67 results on '"Retinal vessel"'
Search Results
2. Feature pyramid U‐Net for retinal vessel segmentation
- Author
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Jing Li, Ronghua Liang, Peng Chen, Liu Yipeng, Rui Xue, Zhanqing Li, and Dongxu Zeng
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business.industry ,Computer science ,Pattern recognition ,Retinal vessel ,QA76.75-76.765 ,Feature (computer vision) ,Signal Processing ,Pyramid ,Photography ,Segmentation ,Computer Vision and Pattern Recognition ,Artificial intelligence ,Computer software ,Electrical and Electronic Engineering ,business ,TR1-1050 ,Software - Abstract
The retinal vessel is the only microvascular network that can be directly and non‐invasively observed in humans. Cardiovascular and cerebrovascular diseases, such as diabetes, hypertension, can lead to structural changes of the retinal microvascular network. Therefore, it is of great significance to study effective retinal vessel segmentation methods and assist doctors in early diagnoses with quantitative results for vascular networks. In this study, we propose a novel convolutional neural network named feature pyramid U‐Net (FPU‐Net) that extracts multiscale representations by constructing two feature pyramids both on the encoder and the decoder of U‐Net. In this representation, objects features with different size like micro‐vessels and pathology will be fused for better vessel segmentation. The experimental results show that compared with state‐of‐the‐art methods, FPU‐Net is superior in terms of accuracy, sensitivity, F1‐score, and area under the curve and capable of stronger domain generalisation across different datasets.
- Published
- 2021
3. Unsupervised automated retinal vessel segmentation based on Radon line detector and morphological reconstruction
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Jamshid Dehmeshki, Alireza Mehdizadeh, Meysam Tavakoli, and Reza Pourreza Shahri
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Signal processing ,Computer science ,business.industry ,cardiovascular ,Detector ,chemistry.chemical_element ,Radon ,Retinal vessel ,QA76.75-76.765 ,Software ,chemistry ,Signal Processing ,Photography ,Segmentation ,Computer vision ,Computer Vision and Pattern Recognition ,Artificial intelligence ,Computer software ,Electrical and Electronic Engineering ,Line (text file) ,business ,TR1-1050 ,computer - Abstract
Retinal blood vessel segmentation and analysis is critical for the computer‐aided diagnosis of different diseases such as diabetic retinopathy. This study presents an automated unsupervised method for segmenting the retinal vasculature based on hybrid methods. The algorithm initially applies a preprocessing step using morphological operators to enhance the vessel tree structure against a non‐uniform image background. The main processing applies the Radon transform to overlapping windows, followed by vessel validation, vessel refinement and vessel reconstruction to achieve the final segmentation. The method was tested on three publicly available datasets and a local database comprising a total of 188 images. Segmentation performance was evaluated using three measures: accuracy, receiver operating characteristic (ROC) analysis, and the structural similarity index. ROC analysis resulted in area under curve values of 97.39%, 97.01%, and 97.12%, for the DRIVE, STARE, and CHASE‐DB1, respectively. Also, the results of accuracy were 0.9688, 0.9646, and 0.9475 for the same datasets. Finally, the average values of structural similarity index were computed for all four datasets, with average values of 0.9650 (DRIVE), 0.9641 (STARE), and 0.9625 (CHASE‐DB1). These results compare with the best published results to date, exceeding their performance for several of the datasets; similar performance is found using accuracy.
- Published
- 2021
4. Improvement of thin retinal vessel extraction using mean matting method
- Author
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V. Sathananthavathi, Rita Mahiya, G. Indumathi, and S. Priyadarshini
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Retinal vessel ,Computer science ,Extraction (chemistry) ,Wavelet transform ,Computer Vision and Pattern Recognition ,Electrical and Electronic Engineering ,Fundus (eye) ,Software ,Electronic, Optical and Magnetic Materials ,Biomedical engineering - Published
- 2021
5. High‐quality retinal vessel segmentation using generative adversarial network with a large receptive field
- Author
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Wanglong Lu, Huang Hui, Hanli Zhao, Xiaogang Jin, and Qiu Xiaqing
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Computer science ,business.industry ,media_common.quotation_subject ,Pattern recognition ,Electronic, Optical and Magnetic Materials ,Retinal vessel ,Receptive field ,Segmentation ,Quality (business) ,Computer Vision and Pattern Recognition ,Artificial intelligence ,Electrical and Electronic Engineering ,business ,Generative adversarial network ,Software ,media_common - Published
- 2020
6. Age‐related changes in the fractal dimension of the retinal microvasculature, effects of cardiovascular risk factors and smoking behaviour
- Author
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Gordana Sunaric-Mégevand, Sophie Lemmens, Charlien Landtmeeters, Ingeborg Stalmans, Julie Vercauteren, Karel Van Keer, Patrick De Boever, Geert Molenberghs, Anna Ivanova, Reinout Peeters, Martial Luyts, Nele Gerrits, Anne-Sophie Simons, Lemmens, Sophie, LUYTS, Martial, Gerrits, Nele, IVANOVA, Anna, Landtmeeters, Charlien, Peeters, Reinout, Simons, Anne-Sophie, Vercauteren, Julie, Sunaric-Megevand, Gordana, Van Keer, Karel, MOLENBERGHS, Geert, DE BOEVER, Patrick, and Stalmans, Ingeborg
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fractal dimension ,medicine.medical_specialty ,Refractive error ,Cardiovascular health ,BIOMARKERS ,Cardiovascular risk factors ,WEIGHT-LOSS ,Fundus (eye) ,ANGIOGRAPHY ,Fractal dimension ,smoking ,chemistry.chemical_compound ,MISSING DATA ,Risk Factors ,Ophthalmology ,Age related ,VASCULATURE ,medicine ,Humans ,refractive error ,age ,cardiovascular health ,retinal ,Science & Technology ,retinal vasculature ,COMPLEXITY ,vasculature ,business.industry ,Smoking ,Retinal Vessels ,Retinal ,General Medicine ,MICROCIRCULATION ,medicine.disease ,eye diseases ,CHAOS THEORY ,Retinal vessel ,Cross-Sectional Studies ,Fractals ,chemistry ,Cardiovascular Diseases ,Heart Disease Risk Factors ,Microvessels ,ENDOTHELIAL DYSFUNCTION ,Human medicine ,business ,Life Sciences & Biomedicine ,CLINICAL-TRIALS - Abstract
PURPOSE: This cross-sectional study investigates the association between retinal vessel complexity and age and studies the effects of cardiovascular health determinants. METHODS: Retinal vessel complexity was assessed by calculating the box-counting fractal dimension (Df ) from digital fundus photographs of 850 subjects (3-97 years). All photographs were labelled as 'non-pathological' by the treating ophthalmologist. RESULTS: Statistical models showed a significantly decreasing relationship between age and Df (linear: R-squared = 0.1897, p
- Published
- 2021
7. Relationship between breathing gas mixtures and retinal vessel regulation
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Uwe Jaeger, Sascha Klee, and Dietmar Link
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Retinal vessel ,Ophthalmology ,Chemistry ,General Medicine ,Breathing gas ,Biomedical engineering - Published
- 2021
8. Birthweight and its association with retinal vessel equivalents – Results from the population‐based German Gutenberg Health Study
- Author
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Manfred E. Beutel, Katharina A. Ponto, Philipp S. Wild, Andreas Schulz, Michael S. Urschitz, Karl J. Lackner, Norbert Pfeiffer, Stefan Nickels, Thomas Münzel, Achim Fieß, and Alexander K. Schuster
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Adult ,Male ,medicine.medical_specialty ,Adolescent ,Association (object-oriented programming) ,610 Medizin ,Blood Pressure ,Population based ,German ,Young Adult ,610 Medical sciences ,Epidemiology ,medicine ,Birth Weight ,Humans ,Prospective Studies ,Child ,Aged ,business.industry ,Infant, Newborn ,Infant ,Retinal Vessels ,General Medicine ,Middle Aged ,language.human_language ,Population based study ,Retinal vessel ,Ophthalmology ,Child, Preschool ,language ,Female ,business ,Demography - Published
- 2020
9. Retinal vessel oxygen saturation and vessel diameter in healthy individuals during high‐altitude exposure
- Author
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Shuning Li, Zheng Zhang, Yuan Xie, Yiquan Yang, Diya Yang, Yunxiao Sun, Shizheng Wu, and Ningli Wang
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Adult ,Male ,China ,medicine.medical_specialty ,Altitude Sickness ,03 medical and health sciences ,chemistry.chemical_compound ,Oxygen Consumption ,0302 clinical medicine ,Ophthalmology ,medicine ,Humans ,Oximetry ,Prospective Studies ,Endothelial dysfunction ,Hypoxia ,Oxygen saturation ,business.industry ,Altitude ,Microcirculation ,Retinal Vessels ,Retinal ,General Medicine ,Effects of high altitude on humans ,medicine.disease ,Healthy Volunteers ,Peripheral ,Oxygen ,Vessel diameter ,Retinal vessel ,chemistry ,Regional Blood Flow ,Healthy individuals ,030221 ophthalmology & optometry ,Female ,business ,030217 neurology & neurosurgery - Abstract
PURPOSE To assess changes of retinal vessel oxygen saturation and vessel diameter in healthy individuals during high-altitude exposure. METHODS Retinal oxygen saturation and vessel diameter were obtained at sea level (SL, 40 m) and high altitude (HA, 3681 m) on 17 healthy individuals from Beijing (six males, 28.06 ± 8.06 years) using Oxymap T1 and then compared with 21 residents from Yushu (10 males, 28.63 ± 6.00 years). Systemic and ocular parameters were also measured before and after high-altitude exposure. Data were presented as mean ± SD and analysed using paired and independent Student t-test with significance accepted at p
- Published
- 2018
10. Active contours with local and global energy based‐on fuzzy clustering and maximum a posterior probability for retinal vessel detection
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Xiaoxia Yin, Jing He, Mengjiao Guo, Guangyan Huang, Xiancheng Wang, Bailing Zhang, Zhangwei Jiang, Roozbeh Zarei, Wei Li, Peng Shi, and Anwaar Ulhaq
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Active contour model ,Global energy ,Fuzzy clustering ,Computer Networks and Communications ,business.industry ,Computer science ,Posterior probability ,Pattern recognition ,Vessel segmentation ,Computer Science Applications ,Theoretical Computer Science ,Retinal vessel ,Computational Theory and Mathematics ,Artificial intelligence ,business ,Software - Published
- 2019
11. Longitudinal data of static and dynamic retinal vessel parameters
- Author
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Rebekka Heitmar
- Subjects
Retinal vessel ,Ophthalmology ,medicine.medical_specialty ,business.industry ,Longitudinal data ,Medicine ,General Medicine ,business - Published
- 2019
12. Retinal vessel oximetry as a sensitive metabolic monitoring method for transcorneal electrical stimulation in retinitis pigmentosa
- Author
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Maria della Volpe Waizel, Margarita Todorova, Hanna Camenzind Zuche, Hendrik P. N. Scholl, and Ursula Müller
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Retinal vessel ,Ophthalmology ,medicine.medical_specialty ,business.industry ,Retinitis pigmentosa ,medicine ,Stimulation ,General Medicine ,Monitoring methods ,medicine.disease ,business - Published
- 2019
13. Dynamic retinal vessel analysis in Alzheimer's disease
- Author
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Konstantin Kotliar
- Subjects
Retinal vessel ,Ophthalmology ,medicine.medical_specialty ,business.industry ,medicine ,General Medicine ,Disease ,business - Published
- 2019
14. Retinal vessel diameters and systemic antioxidant capacity during hypoxia in patients with normal‐tension glaucoma and individuals with ocular hypertension
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Mia Langbøl, Thisayini Baskaran, Niels Vidiendal Olsen, Anne Katrine Toft-Kehler, Miriam Kolko, Peter Koch Jensen, Daniel Tiedemann, Rupali Vohra, Peter S. Jensen, and Sarkis Saruhanian
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medicine.medical_specialty ,business.industry ,Ocular hypertension ,General Medicine ,Hypoxia (medical) ,medicine.disease ,Retinal vessel ,Ophthalmology ,Antioxidant capacity ,Normal tension glaucoma ,medicine ,In patient ,medicine.symptom ,business - Published
- 2019
15. A step towards pigmentation independent retinal vessel oximetry
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Katrin Hirsch, Robert P. Cubbidge, and Rebekka Heitmar
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Retinal vessel ,Ophthalmology ,medicine.medical_specialty ,business.industry ,Medicine ,General Medicine ,business - Published
- 2019
16. Relationship between oxygen saturation of the retinal vessels and visual field defect in glaucoma patients: comparison with each hemifield
- Author
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Takeru Shimazaki, Shino Sato, Yuki Nakano, Kazuyuki Hirooka, Kaori Ukegawa, Akitaka Tsujikawa, and Eri Nitta
- Subjects
Male ,Arteriovenous difference ,medicine.medical_specialty ,Intraocular pressure ,genetic structures ,Vision Disorders ,Glaucoma ,Exfoliation Syndrome ,01 natural sciences ,010309 optics ,Tonometry, Ocular ,03 medical and health sciences ,chemistry.chemical_compound ,0302 clinical medicine ,Ophthalmology ,0103 physical sciences ,medicine ,Humans ,Low Tension Glaucoma ,Oximetry ,Intraocular Pressure ,Aged ,business.industry ,Retinal Vessels ,Retinal ,General Medicine ,Middle Aged ,medicine.disease ,Surgery ,Visual field ,Oxygen ,Retinal vessel ,medicine.anatomical_structure ,chemistry ,Retinal ganglion cell ,030221 ophthalmology & optometry ,Visual Field Tests ,Female ,Visual Fields ,business ,Glaucoma, Open-Angle ,psychological phenomena and processes - Abstract
Purpose This study aimed to elucidate the relationship between visual field defects in the upper and lower hemifields and the corresponding oxygen saturation of the retinal vessels in patients with glaucoma. Methods Patients with glaucoma (n = 44) exhibiting more than a 10 dB difference between the upper and lower total deviation (TD) were enrolled in the study. After measuring the retinal vessel oxygen saturation by a non-invasive spectrophotometric retinal oximeter, the hemifields in one eye of each patient were divided into worse (worse TD) and better (better TD) hemifield areas. We additionally evaluated a separate group of 40 patients with glaucoma who exhibited less than a 5 dB difference between the upper and lower TD. Statistical analysis was performed using a Student's t-test. Results A higher mean venous saturation of oxygen (SaO2) was observed in the worse (59.0 ± 8.0%) hemifield compared to the better (55.4 ± 7.2%) hemifield (p
- Published
- 2016
17. The prognostic value of retinal vessel analysis in primary open-angle glaucoma
- Author
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Selim Orgül, K. Gugleta, A. Kochkorov, A. Polunina, and Nicolas Philipp Waldmann
- Subjects
Male ,Retinal Ganglion Cells ,medicine.medical_specialty ,Intraocular pressure ,genetic structures ,Open angle glaucoma ,Vision Disorders ,Glaucoma ,Diagnostic Techniques, Ophthalmological ,Tonometry, Ocular ,03 medical and health sciences ,chemistry.chemical_compound ,Nerve Fibers ,0302 clinical medicine ,Ophthalmology ,medicine ,Humans ,Prospective Studies ,Prospective cohort study ,Intraocular Pressure ,Aged ,business.industry ,Flicker ,Retinal Vessels ,Retinal ,General Medicine ,Middle Aged ,Prognosis ,medicine.disease ,eye diseases ,Visual field ,Retinal vessel ,chemistry ,030221 ophthalmology & optometry ,Visual Field Tests ,Female ,sense organs ,Visual Fields ,business ,Glaucoma, Open-Angle ,Photic Stimulation ,Tomography, Optical Coherence ,030217 neurology & neurosurgery ,Follow-Up Studies - Abstract
Purpose To analyse a prognostic value of initial retinal vessel flicker response for the 3-year development of functional (visual field) and morphological (nerve fibre layer thickness) damage progression in primary open-angle glaucoma patients. Patients and methods Initially, 70 patients were recruited, and flicker response was measured by standardized procedure with the retinal vessel analyser (RVA). Ocular coherence tomography of retinal nerve fibre layer (OCT RNFL) and a visual field testing were performed at beginning and every 6 months for 3 years; 56 patients completed the study. Results No correlation was found between the progression of visual field (VF) mean defect and retinal nerve fibre layer (RNFL) thinning over 3 years on one and the maximal flicker reaction in arteries and veins on the other side (all p > 0.1). However, the calculated difference of examined parameters in the superior versus inferior retinal halves correlated significantly between the RNFL thinning and the initial maximal flicker response for arteries (p = 0.01) and veins (p = 0.003). Conclusion This longitudinal study did not find a general correlation between initial retinal vessel response to flicker light and the glaucoma damage progression measured by OCT and VF, hence limiting the relevance of the RVA device as a predictor of future glaucomatous damage.
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- 2016
18. The effect of autoimmune retinopathy on retinal vessel oxygen saturation in patients with and without clinical features of retinitis pigmentosa
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Cengiz Türksever, Maria della Volpe Waizel, Margarita G. Todorova, and Annekatrin Rickmann
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Retinal vessel ,Ophthalmology ,medicine.medical_specialty ,business.industry ,Retinitis pigmentosa ,medicine ,In patient ,General Medicine ,medicine.disease ,business ,Autoimmune retinopathy ,Oxygen saturation (medicine) - Published
- 2017
19. Cross-sectional static retinal vessel analysis in routine optometric practice
- Author
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Rebekka Heitmar and C. French
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Retinal vessel ,Ophthalmology ,medicine.medical_specialty ,business.industry ,medicine ,Optometry ,General Medicine ,business - Published
- 2017
20. The effect of caffeine on retinal vessel diameters in the Inter99 eye study
- Author
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L. Kessel, Nina C.B.B. Veiby, Inger Christine Munch, Dragana Drobnjak, Michael Larsen, Charlotte Glümer, Ulla Toft, and Kristine Færch
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education.field_of_study ,medicine.medical_specialty ,business.industry ,Population ,General Medicine ,Retinal vessel ,Ophthalmology ,chemistry.chemical_compound ,chemistry ,population characteristics ,Medicine ,Caffeine ,business ,education - Abstract
Purpose To examine the effect of caffeine on retinal vessel diameters in the Inter99 Study. Methods The Inter99 Study comprised a population‐based age‐and sex‐stratified sample of 13,016 residents of a suburban section of Greater Copenhagen, Denmark. From 6784 participants aged ...
- Published
- 2017
21. Optical coherence tomography-based retinal vessel analysis for the evaluation of hypertensive vasculopathy
- Author
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Joachim E. Fischer, Alexander K. Schuster, Urs Vossmerbaeumer, and Christine Vossmerbaeumer
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Adult ,Male ,medicine.medical_specialty ,genetic structures ,Retinal Artery ,Hypertensive Retinopathy ,chemistry.chemical_compound ,Optical coherence tomography ,Hypertensive retinopathy ,Ophthalmology ,medicine ,Humans ,Arterial Pressure ,medicine.diagnostic_test ,business.industry ,Blood Pressure Determination ,Retinal ,General Medicine ,Middle Aged ,medicine.disease ,Retinal Vein ,Surgery ,Retinal vessel ,Mean blood pressure ,Blood pressure ,chemistry ,Optic nerve ,Arterial blood ,Female ,sense organs ,business ,Venous Pressure ,Tomography, Optical Coherence - Abstract
Purpose Evaluation of retinal vessels in cardiovascular disease traditionally relies upon funduscopy, but more recently digital photo analysis has expanded the spectrum. As spectral domain optical coherence tomography (OCT) allows an in-vivo assessment of retinal tissue and its vessels on a histological scale, our study aimed at using this tool for the analysis of the retinal vasculature. Methods Circumferential peripapillary OCT scans (3DOCT-2000; Topcon Inc., Tokyo, Japan), with centration on the optic nerve head, were taken from 20 eyes (20 participants) with normal blood pressure and 20 eyes (20 participants) with arterial hypertension above 120 mmHg (mean blood pressure). The diameter of all vessels intersecting the scan line was measured in the OCT and used to calculate central vessel equivalents, and the A/V ratios were calculated. Bland-Altman analysis was performed to evaluate reliability. Correlation coefficients were determined for reliability of the method as well as with the individual mean arterial blood pressures. Results Forty eyes (40 participants) were included in the study. Mean arterial blood pressure was 96 ± 4 mmHg in the control group and 132 ± 7 mmHg in the hypertonic group. Mean A/V ratio as determined from OCT scans was 0.82 ± 0.13 (normotonic) versus 0.62 ± 0.11 (hypertonic). A Pearson's correlation coefficient of 0.67 (p
- Published
- 2014
22. Static retinal vessel analysis in routine optometric practice
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C. French and R. Heitmar
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Retinal vessel ,Ophthalmology ,medicine.medical_specialty ,business.industry ,medicine ,Optometry ,General Medicine ,business - Published
- 2016
23. Alterations of retinal vessel size after single injection of intravitreal anti-VEGF for diabetic macular edema
- Author
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M. Kurt, C. Akpolat, and O. Cekic
- Subjects
Retinal vessel ,Anti vegf ,Ophthalmology ,medicine.medical_specialty ,business.industry ,Diabetic macular edema ,Medicine ,General Medicine ,Single injection ,business - Published
- 2016
24. Static and dynamic retinal vessel analyses in patients with stroke as compared to healthy control subjects
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P. De Boever, F. Fazekas, Martin Weger, L. Pertl, M. Kneihsl, I. Trozic, Stefan Palkovits, and Nandu Goswami
- Subjects
medicine.medical_specialty ,business.industry ,General Medicine ,medicine.disease ,Retinal vessel ,03 medical and health sciences ,Ophthalmology ,0302 clinical medicine ,Internal medicine ,Healthy control ,medicine ,Cardiology ,Physical therapy ,In patient ,business ,Stroke ,030217 neurology & neurosurgery - Published
- 2016
25. Visualizing retinal vessel dynamics of young type 1 diabetic patients using self-organizing map
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Joni-Kristian Kamarainen, Janne P. Kytö, Heikki Huttunen, S. Haikonen, Jukka-Pekka Kauppi, Per-Henrik Groop, and Paula Summanen
- Subjects
Retinal vessel ,Self-organizing map ,Ophthalmology ,Computer science ,Dynamics (mechanics) ,General Medicine ,Neuroscience - Published
- 2016
26. Retinal vessel parameters in obstuctive sleep apnea
- Author
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John Stradling, Chris D. Turnbull, A. Blann, and Rebekka Heitmar
- Subjects
Retinal vessel ,Ophthalmology ,medicine.medical_specialty ,business.industry ,Internal medicine ,medicine ,Cardiology ,Sleep apnea ,General Medicine ,medicine.disease ,business - Published
- 2016
27. O3‐12‐04: The Usefulness of Dynamic Retinal Vessel Reaction to Flickering Light as a Biomarker for Alzheimer's Disease
- Author
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Marion Ortner, Timo Grimmer, Claudia Muggenthaler, Arno Schmidt-Trucksaess, Christoph Schmaderer, Christine Hauser, and Konstantin Kotliar
- Subjects
Pathology ,medicine.medical_specialty ,Epidemiology ,business.industry ,Health Policy ,Disease ,Flickering light ,Retinal vessel ,Psychiatry and Mental health ,Cellular and Molecular Neuroscience ,Developmental Neuroscience ,Medicine ,Biomarker (medicine) ,Neurology (clinical) ,Geriatrics and Gerontology ,business - Published
- 2016
28. Retinal vessel diameter can reliably be determined in minipigs using Retinal Vessel Analyser with a microscope-mounted fundus camera
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Efstratios Mendrinos, Anestis Mavropoulos, Ioannis K. Petropoulos, Domniki N. Papadopoulou, Constantin J. Pournaras, and George Mangioris
- Subjects
Microscope ,Swine ,Partial Pressure ,Coefficient of variation ,Analyser ,Video Recording ,Blood Pressure ,Diagnostic Techniques, Ophthalmological ,Fundus camera ,law.invention ,chemistry.chemical_compound ,Optics ,law ,Photography ,Animals ,Medicine ,Observer Variation ,Microscopy ,Reproducibility ,business.industry ,Reproducibility of Results ,Retinal Vessels ,Retinal ,General Medicine ,Repeatability ,Carbon Dioxide ,Hydrogen-Ion Concentration ,Oxygen ,Retinal vessel ,Ophthalmology ,chemistry ,Swine, Miniature ,business ,Biomedical engineering - Abstract
Retinal Vessel Analyser (RVA) is a validated instrument to measure retinal vessel diameter in humans. The purpose of this study was to assess the reproducibility (inter-observer reliability) and the repeatability (test-retest reliability) of RVA with a microscope-mounted fundus camera to determine retinal vessel diameter in minipigs.Ocular fundus image from five anaesthetized minipigs was recorded in a digital videotape for approximately 5 min, under stable systemic arterial pressure and gas conditions. To evaluate the reproducibility, each one of two investigators used RVA to measure the diameter of the superior temporal retinal artery on five separate 30-second video sequences from each minipig, which were the same video sequences for both investigators. To evaluate the repeatability, one investigator performed five measurements on a single, randomly selected, 30-second video sequence from each minipig. The reproducibility was determined using the intra-class correlation coefficient (ICC), and the repeatability was assessed using the coefficient of variation (COV). Bland-Altman plots were also used to assess agreement between the two investigators.Retinal arteriolar diameter measurements with RVA in minipigs were highly reproducible. Differences between the two investigators were lower than 0.7%. The ICC was 1.00, indicating perfect reproducibility, and the mean COV was 0.18%, reflecting excellent repeatability of the measurements with RVA.Retinal vessel diameter can reliably be determined not only in humans, but also in minipigs, using the commercially available RVA apparatus and a microscope-mounted fundus camera.
- Published
- 2012
29. Comparative study of the retinal vessel anatomy of rhesus monkeys and humans
- Author
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Rachel E. Witt, Xinghuai Sun, Kaidi Wang, and Xiangmei Kong
- Subjects
Future studies ,Vascular ring ,Retinal ,Anatomy ,Biology ,medicine.disease ,First order ,Retinal vessel ,Ophthalmology ,chemistry.chemical_compound ,Animal model ,medicine.anatomical_structure ,Adenosine diphosphatase ,chemistry ,medicine ,Optic disc - Abstract
Objectives This study aims to compare retinal vessel anatomy of normal rhesus monkeys and humans and to provide a basis from a structural perspective for the use of rhesus monkey as an experimental model in future studies of retinal vessels. Methods The retinas of six normal rhesus monkey eyes and eight human eyecups following corneal transplantation were obtained and stained using adenosine diphosphatase methods. The distributions, orders, layers of the retinal vessels and the perifoveal vascular ring were compared. Results With adenosine diphosphatase staining, distinct retinal vessels were fully discernable from the first order surrounding the optic disc to the fifth order. There were no statistically significant differences between rhesus monkeys and humans in the percentages of vessels surrounding the optic disc at the equator and the peripheral region. Vascular networks in both species were arranged in several layers around the optic disc, two anastomotic layers at the equator and one sparse layer peripherally. Capillaries at the macular area were quite dense and an intact perifoveal vascular ring was observed. No differences were observed between rhesus monkeys and humans in the percentage area of the vessels and the area, perimeter and diameter of the perifoveal vascular ring. Conclusions The distributions, orders, layers and the perifoveal vascular ring of the retinal vessels of rhesus monkey are quite similar to those of humans. The data suggest that from an anatomical perspective, the rhesus monkey is a good animal model for the study of human retinal vessels, particularly the macular capillaries.
- Published
- 2010
30. Dynamic retinal vessel response to flicker in age-related macular degeneration patients before and after vascular endothelial growth factor inhibitor injection
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M. Maier, Martin Halle, Konstantin Kotliar, Arno Schmidt-Trucksäss, Ines Lanzl, Chris P. Lohmann, and Seid-Fatima Seidova
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Male ,Vascular Endothelial Growth Factor A ,Vascular Endothelial Growth Factor Inhibitor ,medicine.medical_specialty ,genetic structures ,Retinal Artery ,Angiogenesis Inhibitors ,Antibodies, Monoclonal, Humanized ,Macular Degeneration ,Age related ,Ophthalmology ,medicine ,Humans ,Prospective Studies ,Intravitreal bevacizumab ,Aged ,Aged, 80 and over ,business.industry ,Flicker ,General Medicine ,Macular degeneration ,Flickering light ,medicine.disease ,eye diseases ,Bevacizumab ,Vasodilation ,Retinal vessel ,Vasoconstriction ,Female ,sense organs ,business ,Photic Stimulation ,After treatment - Abstract
Retinal vessel responses to flickering light are different in various systemic and ocular diseases and can be improved after successful therapy. We investigated retinal vessel response to flickering light in age-related macular degeneration (AMD) patients before and after treatment with a single intravitreal bevacizumab (Avastin(®) ) injection.In 10 patients with exudative AMD [age: median (1.quartile; 3.quartile) 76.0 (73.5; 80.0) years], retinal vessel reactions were examined by Dynamic Vessel Analyser (DVA) before and 3 months after a single intravitreal application of bevacizumab (1.25 mg). A baseline measurement was followed by three consecutive monochromatic flicker stimulations (530-600 nm, 12.5 Hz, 20 seconds). Temporal retinal vessel reaction was analysed and compared with the reaction in healthy controls.Mean arterial dilation at the end of flicker was not different in all groups. For veins this parameter amounted to: pre-treatment, 2.6 (1.7; 3.9)%; post-treatment, 2.9 (2.4; 4.0)%; control, 4.3 (3.2; 5.7)%; significant: pre-treatment - control (Dunnett's procedure, p0.05). Maximal dilation occurred in arteries at: pre-treatment, 17.5 (14.8; 32.5) seconds; post-treatment, 18.0 (16.6; 30.6) seconds; control, 14.5 (10.8; 17.3) seconds. Both AMD groups were slower (p0.05): in veins at 17.0 (14.5; 20.0) seconds, 12.8 (8.6; 14.8) seconds and 18.5 (17.1; 19.9) seconds, respectively; significant post-treatment - control (p0.05). In the post-treatment AMD group arterial constriction after stimulation occurred more slowly compared with the control group (p0.05).Dynamic retinal arterial and venous reactions to flickering light are altered in AMD compared with controls. Three months after a single injection of a vascular endothelial growth factor inhibitor, the investigated retinal dynamic vascular parameters were not altered in our study.
- Published
- 2010
31. Retinal vessel morphology in rheumatoid arthritis: Association with systemic inflammation, subclinical atherosclerosis, and cardiovascular risk
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Spyros Aslanidis, Areti Triantafyllou, Eugenia Gkaliagkousi, Stella Douma, Vasiliki Galanopoulou, Georgios P. Athanasopoulos, Xenophon Zabulis, Panagiota Anyfanti, and Nikolaos Koletsos
- Subjects
Male ,medicine.medical_specialty ,Pathology ,Physiology ,Inflammation ,030204 cardiovascular system & hematology ,Systemic inflammation ,Retina ,Arthritis, Rheumatoid ,03 medical and health sciences ,chemistry.chemical_compound ,0302 clinical medicine ,Risk Factors ,Physiology (medical) ,Internal medicine ,Image Processing, Computer-Assisted ,medicine ,Humans ,Molecular Biology ,Aged ,030203 arthritis & rheumatology ,Framingham Risk Score ,business.industry ,Retinal Vessels ,Retinal ,Middle Aged ,Atherosclerosis ,medicine.disease ,Retinal vessel ,chemistry ,Retinal arteriolar narrowing ,Subclinical atherosclerosis ,Rheumatoid arthritis ,Cardiology ,Female ,medicine.symptom ,Cardiology and Cardiovascular Medicine ,business - Abstract
Objective Quantification of retinal vessel morphology has emerged as a marker of cardiovascular health. We examined retinal microvascular diameters in RA, particularly in regard with systemic inflammation, subclinical atherosclerosis and cardiovascular risk. Methods Retinal images from RA patients and controls were processed using computerized software, to obtain central retinal arteriolar (CRAE) and venular (CRVE) equivalent and arteriovenous ratio (AVR). Subclinical atherosclerosis was assessed with carotid intima-media thickness (cIMT), and 10-year risk of general cardiovascular disease was calculated. Results Both CRAE (78.8±8.9 vs 90.2±9.9 μm, p
- Published
- 2017
32. Retinal blood vessel width measured on color fundus photographs by image analysis
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Joan Schwoerer, Ramnik Banwatt, Bernard Schwartz, and Da-Ching Wu
- Subjects
Adult ,Male ,genetic structures ,Fundus Oculi ,Color ,Fundus (eye) ,Edge detection ,chemistry.chemical_compound ,Optics ,Reference Values ,Image Processing, Computer-Assisted ,Photography ,medicine ,Humans ,Aged ,Retinal blood vessels ,Analysis of Variance ,Reproducibility ,business.industry ,Retinal Vessels ,Retinal ,Objective method ,Middle Aged ,Retinal vessel ,Ophthalmology ,medicine.anatomical_structure ,chemistry ,cardiovascular system ,Female ,business ,Optic disc - Abstract
The purpose of this paper was to develop a technique using computerized image analysis to measure the width of retinal arteries and veins on color fundus photographs. The width of the retinal vessel was determined from digitized fundus photographs by programs based on edge detection and boundary tracing. The average vessel width was determined at different distances or eccentricities from the center of the optic disc and using various lengths of vessel segment. Measurements of superior and inferior temporal vessel width for 20 eyes by 2 operators showed that about 75% of the measurements could be obtained without the use of plan points. The average percent coefficient of variation of the measurements was 2.17% for 3 measurements of each vessel. This technique provides a reproducible and objective method for obtaining the following parameters: the edges of the vessel, the length of the vessel segment to be measured, location of the measurement along the vessel and subsequent retinal vessel width. This technique is readily suitable for application to clinical studies particularly clinical trials.
- Published
- 2009
33. Increase of retinal vessel width in ocular hypertensives with timolol therapy
- Author
-
Takenori Takamoto, Philip T. Lavin, and Bernard Schwartz
- Subjects
medicine.medical_specialty ,genetic structures ,Fundus Oculi ,Superior temporal vein ,Timolol ,Fundus (eye) ,Placebo ,Models, Biological ,Placebo group ,Double-Blind Method ,Ophthalmology ,Image Processing, Computer-Assisted ,medicine ,Humans ,business.industry ,Retinal Vessels ,eye diseases ,Surgery ,Retinal vessel ,Multivariate Analysis ,Goldmann perimeter ,Ocular Hypertension ,sense organs ,Visual field loss ,business ,medicine.drug - Abstract
Purpose: The purpose of this study was to determine whether timolol drops compared to placebo drops had a significant effect on retinal vessel width in ocular hypertensives. Methods: Thirty-seven ocular hypertensives were randomly assigned to receive placebo or 0.5% timolol drops to both eyes for 18 to 24 months in a double masked clinical trial. Measurements of ocular pressure and retinal vessel width by computerized image analysis from fundus photographs were made at about 3 month intervals for 18 to 24 months of follow-up. Results: None of the subjects developed visual field loss when tested with the Goldmann perimeter by kinetic and static means at six month intervals. Subjects treated with the placebo showed no change in ocular pressure and a significant decrease in retinal vessel width over time especially in the right eye. Subjects treated with timolol had an increase in retinal vessel width compared to the placebo group significant especially for the superior temporal vein. Multivariate analyses indicated that the increase of retinal vessel width was not associated mainly with the ocular pressure on treatment or decrease in ocular pressure on treatment. Conclusion: Timolol treatment was associated with an increase of retinal vessel width. The effect of timolol appears to be related primarily to mechanisms other than the decrease in ocular pressure.
- Published
- 2009
34. The apparent and true width of the blood column in retinal vessels
- Author
-
Halvor Heier and Olaf Brinchmann-Hansen
- Subjects
Materials science ,medicine.diagnostic_test ,Hemodynamics ,Retinal ,General Medicine ,Arteriosclerosis ,Anatomy ,medicine.disease ,Constriction ,Retinal vessel ,Ophthalmoscopy ,Ophthalmology ,chemistry.chemical_compound ,chemistry ,Caliber ,cardiovascular system ,medicine - Abstract
Changes in the caliber of retinal vessels may be of haemodynamic and morphological significance in various local and systemic vascular diseases. In this paper we present a theoretical study on the effects of structural density changes of the vessel wall on the ‘true’ width of the streaming column of erythrocytes. By use of simplified models of an eye and a retinal vessel, we perform numerical experiments using a computer. The results show that variations in the index of refraction and in the thickness of the vessel wall have negligible influence on the apparent width of the blood column. The image of the vessel can safely be measured as a ‘true’ caliber of the retinal blood column. This might implicate that an early differentiation between vessel constriction caused by increased tonus of systemic-hypertension versus irreversible arteriosclerosis is probably not within physical and optical reach, using ophthalmoscopy.
- Published
- 2009
35. Indocyanine green video angiographic findings in acute posterior multifocal placoid pigment epitheliopathy
- Author
-
Mitsuko Yuzawa, Mizuo Matsui, and Akiyuki Kawamura
- Subjects
Adult ,Indocyanine Green ,Vasculitis ,Pathology ,medicine.medical_specialty ,Fundus Oculi ,Video Recording ,Lesion ,chemistry.chemical_compound ,Ophthalmology ,medicine ,Humans ,Fluorescein Angiography ,Fluorescein ,Pigment Epithelium of Eye ,medicine.diagnostic_test ,Choroid ,business.industry ,Acute posterior multifocal placoid pigment epitheliopathy ,General Medicine ,Fluorescein angiography ,Retinal vessel ,chemistry ,Acute Disease ,Angiography ,Female ,medicine.symptom ,Early phase ,business ,Indocyanine green - Abstract
The placoid lesions of acute posterior multifocal placoid pigment epitheliopathy consist of two distinct areas: a light yellow area surrounding a dark yellow center. On two occasions, the authors compared indocyanine green video angiographic with fluorescein angiographic findings in a typical case of acute posterior multifocal placoid pigment epitheliopathy. In the acute stage, the multiple placoid lesions observed in the early phase of indocyanine green video-angiography showed hypofluorescent lesions corresponding to those seen with fluorescein angiography which blocked choroidal vessels. Some fluorescent intermediate sized choroidal vessels, which traversed the hypofluorescent areas, were dark due to a slight degree of blocked fluorescence. On both indocyanine green video and fluorescein angiography, hypofluorescent lesions were almost the same size as the light yellow area and the dark yellow center of a placoid lesion. A hypofluorescent lesion, seen on fluorescein angiography, obscured a retinal vessel. When the placoid lesions had disappeared, fewer hypofluorescent lesions, corresponding to some of the hypofluorescent lesions originally observed, were seen in the early phase of indocyanine green video angiography. They were also smaller in size. These hypofluorescent lesions decreased in size and some had completely disappeared in the late phase. No hypofluorescent lesions were seen in the early phase of fluorescein angiography. Findings in the acute stage suggest that the hypofluorescence observed in the early phase of indocyanine green video and fluorescein angiography is mainly blockage due to a light yellow area of placoid. When the placoid lesion disappeared, filling delays, which were detectable on only indocyanine green video angiography, persisted in the choriocapillaris.
- Published
- 2009
36. Improvement in retinal vessel oxygen saturation after vitrectomy
- Author
-
S.L. Lim, Shamira A. Perera, and L. Tan
- Subjects
Retinal vessel ,Ophthalmology ,medicine.medical_specialty ,Materials science ,medicine.medical_treatment ,medicine ,Vitrectomy ,General Medicine ,Oxygen saturation - Published
- 2015
37. Retinal Vessel Oxygen Saturation and its implications in myopia
- Author
-
Rebekka Heitmar
- Subjects
medicine.medical_specialty ,business.industry ,Retinal ,General Medicine ,Oxygenation ,Retinal photography ,Arterial vessel ,eye diseases ,Surgery ,Retinal vessel ,Vitreous Detachment ,Ophthalmology ,chemistry.chemical_compound ,chemistry ,Venous vessel ,Medicine ,sense organs ,business ,Saturation (chemistry) - Abstract
Purpose To evaluate retinal vessel oxygen saturation and its relationship with ocular volume and axial length. Methods We included 65 healthy individuals (age range: 19–51 years) of varying axial lengths (20.74–28.24 mm). All subjects underwent full ocular examination including intra-ocular pressure measurements and systemic blood pressure measurements which was followed by auto-refraction, axial length, anterior chamber, corneal radii and retinal oxygen saturation assessments. In addition, all subjects underwent routine retinal photography which was used to determine their retinal arterial and venular calibres. Results Retinal vessel calibres, both arteries and venules were significantly decreasing with increasing axial length (arteries: β = −0.37; p
- Published
- 2015
38. Computer-assisted retinal vessel measurement in an older population: correlation between right and left eyes
- Author
-
Tien Yin Wong, Jie Jin Wang, Ava Grace Tan, Paul Mitchell, Elena Rochtchina, Harry Leung, Ronald Klein, and Larry D. Hubbard
- Subjects
Male ,medicine.medical_specialty ,Diagnostic Techniques, Ophthalmological ,Functional Laterality ,Older population ,Correlation ,Random Allocation ,chemistry.chemical_compound ,symbols.namesake ,Ophthalmology ,Image Processing, Computer-Assisted ,Humans ,Medicine ,Diagnosis, Computer-Assisted ,Aged ,Observer Variation ,Random allocation ,business.industry ,Reproducibility of Results ,Retinal Vessels ,Retinal ,Middle Aged ,Pearson product-moment correlation coefficient ,Retinal vessel ,Left eye ,medicine.anatomical_structure ,chemistry ,symbols ,Optometry ,Female ,business ,Optic disc - Abstract
This study assessed the correlation between computer-assisted retinal vessel measurements of right and left eyes, from subjects in a defined, community-based older population. Retinal photographs from participants in the Blue Mountains Eye Study were digitized. All retinal arterioles and venules located 0.5-1.0 disc diameters from the optic disc margin were identified and a computer program measured their diameters. Pearson correlation (R2) statistic was used to assess the correlation in a random subsample of 1546 images. Substantial correlation between right and left eye measurements was found for summary indices of retinal arterioles (R2 = 0.70) and venules (R2 = 0.77). Higher correlation was found for intragrader (R2 0.75-079) than for intergrader assessment (R2 0.67-0.72). Moderate correlation was found in arteriole-to-venule ratio assessed by the same (R2 = 0.57) or different (R2 = 0.52) graders. Measurements from one eye can thus adequately represent the retinal vessel diameters of a person.
- Published
- 2003
39. Reliability of computer-assisted retinal vessel measurement in a population
- Author
-
Paul Mitchell, Jie Jin Wang, Tien Yin Wong, Elena Rochtchina, Lauren M Sherry, Ronald Klein, and Larry D. Hubbard
- Subjects
medicine.medical_specialty ,education.field_of_study ,business.industry ,Population ,Disc diameter ,Retinal ,Retinal vessel ,Ophthalmology ,chemistry.chemical_compound ,medicine.anatomical_structure ,Optics ,chemistry ,Correlation analysis ,medicine ,education ,business ,Reliability (statistics) ,Kappa ,Optic disc - Abstract
The purpose of the study was to assess the intergrader and intragrader reliability of computer-assisted retinal vessel dia-meter measurement in a defined, community-based population. Retinal photographs from participants in the Blue Mountains Eye Study were digitized using standard techniques. A grader identified all retinal vessels located 0.5-1.0 disc diameter from the optic disc margin,and a computer program measured the width of these vessels. Intergrader and intragrader reliability was assessed on a random sub-sample of 184 and 97 images, respectively, using quadratic weighted kappa(kappa) and correlation analysis (R2). Intergrader reliability was high for summary indices of retinal arteriolar (kappa = 0.85, R2 = 0.88)and venular (kappa = 0.90, R2 = 0.90)diameters, and their ratio, the arteriole-to-venule ratio (kappa = 0.75, R2 = 0.79).Intragrader reliability was also high, with kappa values ranging from 0.80 to 0.93 and from 0.80 to 0.92 for graders 1 and 2, respectively. It is concluded that the retinal vessel diameters could be reliably measured using computer-assisted software and may be used for population-based research.
- Published
- 2002
40. The effect of image quality on retinal oximetry
- Author
-
S Hardarson
- Subjects
business.industry ,Image quality ,Retinal ,General Medicine ,Fundus (eye) ,Retinal vessel ,Ophthalmology ,Light intensity ,chemistry.chemical_compound ,Optics ,chemistry ,Medicine ,Dual wavelength ,business ,Oxygen saturation (medicine) ,Biomedical engineering - Abstract
Dual wavelength retinal oximetry has proven to be a useful tool for detecting abnormal retinal vessel oxygen saturation in various diseases. Oximetry images are acquired in a similar fashion as regular fundus images. Oximetry calculations use light intensity measured from oximetry images. A ratio is taken of light intensity at and beside the retinal vessels. This means that the overall illumination of the image has less effect on the result. Despite the ratiometric approach, it is clear from experience and studies on cataract patients that image quality does influence oxygen saturation calculations. The challenge is to estimate or quantify image quality in a reliable manner and to control for image quality in all comparisons between healthy groups and patient groups. Commercial interest
- Published
- 2014
41. A new model for studying diameter regulation of porcine retinal arterioles and capillaries in vitro
- Author
-
Toke Bek and Ps Jensen
- Subjects
Contraction (grammar) ,Thromboxane ,Retinal ,General Medicine ,Anatomy ,Biology ,In vitro ,Retinal microcirculation ,Vessel diameter ,Retinal vessel ,Ophthalmology ,chemistry.chemical_compound ,chemistry ,Vasoactive ,cardiovascular system ,Biomedical engineering - Abstract
Purpose Studies of diameter regulation in retinal arterioles in vitro have mostly been performed on larger vessels, but evidence suggests that perturbations in the retinal microcirculation may also play a role in the development of vision threatening retinal diseases. Therefore, the purpose of the present study was to develop an in vitro technique for studying diameter regulation in both larger and smaller vessels. Methods A special tissue chamber was developed for mounting, cannulating and perfusing porcine hemiretinas while controlling temperature, pH and oxygen saturation. The chamber was mounted in a flourescens microscope, and the effect on the diameter of larger arterioles, pre-capillary arterioles and capillaries was studied after intravascular and extravascular addition of the thromboxane analogue U46619 and lactate (n=6 for each variable) and NMDA (preliminary). Results In all vessel calibers the thromboxane analogue U46619 induced a significant contraction after extraluminal application (p 0.13). Lactate had no effect on the diameter of non-precontracted vessels (p>0.21), but in pre-contracted vessels lactate relaxed the vessel diameter. Conclusion The response to vasoactive compounds is different after intraluminal and extraluminal application, and the diameter response of vasoactive compounds is different in larger and smaller retinal vessels. The dilating effect of lactate depends on the state of contraction of the retinal vessel.
- Published
- 2014
42. Retinal vessel oxygen saturation in diabetic patients with and without cardiovascular disease and its association with renal function
- Author
-
Rebekka Heitmar and Andrew D. Blann
- Subjects
medicine.medical_specialty ,Intraocular pressure ,business.industry ,Renal function ,General Medicine ,Disease ,Phlebotomy ,medicine.disease ,Retinal vessel ,Ophthalmology ,Internal medicine ,Diabetes mellitus ,medicine ,Cardiology ,In patient ,Saturation (chemistry) ,business - Abstract
Purpose To explore the association of renal function and retinal vessel oxygen saturation in patients suffering from diabetes and cardiovascular disease. Methods We examined three groups of patients (1: Diabetics, 2: Diabetics with cardiovascular disease and 3: patients suffering from cardiovascular disease without diabetes). All patients Intraocular Pressure, Systemic Blood Pressure and Dual Wavelength Retinal Vessel Oxygen Saturation (arterial and venous vessel saturation and a-v saturation difference) and Retinal Vessel Calibers were measured following phlebotomy to determine their HbA1c levels. Markers of renal function (ceratinine, eGfr and uACR) were measured in all patients. Results All three groups were age matched (1: 63 (10)yrs; 2: 64 (9)yrs and 3:65 (10)yrs). Unsurprisingly HbA1c was significantly different between groups (p
- Published
- 2014
43. The comparison of OCT findings and retinal artery diameter in good and poor prognosis RAO patients
- Author
-
Su-Yeon Lee, J Park, and S Jo
- Subjects
medicine.medical_specialty ,Poor prognosis ,Central retinal artery ,genetic structures ,medicine.diagnostic_test ,business.industry ,Retinal Artery ,Foveal thickness ,General Medicine ,eye diseases ,Surgery ,Retinal vessel ,Ophthalmology ,Optical coherence tomography ,medicine.artery ,medicine ,In patient ,sense organs ,Good prognosis ,business - Abstract
Purpose To determine the different clinical findings between good and poor prognosis group which is diagnosed with branch retinal artery obstruction(BRAO) and treated with conservative care. We evaluate the average macular thickness, foveal thickness, outer nuclear layer(ONL) on optical coherence tomography(OCT) and retinal artery diameter in both groups. Methods 9 eyes(9 patients) in patients with non-complicated BRAO with good prognosis and a poor prognosis control group with non-complicated BRAO of 11 eyes(11 patients) were used in this study. The average macular thickness, foveal thickness and ONL thickness at the center of fovea on OCT were measured. And branch retinal artery widths were measured by a semi-automated retinal vessel width measurement system retrospectively. Results The average age of the patients was 67.3 ± 11.5 years. The average ONL thickness at the central fovea of the good prognosis group was significantly thicker than that of the control group (p = 0.016). There were no statistically significant result at average macular thickness and foveal thickness. In good prognosis group, Ischemic retinal artery diameter and Central retinal artery equivalent(CRAE) were wider than those of poor prognosis group and they were statistically significant (p = 0.028, p = 0.01). Conclusion In the patients diagnosed with BRAO and treated with conservative care, foveal thickness, ischemic retinal artery diameter and CRAE were statistically significant between good and poor prognosis groups. In the patients diagnosed with BRAO, foveal thickness and retinal artery diameter could be prognostic factors that predict visual prognosis.
- Published
- 2014
44. Optic disc size and retinal vessel characteristics in healthy children
- Author
-
Ann Hellström and Elisabeth Svensson
- Subjects
medicine.medical_specialty ,genetic structures ,business.industry ,Retinal ,Fundus (eye) ,eye diseases ,Retinal vessel ,Ophthalmology ,chemistry.chemical_compound ,medicine.anatomical_structure ,chemistry ,Neuroretinal rim ,Digital image analysis ,Medicine ,Pediatric ophthalmology ,sense organs ,business ,Optic disc size ,Optic disc - Abstract
Purpose To characterize the optic disc and retinal vessels in healthy children and adolescents. Methods Fundus photographs were evaluated by digital image analysis in one hundred healthy Swedish children and adolescents (3-19 years). Results Median optic disc area was 2.67 mm2 (range, 1.93 to 4.39), median cup area was 0.41 mm2 (range, 0 to 1.45) and median neuroretinal rim area was 2.24 mm2 (range, 1.60 to 3.05). The size of the cup and neuroretinal rim increased with increasing size of the optic disc. There were no correlations between the measured variables and age, sex or refraction. Conclusion The measurements of optic disc size in healthy children, between 3 and 19 years of age, are in accordance with optic disc values found in most studies on adults. The resulting reference intervals may be helpful in clinical pediatric ophthalmology, to facilitate identification of children with abnormal optic disc and retinal vessel morphology.
- Published
- 1998
45. Autofluorescence patterns and visual acuity in macular telangiectasia type 2
- Author
-
Irene Leung, Konstantinos Balaskas, A C Bird, Tunde Peto, Te Clemons, and Fb Sallo
- Subjects
medicine.medical_specialty ,Visual acuity ,Distance visual acuity ,genetic structures ,business.industry ,General Medicine ,Diabetic retinopathy ,medicine.disease ,Predictive value ,eye diseases ,Retinal vessel ,Ophthalmology ,Autofluorescence ,medicine ,Optometry ,In patient ,medicine.symptom ,business ,Macular telangiectasia - Abstract
Purpose An analysis was performed with a view of determining potential associations between typical patterns seen on autofluorescence (AF) imaging in patients with Macular Telangiectesia (MacTel) type 2 and distance visual acuity at presentation as well as visual change over a 2-year follow-up period, thus ascribing predictive value to AF patterns in MacTel. Methods A subgroup of 135 patients (229 eyes) enrolled in the MacTel study underwent AF imaging. Images were graded at the Moorfields Eye Hospital Reading Centre. Recorded AF patterns at baseline and at two years included the typical pattern of increased central AF due to loss of foveal masking, localized decreased AF at the end of a retinal vessel and a large area of decreased AF. Best-corrected visual acuity (BCVA) was measured by means of the Early Treatment for Diabetic Retinopathy Study charts at baseline and after two years. Statistical associations were derived by means of a generalized linear model. Results Presence of increased macular AF (p=0.004), a large area of decreased AF (p
- Published
- 2013
46. Retinal oximetry methodology
- Author
-
S. H. Hardarson
- Subjects
medicine.medical_specialty ,business.industry ,Disease mechanisms ,Retinopathy of prematurity ,Retinal ,General Medicine ,Diabetic retinopathy ,medicine.disease ,Surgery ,Retinal vessel ,Ophthalmology ,chemistry.chemical_compound ,chemistry ,medicine ,Optometry ,business ,Oxygen saturation (medicine) - Abstract
Disturbances in retinal oxygenation are believed to play an important role in several eye diseases, such as retinal vessel occlusions, diabetic retinopathy and retinopathy of prematurity. Non-invasive measurements of retinal oxygenation are important for better understanding of disease mechanisms and the technology will hopefully, in the near future, aid in management of the diseases. The technology for retinal oximetry has been developed in the past years and decades and the current oximeters are sensitive to changes in oxygen saturation and give repeatable results. Studies have confirmed differences in retinal vessel oxygen saturation in various eye diseases. Further studies of retinal oxygenation will benefit from development of the methodology. This includes hardware and software development but also standardisation of measurement techniques with the current instruments and better understanding of confounding factors. Commercial interest
- Published
- 2013
47. O3–11–06: Retinal vessel calibers associate differentially with grey matter and white matter atrophy on MRI
- Author
-
Frank Jan de Jong, Caroline C W Klaver, Mohammad Arfan Ikram, Mohammad Kamran Ikram, Wiro J. Niessen, Albert Hofman, Meike W. Vernooij, and Aad van der Lugt
- Subjects
Pathology ,medicine.medical_specialty ,Epidemiology ,Chemistry ,Health Policy ,Grey matter ,Retinal vessel ,Psychiatry and Mental health ,Cellular and Molecular Neuroscience ,medicine.anatomical_structure ,Developmental Neuroscience ,medicine ,Neurology (clinical) ,Geriatrics and Gerontology ,White matter atrophy - Abstract
Association FA b MD b FA b MD b FA b MD b FA b MD b ATR -0.26 0.55 -0.21 0.47 -0.07 0.29 -0.05 0.24 IFO -0.35 0.49 -0.33 0.47 -0.16 0.28 -0.12 0.25 ILF -0.27 0.54 -0.25 0.52 -0.16 0.40 -0.11 0.36 PTR -0.32 0.49 -0.31 0.47 -0.18 0.37 -0.15 0.32 SLF -0.18 0.28 -0.19 0.29 -0.10 0.18 -0.11 0.19 UNC -0.30 0.42 -0.25 0.40 -0.25 0.34 -0.19 0.31 Commissural FMA -0.36 0.41 -0.31 0.36 -0.29 0.36 -0.22 0.30 FMI -0.39 0.40 -0.30 0.34 -0.36 0.35 -0.24 0.25 Limbic CGC -0.22 0.24 -0.23 0.24 -0.22 0.23 -0.23 0.23 CGH -0.29 0.36 -0.29 0.35 -0.29 0.36 -0.29 0.35 Sensorimotor CST -0.01 0.09 -0.03 0.12 0.02 0.08 0.00 0.10 MCP 0.05 0.15 -0.01 0.09 0.06 0.16 0.00 0.09 ML 0.01 0.09 0.01 0.11 0.01 0.09 0.01 0.11 STR -0.03 0.02 -0.04 0.02 0.00 0.02 -0.01 0.02
- Published
- 2013
48. The influence of age on retinal vessel oxygenation
- Author
-
Robert P. Cubbidge and Rebekka Heitmar
- Subjects
Retinal vessel ,Ophthalmology ,medicine.medical_specialty ,business.industry ,Medicine ,General Medicine ,Anatomy ,Oxygenation ,business - Published
- 2012
49. Retinal vessel analysis in animal models
- Author
-
L Schmetterer
- Subjects
Hyperoxia ,Doppler OCT ,medicine.medical_specialty ,Retinal blood flow ,medicine.diagnostic_test ,Fundus photography ,Retinal ,General Medicine ,Anatomy ,Biology ,Retinal vessel ,Ophthalmology ,chemistry.chemical_compound ,chemistry ,medicine ,Breathing ,medicine.symptom ,Hypercapnia - Abstract
Purpose Measurements of retinal blood flow in the rodent is a major challenge because of the small size and the poor optical quality of the eye. We present a technique based on the measurement of retinal vessel diameters using a fundus camera specifically designed for the rodent eye. This is combined with a Doppler OCT technique for measuring retinal blood velocities. Methods In the rat retinal vessel diameters and retinal blood velocities were measured during several stimuli. These included systemic hyperoxia by breathing 100% oxygen, systemic hypercapnia by breathing increasing concentrations of CO2 and by stimulation with diffuse flicker light. Results Retinal blood flow was quantified in larger retinal venules in our studies. As expected systemic hyperoxia induced a pronounced decrease in retinal vessel diameter, retinal blood velocity, and retinal blood flow (p < 0.01 each). Breathing increasing concentrations of CO2 on the other hand induced a dose-dependent increase in retinal vessel diameter, retinal blood velocity and retinal blood flow (p < 0.01 each). Finally, stimulation with flicker-light also increased retinal vessel diameter, retinal blood velocity and retinal blood flow (p < 0.01 each). Conclusion Our data indicate that changes in retinal blood flow in the rodent can be adequately measured using combined fundus photography and Doppler OCT. This technique can also be used to study neurovascular coupling. Our results are important, because the mechanisms of retinal blood flow regulation remain largely obscure.
- Published
- 2012
50. A new technique of noninvasive evaluation of the intracranial pressure with retinal vessel analyzer
- Author
-
Michel Paques, Olivier Genevois, and Marc Muraine
- Subjects
medicine.medical_specialty ,medicine.diagnostic_test ,Lumbar puncture ,business.industry ,Retinal ,General Medicine ,Surgery ,Retinal vessel ,Ophthalmology ,chemistry.chemical_compound ,Vascular network ,chemistry ,Internal medicine ,Edema ,medicine ,Cardiology ,New device ,Stage (cooking) ,medicine.symptom ,business ,Intracranial pressure - Abstract
Purpose One of the clinical signs observed at the funduscopic examination of the eye of the intracranial hypertension patients, apart from the papillary edema is the reduction, even the disappearance of the spontaneous pulsatility of the retinal vessels..A new device, Retinal Vessel Analyzer (Imedos) now makes it possible to measure negligible variations of the vascular diameter (arteriolar and venular) . We thus measured the retinal vascular pulsatility found among patients having a benign intracranial hypertension (BIH) which we compared with a control population. Methods We included 6 patients presenting a benign intracranial hypertension. For each participant, an examination with RVA was carried out right before the lumbar puncture (J0) then at 1 month (M1) and 3 months intervals (3M). We compared these results with a control population (n=76). Results The mean venous pulsatility found at the 76 controls was 5,07m ± 1,57. Our 6 patients presenting a BIH, had a venous pulsatility that was lower than 0,5m at D0 (p < 0,05), lower than 0,8m± 0,52 at M1 (p < 0,05) and between 0,5 and 3m at m3. All the 6 patients had an abnormal measurement of the intracranial pressure . It was not found a correlation between the value of pulsatility and the value of the intracranial pressure Conclusion The variation of the vascular diameter, measured by RVA, is an indirect reflection of the vascular transmural pressure.Our results show that even in the case of a moderate BIH it exist an early, identifiable repercussion at the level of the retinal vascular network quantifiable by RVA.This reduction in the venous pulsatility can be explained by an increase in the intravascular pressure and/or by a parietal remodeling, especially at the later stage.
- Published
- 2012
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