), Johns Hopkins Bloomberg School of Public Health, Baltimore; Division of Behavioral Neurology (D.K.), Mayo Clinic College of Medicine, Rochester, MN; Departments of Biostatistics (D.J.C.) and Epidemiology (S.R.C.), University of North Carolina, Chapel Hill; Department of Ophthalmology and Visual Sciences (R.K.), University of Wisconsin School of Medicine and Public Health, Madison; and Department of Public Health Sciences (L.H.C.), Wake Forest University School of Medicine, Winston-Salem, NC ...
Quantitative retinal signs were mainly analyzed as continuous variables and qualitative retinal signs were analyzed as binary variables. The association between retinal signs and vascular risk factors was assessed using linear and logistic regression to adjust for age, gender, and race.. In the main analysis, we used linear regression to model each of the DSST score, gait speed, and square root of CES-D score as a function of a retinal sign and covariates, and we used logistic regression to model the probability of depressive mood. Standardized coefficients were computed to compare the strength of associations between retinal signs and each outcome. Depressive symptoms were analyzed in 2 different ways: (1) square root of CES-D score among participants not using antidepressant medications, because CES-D score may not accurately represent the burden of depressive symptoms in these participants; and (2) the presence of depressive mood, as defined, in all participants. Of those with data on all 5 ...
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Objective Currently, there are no published data on retinal microvasculature size in human infants born at term. The purpose of this study was to determine the normal retinal microvasculature measurements in human infants born at term with normal birth weight and to compare these results with measurements in children and adults. Methods Retinal arteriole and venule measurements were obtained in a cohort of 20 full-term infants. Digital retinal images were obtained from both eyes after pupillary dilation using a digital retinal camera. Measurements of vessel diameter were then obtained using semi-automated software. Results Twenty infants (9 female infants and 11 male infants) were analyzed. The retinal arteriole diameter was 66.8-123.0 μm (mean, 85.5 (14.3) μm), and the venule diameter was 102.0-167.8 μm (mean, 130.0 (16.0) μm). There were no differences in the arterial or venule diameters between the male and female infants (83.2 (12.2) vs. 88.3 (16.9); P = 0.4372; 124.3 (16.0) vs. 137.0 (18.0); P
TY - JOUR. T1 - BIGH3 protein and macrophages in retinal endothelial cell apoptosis. AU - Mondragon, Albert A.. AU - Betts-Obregon, Brandi S.. AU - Moritz, Robert J.. AU - Parvathaneni, Kalpana. AU - Navarro, Mary M.. AU - Kim, Hong Seok. AU - Lee, Chi Fung. AU - Lebaron, Richard G.. AU - Asmis, Reto. AU - Tsin, Andrew T.. PY - 2015/1. Y1 - 2015/1. N2 - Diabetes is a pandemic disease with a higher occurrence in minority populations. The molecular mechanism to initiate diabetes-associated retinal angiogenesis remains largely unknown. We propose an inflammatory pathway of diabetic retinopathy in which macrophages in the diabetic eye provide TGFβ to retinal endothelial cells (REC) in the retinal microvasculature. In response to TGFβ, REC synthesize and secrete a pro-apoptotic BIGH3 (TGFβ-Induced Gene Human Clone 3) protein, which acts in an autocrine loop to induce REC apoptosis. Rhesus monkey retinal endothelial cells (RhREC) were treated with dMCM (cell media of macrophages treated with high ...
The retina is a highly metabolically active tissue with large demands on the supply of nutrients. Disorders affecting the retina often include some vasculopathy with an impact on retinal circulation. Studies of retinal haemodynamics could thus help to detect, differentiate and diagnose diseases, to monitor changes in disease as well as progression and efficiency of the therapy.. The present studies were an attempt to validate and determine the clinical usefulness of a newly developed technique for studying the retinal circulation in human eyes.. We used different techniques to evaluate different parameters of retinal circulation. We examined how leukocyte velocity determined with Blue Field Simulation and transit times, mean transite time (MTT) and arterio-venous passage (AVP), and vessel diameter, determined from fluorescein angiograms, together reflects the retinal circulation. MTT was determined with a method based on an Impulse-Response technique, MTTIR.. In a study on monkeys we compared ...
A retinal vessel occlusion is a blockage in the blood vessel of your eye that can result in sight loss. There are two types of retinal blood vessels, arteries and veins. Either of these can become blocked and each of them can affect the eye in different ways. The visual loss caused by retinal vein and artery occlusions is painless. It is usual for only one eye to be involved at a time, but occasionally both eyes may be affected at the same time.
Cellular metabolic memory occurs in diabetic microvascular and macrovascular complications, but the underlying mechanisms remain unclear. Here, we investigate the role of sirtuin 1 (SIRT1) and metformin in this phenomenon. In bovine retinal capillary endothelial cells (BRECs) and retinas of diabetic rats, the inflammatory gene, nuclear factor-κB (NF-kB), and the proapoptotic gene, Bax, induced by hyperglycemia, remained elevated after returning to normoglycemia. BRECs with small interfering RNA-mediated SIRT1 knockdown had increased sensitivity to hyperglycemia stress, whereas SIRT1 overexpression or activation by metformin inhibited the increase of mitochondrial reactive oxygen species-mediated glyceraldehyde-3-phosphate dehydrogenase by poly (ADP-ribose) polymerase (PARP) activity through the upregulation of liver kinase B1/AMP-activated protein kinase (LKB1/AMPK), ultimately suppressing NF-κB and Bax expression. Furthermore, we showed that hyperglycemia led to PARP activation, which in turn ...
Diabetic neuropathy, nephropathy and retinopathy cause significant morbidity in patients with type 1 diabetes, even though improvements in treatment modalities delay the appearance and reduce the severity of these complications. To prevent or further delay the onset, it is necessary to better understand common underlying pathogenesis and to discover pre-clinical biomarkers of these complications.. Retinal vessel calibers have been associated with the presence of microvascular complications but their long-term predictive value has only been sparsely investigated.. We examined retinal vessel calibers as 16-year predictors of diabetic nephropathy, neuropathy and proliferative retinopathy in a young population-based Danish cohort with type 1 diabetes. We used semi-automated computer software to analyze vessel diameters on baseline retinal photos. Calibers of all vessels coursing through a zone 0.5-1 disc diameter from the disc margin were measured and summarized as the central artery and vein ...
Using various techniques to study retinal blood flow in patients with diabetes, researchers have drawn different conclusions regarding whether blood flow is increased or decreased (2-10,19,20). The present study indicates that retinal blood flow in diabetic patients with no or mild retinopathy is slightly elevated before the patients take their insulin but is reduced toward normal when blood glucose levels are normalized.. Compared with previous studies addressing the question of retinal blood flow in diabetes, the present approach offers several methodological advantages. Most importantly only a few studies have measured total retinal blood flow (3,4). The technique applied in this study, combining velocity data with diameter data is currently the only approach to study this in humans. As such, our data are in good agreement with a previous study indicating increased retinal blood flow in diabetes before the onset of diabetic retinopathy (4). Compared with this previous study, though, the ...
TY - JOUR. T1 - Characteristics of the retinal microvasculature in association with cardiovascular risk markers in children with overweight, obesity and morbid obesity. AU - Berendschot, Tos T..J.M.. AU - Rijks, Jesse. AU - Vreugdenhil, Anita. AU - Dorenbos, Elke. AU - Karnebeek, Kylie. AU - Joris, Peter. AU - Mensink, Ronald. AU - Plat, Jogchum. PY - 2019. Y1 - 2019. U2 - 10.1159/000499516. DO - 10.1159/000499516. M3 - Meeting Abstract. VL - 56. SP - 13. EP - 13. JO - Journal of Vascular Research. JF - Journal of Vascular Research. SN - 1018-1172. IS - S1. ER - ...
Oxidative Medicine and Cellular Longevity is a unique peer-reviewed, Open Access journal that publishes original research and review articles dealing with the cellular and molecular mechanisms of oxidative stress in the nervous system and related organ systems in relation to aging, immune function, vascular biology, metabolism, cellular survival and cellular longevity. Oxidative stress impacts almost all acute and chronic progressive disorders and on a cellular basis is intimately linked to aging, cardiovascular disease, cancer, immune function, metabolism and neurodegeneration. The journal fills a significant void in todays scientific literature and serves as an international forum for the scientific community worldwide to translate pioneering
Systemic VEGF blockade does not alter retinal vessels ultrastructure or choriocapillaris fenestration.(A) TEM of a microvessel located in the GCL of sFlt1 expre
Abnormalities in the vascular pattern of the retina are associated with retinal diseases and are also risk factors for systemic diseases, especially cardiovascular diseases. The three-dimensional retinal vascular pattern is mostly formed congenitally, but is then modified over life, in response to aging, vessel wall dystrophies and long term changes in blood flow and pressure. A characteristic of the vascular pattern that is appreciated by clinicians is vascular tortuosity, i.e. how curved or kinked a blood vessel, either vein or artery, appears along its course. We developed a new quantitative metric for vascular tortuosity, based on the vessels angle of curvature, length of the curved vessel over its chord length (arc to chord ratio), number of curvature sign changes, and combined these into a unidimensional metric, Tortuosity Index (TI). In comparison to other published methods this method can estimate appropriate TI for vessels with constant curvature sign and vessels with equal arc to ...
Harvard Medical School researchers have identified a method to control a hormone that may be responsible for the most common cause of blindness. This discovery could lead to new ways of preventing and treating certain eye diseases - including diabetic retinopathy, retinopathy of prematurity, and prehaps age-related macular degeneration. The findings are reported in the June 13 Science.
There is growing evidence supporting the notion that endothelial dysfunction and inflammation are common events driving the development of various retinal microvascular changes in patients with hypertension, diabetes, and other metabolic disorders [30,31]. However, the synergistic impact of these commonly coexisting conditions on the development of retinopathy has not been fully elucidated. Our current study aimed to model the early and established detrimental effects of combining hypertension with diabetes on the development of retinopathy and retinal microvascular degeneration using diabetic spontaneously hypertensive rats, an established model for studying hypertension. Clinical evidence highlights the role of oxidative stress and endothelial dysfunction as previously indicated by increased levels of lipid peroxidation and platelet activation in patients with hypertension-related microvascular changes when compared with patients with or without early signs of retinopathy [3,30]. Our results ...
Trypsin digest is one of the most commonly used methods to analyze retinal vasculature. This manuscript describes the method in detail, ...
Figure 4. Protective effect of catalase on HREC outgrowths. Protective effect of catalase on H2O2 induced cytotoxicity in 6 days HREC outgrowths. A: HREC aggregate grown in basal tissue culture medium shows normal sprouting after 6 days. B: HREC aggregate in medium supplemented with 1 mM H2O2, demonstrating that oxidative stress blocks sprouting. C: HREC aggregate grown in medium + 1 mM H2O2 in presence of catalase administered through an AnoporeTM filter (starting concentration in the upper compartment: 400 U/ml). The sprouts develop normally, showing that filter administered catalase can exert a protective effect on endothelial cells against oxidative stress induced injury. Phase contrast micrographs. Original magnifications: x80. D: SigmaScan Pro quantification of the outgrowth pattern illustrated in A.. ...
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Retinal, Association, Blood, Blood Vessels, Human, Hyperoxia, Light, Microvasculature, Retinal Blood Vessels, Vasoconstriction, Vasodilation
The arteriovenous ratio is an objective way to assess the arteriolar narrowing related to several diseases such as hypertension. It is computed as the ratio between the artery and vein mean widths. However, its calculus is not straightforward since the experts do not use all the retinal vessels. This paper presents an automatic, precise and reproducible methodology for the AVR computation. We analyze the way the experts select the vessels in order to build a system which emulates them. The system was evaluated by two ophthalmologists in a data set of 86 images. The correlation results among the system and the experts are an indication of the reproducibility of the results.
Automated image processing has the potential to assist in the early detection of diabetes, by detecting changes in blood vessel diameter and patterns in the retina. This paper describes the development of segmentation methodology in the processing of retinal blood vessel images obtained using non-mydriatic colour photography. The methods used include wavelet analysis, supervised classifier probabilities and adaptive threshold procedures, as well as morphology-based techniques. We show highly accurate identification of blood vessels for the purpose of studying changes in the vessel network that can be utilized for detecting blood vessel diameter changes associated with the pathophysiology of diabetes. In conjunction with suitable feature extraction and automated classification methods, our segmentation method could form the basis of a quick and accurate test for diabetic retinopathy, which would have huge benefits in terms of improved access to screening people for risk or presence of diabetes ...
Although it has become acceptable that neuroretinal cells are also affected in diabetes, vascular lesions continue to be considered as the hallmarks of diabetic retinopathy. Animal models are essential for the understanding and treatment of human diabetic retinopathy, and the mouse is intensively used as a model because of its similarity to human and the possibility to be genetically modified. However, until today not all retinal vascular lesions developed in diabetic patients have been reproduced in diabetic mice, and the reasons for this are not completely understood. In this review, we will summarize retinal vascular lesions found in diabetic and diabetic-like mouse models and its comparison to human lesions. The goal is to provide insights to better understand human and mice differences and thus, to facilitate the development of new mouse models that mimic better human diabetic retinopathy ...
The broad functions of Tissue Culture Module are 1) isolation of primary cells from ocular tissue; 2) maintenance and passage of established cell lines, including storage; 3) large scale amplification of cell lines; 4) transient transfection of cells; 4) generation of stably transfected cell lines; 5) training in growth and maintenance of cells; 6) strategic advice in planning experiments and determining their feasibility; and 7) mycoplasma testing. Specialized cell types currently stored include human and bovine retinal capillary endothelial cells, human and bovine retinal capillary pericytes, a rat retinal Muller cell line, a human retinal pigmented epithelial cell line, human corneal epithelial cells, a rat retinal ganglion cell line, human umbilical vein and aortic endothelial cells, mouse and human lens epithelial cells and cell lines, and mouse photoreceptor cell line. Equipment used in the Tissue Culture Module includes: 6 single chamber water jacket CO2 incubators, Nikon TS 100 with ...
The expression profiles of normal human brain and retinal pericytes are shared with respect to several cytoskeletal, cellular adhesion and proinflammatory biomarkers. This suggests that pericytes from different vascular beds within the CNS are similar and that their physiology may be governed by their respective microenvironments. We found that brain and retinal pericytes were equally permissive for HCMV lytic replication by both laboratory adapted and clinical strains of virus. In IBRB, retinal pericytes were most permissive for HCMV infection when compared to retinal microvascular endothelial cells and Müller cells. HCMV infection elicited an angiogenic and proinflammatory cytokine response in pericytes after infection. From these studies we proposed a disease model (Figure 11) for HCMV dissemination across the IBRB into the retina that is similar to the model we proposed for HCMV dissemination across the BBB into the brain [20]. Our working model is that as HCMV traffics the IBRB initially, ...
en] PURPOSE. To examine the ability and mechanism of the 16 kDa N-terminal fragment of human prolactin (16K hPRL) in the inhibition of abnormal retinal neovascularization. METHODS. The 16K hPRL-encoding sequence was inserted into an adenoviral vector (16K-Ad). Western blot analysis verified the expression of 16K hPRL and inhibition of proliferation, confirming functional activity of the 16K hPRL in virus-infected adult bovine aortic endothelial (ABAE) cells. 16K hPRL inhibited retinal neovascularization in a mouse model of oxygen-induced retinopathy. The ability of recombinant 16K hPRL expressed in E. coli (r16K hPRL) was compared to that of endostatin in inducing apoptosis of cultured human retinal endothelial cells (HREC). RESULTS. 16K was expressed in virus-infected ABAE cells and resulted in a dose-dependent inhibition of cell proliferation. Eyes injected with 16K-Ad showed a reduction in preretinal neovascularization of 82.3 +/- 9.3% (P , 0.00001) when compared to uninjected controls. r16K ...
Blood Vessel Segmentation in Complex-Valued Magnetic Resonance Images with Snake Active Contour Model: 10.4018/jehmc.2010010104: Accurate blood vessel segmentation plays a crucial role in non-invasive blood flow velocity measurement based on complex-valued magnetic resonance images. We
Introduction: Oxygen delivery, or utilization, is a function of retinal blood flow and blood oxygen saturation. The retinal pigment epithelium (RPE), in particular, has been shown to have the highest levels of metabolic activity within the human body. Oxygen delivery is therefore of extreme importance to the maintenance of the health and integrity of the retina. Animal models presuppose that the oxygen tension in the retina is highest in the innermost layers at the level of the choriocapillaris, less in the photoreceptors and further decreases throughout the outer retinal structures. The choroid provides by far the largest component of the oxygen for consumption by the photoreceptors. A lack of oxygen stores in the inner retina therefore makes a constant supply crucial for its normal functioning. Blood flow dysfunction and subsequent hypoxia are both a feature in the pathogenesis of several major ocular diseases such as retinopathy of prematurity (ROP), age-related macular degeneration (ARMD), ...
This book provides comprehensive and up-to-date information on diagnosis, medical and surgical treatments for pediatric retinal vascular conditions, which are leading causes of childhood blindness throughout the world. Experienced ophthalmologists in the field discuss basic knowledge about these diseases and practical aspects of management such as exam under anesthesia, diagnostic approaches including spectral-domain hand-held optical coherence tomography (OCT) and OCT angiography. The reader will learn about the recent advances in medical and surgical treatments for pediatric retinal vascular diseases. The surgical treatments, anti-VEGF injections, laser photocoagulation and lens sparing vitrectomy are explained step-by-step and can be observed in several videos.. Both the general ophthalmologist who cares for children with retinal diseases and the specialist (pediatric ophthalmologists and vitreoretinal surgeon) will find this book to be an informative resource in providing best care for ...
Recognised as the most common diabetic eye disease, diabetic retinopathy occurs due to changes in the blood vessels of the retina. A serious sight-threatening complication of diabetes, diabetic retinopathy occurs when blood vessels in the retina change. With this condition, retinal blood vessels may swell and leak fluid, or close off completely. In other circumstances, the surface of the retina may develop abnormal growth of new blood vessels. Two classifications for diabetic retinopathy describe its progression. In infancy, it is referred to as Non-Proliferative Diabetic Retinopathy (NPDR). ). In its more advanced form, Proliferative Diabetic Retinopathy (PDR) is the term applied to this condition.. There is a trusted eye doctor local to Wallaceburg who is able to provide diabetic retinopathy testing. Dr. David Oliphant is ready to help you establish effective management of your diabetic retinopathy symptoms before they can deteriorate.. ...
PURPOSE: Advanced glycation endproduct (AGE) formation on the basement membrane of retinal capillaries has been previously described but the impact of these adducts on capillary endothelial cell function vascular repair remains uncertain. This invest
Diabetic retinopathy is one of the leading causes of vision loss in industrialized countries. Despite recent advances, the biochemical basis for the development of this diabetic complication is uncertain. Although retinal circulation is unique in that it is readily observable noninvasively, retinal tissue is extremely difficult to study in humans because of the problems inherent in obtaining fresh, appropriate biopsy material. Moreover, because of the difficulties in working with animal models of diabetic retinopathy, such as the dog, many investigators have turned to cell-culture models, especially those using primary cultures of retinal capillary endothelial cells and pericytes. Diabetic retinopathy involves both morphological and functional changes in the retinal capillaries. Morphological changes include basement membrane thickening and pericyte disappearance; functional changes include one important early change-increased permeability-which may be attributable to endothelial cell changes ...
diabetes, it wont normally show any diabetic retinopathy symptoms.. Types of Diabetic Retinopathy. The two types include Background diabetic retinopathy (BDR) and Proliferative diabetic retinopathy (PDR).. Background Diabetic Retinopathy. BDR is characterized as initial stage of the disease and results in hemorrhages, lipoid exudates and microaneurysms. This causes leakage of blood vessels just under macula.. Proliferative Diabetic Retinopathy. It results in neovascularization, which is growth of blood vessels inside retina of human eye. This growth is dangerous as it shoots off blood vessels over retina. Sometimes, this growth moves into iris and may possibly rupture retina resulting in hemorrhages. It is also observed that blood vessels can separate retina and result in retinal detachment for the eye.. Also Read about Diabetic Neuropathy and its Symptoms. How to Diagnose Retina Problems?. The method of diagnosis is not sophisticated and rather easy. When diagnosing the issue, majority of ...
The blood vessels in the retina of the eye are abnormal in individuals with schizophrenia, according to the study "Microvascular Abnormality in Schizophrenia as Shown by Retinal Imaging" in the American Journal of Psychiatry. The senior researcher was Richie Poulton, Ph.D., codirector of the National Centre for Lifecourse Research at the University of Otago in Dunedin, New Zealand. The cohort included more than 1,000 individuals who were followed from birth to adulthood. At age 38, the subjects underwent retinal imaging. The researchers compared the retinal imaging results of 27 individuals who had developed schizophrenia with those of individuals who had not and found that the former had microvascular abnormalities reflective of insufficient brain oxygen supply. ...
My research focuses on assessing oxygen tension in retinal blood vessels from phosphorescence lifetime imaging data. To acquire phosphorescence lifetime images, a diode laser at a wavelength of 532 nm is expanded to a line with a cylindrical lens and focused at an oblique angle on the retina following intravenous injection of an oxygen-sensitive molecular probe. The level of retinal oxygenation is thought to play a significant role in retinal diseases, such as diabetic retinopathy and vascular occlusions. Imaging oxygen tension in the retinal vasculatures will provide information on fundamental mechanisms that implicate hypoxia in the development of retinal pathologies. The long-term goal of this project is to broaden knowledge of disease patho-physiology, and thereby advance diagnostic and therapeutic procedures ...
Having high levels of uncontrolled sugar in your blood can/will cause a blockage of the tiny blood vessels that bring oxygen to the retina. When the retina does not receive enough oxygen, the body will try to remedy this issue by producing new blood vessels which do not develop properly and may leak. People with untreated diabetes have a 25 per cent higher risk for blindness.. There are four types/progressive levels of diabetic retinopathy:. Early/mild diabetic retinopathy (nonproliferative diabetic retinopathy (NPDR). Nonproliferative means that new blood vessels are not growing or proliferating. This type of retinopathy is the most common form with the walls of the blood vessels in the retina becoming weak. There may be microaneurysms (tiny bulges in the walls of the blood vessels) which will leak blood and fluid into the retina. While this is occurring, the larger blood vessels may begin to dilate. As more blood vessels are involved and become blocked, NPDR progresses from mild to severe. In ...
Diabetic retinopathy (DR), one of the most common vascular complication of diabetes, is the leading cause of visual deficits and blindness around the world. The development of DR is divided into two stages: in the early stages, also called as nonproliferative stage, it is asymptomatic because the signs are not visible to the eye. however, some defects including microaneurysms, intraretinal hemorrhaging, narrowing or blocked retinal blood vessels can be seen by detection; in the second stage, known as proliferative diabetic retinopathy, where neovascularization appears at the back of the eye and extend into the vitreous of the eye, and these new blood vessels are fragile. If they leak blood, the bleeding causes shrinkage of the retina, leading to retinal detachment, and ultimately to blindness. It has been reported that vascular endothelial growth factor A, angiotensin-converting enzyme, paraoxonase, erythropoietin are associated with DR development and progression ...
Title: Retinal Blood Vessel Segmentation Using Extreme Learning Machine | Keywords: retinal image, vessel segmentation, Extreme Learning Machine (ELM), Gabor filter, Hessian matrix, bottom-hat transformation | Author: Fan Guo, Da Xiang, Beiji Zou, Chengzhang Zhu, and Shengnan Wang
Ocular diseases characterized by retinal neovascularization are among the principal causes of visual loss worldwide. In an effort to understand the components of the retinal angiogenesis and its regulation by various molecules, I developed a procedure to isolate retinal microvascular endothelial cells (EC) and pericytes from ...