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Optical coherence tomography angiography (OCTA) flow speed mapping technology for retinal diseases
摘要： Introduction: Optical coherence tomography angiography (OCTA) is a noninvasive imaging modality for depth-resolved visualization of retinal vasculature. Angiographic data couples with structural data to generate a cube scan, from which en-face images of vasculature can be obtained at various axial positions. OCTA has expanded understanding of retinal vascular disorders and has primarily been used for qualitative analysis. Areas covered: Recent studies have explored the quantitative properties of OCTA, which would allow for objective assessment and follow-up of retinal pathologies. Various quantitative metrics have been developed, such as foveal avascular zone area and vessel density. However, quantitative assessment of the characteristics of retinal blood flow remains limited, as OCTA provides an image depicting either the presence or absence of flow at a particular region without information of relative velocities. The development of variable interscan time analysis (VISTA) overcomes this limitation. The VISTA algorithm generates a color-coded map of relative blood flow speeds. VISTA has already demonstrated utility in furthering our understanding of various retinal pathologies, such as geographic atrophy, choroidal neovascularization, aneurysmal type 1 neovascularization, and diabetic retinopathy. Expert commentary: VISTA, an OCTA flow speed mapping technique, may have a role in developing the utility of OCTA as a screening tool.
关键词： flow speed mapping,diabetic retinopathy,age-related macular degeneration,VISTA,quantitative OCTA,OCTA,Optical coherence tomography angiography,variable interscan time analysis,OCT
更新于2025-09-10 09:29:36
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Scan, dwell, decide: Strategies for detecting abnormalities in diabetic retinopathy
摘要： Diabetic retinopathy (DR) is a disease which is widely diagnosed using (colour fundus) images. Efficiency and accuracy are critical in diagnosing DR as lack of timely intervention can lead to irreversible visual impairment. In this paper, we examine strategies for scrutinizing images which affect diagnostic performance of medical practitioners via an eye-tracking study. A total of 56 subjects with 0 to 18 years of experience participated in the study. Every subject was asked to detect DR from 40 images. The findings indicate that practitioners use mainly two types of strategies characterized by either higher dwell duration or longer track length. The main findings of the study are that higher dwell-based strategy led to higher average accuracy (> 85%) in diagnosis, irrespective of the expertise of practitioner; whereas, the average obtained accuracy with a long-track length-based strategy was dependent on the expertise of the practitioner. In the second part of the paper, we use the experimental findings to recommend a scanning strategy for fast and accurate diagnosis of DR that can be potentially used by image readers. This is derived by combining the eye-tracking gaze maps of medical experts in a novel manner based on a set of rules. This strategy requires scrutiny of images in a manner which is consistent with spatial preferences found in human perception in general and in the domain of fundus images in particular. The Levenshtein distance-based assessment of gaze patterns also establish the effectiveness of the derived scanning pattern and is thus recommended for image readers.
关键词： eye-tracking,visual perception,diagnostic strategies,Diabetic retinopathy,medical imaging
更新于2025-09-10 09:29:36
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[IEEE 2018 2nd International Conference on Engineering Innovation (ICEI) - Bangkok (2018.7.5-2018.7.6)] 2018 2nd International Conference on Engineering Innovation (ICEI) - Diabetic retinopathy fundus image classification using discrete wavelet transform
摘要： Diabetes is an incurable disease which erodes away body slowly, this disease in becoming common and becoming a cause of social distress. The only solution to this problem is early detection of disease and take precautionary measure to keep its effects to minimum. Since it affects various parts of body, the affected organ also includes eye which is very sensitive to any kind of distress. Diabetic Retinopathy effects of diabetes on eye retina, which includes rupturing of retina blood vessels and abnormal growth of blood vessels in retina, which ultimately causes blindness. Diabetic Retinopathy can be identified by examining the retinoscopy images. In this paper, retinoscopy images were processed using wavelet transform. Wavelet coefficients extracted from the images were obtained to identify Diabetic Retinopathy. KNN and SVM were used to classify the retinoscopy images. This papers have shown remarkable improvement as compared to previous studies, with KNN at 98.16 % accuracy and SVM at 97.85 % accuracy.
关键词： sensitivity,specificity,Discrete Wavelet Transform (DWT),accuracy,KNN,Diabetic Retinopathy (DR),histogram equalization,SVM
更新于2025-09-10 09:29:36
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Relative Importance and Contribiton of Risk Factors for Diabetic Retinopathy and Macular Edema
摘要： Purpose: This study determined the relative importance of risk factors for Diabetic Retinopathy (DR) and Diabetic Macular Edema (DME) and assessed their independent and joint contributions. Methods: A prospective study of patients with type 2 diabetes was conducted in a tertiary eye hospital in Melbourne, Australia. Patients underwent a comprehensive eye examination and completed standardized administered questionnaires. Blood samples were assessed for glycated haemoglobin (HbA1c); fasting blood glucose; and serum lipids. Dilated fundus photographs were obtained and graded for DR and DME. The relative importance of the risk factors was determined by the independent and common variance explained in DR and DME using Commonality analysis. Results: A total of 497 patients with type 2 diabetes were included in this analysis. The key risk factors accounted for 44.6% and 19.5% of total variances in DR and DME, respectively. The most important risk factor for any DR was duration of diabetes (16.5% of total explained variance), followed by insulin use (13.1%), HbA1c (8.5%), age (3.7%) and gender (2.8%). The most important risk factor for any DME was HbA1c (9.45%); followed by age (5.75%); duration of diabetes (3.92%) and systolic blood pressure (SBP) (0.36%). Sixty-one percent of the total explained variance in DR was due to common variance among these risk factors, compared to only 31% of the in DME. Conclusion: The total, independent and joint contributions of the key risk factors for DR and DME differ in patients with type 2 diabetes, which suggest that may require specific prevention and intervention strategies for these two diabetic complications.
关键词： Commonality analysis,Haemoglobin A1c,Diabetic retinopathy,Diabetic macular edema,Duration of diabetes
更新于2025-09-09 09:28:46
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Patients with Advanced Diabetic Retinopathy’s Understanding of Diabetes Mellitus and Their Diabetic Eye Disease: A survey of 100 patients currently undergoing treatment for Diabetic Retinopathy in a Large Retinal Practice
摘要： Objective: To better understand what patients with advanced diabetic retinopathy understand about their DED and treatment, control of their diabetes, and risk factors for disease progression, and to assess which areas clinicians may want to target for education to increase patient understanding. Methods: 100 consecutive patients with at least 5 previous visits to a retinal clinic were surveyed to better understand patients’ understanding of diabetes mellitus (DM), diabetic eye disease (DED), and the treatments they were receiving for DM and their DED. Demographic information (age, gender, educational status, ethnicity, language, duration and treatments for DM) was collected, along with information about treatments and understanding of risk and modifiable factors about DM. Data was verified against the chart. Results: 100 surveys were completed; 97% of patients said they “understand DM”. 61% of patients were 60 years or older, and half of the patients had done some post-secondary educational training. The ethnic breakdown included 27% Caucasian and 38% Hispanic. Fasting blood glucose (FBG) was known in 89% of patients and when asked the range of FBG: 6% did not know; 17% had FBG as >160 mg/dl; and 35% had a FBG of <130 mg/dl. Regarding controlling their DM, 74% of patients did not identify exercise and 33% did not identify dietary habit as important in control. 95% identified blood pressure (BP) as important to monitor. 39% were unable to identify their current BP range, 31% identified their systolic BP as ≥ 130mmHg, and 7% described it as usually >150mmHg. Patients were asked to identify DM related ocular complications: 23% said bleeding; 7% said diabetic macular edema; and 73% said blindness or visual loss. As patient age increased, the ability to correctly identifying current treatments, and knowledge of hemoglobin A1C (HbA1C), decreased. Ability to correctly identify HbA1C increased with increasing education. Conclusions: This survey shows patient misunderstanding in how DM is treated, risk factors for DM, and how monitoring should be done. Emphasis is likely needed in diet modification and exercise for control of DM. Patients may be at risk for poor understanding of DM care/treatment (particularly those with lower educational achievement, or more elderly). Additional resources may need to be developed for sub-sets of patients.
关键词： Diabetic eye disease,Patient understanding,Diabetes mellitus,Risk factors,Diabetic retinopathy,Hemoglobin A1C
更新于2025-09-09 09:28:46
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The potent small molecule integrin antagonist THR-687 is a promising next-generation therapy for retinal vascular disorders
摘要： Integrins are associated with various eye diseases such as diabetic retinopathy (DR) and wet age-related macular degeneration (AMD) and implicated in main pathologic disease hallmarks like neovascularization, inflammation, fibrosis and vascular leakage. Targeting integrins has the potential to attenuate these vision-threatening processes, independent of anti-vascular endothelial growth factor (VEGF) responsiveness. The current investigation characterized THR-687 as a novel pan RGD (arginylglycylaspartic acid) integrin receptor antagonist able to compete for binding with the natural ligand with nanomolar potency (e.g. αvβ3 (IC50 of 4.4±2.7 nM), αvβ5 (IC50 of 1.3±0.5 nM) and α5β1 (IC50 of 6.8±3.2 nM). THR-687 prevented the migration of human umbilical vein endothelial cells (HUVECs) into a cell-free area (IC50 of 258±113 nM) as well as vessel sprouting in an ex vivo mouse choroidal explant model (IC50 of 236±173 nM), and was able to induce the regression of pre-existing vascular sprouts. Moreover, combined intravitreal and intraperitoneal administration of THR-687 potently inhibited VEGF-induced leakage in the mouse retina. In addition, THR-687 injected intravitreally at 3 different dose levels (0.45 mg, 2.25 mg or 4.5 mg/eye) potently inhibited neovascularization-induced leakage in the cynomolgus laser-induced choroidal neovascularization (CNV) model. These data suggest that THR-687 is a promising drug candidate for the treatment of vision-threatening retinal vascular eye diseases such as DR and wet AMD.
关键词： diabetic retinopathy,retinal vascular disorders,angiogenesis,THR-687,Integrin antagonist,wet age-related macular degeneration,vascular leakage
更新于2025-09-09 09:28:46
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[IEEE 2018 International Conference on Advances in Computing, Communications and Informatics (ICACCI) - Bangalore, India (2018.9.19-2018.9.22)] 2018 International Conference on Advances in Computing, Communications and Informatics (ICACCI) - Detection of Exudates in Diabetic Retinopathy
摘要： Diabetic Retinopathy (DR) is an eye abnormality in which the human retina will get affected and is becoming one of the leading cause of preventable blindness. In the world, it is found that nearly 4.8% of blindness is caused due to DR. Preliminary symptoms include the formation of microaneurysms, exudates and hemorrhages. Early detection of DR can save the vision of diabetes patients and manual diagnosis takes time and effort for confirmation. In this paper, a Computer-aided Automated Diagnosis (CAD) is developed to solve this problem. The proposed approach uses edge-based segmentation method for segmenting the optic disc and blood vessels more accurately than region-based methods, followed by extraction of most probable exudates regions, feature extraction and the classifier stage to detect the presence of exudates. This system achieved sensitivity 82.61%, specificity 92.31% and moreover an accuracy of 87.75% for DIARETDB dataset.
关键词： Blindness,edge-based segmentation,Diabetic Retinopathy,CAD,exudates,NPDR,PDR
更新于2025-09-09 09:28:46
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Use of Expectation Disconfirmation Theory to Test Patient Satisfaction with Asynchronous Telemedicine for Diabetic Retinopathy Detection
摘要： Objective. The purpose of the study is to extend research on patient satisfaction with telemedicine services by employing the theoretical framework of Expectation Disconfirmation Theory (EDT) for diabetic retinopathy screenings focusing on rural patients. Method. Adult subjects (n=220) with diabetes were recruited from a single family practice office in rural Iowa. Subjects completed a “pre” survey concerning their forward-looking perceptions of telemedicine prior to using telemedicine for detection of diabetic retinopathy and a “post” survey after they received recommendations from the distant ophthalmologists. Results. All hypotheses of the EDT model were supported. Patient satisfaction is influenced by both patients’ expectations (P<.001) and disconfirmation of expectations (P<.001), and patient satisfaction has a positive impact on patient preference for telemedicine services (P<.001). Overall, patients who received telemedicine services were highly satisfied with telemedicine and developed a favorable disposition towards telemedicine services. Conclusions. The EDT model is a viable framework to study patient satisfaction of telemedicine services. While previous feasibility studies have shown that telemedicine for diabetic retinopathy screenings yields diagnostic efficacy, this study applies a theoretical framework to demonstrate the viability of telemedicine for diabetic retinopathy screenings in rural areas.
关键词： diabetic retinopathy,telemedicine,rural healthcare,patient satisfaction,Expectation Disconfirmation Theory
更新于2025-09-09 09:28:46
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[IEEE 2017 IEEE Nuclear Science Symposium and Medical Imaging Conference (NSS/MIC) - Atlanta, GA (2017.10.21-2017.10.28)] 2017 IEEE Nuclear Science Symposium and Medical Imaging Conference (NSS/MIC) - Comparing Different Preprocessing Methods in Automated Segmentation of Retinal Vasculature
摘要： Computer methods and image processing provide medical doctors assistance at any time and relieve their work load, especially for iterative processes like identifying objects of interest such as lesions and anatomical structures from the image. Vescular detection is considered to be a crucial step in some retinal image analysis algorithms to find other retinal landmarks and lesions, and their corresponding diameters, to use as a length reference to measure objects in the retina. The objective of this study is to compare effect of two preprocessing methods on retinal vessel segmentation methods, Laplacian-of-Gaussian edge detector (using second-order spatial differentiation), Canny edge detector (estimating the gradient intensity), and Matched filter edge detector either in the normal fundus images or in the presence of retinal lesions like diabetic retinopathy. The steps for the segmentation are as following: 1) Smoothing: suppress as much noise as possible, without destroying the true edges, 2) Enhancement: apply a filter to enhance the quality of the edges in the image (sharpening), 3) Detection: determine which edge pixels should be discarded as noise and which should be retained by thresholding the edge strength and edge size, 4) Localization: determine the exact location of an edge by edge thinning or linking. From the accuracy view point, comparing to manual segmentation performed by ophthalmologists for retinal images belonging to a test set of 120 images, by using first preprocessing method, Illumination equalization, and contrast enhancement , the accuracy of Canny, Laplacian-of-Gaussian, and Match filter vessel segmentation was more than 85% for all databases (MUMS-DB, DRIVE, MESSIDOR). The performance of the segmentation methods using top-hat preprocessing (the second method) was more than 80%. And lastly, using matched filter had maximum accuracy for the vessel segmentation for all preprocessing steps for all databases.
关键词： contrast Enhancement,image processing,Diabetic retinopathy,top hat transformation,Laplacian-of-Gaussian edge detector,Illumination Equalization,retinal blood vessel,Match filter,Canny edge detector
更新于2025-09-09 09:28:46
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Association between microRNAs expression and signaling pathways of inflammatory markers in diabetic retinopathy
摘要： Diabetic retinopathy is one of the common and serious microvascular complications of diabetes mellitus, as hyperglycemia has metabolic effects on the retina. Hyperglycemia induces increased oxidative stress, which stimulates inflammation pathways and promotes vascular dysfunction of the retina that leads to increased capillary permeability and vascular leakage. One of the main factors involving diabetic retinopathy is the inflammation signaling pathways. In contemporary times, microRNAs (miRNAs) are identified as functional biomarkers for early detection and treatment of numerous diseases specifically diabetic retinopathy. MiRNAs can modulate gene expression through regulation of transcriptional and posttranscriptional of target genes. With that, miRNAs can regulate almost every cellular and developmental process, including the regulation of instinct immune responses and inflammation. The aim of this study is to investigate the role of miRNAs in inflammation pathways and the pathogenesis of diabetic retinopathy.
关键词： miRNAs,inflammation pathway,diabetic retinopathy
更新于2025-09-09 09:28:46