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Perceptual Impairments
Published in Julie A. Jacko, The Human–Computer Interaction Handbook, 2012
Julie A. Jacko, V. Kathlene Leonard, Molly A. McClellan, Ingrid U. Scott
There are two main types of diabetic retinopathy: nonproliferative and proliferative. Nonproliferative diabetic retinopathy refers to retinal microvascular changes that are limited to the confines of the retina and include such findings as microaneurysms, dot and blot intraretinal hemorrhages, retinal edema, hard exudates, dilation and bleeding of retinal veins, intraretinal microvascular abnormalities, nerve fiber layer infarcts, arteriolar abnormalities, and focal areas of capillary nonperfusion. Nonproliferative diabetic retinopathy can affect visual function through two mechanisms: intraretinal capillary closure resulting in macular ischemia, and increased retinal vascular permeability resulting in macular edema. Clinically significant macular edema is defined as any one of the following: (1) retinal edema located at or within 500 μm of the center of the macula; (2) hard exudates at or within 500 μm of the center if associated with thickening of adjacent retina; and (3) a zone of retinal thickening larger than one optic disc area if located within one disc diameter of the center of the macula.
First Therapeutic Aptamer: VEGF-Targeting Macugen
Published in Rakesh N. Veedu, Aptamers, 2017
Nicholas Leonard, Xiaoting Zhang
Macugen has since become one of the preferred treatments for wet AMD, alongside with other angiogenesis inhibitors like Eylea and Lucentis. Patients treated with Macugen experience numerous benefits that include greater improvement of visual acuity and reduction in the risk level of vision loss in patients with both wet AMD and macular edema. Though there are some adverse effects observed following Macugen treatment, they are mainly caused by the injection procedure used to administer the drug. These include some cases of infections, retinal detachment, eye irritation, and eye pain. Reported minor adverse reactions associated with Macugen administration included increased levels of vitreous floaters, inflammation level, and vitreous opacities [18]. More serious Macugen-associated injection-related adverse effects reported were endophthalmitis, retinal detachment, and traumatic injury to the lens; but the occurrence of these events was pretty rare and not statistically relevant [18]. Overall, Macugen is pretty safe for the treatment of neovascular AMD and diabetic macular edema. Importantly, the treatment response occurs quickly and is maintained for as long as two years, although a regression in the response level could endure during the second year of treatment [30]. In addition, long-term tolerability of this drug appears to be beneficial for the treatment of ocular neovascularization disorders. With these, the benefits of the treatment significantly outweigh the potential adverse side effects and make Macugen, the first therapeutic aptamer, a success in the treatment of AMD and macular edema patients.
Automated OCT Segmentation for Images with DME
Published in de Azevedo-Marques Paulo Mazzoncini, Mencattini Arianna, Salmeri Marcello, Rangayyan Rangaraj M., Medical Image Analysis and Informatics: Computer-Aided Diagnosis and Therapy, 2018
Sohini Roychowdhury, Dara D. Koozekanani, Michael Reinsbach, Keshab K. Parhi
Diabetic macular edema (DME) is a leading cause of vision loss in patients with diabetes. The World Health Organization estimates that by the year 2020, there will be 75 million blind people and 314 million partially blind people in the world [1]. While treatments are available, including intravitreal injections and macular laser therapy, not all patients respond to these. Currently, there are no reliable methods for predicting patient response to therapy. Therefore, analysis of the patient images prior to treatment may allow the development of measures to predict patient response. Computer-aided diagnostic (CAD) systems enable automated detection of ophthalmic pathological sites, monitoring the progression of pathology, and can guide follow-up treatment processes. Optical Coherence Tomography (OCT) images have been widely used to assess macular diseases, and they have enabled analysis of the extent of disorganization in the sub-retinal layers due to DME [2,3]. Sub-retinal layer disorganization refers to the variation in the underlying retinal microstructure due to the presence of cystoid regions or to disruptions in the cellular architecture of the sub-retinal layers due to pathology [4]. For each patient’s eye under analysis, a stack of images centered at the macula are acquired, such that reconstruction of the sub-retinal surfaces from the OCT image stacks aid localization of disease-related abnormalities in the retinal microstructure. In this work, a CAD system is presented that automatically segments sub-retinal surfaces and layers in OCT image stacks from normal patients and abnormal ones with DME, such that thickness maps corresponding to the sub-retinal layers can be further analyzed for their clinical relevance to the severity of DME.
Automated system for detection and classification of cystoid macular oedema using OCT images
Published in Computer Methods in Biomechanics and Biomedical Engineering: Imaging & Visualization, 2023
Priyanka Kaushik, S. R. Nirmala
Macular oedema is a condition characterised by the accumulation of fluid in the macula, the central part of the retina which is responsible for sharp, detailed vision. The fluid accumulation leads to the swelling of the macula, causing disturbed vision and then to vision loss. For macular oedema detection, OCT imaging is preferred. The retina has several layers as shown in Figure 1. Each layer has its own unique structure and has a different response to light and hence different reflectivity. The OCT system works on imaging of reflected light. It provides high-resolution, cross-sectional images of the retina, allowing for detailed visualisation of the macular region (Huang et al. 1991). It provides information about the thickness and structural changes in the macula, which is essential for detection and classification of macular oedema. The OCT image obtained from the imaging device is shown in Figure 2.
Detection of macular diseases in optical coherence tomography image
Published in International Journal of Parallel, Emergent and Distributed Systems, 2020
Xiaoming Liu, Zhou Yang, Wei Hu, Jun Liu, Kai Zhang
Many macular diseases can lead to vision decreasing or blindness such as macular edema, macular hole and age-related macular degeneration (shown in Figure 2). Macular edema [3] occurs when fluid and protein deposit on the macular and cause retina to thicken or swell. It can be classified into cystoid macular edema involving fluid accumulation in the outer plexiform layer, and diabetic macular edema caused by leaking macular capillaries. Macular hole [4] is a small break in the macular. The vitreous is a jelly-like substance in the eye, and it is usually adherent to retina. Along with the growth of age, vitreous get watery and begin to separate from the retinal surface. The higher the degree of attachment between vitreous and retina, the more likely macular hole is developed. Age-related macular degeneration [5] typically occurs in older people where the severity is divided into early, intermediate and late types. Drusen, which appear as a bulge, is an important clinical indicator for this disease, and it occurs at the neighbourhood of retinal pigment epithelium (RPE).
A Novel Design of Epidermal Flexible Antenna on Supraorbital Nerve to Correlate Diabetes and Anemia
Published in IETE Journal of Research, 2023
Kannagi V, A Jawahar, Vijay Nath
Diabetes may lead to eye damage such as diabetic retinopathy, cataract, glaucoma, and diabetic macular edema. The increase in the blood glucose level causes eye tissue to swell and blurs vision. The excess sugar in blood prevents blood from flowing through small blood vessels, which carry nutrients to nourish the retina of the eye. The absence of blood hinders nourishment and causes new blood vessels to form. The new blood vessels become weak due to the high sugar level.